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How didn't large, highly active dinosaurs overheat?

How didn't large, highly active dinosaurs overheat?



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The cube-square law seems to be the deciding factor when it comes to biological heat management. Small organisms with large surface areas relative to their volumes, like mice, need fast heartbeats and huge energy consumption relative to their size to keep themselves warm. Large organisms like elephants with small surface areas relative to their volumes need slow metabolisms and fairly little energy consumption relative to their size to keep from overheating.

But, dinosaurs. Most research seems to indicate they were basically warm-blooded (yes, that wording really bothers me too, but research as recent as 2015 states that they seem to lean decidedly toward warm-bloodedness, though they are technically somewhere in between). Modern-day creatures of that size tend to divide neatly depending on whether they live on land or in water, with the former being fairly inactive and herbivorous and the latter sometimes able to support the metabolic needs of predation by having water to help disperse the heat.

Dinosaurs, though, are an exception. Many of the fiercer predators were large, highly-active land-dwellers, three conditions that are mutually exclusive in modern organisms. How was this possible?


There has been a long debate whether dinosaurs were ectotherms or endotherms but most of the recent studies (hypotheses)1 show that they were endotherms. In one of the most promising recent studies (in 2011), a technique called clumped-isotope thermometry2 (which is based on a reaction involving the bond between carbon and oxygen; and used in paleoclimate reconstruction) is applied to bioapatite (a form of calcium phosphate in bones and teeth) which acts like a thermometer.

The nature of the physiology and thermal regulation of the nonavian dinosaurs is the subject of debate. Previously, arguments have been made for both endothermic and ectothermic metabolisms based on differing methodologies. Here, we used clumped isotope thermometry to determine body temperatures from the fossilized teeth of large Jurassic sauropods. Our data indicate body temperatures of 36 to 38°C, which are similar to most modern mammals. This temperature range is 4 to 7°C lower than predicted by a model that showed scaling of dinosaur body temperature with mass, which could indicate that sauropods had mechanisms to prevent excessively high body temperatures being reached due to their gigantic size.

Dinosaur Body Temperatures Determined from Isotopic (13C-18O) Ordering in Fossil Biominerals
Robert A. Eagle, Thomas Tütken, Taylor S. Martin, Aradhna K. Tripati, Henry C. Fricke, Melissa Connely, Richard L. Cifelli, John M. Eiler http://science.sciencemag.org/content/early/2011/06/22/science.1206196
(emphasis mine)

However, a study as of 2014 claims that dinosaurs were mesothermic3 (meaning the blood runs neither hot nor cold, a thermoregulatory strategy intermediate to cold-blooded ectotherms and warm-blooded endotherms) based on the metabolic rates of dinosaurs by looking at changes in body size as animals grew from birth to adults.

In early depictions, dinosaurs lumbered slowly, dragging their tails. More recently, we have imagined them lifting their tails and running. The question boils down to whether dinosaurs had energetic systems closer to those of rapidly metabolizing mammals and birds, or to those of slower reptiles that do not internally regulate their body temperature. However, determining the metabolic rate of extinct organisms is no easy task. Grady et al. analyzed a huge data set on growth rate in both extinct and living species, using a method that considers body temperature and body size. Dinosaur metabolism seems to have been neither fast nor slow, but somewhere in the middle-so, dinosaurs did not fully regulate their internal temperature but they were also not entirely at the whim of the environment; neither slow goliaths nor supercharged reptiles.

Evidence for mesothermy in dinosaurs
John M. Grady1,*, Brian J. Enquist2,3, Eva Dettweiler-Robinson1, Natalie A. Wright1, Felisa A. Smith1 http://science.sciencemag.org/content/344/6189/1268
(emphasis mine)

As we covered the thermoregulation system of dinosaurs, we can start with the question "How didn't large dinosaurs overheat?". As explained above, whether they were endothermic or mesothermic, dinosaurs had mechanisms to regulate their internal temperature not to overheat. There are theories that say that some larger dinosaurs relied on shade and dense flora to keep cool or they might have migrated due to seasonal changes. Other theories claim that they used large surface area organs (like long necks and tails) as a heat radiator4.

One of the most plausible explanations is that large dinosaurs displayed tachymetabolism. Tachymetabolic animals have high resting metabolic rates, usually resulting in endothermy and homeothermy. Further explanation of how big tachymetabolic dinosaurs coped with high heat loads5:

BIG TACHYMETABOLIC DINOSAURS WOULD HAVE COOKED IN THE HEAT

Myth: Because tachymetabolic rates scale to W0.75, while surface area scales to W0.67, it is almost universally believed that big endotherms suffer serious heat stress in tropical climes. Big dinosaurs, sauropods especially, should have had low metabolic rates to avoid this dire fate (Martin, 1979; Regal and Gans, 1980; Spotila, 1980; Reid, 1984; Schmidt-Nielsen, 1984; Carroll. 1988; Alexander. 1989; Prothero, 1989: Russell, 1989). Alternately. tachymetabolic sauropods needed well developed cooling systems (Bakker. 1980, 1986).

Figure 5 This plot shows the time it takes high level endotherms to overheat if they store all internal heat production and exclude external heat by allowing their body temperature to rise to maximum tolerable levels. The mass range approximates that of adult dinosaurs (including lagosuchians), with the highest masses of mammals also indicated: note that giant endothermic dinosaurs would have been more resistant to overheating than giant mammals! Energy storage capacity is in kcal assuming a 6-8°C rise in body temperature (up to 46.5°C), with 0.83 kcal/kg stored for each 1°C rise in body temperature; total active metabolic rates are either 2.0 times endothermic standard energy production/bout, or only 1.3 times normal standard metabolic rates due to suppressed levels of activity and/or standard metabolic rates. The results are in good agreement with thermal tolerances observed among large tropical endotherms.
Reality: This is a major misconception (Costanzo and Paul. 1978; Paul, 1988a. 1990a). Many tropical mammals have reached from 1 to 20 tonnes, but no classic reptiles have done so, exactly opposite the predicted pattern. Elephants lack well developed evaporative cooling systems. Elephants living in treeless habitats do not drop dead from heat stroke, even in the most dangerous conditions of an extremely hot drought when it is not possible to dump excess heat by radiation or evaporative cooling in the first place, and shade is not available. Instead, large bull elephants have the highest survival rates under such circumstances, again opposite the predicted pattern (Owen-Smith, 1988). Field biologists have long known that endotherms from 100 kg on up use a classic thermal strategy in which their great mass is used to store a relatively low rate of internal heat production for most or all of the day, body temperatures are allowed to rise 3-10°C, and water loss is kept to a minimum (Schmidt-Nielsen et al., 1957; Taylor. 1969, 1970. 1972: Gordon. 1972; Finch and Rohertshaw, 1979: Schmidt-Nielsen. 1984). The built up heat is then unloaded into the cool night sky. This makes large endotherms practically invulnerable to over-heating under the harshest conditions, small endotherms must seek refuge or quickly die from heat stroke or dehydration. The large size of dinosaurs may have been an adaptation for better coping with high heat loads with a tachymetabolic level of heat production (Figure 5).


References:

1. The Evidence for Endothermy in Dinosaurs - Top Ten Hypotheses http://www.ucmp.berkeley.edu/diapsids/endothermy.html

2. Paleoclimate reconstruction using carbonate clumped isotope thermometry (John M.Eiler) https://www.sciencedirect.com/science/article/pii/S027737911100268X

3. Why Dinosaurs Were Like Tuna, Great Whites, and Echidnas http://phenomena.nationalgeographic.com/2014/06/12/dinosaurs-tuna-great-whites-echidnas/

4. Sauropod Necks: Are They Really for Heat Loss? (Donald M. Henderson)
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0077108

5. Dinosaur Studies - Commemorating the 150th Anniversary of Richard Owen's Dinosauria (By L. B. Halstead)


Further readings (supporting above theories or with different theories):

  • GEOL 104 Dinosaurs: A Natural History - University of Maryland - Department of Geology - https://www.geol.umd.edu/~tholtz/G104/lectures/104endo.html

  • Body Temperatures in Dinosaurs: What Can Growth Curves Tell Us? (Eva Maria Griebeler)
    http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0074317

  • Ecology and Behaviour of Mesozoic Reptiles (by John L. Cloudsley-Thompson)

  • Dinosaur Paleobiology (by Stephen L. Brusatte)

  • The Dinosauria (edited by David B. Weishampel, Peter Dodson, Halszka Osmólska)

  • The Complete Dinosaur (edited by James Orville Farlow, M. K. Brett-Surman)

  • Encyclopedia of Dinosaurs (edited by Philip J. Currie, Kevin Padian)

  • Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution (Phil R. Bell, Nicolás E. Campione, W. Scott Persons IV, Philip J. Currie, Peter L. Larson, Darren H. Tanke, Robert T. Bakker) - http://rsbl.royalsocietypublishing.org/content/13/6/20170092

  • Dinosaurs used nasal passages to keep brains cool - https://phys.org/news/2015-10-dinosaurs-nasal-passages-brains-cool.html


Talk:Dinosaur/Archive 12

I'm a bit puzzled as to why there's very little on the extinct dinosars' diet and digestion, whether under a topic of physiology or major divisions between carnivorous and herbivorous exemplars, e.g. Apatosaurus vs. Albertasaurus. I found a nice reference to the herbivorous one being almost certainly hindgut fermenters [1] and I want some place to put it! Monado (talk) 19:17, 22 December 2012 (UTC)

Nice find! I'll see what I can do over the weekend. Petter Bøckman (talk) 00:27, 23 December 2012 (UTC) Bunch of stuff in the Sauropod Biology volume by Klein et al. 2011 HMallison (talk) 18:24, 31 December 2012 (UTC)

References

  1. ^ Farrow, James O. (1987). "Speculations about the diet and digestive physiology of herbivorous dinosaurs". Palaeobiology. 13 (1). Unknown parameter |season= ignored (help) CS1 maint: postscript (link)

I whipped up a revised version of the current taxobox image that's a bit more representative of the six major sub-grups of dinosaurs currently listed (with a 'transitional' feathered theropod for a link with modern birds). What do you guys think? MMartyniuk (talk) 15:00, 28 December 2012 (UTC)

Look good, nice pictures and a good selection of representative lineages! Petter Bøckman (talk) 17:55, 28 December 2012 (UTC) Nice update. I actually prefer the current picture's Stegosaurus, since the thagomizer isn't cut off. Otherwise, the pictures look really good. You should link the individual uploaders' names, though. Firsfron of Ronchester 18:04, 28 December 2012 (UTC) Yeah, will do. The issue with the current image is that it seems to have been stretched vertically to forshorten it and include the distal tail! MMartyniuk (talk) 18:31, 28 December 2012 (UTC) Much better than old one, since theropods aren't overrepresented either. And ouch, the radius and ulna are crossed on that Triceratops. Pronation alert, kill, kill! FunkMonk (talk) 00:41, 29 December 2012 (UTC) We should really have a Passer in there, given that it's an anchor taxon in most definitions of Dinosauria anyway. Abyssal (talk) 03:14, 29 December 2012 (UTC)

Here are a couple more variations! MMartyniuk (talk) 13:31, 31 December 2012 (UTC)

I like Abyssal's idea of using a Passer in the image it helps establish the point, visually, that not all dinosaurs are extinct. Firsfron of Ronchester 18:41, 31 December 2012 (UTC) Neutrality, guys! Let's not get into this whole thing again. For reasons we do not have to waste more server space on, you are not going to get agreement from me or Petter Bøckman for including Passer. As WP:CONSENSUS notes, "a lack of consensus commonly results in retaining the version of the article as it was prior to the proposal or bold edit", and there's nothing significantly "uncommon" here. Ego White Tray's proposal above, Recommend using the lay definition in most dinosaur articles, has failed of consensus, so it will not be implemented, and the same should apply to the collages containing Passer. Petter Bøckman has agreed to File:Various_dinosaurs2.png, as do I, but using Passer instead of Microraptor as the theropod representative is not acceptable. Peter Brown (talk) 21:36, 31 December 2012 (UTC) I had an idea a while back. Why not create an article called "Mesozoic dinosaur" to specialize in Mesozoic dinosaurs? It should still use a phylogenetic definition, but an article focusing content-wise on the Mesozoic forms sounds perfectly valid. Abyssal (talk) 23:31, 31 December 2012 (UTC) In the interest of tranquility, how about "Mesozoic Dinosauria", defined phylogenetically? Discuss the Archaeornithes and the Enantiornithes freely, but note that not everyone calls them "dinosaurs". Peter Brown (talk) 00:03, 1 January 2013 (UTC)

I like any of the versions including Passer - There's no neutrality issue here - numerous current reliable secondary sources say that birds are dinosaurs. Excluding Passer for the reason that "birds aren't dinosaurs" gives undue weight to non-technical sources. de Bivort 22:55, 1 January 2013 (UTC)

  • 1: " fossils are offering a pretty consistent picture that the Birds-Are-Dinosaurs hypothesis is correct"
  • 2: "MODERN BIRDS ARE REALLY BABY DINOSAURS" (that's the title, doesn't require much checking).
  • 3: "When we look at birds, we are actually looking at juvenile dinosaurs"
  • 4: "Birds really are dinosaurs" (subtitle)
  • 5: "the dinosaur suborder that includes Tyrannosaurus rex as well as birds"
  • 6: "Birds are Dinosaurs" (title)
  • 7: "WHY BIRDS ARE BIRDS" (title)
  • 8: "Archaeopteryx is a bird and a dinosaur" (for this one, you'd have to watch the video, which is intended for PreK-1st graders)
  • 9: "birds actually ARE dinosaurs" (first line of text)
  • 10: "The answer is yes: all birds are indeed dinosaurs" (second paragraph)
  • 11: "While the turkey on the table may not seem quite as fierce as the Cretaceous “terrible claw” Deinonychus, they are both feathered dinosaurs" (first paragraph).
  • 12: "Birds are dinosaurs. That’s hardly the stuff of headlines any more" [1] (secondary).
  • 13: "Anchiornis huxleyi . a basal avialan filling the morphological gap between non-avian and avian dinosaurs" [2] (primary, prestigious).
  • 14: "The first birds were simply feathered dinosaurs with respect to growth and energetic physiology" [3] (primary).
  • 15: "These results indicate that prior knowledge of the specific taxa can interfere with successful tree thinking. Student's justifications underscore the conflict they had with reasoning with the information that birds are dinosaurs" [4] (primary science education research relevant?).
  • 16: "Birds are considered dinosaurs that passed the 65 million years ago bottleneck" [5] (primary bird journal1st sentence abstract).
  • 18: "Les oiseaux sont des dinosaures" [6] (secondary)
  • 19: Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins (primary, prestigious).
  • 20: bone allometry during postnatal ontogeny in non-avian dinosaurs (primary).
  • 21: "Recent fossil discoveries have substantially reduced the morphological gap between non-avian and avian dinosaurs" [7] (primary).
  • 22: reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities (primary).
  • 23: "Pennaceous (vaned) feathers and integumentary filaments are preserved in birds and non-avian theropod dinosaurs" [8] (primary, prestigious).
  • 24: Evolution of olfaction in non-avian theropod dinosaurs and birds (primary).
  • 25: Variation in the tail length of non-avian dinosaurs (primary).
  • 26: The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non-Avian Theropods (primary).
  • 27: preserved in fossilized organelles reveal the true colours of non-avian dinosaurs and extinct birds (secondary, prestigious).
  • 28: theropod dinosaurs from the early Late Cretaceous of central Europe (primary).
  • 29: "bird and non-avian theropod relationships" [9] (secondary).
  • 30: "Modern debate regarding the extinction of non-avian dinosaurs was ignited by. " [10] (primary).
  • 31: "Release from these pressures, by extinction of non-avian dinosaurs at the Cretaceous–Paleogene boundary" [11] (primary, prestigious).
  • 33: "EBFFs differ from the typical slender filamentous feathers of non-avian theropods. " [12] (primary, prestigious).
  • Wang, GZ Ma, BG Yang, Y Zhang, HY (2005). "Unexpected amino acid composition of modern Reptilia and its implications in molecular mechanisms of dinosaur extinction". Biochemical and Biophysical Research Communications. 333 (4): 1047–49. doi:10.1016/j.bbrc.2005.05.039. Unknown parameter |author-separator= ignored (help) Cite has empty unknown parameter: |author-name-separator= (help) CS1 maint: ref=harv (link)

I can't decide which I find more depressing, the argued implication in the year 2013 that Passer is not a dinosaur or the argued implication in the year 2013 that Microraptor is not a bird while Archaeopteryx is! ) That said, the reason I initially included M. is that in general, taxobox images represent more basal members of a clade, so that you can visually see the evolution of a group as you click through the subgroup links. Maybe we should just slap an Eoraptor in there and call it a day. Anyway, using Microraptor visually shows the reader the link between birds and dinosaurs rather than simply including a modern specifier, which may be initially baffling and off-putitng for some who don't bother to carefully read the text. I had wanted to use the Berlin Archaeopteryx for this reason as it's far more iconic, but it didn't really fit the orientation unless I flipped it horizontally, which seemed wrong for some reason. MMartyniuk (talk) 21:58, 2 January 2013 (UTC)

On flipped Archaeopteryx, take a look at this: http://commons.wikimedia.org/w/index.php?title=File:EB1911_-_Volume_02.djvu&page=376 FunkMonk (talk) 11:38, 3 January 2013 (UTC) I would just offer my support for Peter Brown's attempt to curb the frontloading of phylogenetic taxonomy going on here. The picture with Microraptor is perfectly acceptable from both a phylogenetic standpoint, the only reason I can see for insisting on one with Passer is to emphasize phylogenetic nomenclature. The solution MMartyniuk suggested above has the benefit of catering to both sides as well as following the general Wikipedia trend. I do not intend to stay and argue my case here though, life's too short to end up like this. Petter Bøckman (talk) 11:27, 3 January 2013 (UTC) ha! . sort of. de Bivort 17:39, 3 January 2013 (UTC)

http://www.quackwatch.com/01QuackeryRelatedTopics/pseudo.html I recommend that three certain editors read this linked article and ask themselves if they really wish to waste everybody's time any further. You're smart and knowledgeable, please help instead of obstruct. HMallison (talk) 14:02, 3 January 2013 (UTC)

It is very difficult to attribute to any of the editors on this page any of the characteristics of the "pseudoscientists" condemned here. de Bivort did cite "literature aimed at the general public", The Guardian for example, but Wikipedia standardly considers reputable newspapers to be reliable sources. Peter Brown (talk) 14:35, 3 January 2013 (UTC) Good Grief! Bandits, pseudoscience? Seriously? Petter Bøckman (talk) 16:32, 3 January 2013 (UTC) BANDits are indeed psuedoscientists, as they employ every logical fallacy in the book, most notably moving the goalposts (er, ah, dromaeosaurs are birds now, so there!), straw man (BAD is wrong because birds evolved from arboreal animals and no dinosaurs were arboreal!), and no true Scotsman (an arboreal dinosaur you say? hogwash--if it's arboreal, it's a bird, as no true dinosaur lived in trees). However, the implication that the people posting here are pseudoscientists is wrong, because taxonomy is not objective and is therefore not a science. Whether or not we call Microraptor a bird or a dinosaur has no basis in objective fact. It's a label. MMartyniuk (talk) 20:05, 3 January 2013 (UTC) That's the problem, though: they're not really BANDits. The BANDits claim that birds are not dinosaurs in any sense, that birds derived from some other, unspecified amniote group. Peter, Petter, and Ego admit that birds are dinosaurs in the cladistic sense, but cite shaky sources (online dictionaries, coloring books, a single press release) to state that birds are descended from dinosaurs, but cannot be dinosaurs, because dinosaurs are extinct. At no point have they cited BANDit papers. The literature they've cited is not even close to BANDit research. In fact, they appear to be unaware of the BANDits, which by 2013 is a WP:FRINGE idea. I also disagree that the three editors are obstructing anything. It's just a discussion, and people can feel free to take part or not. Their comments are meant in good faith, and if the worst that happens because of this debate is that we don't have a picture of a living bird in this article, it won't be too terrible. I liked Abyssal's suggestion (still do), but I won't press it too hard because any of the new pictures would be okay scientifically, as we'd expect from pictures compiled by Martin. er, Matt. ) Firsfron of Ronchester 18:10, 3 January 2013 (UTC) Thank you guys putting me on the tracks to clarifying what a BANDit is supposed to mean. I thought it referred to some WP.policy, and tried every permutation of the word with no result. I was a bit puzzled, because I believe Mallison has called me that before, and I could not for the life of me fathom why he would accuse me of earning my living as a criminal (I don't even have a parking ticket on my record). I an quite familiar with Fediccia & Co though. Their opposition did actually bring one good thing in starting the investigation that eventually lead to the discovery of the frameshift of finger developement. I just never had heard them called BANDits before. As for the colouring book, I cited it only to counter you argument that feathers and small wings on dinosaurs close to birds were somehow discovered around 2006 and this prompted the change of wording. The colouring book mas merely an example of this being known back in 2002, as in "even this childrens colouring book got that right in 2002". I never forwarded it as scientific literature. Neither did any of us "admit" birds evolved from dinosaurs, that point was never in dispute. The actual phylogeny is possibly the only thing we ever agreed fully on here. It is a bit hard to discuss thing when the opposition do not care to actually read your argument. In a related note, I guess MMartyniuk was implying the Xu & al. paper above. This is an interesting paper, but I haven't followed the field closely enough to know if this analysis is now conventional wisdom. Didn't Lee & Worthy (2011) claim Xu & al was wrong? If we for the sake of the argument assume Xu's right, I can only see two possible scenarios: 1) flight evolved once, and Troodontidae and Dromeosauridae are both secondarily flightless (I suppose this is the "modified birds-came-first stance"?) or 2) flight evolved twice, and Archaeopteryx was a "para-bird". If I read Xu right, nr 2 is his position. It's however neither mentioned here or in Evolution of birds, and only implicitly in Archaeopteryx. As an ecologist I find this scenario extremely interesting. Shouldn't something about this be added? Petter Bøckman (talk) 21:54, 3 January 2013 (UTC) I disagree with with Xu et al's analysis and I think the problems with it have been pointed out by Lee and worthy as well as others online. current consensus of data is that Archie is slightly closer to modern birds than Microraptor. I was referring to gross morphological similarity. Both have fully-formed wings and may or may not have been capable of powered flight. Any reasonable Linneaan classification would place these in the same "order" if not "family" and certainly not different "classes". The only reason Microraptor is considered a 'dinosaur' rather than a 'bird' is the vagaries of arbitrary cladistic definitions, so it baffles me why people who complain about phylo-loading these articles are alright with letting the cladists determine what is or isn't bird, a line which even I think is currently at the most ridiculously arbitrary and illogical point possible! The article Bird states in the first line of the introduction that birds are "are feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals." Based on current knowledge, this definition applies to all maniraptoriform 'dinosaurs' at least including ornithomimosaurs, oviraptorosaurs, and deinonychosaurs. To turn this into something other than a rant, I'd be curious to see you and Peter Brown state what you think is a dinosaur and what is a bird, and why. It's apparently ok to include Microraptor but not Passer. Ok, what about Archaeopteryx? Jeholornis? Confuciusornis? Hesperornis? We're obviously going to need some ground rules here or at least be able to understand where each side is coming from to start to resolve this. MMartyniuk (talk) 13:50, 5 January 2013 (UTC) Which archosaurs were birds and which were not isn't one of the points at issue. Many articles, this one for example, call Microraptor a dinosaur and do not call it a bird we are simply basing our preferred terminology on this literature. You seem to be proposing to do away entirely with Aves as a taxon perhaps that is a good idea, but it is hardly a common one in the field. Peter Brown (talk) 15:52, 5 January 2013 (UTC) I must admit I am not intimately familiar wit the detail at the bottom of the avian tree. Like Peter B. and yourself pointed out, I've never seen Microraptor being called anything other than a dinosaur, and I was under the impression it was a glider only, so I assumed it belonged somewhere further down the tree than Archy. It appears I'm not the only one. Microraptor frequently figure on "smallest dinosaur" lists. Either that honour goes to Compsognathus, or one has to include birds and ad a humming-bird. Even if one stick to "Mesozoic dinosaurs", some of the enanornithes were sparrow-sized, so it seems it's a widespread misunderstanding. As for what makes a bird, I'm fairly certain flapping has something to do with it. The general consensus seems to be Archy had some limited powered flight abilities or at least "flapping assisted gliding". Gliders are dime a dozen in this world, birds are true fliers. So: Flapping things with feathers = bird, non-flapping things with or without feathers =/= not bird. Of course, in Linnaean taxonomy you will have these critters that falls right at the divide (the transitionals), the things that adds spice to life (and any text dealing with evolution). Petter Bøckman (talk) 22:18, 5 January 2013 (UTC) But doesn't this definition illustrate the flaw at the heart of Linnean taxonomy - "if it doesn't flap, it's not a bird." What about ratites, penguins? As soon as you (sensibly) extend the definition to "flappers plus their descendants", then you have laid the (cladistic) groundwork for birds being classified as dinosaurs, no? de Bivort 04:09, 6 January 2013 (UTC) For the record, the pectoral anatomy of Microraptor and Archaeopteryx are very similar, and that of Microraptor is actually more advanced in some ways (Microraptor had a fused, ossified sternum while Archaeopteryx did not Microaptor had an alula-like structure on the first wing digit while this has not been reported for Archaeopteryx). The common belief that Archaeopteryx had limited flapping and that Microraptor was strictly a glider is demonstrably false. It is currently debatable whether either could flap, but whatever aerial capability Archaeopteryx had (if any), Microraptor also must have had. MMartyniuk (talk) 17:02, 10 January 2013 (UTC) I can't see any flaw here, unless one insist on a purely phylogenetic approach. Since the world is (and presumably was) full of vertebrate gliders, then I hope we can agree that powered flight really made a difference, and put birds on an evolutionary course very different from their relatives? It's no more problematic to say birds are not dinosaurs that to say you and I are are not fish. Both the ecological shifts in question (land-air, water-land) represent major transitions with enormous consequences for anatomy and ecology and to me make sensible goalposts for classes. Of course, today our knowledge is so great the shifts are known almost down to species level. Then again, we usually have no problem accepting grades at the species level, so I see no problem in continuing this approach upwards. Petter Bøckman (talk) 08:14, 6 January 2013 (UTC) I'm sorry, but I don't follow at all. Should I conclude that you don't in fact think that ratites and penguins are birds? de Bivort 14:46, 6 January 2013 (UTC) No, they are birds, just like snakes are tetrapods, despite lacking legs. Come one, it's not like you don't know the normal Linnaean classification scheme, is it? Petter Bøckman (talk) 15:00, 6 January 2013 (UTC) Perhaps I don't, but I was just going off of your line that "non-flapping things with or without feathers =/= not bird" de Bivort 17:12, 6 January 2013 (UTC) You don't? Aren't you a biologist working with fruit-flies? Well, the Linnaean system works in the sensible way you suggested five posts up. Just to be snarky, I'd like to point out that both penguins and ratites do actually flap their wings now and then, they just don't fly with them.Petter Bøckman (talk) 19:26, 6 January 2013 (UTC) Linnean taxonomy was never taught as anything other than a historical referent in my undergrad or grad training. I think you're referring to evolutionary taxonomy which permits paraphyletic groups. The sensible definition I gave above, an organism plus its descendants, is precisely a cladistic, rather than [13] definition. I just want to double check: If we were to define dinosaurs as something like "an Eoraptor-like archosaur with characters X Y and Z, and all its descendants" you'd agree that it would include birds, right? de Bivort 21:37, 6 January 2013 (UTC) Sorry, I mixed up the two, traditional taxonomy often goes by the name "Linnaean taxonomy". You are of course right. As for your example, whether your dinosaurs would include birds depends on what X, Y and Z are. If e.g. Z is "non-volant", then birds fall outside. All this is quibbling though. Birds are a very derived group with a quite limited anatomical range (due to flying), had you put up all dinosaur (clade) species that ever lived side by side, the birds would still stick out like a sore thumb. A few, like Microraptor would be sort of in between, but that is how it is with transitional fossils. The reason traditional taxonomy is how it is (with warts and grades and all) is that its primary purpose is to be a practical way of squaring animals away. One of the most important traits is stability, and birds were a separate class to begin with. As many of the PhyloCode proponents has argued, had we stated all over, things would (I'd say might) look different, but we are not starting all over. Er, I think whatever characters you use to define the eoraptor-like beast that is the ancestor of both Triceratops and Tyrannosaurus (even if one of them is "non-volant"), then the group defined as "said beast and all descendants of it" includes birds. de Bivort 23:08, 6 January 2013 (UTC) I work in an educational institution, and one of my tasks is to keep track of all animal groups, even jellyfish, sipunculids, hemichordates and earthworms, not just vertebrates. I need a good filing system and a way to express things to the lay public. I have little use for a taxonomy grouping crocodiles with birds and not with lizards. When I finally come to the point where I do present surviving archosaurs, it is only after about an hour of touring school kids in dinosaur anatomy and habits and the origin of birds. Petter Bøckman (talk) 22:55, 6 January 2013 (UTC) I can sympathize with the challenge of portraying all of this to the lay public as coherently as possible. But, I would personally use the filing system that evolution has provided for us. de Bivort 23:08, 6 January 2013 (UTC)

I agree. i have read a paper about how birds are apparently not dinosaurs that was written by a BANDit and to tell the truth it was not very good. the writer despite being a "Professional Ornithologist" seemed to lack basic knowledge of bird anatomy, as what he calls a bird's knees are actually a it's ankles. and the said that Theropod dinosaurs use their thighs even though the majority of them didn't (only Oviraptorosaurs did). that's pretty embarassing already but second he did not provide an alternative for what birds might have evolved from and the entire paper devolved into the author patronizing and insulting the intelligence of the reader. BANDits should not be considered professional Ornithologists as they seem to lack essential knowledge of birds. and they should definetly not be considered scientists as they do not utilize ths scientific method. their logic is also very flawed, according to them every feathered dinosaur is actually a bird which if that is true, it means Yutyrannus and Concavenator are birds, which makes no sense. and they extend it to that every feathered dinosaur should be classified under at least Avialae, which makes no sense because what will happen if we discover a feathered sauropod?--50.195.51.9 (talk) 16:51, 9 January 2013 (UTC)

Yes, there is some pretty awful stuff out there. I don't see that a detailed critique of such trash advances the discussion here, however. Petter Bøckman, with vast experience in the matter, thinks that the cause of educating the public is better served by grouping crocodiles with lizards than by grouping them with birds. From my very limited training and experience as a volunteer guide at the Harvard Museum of Natural History, I see no reason to question his opinion. If you have some expertise in educating the public in zoology, you are certainly welcome to share it, since this is something that Wikipedia is trying to do. Peter Brown (talk) 18:08, 9 January 2013 (UTC) But why should we group Crocodylians with Squamates? If the goal is to educate the public, wouldn't it be counterproductive to state that Crocodylians are lizards? Currently Crocodylians are not considered lizards (Assuming the definition of "lizard" is belonging to the Squamata) and are instead considered Archosaurs. 50.195.51.9 (talk) 12:59, 10 January 2013 (UTC)

Perhaps the best way to satisfy laypeople whose eyes glaze over when they find little in the article of what they expected would be a generally accessible, less technical introduction, comparable to Introduction to evolution. In that article, simplified trees could be shown which give an overview and contrast the current technical definition with lay concepts of "dinosaurs". It can provide lists of highly recognisable species that laypeople tend to be most interested in, links to non-dinosaur sauropsids that are typically discussed in the same context in popular accounts (Dimetrodon, pterosaurs, ichthyosaurs, plesiosaurs, mosasaurs) so that people will not be confused at their absence but educated about the taxonomy, discussion of records such as largest and smallest, etc. I realise that a lot of this has already been incorporated into the article, but perhaps it is still a bit too much buried there for the general reader. Evaluating feedback from outsiders, whether personally prompted or collected automatically, should provide useful indications if the needs of the readers are met. (Strangely, I can't find the link to the feedback section on this talk page.) Unfortunately, I can't be of much help with this, being a layman myself, however, even if one who is (I'd think) much more comfortable with highly technical articles than the average reader. --Florian Blaschke (talk) 01:02, 5 January 2013 (UTC)

Hi Florian! The feedback section for this article is at the very bottom of Dinosaur, under the navigation templates. I agree that a simplified tree diagram could help the article. The General description portion of the article does try to point out that many "pop culture" 'dinosaurs', like the ones you mention, are not dinosaurs. Perhaps this fact could be re-added to the lead of the article (it used to be there). Firsfron of Ronchester 01:26, 5 January 2013 (UTC) Sorry for being unclear, I meant the subpage where comments from readers are collected and can be inspected by editors. I have found links to such subpages on other talk pages, somewhere in the templates on the top, but not here. I do suspect that lay readers would like to find links to popular real dinosaur genera and species such as Tyrannosaurus rex, Triceratops, Iguanodon, Stegosaurus, Apatosaurus, Diplodocus or Velociraptor in the article, too, not only mention of the "pseudo-dinosaurs". It might be difficult to find a source for such a "top 10 most popular dinosaurs list", though. It may also seem unencyclopedic, but the high profile of these dinosaur genera and species can be ascertained objectively, in principle. Admittedly, I can't think of a good way to incorporate such a list that wouldn't have the experts objecting. --Florian Blaschke (talk) 01:43, 5 January 2013 (UTC) I suppose a bubble diagram of reptiles down to order level with silhouettes of typical representatives would help, something like this, only with less fish and more detailed amniotes. Do you think this would help, Florian? Petter Bøckman (talk) 08:37, 6 January 2013 (UTC) That sounds like a good idea! However, in practical implementation, it should also be quite ambitious. Could this possibly remain manageable? I'm not quite sure what exactly you have in mind. I would really like to see an attempt. I think you would need two diagrams, one to show the place of the dinosaurs and the various other -saurs within the amniotes, and one to show the place of several representative genera within the dinosaurs. --Florian Blaschke (talk) 21:49, 12 January 2013 (UTC)

I just wanted to say that I think this is a good addition. de Bivort 02:12, 25 January 2013 (UTC)

Yes, the range includes birds, sauropods, and guaibasaurids, among many other groups which were not originally considered dinosaurs. Weird how we're constantly discovering new things ) MMartyniuk (talk) 12:40, 25 January 2013 (UTC)

These edits are a bit bewildering. I'd say that if you're going to remove a cite, either remove the pertinent reference completely or find another place where it is pertinent as a cite. As it is Zhou 2004 under the Further Reading heading is the odd man out: a review article among mostly popular and semi-technical books. As for the pertinence of the removal of the cite I'd point out the use of "non-avian dinosaur" in the paper:

Until now, no enantiornithine has been reported from the Cenozoic: thus it is likely that this group of early birds became extinct at the end of the Mesozoic together with non-avian dinosaurs.

The elongated prezygopophyses and chevrons of the caudal vertebrae bear a close resemblance to those of dromaeosaurs, confirming a close link between birds and this lineage of non-avian theropod dinosaurs.

With 10 other mentions to go with those above quoted. Now it is peculiar that "feathered dinosaur" is used as well, though it can be argued that the removal of "non-avian" from the expression is to avoid being repetitive. Besides what else would you call a dinosaur that was found with feathers and doesn't have the skeletal hallmarks of a bird? Feathered dinosaur is the minimum I'd say. Dracontes (talk) 10:37, 18 February 2013 (UTC)

Well, I don't think it an objection that Zhou 2004 is the "odd man out". The world could use a few more odd men. As regards pertinence: Zhou 2004 is cited to back up the claim that birds "are considered a subgroup of dinosaurs in most modern classification systems". Yet Zhou identifies only a single source to the effect that birds are dinosaurs, a 2002 paper by Prum. This is wholly inadequate as support for a claim about "most modern classification systems". Peter Brown (talk) 04:47, 19 February 2013 (UTC)

Please add the following paragraph to the "Size" section of the "Biology" part of the article: The Expanding/Growing Earth Hypothesis regarding the evolution of the Earth itself suggests there was less gravity on Earth when dinosaurs roamed it, which would explain why the largest dinosaurs evolved to be so massive. Neal Adams demonstrates the Expanding Earth Hypothesis with some compelling evidence here: http://www.youtube.com/watch?v=oJfBSc6e7QQ Exmodione (talk) 07:54, 17 April 2013 (UTC)

Sorry, but we don't need fringe material sourced to a you-tube video, fails WP:RS. Vsmith (talk) 09:59, 17 April 2013 (UTC)

Interesting hypothesis, the old classic one. But if birds are dinosaurs, then dinosaurs are today still the most specious group of all tetrapods - a wonder of adaption and variety, the greatest comeback before Lazarus. Failure to adapt new conditions? Ridiculous. --W-j-s (talk) 23:53, 9 February 2013 (UTC)

Well, all but one dinosaur lineage went extinct at the K-P boundary, so in the majority of cases, they failed to adapt, yeah. de Bivort 03:30, 10 February 2013 (UTC) Technically, that's debatable. Though rumor has it some of this may be challenged in upcoming papers, but based on current understanding of Cretaceous avialan diversity, there seem to have been at least five or six lineages of Avemetatarsalia that crossed the K-Pg boundary. Most of them just happen to be members of Aves, though it's possible that at least one non-avian avialan lineage got through, represented by Qinornis. As mentioned, it is possible that some Cretaceous "avians" aren't really avian at all, and that crown-group Aves didn't originate until the Paleogene, but that would be quite a trick given the presence of undisputed paleognaths and anseriformes very early in the Paleogene. MMartyniuk (talk) 15:14, 24 February 2013 (UTC) It's a matter of choice whether one calls several Avemetatarsalia lineages "several lineages" or "one lineage" - but that said, measured just as biodiversity / # species - the majority of dinosaurs went extinct at the boundary, no? Or was the majority of dinosaur diversity pre-meteor birdlike? de Bivort 15:31, 24 February 2013 (UTC) This is an active area of controversy/research. One reason why the "Toroceratops" thing is so prominent is because it has huge implications for the pre-K-Pg diversity of non-avialan avemetatarsalians. If you lump Torosaurus and Nedoceratops into Triceratops, lump all Maastrichtian pahycephalosaurs into P. wyomingensis, lump all NA Maast. duckbills into E. annectens, lump Nanotyrannus into T. rex, etc., suddnely non-avialan dinosaurs look like the vast minority of dinosaurs compared to Maastrichtian bird lineages. There are Maastrichtian non-avialan dino faunas in other parts of the world besides NA like Madagascar and the Shantungosaurus fauna of Asia, but their proximity to the K-Pg boundary isn't secure AFAIK. Then there's the late Maastrichtian fauna of Antarctica which so far seems to be exclusively avian. MMartyniuk (talk) 18:57, 24 February 2013 (UTC) What's your intuition about error bars on these estimates? I assume there were far far more than few dozen dinosaur species, and that we know about only this many for sampling reasons. Is there likely to be a sampling bias, or do you think that the avian/non-avian ratio (once lumping is resolved) will likely extend to all species world wide? What about the other reasonable metric: number of individuals. Were the avian species as abundant as non-avian species? de Bivort 14:58, 25 February 2013 (UTC) Worldwide, it's probably a sampling thing. In fact if I had to put money on true Paleogene non-avialan dinosaurs, it would be in the Danian of Antarctica ) However, North America is pretty thoroughly sampled, and though many species are known from scraps, I think we have a pretty good idea of diversity. MMartyniuk (talk) 22:12, 25 February 2013 (UTC) So, how about abundance? No. of avian vs non-avian individuals? de Bivort 01:44, 26 February 2013 (UTC) If you want to call it a "lack of adaptation" that a catastrophic event, which previously had never exerted evolutionary pressure, wiped them out. HMallison (talk) 12:01, 10 February 2013 (UTC) @Debivort: That's the point: toothless dinosaurs survived the impact and after that, their ability to adapt to the new conditions was very successful. The classic hypothesis says, that even before the impact the dinosaurs failed to adapt to changing conditions, e.g. in the flora. This means, that there must have been a fundamental difference between feathered dinosuars with teeths and those without. I cannot see this. So I conclude, that the only reason for the extinction of nearly all dinosaurs was the impact. --W-j-s (talk) 12:49, 24 February 2013 (UTC) Interesting, but for editing purposes it's OR unless you can cite authors to support that. There's the problem of dividing the Theropoda into avian and non-avian. To some extent the division is quite arbitrary and gives rise to some very pedantic argument re the survival of the Dinosauria beyond the KT. Also I don't think there's much dispute that the dinosaurs were declining before the impact event. A number of avians did not survive the Cretaceous, as did numbers of the groups that persisted in to the Cenozoic,ie., crocodiles, turles, mammals and many of the invertebrates. The Cretaceous was an indiscriminate killer, and why some survived and others did not is still a mystery.Gazzster (talk) 20:38, 25 February 2013 (UTC) Not much dispute that dinosaurs were declining before the impact event? Check out, e.g., Lloyd et al. (2008). Peter Brown (talk) 23:36, 25 February 2013 (UTC) @Gazzter: As Peter M. Brown said, there is much dispute about the hypothesis of declining dinosaurs before the K-T-event. Because as birds have to be regarded as dinosaurs they proof that dinosaurs had the ability to adapt very well. Birds - and this means also theropod dinosaurs - are today the most specious group of all tetrapods, they outnumber the mammal species more than twice. And because birds are very similar to other maniraptora it is simply not plausible, that the other maniraptora did not had this ability of adaption, either. In fact, there is more and more evidence, that only a few groups of dinosaurs declined while others florished until the impact. And this is not a surprise. In the last 65 million years one can sea a decline of some groups of mammals, too, while others began grew. In fact, there is now much more evidence, that the impact killed nearly all animal species larger than 20 kg and especially most warm blooded species. New interpretations of fossils show, that the adaptive radiation of the mammals started after the K-T-event and not - as molecular genetics suggested - millions of years before. This means, that perhaps only a handful placentalia species and only a handful species of birds survived the impact. Cold blooded species on the other hand could much easier survive a long cold and dark period with very rare food, so it is not suprising, that much more species of crocodiles, turtles, amphibia or insects survived the impact. btw, as I am not a native English speakers my ability to edit and correct the article is very limited. But I think, it's not OR to point on the fact, that that hypothesis of declining dinosaurs does not fit with the success and variety of today's birds. --W-j-s (talk) 20:28, 27 February 2013 (UTC) This is all very interesting, but what do we want to change in the article? I would however point out the dangers inherent in the syllogism you seem to be relying upon: 'birds adapt superbly to changing environments. Birds are dinosaurs. Therefore dinosaurs adapted superbly to changing conditions'. The first premise needs qualification. So does the second. Birds may be dinosaurs (though it is still not a scientific dogma mind you, though a number of editors assumes it is) but not all dinosaurs are birds. Consequently the conclusion needs to be qualified.Gazzster (talk) 02:08, 4 March 2013 (UTC) This is not my argumentation. I just say, if birds are dinosaurs, they proved, that some - not all - dinosaurs had the ability to adapt very well. The thesis critisized by me is, that the dinosaurs became extinct because they failed to adapt long before the K-T-event. Birds - if they are dinosaurs - show that this is wrong. So the new formulated thesis must be: some dinosaurs failed long before the K-T-event to adapt to new conditions, while some have been very sucessful (and maybe not only toothless birds with pygostyl). But if some species of a clade became extinct, while their relatives are successful, that's just life: By numbers of species hominidae failed to adapt, too. As fossile records show, there have been much more species of Hominidae some 20 million years ago than today. And by number of specimen, all species of hominidae together have less then 200.000 individuals, while other apes have far more. So hominidae have failed like the dinosaurs. To be correct: non-human hominidae, because I've excluded 7 billion individuals of homo sapiens when talking about hominidae. --W-j-s (talk) 17:42, 8 March 2013 (UTC) I understand your reasoning -thanks for clarifying - but what does it mean to say that some dinosaurs had the ability to adapt better than others? Did they possess some mysterious quality or organ (as do birds apparently according to your theory) that allowed them to evolve faster than other creatures? Or were they so 'generalised' in structure as to be able to survive in varying environments? The dinosaurs of the Late Cretaceous were, if anything, more specialised than many of their predecessors. Dinosaurs were 'failing' to adapt to new conditions, and being replaced, throughout the Mesozoic! Gazzster (talk) 06:54, 20 April 2013 (UTC) I don't think that there is a mystery, why some species adapt better than others, even their relatives. One should expect that in a normal distribution. The article suggests, that the dinosaurs were on a declining paths and the impact (and/or the vulcanoes in India) were only the last nail in the çoffin. Birds (and other maniraptorians) show, that the thesis of a decline of all dinosaurs is wrong. And I don't suggest, that some birds survived because of some mysterious quality or organ. There is no evidence for something like this. This means birds in the creteceous have been just a normal clade of maniraptorian dinosaurs with a normal ability to adapt to new conditions. Only a few specialised birds survived the K-T-event, and I don't think, it was because of their "adaptiveness", I think it was just luck. The surviving birds showed indeed a fantastic ability to adapt to new conditions, but there is no reason to assume, that other dinosaurs, if they had survived, too, wouldn't have shown a similiar ability. --W-j-s (talk) 22:11, 25 April 2013 (UTC)

The hypothesis that the earth's diameter increased until some time in the Mesozoic and later contracted, with resulting effects on the force of gravity at the earth's surface, has no support from reliable sources. Owen (1976), p. 230, has proposed a constant increase in diameter from the Cryogenian to the present, but with no reversal in the Mesozoic Cox (1990) has extensively reviewed this proposal and several similar ones, but no one has apparently suggested a contraction. The suggestion by 79.55.252.35 appears to be pure OR. Peter Brown (talk) 16:56, 26 April 2013 (UTC)

  • Owen, H. G. (1976). "Continental Displacement and Expansion of the Earth during the Mesozoic and Cenozoic". Philosophical Transactions of the Royal Society of London. Series A. 281 (1303): 223–291. CS1 maint: ref=harv (link)
  • Cox, C. Barry (1990). "New Geological Theories and Old Biogeographical Problems". Journal of Biogeography. 17 (2): 117–130. CS1 maint: ref=harv (link)

Your article says the following: "Although the word dinosaur means "terrible lizard", the name is somewhat misleading, as dinosaurs are not lizards. Rather, they represent a separate group of reptiles with a distinct upright posture not found in lizards, and many extinct forms did not exhibit traditional reptilian characteristics."

If dinosaurs do not exhibit reptilian characteristics, how can you say they are a "separate group of reptiles"? Dinosaurs were not and are not reptiles. The sentence should be changed to: 'a separate group' and the 'of reptiles' should be removed.

Anthony Anthony_Mendoza (talk) 06:38, 12 February 2013 (UTC)

Dinosaurs are definitely reptiles. Abyssal (talk) 11:37, 12 February 2013 (UTC) This of course depends on how you define reptile. If dinosaurs are reptiles, so are birds. Most people don't have a problem with this, some do. On the other hand, the sentence is wrong wither way. If something is a reptilian characteristic, it must be shared with most or all reptiles. If a characteristic is not common to all reptiles, it is therefore not a reptilian characteristic. I'd agree the statement should be removed unless examples of these supposed characteristics (diapsid skulls? scales? hard-shelled eggs?) are given and sourced. The statement seems to oversimplify the difference between lizards and other reptiles to the point that it's useless and misleading as currently listed. MMartyniuk (talk) 12:26, 12 February 2013 (UTC) I think that the operative word here is "traditional". As such scaled, cold-blooded and crawling is probably what the text Anthony quoted is getting at. As for actual sauropsid synapomorphies, if the counterpoint should be needed, this seems to be a good start. Dracontes (talk) 21:03, 17 February 2013 (UTC) Just drop the second of the two sentences, which contributes nothing. No need to get into phylogeny at this point. Saying that dinosaurs are a separate group just repeats the statement in the first sentence that dinosaurs are not lizards. "Traditional reptilian characteristics" is hopelessly vague. Peter Brown (talk) 21:39, 17 February 2013 (UTC) Or we could cite a relatively consensual semi-technical source for what is traditionally reptilian and how dinosaurs differ from that. The new edition of Grzimek's Animal Life Encyclopedia seems a good one from the skim I gave to the intro on the reptile volume. Fair enough regarding such an early introduction of taxonomy and the two phrases could be subsumed into one.

Although the word dinosaur means "terrible lizard", the name is somewhat misleading, as dinosaurs are not lizards, representing instead a separate group of reptiles which, like many extinct forms, did not exhibit characteristics had as traditionally reptilian, such as a sprawling limb posture or ectothermy.

Although the word dinosaur means "terrible lizard", the name is somewhat misleading, as dinosaurs are not lizards, representing instead a separate group of reptiles which, like many extinct forms, did not exhibit characteristics historically had as reptilian, such as a sprawling limb posture or ectothermy, due to their limited extant diversity.

Birds should be classified as reptiles if dinosaurs are too. --209.188.40.63 (talk) 21:36, 29 April 2013 (UTC)

I second this, People are too hesitant to admit that Birds are reptiles.--65.96.242.22 (talk) 19:05, 30 April 2013 (UTC) But dinosaurs aren't classified as reptiles. Farsight001 (talk) 19:25, 30 April 2013 (UTC) Not so classified by whom? In 1842/3 Richard Owen defined Dinosauria as "a distinct tribe or suborder of Saurian Reptiles". Peter Brown (talk) 19:45, 30 April 2013 (UTC) Dinosaurs are indeed classified as reptiles. Birds are dinosaurs. However, birds are not classified as reptiles. Similarly, synapsids are reptiles, and mammals are synapsids, but mammals are not classified as reptiles. It's because reptiles are a paraphyletic group. It really doesn't make much sense. I don't consider it proper, but that's just the way it is. Ferocious Flying Ferrets 19:46, 30 April 2013 (UTC) If all As are Bs and all Bs are Cs, then all As are Cs. There are various ways of sorting out the terminology, but let's not defy the rules of logic. Peter Brown (talk) 19:56, 30 April 2013 (UTC) It should be that simple, but it isn't. Ferocious Flying Ferrets 20:06, 30 April 2013 (UTC) I guess science is finally realising how arbitary and artificial the Linnaean system is. In fact any system is artificial insofar as it is an attempt to impose order on nature for the sake of human understanding. So based on shared characteristics a bird could be a dinosaur. Heck, one could even make a case for classifying Diplodocus as a bird, or even a mammal, on the basis of shared characteristics. It all depends upon what set of characteristics scientists are going to agree on. However, for the sake of a wiki encyclopedia it's problematic to start calling birds reptiles. I do see the logic though.Gazzster (talk) 01:15, 1 May 2013 (UTC) These are deep questions. Gazzster seems to adopt something like Protagoras' dictum that man is the measure of all things, that objectivity is nothing but intersubjectivity. The contrary view is Plato's, that nature should be carved at the joints, which presupposes that there are joints, distinctions between natural kinds or something like that. It is difficult to explain the progress of science unless Plato's view is roughly correct. Diplodicus distinguished from Aves only because humans like to think of them as different? Paleontology, it seems, would then be an idle pursuit. Peter Brown (talk) 02:07, 1 May 2013 (UTC) What do the sources say? de Bivort 03:51, 1 May 2013 (UTC) Reptiles#Phylogenetics and modern definition. Many contemporary researchers agree with the initial statement: birds are indeed reptiles in a phylogenetic sense. The traditional definition has lost importance and is increasingly seen as an artifact of history, much like former conceptions that would treat whales as fish (but not land mammals, which we now realise ultimately descend from fish, too) and even much stranger early classifications, compare Kingdom (biology)#Summary. --Florian Blaschke (talk) 21:18, 1 May 2013 (UTC) The distinction between birds and reptiles has lost no importance except in academic disputations. No zoo includes birds in a "reptile house". Kingdom (biology)#Summary is irrelevant. Peter Brown (talk) 22:42, 1 May 2013 (UTC) It's not a zoo, but the AMNH is in fact organized this way. [14]. de Bivort 00:19, 2 May 2013 (UTC) Perhaps the distinction has lost importance in some public exhibits, but it is quite robust in others. In the National Zoo in Washington, D.C., the walk from the reptiles to the birds is not short. Overall, has the distinction lost importance? To argue so, I expect, would be quite difficult. Peter Brown (talk) 02:40, 2 May 2013 (UTC) Then again, the prairie dogs aren't housed in the small mammal house, even though they are small mammals. We can count ourselves lucky that what matters for the article is what reliable secondary and tertiary sources say, rather than how zoos and museums are organized. de Bivort 05:05, 2 May 2013 (UTC) Quite so. What is a reliable source for the thesis that the traditional definition has lost importance and is increasingly seen as an artifact of history? There certainly is contemporary work, in Palaeos for example, that makes the distinction quite unapologetically. Peter Brown (talk) 16:51, 2 May 2013 (UTC) It feels like you're trying to broaden the argument. I'm just saying that to resolve this "birds and dinosaurs as reptiles" section, we should appeal to sources herpetological, ornithological and paleontological. There's no point in arguing without sources. de Bivort 17:13, 2 May 2013 (UTC) Agreed, arguing without sources is pointless. Accordingly, I'm requesting a source for a very specific point: that "the traditional definition" is increasingly seen as an artifact of history. I don't see how that broadens the argument. If Petter Bøckman is correct, below, that we will have to live with the relevant terminological diversity for decades, then the traditional distinction will not be seen as "an artifact of history" for some time. Of course, if you can rebut his thesis with a reliable source, that will be a different matter. Peter Brown (talk) 19:02, 2 May 2013 (UTC) Well, that's on Florian, not me. I was just trying to bring the focus back in this discussion. That said, I don't think a reference is need that says that per se. Those are your goalposts. What is needed are (current, reliable, secondary, etc) references that either say "birds are reptiles" or "birds aren't reptiles." I have nowhere near the passion for this point as I did for the BAD / BAND question, so I'll leave it to others to hit up google scholar. de Bivort 22:26, 2 May 2013 (UTC) Snyspida is not a reptiles in any sense, since it appeared before reptiles. I don't think synspdida is in repiles, but they are in amoate. Also, birds are underneath reptiles. I think this is non-standard and unneacpetlbe to exclude birds just because they are warm blooded. --209.188.46.176 (talk) 22:25, 1 May 2013 (UTC) I would have ignored this as nonsense. Petter Bøckman, a more patient and considerate editor than I, has graciously responded to your concern at Talk:Synapsid#Class or subclass?. Engage him there, if you think you really have a point, rather than cluttering up various talk pages. Peter Brown (talk) 22:42, 1 May 2013 (UTC)

Hardly Peter -) The basic problem is of course that taxonomy is trying to cater to two aims these days: The original aim of ordering and the post-Darwinian aim of reflecting phylogeny. There are ways of letting the two live side by side on one system (Evolutionary taxonomy), but the proponents of phylogenetic nomenclature are these days pressing for a purely phylogenetic approach, at the expense of ordering. The problem of course is that we need both a handy way of classifying animals and a system of reflecting phylogeny without drawing trees all the time. I suspect this is a situation we will have to live with for decades, until either a) classification and phylogeny part ways or b) taxonomy are replaced by a new system. Only time will tell. Petter Bøckman (talk) 13:33, 2 May 2013 (UTC)

An interesting and well-argued discussion. So I take it there is no consensus for referring Aves as a sub-classification of Reptilia?Gazzster (talk) 01:08, 3 May 2013 (UTC)

Peter M. Brown, is this section really necessary? I feel this is covered adequately in Definition. Also, it seems that you are confusing use of "dinosaur" as a vernacular or colloquial term with support for a formal paraphyletic group. When a paper title includes the word "fish", it does not necessarily follow that the authors of that paper implicitly support the use of a paraphyletic taxon Pisces. MMartyniuk (talk) 17:23, 23 June 2013 (UTC)

The full title of the paper I cite is, "The first hatchling dinosaur reported from the eastern United States: Propanoplosaurus marylandicus (Dinosauria: Ankylosauria) from the Early Cretaceous of Maryland, U.S.A." Neither "dinosaur" nor "Dinosauria", in context, is a vernacular or colloquial use. Peter Brown (talk) 17:53, 23 June 2013 (UTC) If you honestly believe Weishampel, at least (one of the co-authors) advocates for a paraphyletic Dinosauria, I suggest you read any of his books. "Hatchling dinosaur" here is clearly being used colloquially. At the very least, there is no possible way you can seriously argue this kind of usage is a tacit, professional advocation of a paraphyletic taxon excluding birds. MMartyniuk (talk) 20:30, 23 June 2013 (UTC)

My addition of a new section to the article has been rejected as "synthesis". The only argument for birds' being dinosaurs that I know about, however, is that birds are descended from dinosaurs, and I can produce sources presenting that as the reason. If there is another reason, it needs to be included in the article. Descent works as a reason only if paraphyletic taxa are rejected, however, and such rejection is a controversial matter, much too controversial for Wikipedia to takes sides on. Peter Brown (talk) 17:39, 23 June 2013 (UTC)

And so we need a disclaimer on every single biology article? I don't think so. This should be discussed on Phylogenetic taxonomy etc., not Dinosaur. Or Mammal. Frankly, the opinion that paraphyletic groups are ok is a minority in dinosaur science and should be treated with the same amount of space as the BAND hypothesis (i.e., one or two lines, not an entire sub-header). Yes, paraphyletic groups are advocated by workers in other fields, but dinosaur paleontology is nearly 100% in favor of clades nowadays. Suggesting or implying otherwise is dishonest. Rejection of paraphyly may be controversial in general, but this is not a general article on the philosophy of biological classification. MMartyniuk (talk) 20:26, 23 June 2013 (UTC) OK, I'll compose the one or two lines. Maybe a few more. Peter Brown (talk) 21:56, 23 June 2013 (UTC) Just to add, I don't see what the point is of writing in these kinds of disclaimers and contrarianism. Like BANDits, opponents of cladistics and PN have not proposed any decent alternatives. If I were to decide to follow a paraphyletic concept of Dinosauria, how exactly would that work? What is the alternate definition or diagnosis of Dinosauria vs birds (Aves, or Avialae, btw?)? Is Microraptor a dinosaur or not and why? What about Aurornis? Archaeopteryx? Is Aves the crown, the branch, the Archaeopteryx node, or something else? These questions all have practical problems for Wikipedia (what date goes in the Bird taxobox for their origin, for example?) Until such things are worked out by supporters of paraphyly and validly published on by numerous researchers and a consensus is reached, all of this anti-monophyly stuff is extremely counter-productive. MMartyniuk (talk) 20:37, 23 June 2013 (UTC) Here I disagree. Pointing out difficulties with the dominant paradigm is an essential part of the endeavor. Were it not for papers like James & Pourtless (2009), there would reason to fear that the birds-from-dinosaurs theory was not being adequately challenged. Alternative theories are not necessary at all stages only when the network of auxiliary assumptions needed to support the dominant theory becomes unwieldy is a new paradigm required. Peter Brown (talk) 21:56, 23 June 2013 (UTC)

  • James, Francis C. Pourtless, John A., IV (2009). "Cladistics and the Origin of Birds: A Review and Two New Analyses". Ornithological Monographs. 66: 1–78. CS1 maint: ref=harv (link)

This page mentions that dinosaurs are 150 million (or somewhere around there) years old, which I disagree with. How can you tell how old the dinosaur is? --Dianasweetiegina (talk) 04:10, 24 June 2013 (UTC)Dianasweetiegina

150 million years old? Not close have you even read the page? We can "tell" by reading reliable sources, which are provided abundantly. Peter Brown (talk) 14:13, 24 June 2013 (UTC)

Scientists have been able to determine beyond reasonable doubt that dinosaurs are between 230 and 66 million years old using various methods for dating the age of geological formations, most of which are generally very reliable. --24.36.130.109 (talk) 01:51, 8 July 2013 (UTC)

In the Distinguishing anatomical features section, the text reads ". S. Nesbitt confirmed or found the following 12 unambiguous synapomorphies, some previously known:". By my count, only 11 bullet points follow. Somehow one was either lost, never added during the original edit, or the count is simply wrong.

Good point. The twelfth point has now been added.--MWAK (talk) 16:13, 2 September 2013 (UTC) Twelve seems like an implausibly large number of synapomorphies for any group, the dinosaurs in this case. I infer from the Synapomorphy article that a synapomorphy, by definition, is present in the last common ancestor of a group but absent in its immediate ancestor. That would mean, would it not, that the twelve traits jumped aboard all at once in a single speciation event? This does not accord with the gradual nature of evolution that I thought was the dominant view. The synapomorphies can be grouped, somewhat, cutting down on the total number the two listed items relating to the fourth trochanter of the femur can surely be combined into one. We are left, however with changes to the skull roof, the cervical vertebrae, the limb bones, and the pelvis, all of which happened at once according to Nesbitt. Can a case can be made out that these are interdependent that no one change could have occurred without all the others if the animal was to remain functional? If not, the proposition that all twelve traits are synapomorphies of the dinosaurs is difficult to accept. Peter Brown (talk) 23:19, 2 September 2013 (UTC) If any group has a large number of synapomorphies, doesn't that just mean there's a relatively large gap between it and more basal groups? That is, we would expect the number of synapomorphies to drop steadily as we find more near-dinosaurs. MMartyniuk (talk) 21:15, 3 September 2013 (UTC) Exactly. However, this also means that those near-dinosaurs were the first species showing the apomorphies and thus are implicitly referred to by the original larger list of synapomorphies. Also, those apomorphies might first have been acquired by very basal dinosaurs, although this requires a degree of parallel evolution. The synapomorphies were in such cases not changes in the real last common ancestor but in a range of species. It is this range that is represented by the larger list.--MWAK (talk) 09:09, 4 September 2013 (UTC) Well, these traits would not have to be acquired all at once. Indeed, at the moment of speciation, e.g. by allopatry, the last common ancestor of dinosaurs might well have been morphologically indistinguishable from its ancestor. During the, perhaps many, million years of its subsequent existence — of course the "ancestor" is now seen as an ancestral species, not a single individual — new traits could gradually have evolved. However, it is indeed quite implausible (though not impossible) that the actual last common ancestor of the Dinosauria really was the species showing for the first time these twelve innovations. The high number in all probability indicates a serious gap in the fossil record. You see, in cladistics, the "last common ancestor", when related to a set of synapomorphies is always a methodological fiction. It might truly have been a single species but more often will have been a group. The data — the actually discovered extinct and extant species — do not allow us to resolve this group and therefore we treat it as if it were one species. One has to keep this in mind :o). By the way, in general traits should only be combined if there is a material implication.--MWAK (talk) 06:50, 3 September 2013 (UTC) So a last common ancestor is usually not a species but a species group? And what species are in the group depends on what, in our present state of knowledge, we are able to resolve? "Synapomorphy" is defined in terms of LCA, so this would mean that what traits are synapomorphies is also relative to our state of knowledge. If we called something a synapomorphy last year but refuse to call it one this year, apparently we need not have changed our minds due to new discoveries and enhanced technology, the scope of the term can change from year to year so that a 2012 synapomorphy need not be a 2013 one. Is this made clear anywhere in Wikipedia? For starters, Last common ancestor#MRCA of different species and Synapomorphy are seriously in need of updating. In the Erythrosuchus article, it is stated, The hypothetical last common ancestor of archosaurs is thought to have shared many features with Erythrosuchus, many of which are found in the braincase. Is the "last common ancestor" in this context a species group? Does calling it "hypothetical" mean that no fossil in any of the group members has been found? Or is it a particular species, and the implication of "hypothetical" is that we have no fossils in that species? Similar questions arise for a huge number of articles. Peter Brown (talk) 15:59, 3 September 2013 (UTC) "So a last common ancestor is usually not a species but a species group? " I guess that depends on how you define "species", but I think it would be better to think of the LCA as a population. When two populations within a species become isolates, they remain the same species for quite a while under most species concepts before speciation occurs. MMartyniuk (talk) 21:17, 3 September 2013 (UTC) The term "group" isn't mine I'm trying to understand MWAK's statement You see, in cladistics, the "last common ancestor", when related to a set of synapomorphies is always a methodological fiction. It might truly have been a single species but more often will have been a group. The data — the actually discovered extinct and extant species — do not allow us to resolve this group and therefore we treat it as if it were one species. You prefer populations as ancestors, which is in better accord with the Phylocode than MWAK's groups. Do you agree with MWAK that LCA is "a methodological fiction"? Peter Brown (talk) 21:40, 3 September 2013 (UTC) "Do you agree with MWAK that LCA is "a methodological fiction"" It depends on the context. Certainly, any two given eukayotic organisms had a singe LCA that was a real genetic population of organisms. My understanding, which could be wrong, is that not only is the actual LCA incredibly unlikely to be preserved in the fossil record due to its incompleteness, but that even if this ancestor does indeed exist in a form that can be coded, cladistic methodology will recover it as a basal sister group rather than as an ancestral node. LCAs exist, but cladistic methodology alone cannot tell us what they are without extra interpretation of the data. For example, it is possible that the population of ceratopsids that contains the type specimen of Rubeosaurus is directly ancestral of the population that contains the type specimen of Einiosaurus, which in turn may be ancestral to the clade Pachyrostra in an anagenic lineage. Nevertheless, cladistic analyses usually recover the former two specimens as successive outgroups to pachyrhinosaurs, which is not inconsistent with the hypothesis that this is a single lineage--it's just an artifact of how cladistic analyses work. In the above example, the last common ancestor of Rubeosaurus ovatus + Pachyrhinosaurus canadensis (=clade Pachyrhinosaurini) would be Rubeosaurus ovatus itself. But because phylogenetics does not allow for paraphyletic taxa, this can't be expressed directly, though we must realistically acknowledge that all species evolved from some other species, and thus most species are paraphyletic in one way or another. MMartyniuk (talk) 10:58, 5 September 2013 (UTC) MWAK carefully distinguishes the "actual last common ancestor", a real population or whatever, from "the last common ancestor when related to a set of synapomorphies" which is always a methodological fiction. Do you agree that there is an important distinction here? I don't think that coding an ancestral group as a basal sister is really "fictional", since it represents a hypothesis that is correct for all we know. Peter Brown (talk) 17:13, 5 September 2013 (UTC) Well, a "last common ancestor" to which synapomorphies are attributed in a cladistic analysis will usually be a species group. The actual last common ancestor is by definition a species or a certain set of individuals (depending on the definition). Indeed, what we know to have been the synapomorphies, is dependent on our present state of knowledge. As our knowledge increases, the number of synapomorphies will eventually decrease and the number of species factually included in the species group will decline, approaching the one species that is the actual last common ancestor. That actual last common ancestor is referred to in a clade definition such a definition does not indicate a species group. The sentence "The hypothetical last common ancestor of archosaurs is thought to have shared many features with Erythrosuchus. " confuses the actual last common ancestor ("the hypothetical last common ancestor of archosaurs" — it is both actual and hypothetical, i.e. not known to have been found yet) with the fictional last common ancestor (the species group sharing those synapomorphies with Erythrosuchus). The fact that we are unable to resolve a group does not necessarily mean we haven't found any fossils of these species, just that we as yet don't know this.--MWAK (talk) 09:09, 4 September 2013 (UTC) You write of "what we know to have been the synapomorphies". Based on the following sentence, I think you mean "what are the synapomorphies." The phrase "have been" refers to an indefinite time in the past and, as you say, the set of synapomorphies varies with the state of knowledge. Prior to 1842, there were no dinosaur synapomorphies because the dinosaur-concept hadn't even been formulated. Such details aside, I find your POV quite convincing. Is it OR or can you provide sources so that these ideas can be incorporated in Wikipedia articles? Peter Brown (talk) 16:52, 4 September 2013 (UTC) Ah, I fear in many matters I'm rather a Realist :o). Certainly I do not see the synapomorphies as merely (I would say, being a Realist) a social construct. "Hidden species" are a well-known problem in the phylogenetic species concept. Our discussion is perhaps simply about the relation between the phylogenetic species concept and the biological species concept. An elegant solution was offered by this article: Pleijel F. and Rouse G.W., 2000, "Least-inclusive Taxonomic Unit: A New Taxonomic Concept for Biology", Proceedings of the Royal Society of London – Series B: Biological Sciences 267: 627–630. The LCA is then in cladistic analyses a LITU, without any claims about it being a species. In most Wikipedia articles it is unnecessary to reveal such implicit problems.--MWAK (talk) 07:01, 5 September 2013 (UTC) I'll take a look at the paper. You have written: "in cladistics, the 'last common ancestor', when related to a set of synapomorphies is always a methodological fiction." Are the synapomorphies themselves methodological fictions even though they're not social constructs? Since synapomorphies are generally defined in terms of LCAs, I would expect them to be no less fictional. Peter Brown (talk) 17:38, 5 September 2013 (UTC) The traits as such are to be considered real their combination in a set of synapomorphies is in cladistics a methodological fiction: you pretend that there is a single species for the first time showing certain modifications, while it is likely these modifications were acquired by a range of species. However, a degree of fictionality has always been overt, as such a set clearly functions as an hypothesis.--MWAK (talk) 08:22, 6 September 2013 (UTC)

This page mentions that dinosaurs are 150 million (or somewhere around there) years old, which I disagree with. How can you tell how old the dinosaur is? --Dianasweetiegina (talk) 04:10, 24 June 2013 (UTC)Dianasweetiegina

150 million years old? Not close have you even read the page? We can "tell" by reading reliable sources, which are provided abundantly. Peter Brown (talk) 14:13, 24 June 2013 (UTC)

Scientists have been able to determine beyond reasonable doubt that dinosaurs are between 230 and 66 million years old using various methods for dating the age of geological formations, most of which are generally very reliable. --24.36.130.109 (talk) 01:51, 8 July 2013 (UTC)

In the Distinguishing anatomical features section, the text reads ". S. Nesbitt confirmed or found the following 12 unambiguous synapomorphies, some previously known:". By my count, only 11 bullet points follow. Somehow one was either lost, never added during the original edit, or the count is simply wrong.

Good point. The twelfth point has now been added.--MWAK (talk) 16:13, 2 September 2013 (UTC) Twelve seems like an implausibly large number of synapomorphies for any group, the dinosaurs in this case. I infer from the Synapomorphy article that a synapomorphy, by definition, is present in the last common ancestor of a group but absent in its immediate ancestor. That would mean, would it not, that the twelve traits jumped aboard all at once in a single speciation event? This does not accord with the gradual nature of evolution that I thought was the dominant view. The synapomorphies can be grouped, somewhat, cutting down on the total number the two listed items relating to the fourth trochanter of the femur can surely be combined into one. We are left, however with changes to the skull roof, the cervical vertebrae, the limb bones, and the pelvis, all of which happened at once according to Nesbitt. Can a case can be made out that these are interdependent that no one change could have occurred without all the others if the animal was to remain functional? If not, the proposition that all twelve traits are synapomorphies of the dinosaurs is difficult to accept. Peter Brown (talk) 23:19, 2 September 2013 (UTC) If any group has a large number of synapomorphies, doesn't that just mean there's a relatively large gap between it and more basal groups? That is, we would expect the number of synapomorphies to drop steadily as we find more near-dinosaurs. MMartyniuk (talk) 21:15, 3 September 2013 (UTC) Exactly. However, this also means that those near-dinosaurs were the first species showing the apomorphies and thus are implicitly referred to by the original larger list of synapomorphies. Also, those apomorphies might first have been acquired by very basal dinosaurs, although this requires a degree of parallel evolution. The synapomorphies were in such cases not changes in the real last common ancestor but in a range of species. It is this range that is represented by the larger list.--MWAK (talk) 09:09, 4 September 2013 (UTC) Well, these traits would not have to be acquired all at once. Indeed, at the moment of speciation, e.g. by allopatry, the last common ancestor of dinosaurs might well have been morphologically indistinguishable from its ancestor. During the, perhaps many, million years of its subsequent existence — of course the "ancestor" is now seen as an ancestral species, not a single individual — new traits could gradually have evolved. However, it is indeed quite implausible (though not impossible) that the actual last common ancestor of the Dinosauria really was the species showing for the first time these twelve innovations. The high number in all probability indicates a serious gap in the fossil record. You see, in cladistics, the "last common ancestor", when related to a set of synapomorphies is always a methodological fiction. It might truly have been a single species but more often will have been a group. The data — the actually discovered extinct and extant species — do not allow us to resolve this group and therefore we treat it as if it were one species. One has to keep this in mind :o). By the way, in general traits should only be combined if there is a material implication.--MWAK (talk) 06:50, 3 September 2013 (UTC) So a last common ancestor is usually not a species but a species group? And what species are in the group depends on what, in our present state of knowledge, we are able to resolve? "Synapomorphy" is defined in terms of LCA, so this would mean that what traits are synapomorphies is also relative to our state of knowledge. If we called something a synapomorphy last year but refuse to call it one this year, apparently we need not have changed our minds due to new discoveries and enhanced technology, the scope of the term can change from year to year so that a 2012 synapomorphy need not be a 2013 one. Is this made clear anywhere in Wikipedia? For starters, Last common ancestor#MRCA of different species and Synapomorphy are seriously in need of updating. In the Erythrosuchus article, it is stated, The hypothetical last common ancestor of archosaurs is thought to have shared many features with Erythrosuchus, many of which are found in the braincase. Is the "last common ancestor" in this context a species group? Does calling it "hypothetical" mean that no fossil in any of the group members has been found? Or is it a particular species, and the implication of "hypothetical" is that we have no fossils in that species? Similar questions arise for a huge number of articles. Peter Brown (talk) 15:59, 3 September 2013 (UTC) "So a last common ancestor is usually not a species but a species group? " I guess that depends on how you define "species", but I think it would be better to think of the LCA as a population. When two populations within a species become isolates, they remain the same species for quite a while under most species concepts before speciation occurs. MMartyniuk (talk) 21:17, 3 September 2013 (UTC) The term "group" isn't mine I'm trying to understand MWAK's statement You see, in cladistics, the "last common ancestor", when related to a set of synapomorphies is always a methodological fiction. It might truly have been a single species but more often will have been a group. The data — the actually discovered extinct and extant species — do not allow us to resolve this group and therefore we treat it as if it were one species. You prefer populations as ancestors, which is in better accord with the Phylocode than MWAK's groups. Do you agree with MWAK that LCA is "a methodological fiction"? Peter Brown (talk) 21:40, 3 September 2013 (UTC) "Do you agree with MWAK that LCA is "a methodological fiction"" It depends on the context. Certainly, any two given eukayotic organisms had a singe LCA that was a real genetic population of organisms. My understanding, which could be wrong, is that not only is the actual LCA incredibly unlikely to be preserved in the fossil record due to its incompleteness, but that even if this ancestor does indeed exist in a form that can be coded, cladistic methodology will recover it as a basal sister group rather than as an ancestral node. LCAs exist, but cladistic methodology alone cannot tell us what they are without extra interpretation of the data. For example, it is possible that the population of ceratopsids that contains the type specimen of Rubeosaurus is directly ancestral of the population that contains the type specimen of Einiosaurus, which in turn may be ancestral to the clade Pachyrostra in an anagenic lineage. Nevertheless, cladistic analyses usually recover the former two specimens as successive outgroups to pachyrhinosaurs, which is not inconsistent with the hypothesis that this is a single lineage--it's just an artifact of how cladistic analyses work. In the above example, the last common ancestor of Rubeosaurus ovatus + Pachyrhinosaurus canadensis (=clade Pachyrhinosaurini) would be Rubeosaurus ovatus itself. But because phylogenetics does not allow for paraphyletic taxa, this can't be expressed directly, though we must realistically acknowledge that all species evolved from some other species, and thus most species are paraphyletic in one way or another. MMartyniuk (talk) 10:58, 5 September 2013 (UTC) MWAK carefully distinguishes the "actual last common ancestor", a real population or whatever, from "the last common ancestor when related to a set of synapomorphies" which is always a methodological fiction. Do you agree that there is an important distinction here? I don't think that coding an ancestral group as a basal sister is really "fictional", since it represents a hypothesis that is correct for all we know. Peter Brown (talk) 17:13, 5 September 2013 (UTC) Well, a "last common ancestor" to which synapomorphies are attributed in a cladistic analysis will usually be a species group. The actual last common ancestor is by definition a species or a certain set of individuals (depending on the definition). Indeed, what we know to have been the synapomorphies, is dependent on our present state of knowledge. As our knowledge increases, the number of synapomorphies will eventually decrease and the number of species factually included in the species group will decline, approaching the one species that is the actual last common ancestor. That actual last common ancestor is referred to in a clade definition such a definition does not indicate a species group. The sentence "The hypothetical last common ancestor of archosaurs is thought to have shared many features with Erythrosuchus. " confuses the actual last common ancestor ("the hypothetical last common ancestor of archosaurs" — it is both actual and hypothetical, i.e. not known to have been found yet) with the fictional last common ancestor (the species group sharing those synapomorphies with Erythrosuchus). The fact that we are unable to resolve a group does not necessarily mean we haven't found any fossils of these species, just that we as yet don't know this.--MWAK (talk) 09:09, 4 September 2013 (UTC) You write of "what we know to have been the synapomorphies". Based on the following sentence, I think you mean "what are the synapomorphies." The phrase "have been" refers to an indefinite time in the past and, as you say, the set of synapomorphies varies with the state of knowledge. Prior to 1842, there were no dinosaur synapomorphies because the dinosaur-concept hadn't even been formulated. Such details aside, I find your POV quite convincing. Is it OR or can you provide sources so that these ideas can be incorporated in Wikipedia articles? Peter Brown (talk) 16:52, 4 September 2013 (UTC) Ah, I fear in many matters I'm rather a Realist :o). Certainly I do not see the synapomorphies as merely (I would say, being a Realist) a social construct. "Hidden species" are a well-known problem in the phylogenetic species concept. Our discussion is perhaps simply about the relation between the phylogenetic species concept and the biological species concept. An elegant solution was offered by this article: Pleijel F. and Rouse G.W., 2000, "Least-inclusive Taxonomic Unit: A New Taxonomic Concept for Biology", Proceedings of the Royal Society of London – Series B: Biological Sciences 267: 627–630. The LCA is then in cladistic analyses a LITU, without any claims about it being a species. In most Wikipedia articles it is unnecessary to reveal such implicit problems.--MWAK (talk) 07:01, 5 September 2013 (UTC) I'll take a look at the paper. You have written: "in cladistics, the 'last common ancestor', when related to a set of synapomorphies is always a methodological fiction." Are the synapomorphies themselves methodological fictions even though they're not social constructs? Since synapomorphies are generally defined in terms of LCAs, I would expect them to be no less fictional. Peter Brown (talk) 17:38, 5 September 2013 (UTC) The traits as such are to be considered real their combination in a set of synapomorphies is in cladistics a methodological fiction: you pretend that there is a single species for the first time showing certain modifications, while it is likely these modifications were acquired by a range of species. However, a degree of fictionality has always been overt, as such a set clearly functions as an hypothesis.--MWAK (talk) 08:22, 6 September 2013 (UTC)

This article is lacking citations for many sentences and even paragraphs. Might threaten its status as FA. FunkMonk (talk) 11:18, 5 October 2013 (UTC)


Contents

The Elithian Alliance roleplay takes place several hundreds of years into the future. In the original roleplay, Earth was hit by a massive asteroid, and the Aegi are descendants of the humans who fled Earth. The remaining human population didn't survive for long after the asteroid's impact, and the human race had gone functionally extinct.

The ancestors of the Aegi fled Earth when humans were still very early in their exploration of space. In the THEA canon, those ancestors would have fled Earth maybe a hundred years from our current (in-real-life) time period. Space exploration would have been limited to the Solar System and possibly one or two nearby stars, but they had no knowledge of other intelligent life at that point.

In the THEA canon, Earth was hit with the full force of the asteroid's impact, and much of humanity was wiped out on impact. There were survivors, but these didn't last very long (the planet was cast into an impact winter and resources quickly dwindled) and within a few decades, all human life on Earth had been rendered extinct. The only survivors of the human species were those on board the two Exodus fleets, called the Endurance Company and the Voyager Company.

The Endurance Company was the fleet that had set course for the planet that would later be named Elithia. They arrived on an alien world much like Earth, and settled the planet. These humans eventually became known as the Aegi, which you see in the mod. They were given this name by the Dremeton, an alien species native to Elithia, as it translates to "friend" in the Dremetonian language. Contact with the Voyager Company was lost a few years into the interstellar journey, and no trace of that fleet has ever been found. They're not at the planet they were meant to colonize, and have been considered missing for centuries.

A few nuclear attacks may have happened, but there was no large-scale nuclear war. The asteroid impact threw so much dirt, dust and ash into the air that the entire planet got covered in thick clouds for several years, preventing sunlight from reaching the surface, and causing the death of many plants, then animals, and eventually humans. Most nations were too preoccupied with their own survival to fight large-scale wars with others.

They were genetically altered during the flight to Elithia, to prepare them for a potentially less hospitable planet.

The journey from Earth to Elithia doesn't have an exact timeframe right now, but it definitely took a few centuries. There was some use of cryosleep on the ships, but usually only for a few decades at a time - none of the original crews made it to Elithia, only their descendants (who were genetically modified into the modern-day Aegi) did.

Elithia turned out to be very close to Earth in terms of environments, but the enhancements were still extremely useful for surviving the years after the (crash)landing on Elithia, and for adjusting to the slightly higher gravity and somewhat altered air composition.

Internal sentiments, that was before they met any of the other races of the Alliance. They had only had some encounters with the still primitive Dremeton at that point, but there hadn't been any communication between the two species as they didn't yet understand each other.
The Aegi decided to change many of the old human traditions and habits as Terra had gotten pretty polluted by the time they arrived on Elithia, and with such a small group and a new planet, they were finally able to really start over and fix some of the mistakes of their ancestors.

The Alliance has thus far been able to prevent infighting. Excluding the wars with the Craton, who had signed the Elithian Code (the predecessor of the Alliance) and broke the agreements. No significant ones amongst the members of the Alliance, though there were small conflicts within some of the nations.

The Alliance started with the first interactions between the Aegi (who were still called humans back then) and the Dremeton (who are native to Elithia). At first, the two species had some conflicts, and the matter of how to deal with the Dremeton split the human faction in two. The cities of Creon and Lonro were built by the two human sides, and that original split is why the Union grew into a federation and not a single state. When the inhabitants of Creon finally started making progress on cooperating with the Dremeton, Lonro eventually joined with Creon again to form the Aeginian Federal Union. The Aegi and Dremeton later signed a common set of laws, the Elithian Code, which the Craton ended up signing too.
When the Craton eventually assaulted Aeginian and Dremetonian transport - breaking the code - the Aegi and Dremeton started working together even more closely, and thus the Elithian Alliance was born. They continued to engage in conflicts with the Craton, but eventually encountered other alien species (like the Hymid) and managed to secure friendly relations with them very early on.

There are plenty of well-known people throughout the Union's history. The Union is only a few hundred years old and hasn't been in many massive conflicts, so there hasn't been much time nor opportunity for legends to rise.


Two hundred and twenty-five million years ago — about the time the first dinosaurs arrived on the scene — the ancestors of the tuatara were roaming the world. Now, 65 million years after the last Tyrannosaurus bit the dust, tuatara are still here, little changed from their ancient predecessors. But how much longer can they survive on their remote island homes?

Hatching is Too gentle a word to describe the birth of a tuatara. Over a period of months, the soft-shelled tuatara egg absorbs moisture from the soil, swelling up like a balloon until it is a tight-skinned capsule. Then, us­ing its egg tooth — a sharp-pointed spike on the end of its snout — the baby tuatara punctures the shell, and its wet head literally explodes into view. Over the next few hours a se­ries of abrupt wriggling movements will free the hatchling from the egg that has been its home for the last 12 months.

Few people have observed the hatching of a tuatara, which usually occurs in a cool, dark nest about 15 centimetres below ground. But in May of this year, 30 tuatara eggs from North Brothers Island in Cook Strait were hatched in incubators at Wellington’s Victoria University, giving us the opportunity to observe closely an event that has been hap­pening for more than 200 million years.

Tuatara are the last surviving members of a lineage that stretches back to the Mesozoic — the begin­ning of the ‘Age of Reptiles’. Their ancestors witnessed not only the immense, terrifying diversity of the dinosaurs, but also geological up­heavals that shuffled the continents around the globe like jigsaw pieces. Perhaps they even watched from their burrows as the earth shuddered under the impact of a giant meteorite — a disaster some scientists think occurred about 65 million years ago and led to the extinction of the dino­saurs.

Somehow the `proto-tuatara’ sur­vived this cataclysm, hung on during the proliferation of birds and mam­mals, and eventually gave rise to the modern version, which survives only in New Zealand, and only just. Since humans arrived, about a thousand years ago. tuatara numbers have declined rapidly. They disappeared from the mainland a hundred years ago, and are now found only on a di­minishing number of offshore ref­uges.

The birth in captivity of 30 healthy tuatara may mark a turning point in the long history of the animal, for these juveniles are destined to re-colonise some of the islands from which tuatara have vanished. They are the culmination of a long-term research programme that we hope will turn the tide of fate in the tuatara’s favour, away from an ex­tinction that many have felt to be inevitable.

Tuatara have puzzled and fascinated scientists for more than a cen­tury. Since the late 1800s. naturalists have beaten a path to these shores to collect tuatara — sometimes hun­dreds at a time — for the world’s mu­seums. But studying pickled speci­mens doesn’t save a species, and the emphasis in tuatara research is now on their behaviour and ecology.

During the last five years, teams of biologists and conservationists, working together in a project organ­ised by Victoria University, have tried to answer basic questions about the tuatara’s reproductive biology, social behaviour and genetics. Such re­search is not easy. Access to the is­lands on which tuatara occur has long been restricted by both weather and New Zealand law. That tuatara are mainly nocturnal and have a life span that is longer than the normal scientific career does not make the job any simpler.

Besides rock-climbing skills, a good pair of sea-legs and the capacity to survive on dried foods for extended periods, all tuatara researchers re­quire one crucial skill: the ability to catch the subjects of their study.

Tuatara emerge at dusk from their burrows and spend most of the night near the burrow entrance, waiting for a tasty meal such as a large weta or lizard to wander within striking distance. Sometimes they forage away from the burrow, perhaps on sun-warmed rocks near the high tide mark, where lizards are also search­ing for a meal. If the tuatara is lucky, an unwary skink may soon become supper.

Spotlit by the beam of a torch, a tuatara will do one of two things: turn tail and scuttle down the near­est burrow, or freeze like a possum. Fortunately, most choose the second option. Then, cautiously, a quick grab around the neck, just behind the powerful jaws, and the capture is successful.

Some of us have learned the hard way that a moment’s carelessness act a painful price: a bite from teeth perfected over tens of millions of years for grasping prey securely, crushing it in powerful jaws and shearing it apart even as it struggles to escape. When a tuatara clamps its sharp teeth into your bare finger. the searing pain endures until the tua­tara finally decides to let go — which may be many minutes, because the tuatara has nothing if not patience (See box: its bite is worse than its bark.’)

Even if we avoid being bitten. tuatara can be very difficult to hold. Large males, the biggest as long as your arm and weighing over a kilo­gram, can put up a real fight, clawing and thrashing and grunting fiercely. Equally often, however, the tuatara is almost docile, displaying a stoicism that seems somehow appropriate to its antiquity.

While tuatara may be compara­tively fearless at night, they are se­cretive and extremely wary during the day-time. Perhaps it is because the danger from predators, especially harriers circling relentlessly above many islands, is greater during the day. As a consequence, they are diffi­cult to catch, and the risks are con­siderably higher. Tuatara seldom venture far from the burrow entrance during daylight hours. Usually, only the head is seen — especially if a ray of sunlight can warm it. But it’s nearly impossible to sneak up and grab the animal before it swiftly retreats to safety clown a burrow that may ex­tend five or more metres below ground.

Often, no tuatara at all can be seen during the day. Then, the only way to find, and possibly catch, one is to go in after it. Lying face down on the fine, bare, cold soil, you slowly reach your arm into the burrow, searching blindly and gingerly for the soft skin of a tuatara — and often hoping you find nothing at all!

The word tuatara means “spiny-back” in Maori. The spines, like the skin, are surprisingly soft, much like cool, dusty linen cloth to the touch, and pose no threat. If you are lucky, your hand lands on an exposed tail or leg or, best of all, the spines and hack. Then, you press the tuatara firmly to the ground, securing it until you get a grip strong enough to pull the reluctant reptile out of the bur­row. If unlucky, you find nothing, or you may just touch a tuatara as it retreats beyond your reach. Or, some­thing may grab you. Petrels and shear-waters often use the same burrows as tuatara, and some of them have strong bites if disturbed. Worse, large centi­pedes with painful, poisonous stings also share burrows with birds and tuatara on islands in the Hauraki Gulf and the Bay of Plenty. Or, a large tuatara may express its displeasure with a sharp, unrelenting bite.

Bitten or not, a visit to a tuatara island is the experience of a lifetime. Few people ever get the opportunity, though, because tuatara have been fully protected since 1895, and permits to land on their home turf are not given lightly.

But what astonishing places these islands are! Many, like Stephens Is­land in Cook Strait or Tawhiti Rahi and Aorangi Islands in the Poor Knights, rise straight up from the sea like stark, primeval fortresses. Cliffs a hundred metres high are topped with thick carpets of wind-shaped scrub: taupata, ngaio, or mahoe. In spring, the northern islands are red with flowering pohutukawa and, on a few islands, the glorious Poor Knights lily.

The surrounding seas are often turbulent, and landing a dinghy can be both difficult and dangerous on many of these islands there is no such thing as a beach. A research team of four to six people must be shuttled ashore, the dinghy stacked high above the gunwales with sup­plies. There’s no going back for for­gotten gear, so everything required for a week’s work has to be remem­bered and included: food, tents, per­sonal gear, scientific supplies, and plenty of torches and batteries, be­cause most work is done at night. Often, all our drinking water has to be taken with us, too.

Once ashore, several hours are spent drying out wave-swamped gear, pitching tents in tiny openings at the margin of the scrub, and pre­paring gear for the first night’s work. In daylight, tuatara islands often seem strangely quiet, with only a few parakeets or bellbirds for company, so the first few hours ashore are a peaceful interlude before the real work — and excitement — begins.

Signs of life are everywhere. The soil is usually bare from continual digging and trampling by birds and tuatara, and is riddled with burrows. But the scrub is thick, and we often have to crawl under or through the brittle, scratching branches. The combination of forest, soil and bird drop­pings gives the area a distinctive, pungent bouquet. Particularly ripe is the smell of a blue penguin nest, full of decaying faeces and the remnants of fish and squid regurgitated by the parents as food for the young.

As night approaches, there is an explosion of life. Most tuatara is­lands are free from mammals, and thus teem with birds, lizards, weta, and beetles. From August to Novem­ber, when seabirds return for breed­ing, the night-time cacophony of tens of thousands of these creatures cre­ates a wall of noise. Sleep is almost impossible, not only because of the din, but because petrels crash-land on your tent with monotonous — but nevertheless startling — regularity. Then, just as you manage to doze off with the approaching dawn, an army of aucous penguins marches past your tent on their way to the sea!

Walking around these islands at night can be unnerving, as some seabirds seem attracted to the head­lamps we wear for illumination. Every few steps a surprised bird bounces off an equally surprised scientist. On islands in the Hauraki Gulf, the beaches are alive with lizards, too — black Suter’s skink and the brown, velvety Duvaucel’s gecko, the largest surviving gecko in New Zealand. Under the low forest can­opy on several islands, giant weta prowl through the vegetation, care­ful to stay out of the way of tuatara.

Tuatara islands differ dramatically from the New Zealand that humans have created with their cities, high­ways, farms, orchards, exotic forests, rabbits and hedgehogs. The forests are silent because the birds that once teemed in them have been killed by rats, cats, and stoats the trees them­selves dying because of possums brought from Australia. To visit a tuatara island is to travel backwards in time for a thousand years, or a million, or ten million — to a time when most of New Zealand shared the extraordinary biological diver­sity now found only on those few offshore islands where introduced mammals are absent.

Some species are gone forever, of course: moa, sea eagles, the giant gecko. But on tuatara islands, life is super-abundant. Seabirds fertilise the soil with their droppings, producing the rich plant communities that in turn provide food for insects, lizards, forest birds, and, at the top of the food chain, tuatara.

On Stephens Island, in Cook Strait, the average tuatara weighs 400-500 grams, and in some places as many as 2000 tuatara share one hectare of forest — almost a tonne of tuatara per hectare. Even in poorer habitats, numbers are as high as 500 per hec­tare. Such numbers are possible only because the soil, enriched by the tens of thousands of fairy prions that re­turn to Stephens each year to breed, supports a diverse biological com­munity that tuatara see as an enormous buffet.

Anything that moves is fair game to a tuatara: earthworms, beetles, lizards (seven species on Stephens Island), frogs, weta, injured or juve­nile prions, and even, as our col­league Mary McIntyre discovered, young tuatara. Mary was studying hatchling and juvenile tuatara on Stephens Island. The behaviour and ecology of young tuatara have long been a mystery, because they are seen so infrequently, even on islands where adult numbers are high. To discover where the young hide, Mary taped small spools of cotton thread to the tails of a few juveniles and tied the ends of the threads to nearby plants. As the juvenile moved about, the thread unwound behind it, leav­ing a complete track of all its move­ments. Twice daily, she would begin at the tied end and follow each ani­mal, mapping its entire path, finally clipping off the unwound thread when she caught up to the young one, and starting the process over again.

Day after day, Mary followed ju­venile tuatara this way, showing that they sought shelter from the hot summer sun under small rocks in open areas, under thick clumps of grass, even under the leaves of thistles, and along the forest margin. Unexpectedly, however, they were most likely to move about in the daytime, despite the danger of over­heating or drying out.

The reason soon became appar­ent: “I followed the thread trail of a year-old tuatara that disappeared under a rock in the lighthouse keeper’s sheep pasture. Gently lift­ing the rock to find the juvenile, I was shocked to see the thread disap­pearing into the mouth of a large adult male along with the tip of the tail of the young on

Mary concluded that adult tuatara are probably an important predator of baby tuatara, which may explain why juveniles are most active in the daytime, seeking shelter at night when adults are foraging for food.

Studies of tuatara on Stephens Island began in earnest over 40 years ago. Bill Dawbin, then a lecturer at Victoria University specialising in whale biology, visited Stephens with an American herpetologist. Dawbin was captivated by what he saw, and returned repeatedly between 1949 and 1981 with teams of field workers who marked and measured hundreds of tuatara each trip. The capture and measurement of the same individu­als over a 30-year period allowed

Dawbin and others to confirm that tuatara are extremely slow growing, reaching reproductive maturity be­tween ages 10-15, continuing to grow until age 30, and living for at least 60­70 years. Other studies during the 1970s and early 1980s by Don New­man and Geoff Walls, both now with the Department of Conservation, provided important additional infor­mation about numbers, food, and territory size of tuatara on Stephens.

A new set of studies began in 1985, when Mike Thompson, a tall, gre­garious Australian, arrived at Victo­ria University. An expert in the nest­ing ecology and egg incubation of turtles, Mike quickly convinced us that similar knowledge for tuatara was essential for their preservation.

The first problem was finding tuatara nests. Previous reports of nesting were scarce, at best anec­dotes that required confirmation. Even the timing of nesting was un­certain. Don Newman had taken X-rays of tuatara, indicating that egg­shell formation occurred as early as September, but some females were obviously still carrying eggs as late as December. Mike began intensive searches for nesting females in Sep­tember 1985, continuing until the end of November. None was found.

The next year, Mike assembled a small army of volunteers (including one of us — Alison Cree) to conduct nightly patrols for nesting females on Stephens Island from September until December. Team members searched either for females digging burrows or for ‘scrapes’, evidence of such digging. For weeks, we followed numerous female tuatara daily, re­cording their every movement, but finding no evidence of nesting.

At last, in November 1986, the action we had long anticipated was discovered. Several females that had not moved more than a few metres from their home burrows since Sep­tember suddenly sprinted several hundred metres in a few nights, dis­appearing down cliff faces too steep for us to follow. Later that month, other nest sites were found, but in a surprising location. In the previous year, searches for nesting females had focused on the small patches of remnant forest on top of the island. In 1986, Mike established a search pattern that covered not only the forest areas, but also the expanses of pasture used for the past century by lighthouse keepers to raise sheep. (Most of Stephens Island was cleared of forest last century, making it the least natural of any tuatara island.)

On a warm night in November 1986, Mike stumbled on a nesting tuatara that was within sight of the front window of the field station. A rapid search revealed that females were nesting in rookeries all over the sheep pasture. Months of despon­dency changed to instant elation, and we immediately began marking the locations of all nest sites, using metre-high stakes topped with reflective tape. Lou Guillette, a visiting scien­tist from the University of Florida, couldn’t believe his eyes on arriving at Stephens a few days later: “The hillsides were transformed at night — the twinkling stakes in our head­lamp beams looked like a road con­struction site. I’d read that almost nothing was known about tuatara nesting, yet here it was happening en masse!”

It turns out that the nesting behav­iour of tuatara can be easily observed, once you know where to look. Apart from sea turtles that come ashore in large numbers to nest on sandy beaches, most reptiles are very secre­tive during egg-laying. Female tua­tara, however, have prolonged, highly visible and surprisingly active nest­ing behaviour. Mike Thompson de­scribes it: “They come to nesting areas from hundreds of metres away, spend several days or even weeks digging a shallow nest hole, and then lay about ten eggs in it. Once the eggs are laid, the female fills the nest hole with soil and grass, returning to it nightly for up to a week after laying. Females even appear to guard the nest, presumably from other females, who have been seen digging up other females’ nest holes to use for their own eggs.”

For the next three years, Mike and Alison returned monthly to check on the development of nests and to study the reproductive cycle of adult tua­tara. Some of the animals studied were, in fact, the same animals marked decades earlier by Bill Dawbin and his teams. Many had not grown in the intervening period and were probably at least 60-70 years old. Scientists of the future will check on the survival of these well-known animals. and when such studies are made, we may discover that a few of the biggest, oldest tuatara on Stephens Island watched Captain Cook sail by in 1769.

To hold a tuatara is to be forced, inevitably, to contemplate history. Not only the history of that individual, but the history of its ancestors in New Zealand and even before. when New Zealand was part of the ancient continent of Gond­wanaland. For tuatara are the great survivors in New Zealand. Their ancestors, the first sphenodontidans (a name meaning ‘wedge tooth’), shared virtually all continents with dino­saurs. They appear as fossils from North America, Europe, England and Africa, from 225 million years ago until about 120 million years ago. Most are smaller than tuatara, and they would not have threatened the reptilian giants with whom they shared the earth. They probably sur­vived in much the same way as to­day: by being nocturnal, or at least cautious and secretive.

But eventually, like the dinosaurs, they, too, became extinct. Every­where except in New Zealand, that is. About 80 million years ago New Zealand broke free from Gondwana­land, not long before the last of the dinosaurs disappeared. Mammals then began their spectacular evolu­tionary rise, dominating all conti­nents except Antarctica ever since.

For reasons unknown, the sample of animals stranded on New Zealand as it drifted northward through the Pacific, away from Antarctica and Australia, differed (or came to differ) from those that survived or prospered on the other southern continents. Most importantly, no terrestrial mammals survived in New Zealand. Nor did land snakes or tortoises. But the ancestors of tuatara did, and in the absence of mammals they thrived. Bones of tuatara from coastal dunes show that tuatara were abundant throughout the North and South Is­lands until the arrival of humans.

New Zealand is famous for its giant extinct birds, but research in the past decade shows that pre-human New Zealand was as much the land of reptiles as of birds. Most spectacular was the giant gecko, Hoplodactylus delcourti, as large as a possum and possibly the taniwha of Maori legend. (See Geonews.)This animal may have stalked the forests of New Zealand and been an impor­tant predator of birds and reptiles. The rich lizard faunas of many off­shore islands and a few mainland locations show that lizards can be extraordinarily abundant. In some sites today, numbers are as high as 4000 per hectare, even with mam­malian predators. They could have been even higher a millennium ago.

Even native frogs have been under­estimated in importance. Now, only three small species survive, almost exclusively in the North Island, and two of these are extremely rare. But a thousand years ago, twice as many species of native frogs occurred throughout the country, and one of these was the size of a bull frog.

So, when the first Polynesians stepped ashore in New Zealand a thousand years ago, they would have confronted a relict fauna from the Age of Reptiles. Their first meal of New Zealand food was as likely to have been tuatara as birds or shell­fish. And from then until today, the effects of humans and their mam­malian followers — rats, dogs, pigs, goats, cats, stoats — were as disas­trous for reptiles as for birds, frogs, wetas, and virtually all other ancient New Zealanders.

But the tuatara has survived. Just as the ancestors of tuatara escaped extinction through the good fortune of finding a last refuge in New Zea­land — that “ultimate storehouse for discontinued zoological models,” as Time magazine put it — so the tua­tara itself has survived by finding refuge on a few coastal islands, some barely the size of a tennis court.

During hundreds of years of Maori occupation of New Zealand, tuatara numbers probably declined steadily, but when Europeans arrived, tuatara were still found on both main is­lands. (None has ever been known from Stewart Island.) Maori hunting seabirds must have known tuatara all too well— a hand thrust down a bird burrow in search of a meal might frequently have been withdrawn with a tuatara attached instead. The Maori had many names for the spe­cies, including ruatara, tuatete, and narara or ngarara, in addition to tua­tara. And while it may have been an important food item for some tribes, the tuatara, like the lizard, was re­garded with respect, as an embodi­ment of supernatural powers, some­times evil.

No member of Captain Cook’s expeditions records having seen tuatara, although during Cook’s third expedition two Maori boys described “a monstrous animal of the lizard kind” that may have been a reference to it. Early Europeans called them `guana’, ‘the great fringed lizard’, and ‘the tuatara lizard’. It was a full 50 years after Captain Cook’s first land­ing before the species came to the attention of European scientists. Even then, it was another half cen­tury before its full scientific impor­tance as a ‘living fossil’ was appreci­ated. Since recognition of its impor­tance in 1867, the tuatara has been the subject of at least 1500 scientific papers.

Nonetheless, much remains to be learned about tuatara, especially its requirements for survival. On only seven islands are tuatara populations reasonably secure (See ‘The fight for survival.’) As with many other New Zealand species that now survive only on offshore islands, the tuatara’s future may be precarious for many decades. But we are betting that tua­tara pull through, just as they have for tens of millions of years. Fortu­nately, the respect, perhaps awe, which the later Maori accorded tua­tara is shared by increasing numbers of modern New Zealanders, what­ever their origins. Even more respect, combined with vigilant conservation care, is required to ensure that the tuatara has a chance for a future as long as its past.

Its bite is worse than its bark

It was 2.00 am and bitterly cold as I struggled up the steep Stephens Island hillside on my last hunt for tuatara that night. I spied one in the beam of my torch, sitting motionless in the wet grass. Tired, I bent down to catch it, carefully spreading my fingers to grasp it around the neck and subdue the powerful jaws. But not carefully enough. I groaned as its head turned quickly and its teeth clamped, as securely as a vice, on to my finger. A sharp pain shot up my arm. Tuatara do almost every­thing slowly, but they bite quickly, and they don’t let go.

Teeth are one of the features that distinguish tuatara from lizards, which they otherwise resemble. Tuatara have a single row of teeth in the lower jaw, and two upper rows: one on the jaw and one on the palate. The bottom row fits between the two top rows, and moves forward. like shears, when the mouth has closed on prey. The grip is so strong that the jaws cannot be prised open. No lizard has this arrangement of shearing teeth.

As the pain in my finger in­creased, I began to feel sorry for weta, and for seabirds that are decapitated by hungry tuatara. Sitting on the ground, I was also getting colder and colder and began to imagine the newspaper headlines: ‘Frozen scientist killed by tuatara.’

After about 15 minutes that seemed like a month, the tuatara suddenly relaxed its grip. I slowly pulled free and, cradling my throbbing finger, returned to the field quarters and the inevi­table laughter of my compan­ions. A day later, the only signs of the bite were a few tiny teeth marks and a deep bruise that lasted several weeks. My pain, though, seemed small compared with the terror that must have seized a male colleague who had a tuatara run up his trouser leg. Fortunately, the adventur­ous reptile was subdued before causing any major harm.

When is a 'lizard' not a lizard?

Scientists have known for over a century that tuatara are special in the world of reptiles. In 1867, Dr Albert Gunther of the British Museum described the anatomical features that dis­tinguish them from lizards, which they superficially re­semble. These include extra holes in the skull, bony proc­esses on the ribs and the lack of a copulatory organ in males. Gunther classified tuatara in their own group, the Rhyn­chocephalia, or ‘beak-heads’. The order is now called the Sphenodontida, and has no other living representatives ­the only other sphenodontidans are fossils.

This group has a lengthy evo­lutionary history, beginning at least 225 million years ago. In contrast, humans have existed for less than three million years, just over one per cent of the duration of the sphenodontidan lineage.

Tuatara have thus earned the title ‘living fossil’, which is given to only a very few species, such as the famous coelacanth fish, the horseshoe crab, and the native frogs of New Zealand ­species that have apparently changed little from extraordinarily ancient origins. But if this term implies that they are un­changed relicts that are doomed to extinction, then it is wrong. Tuatara are highly specialised, unique in many aspects of their biology, and well suited to the sometimes hostile New Zealand environment. Perhaps these characteristics make the tuatara a prime candidate for our national symbol.

Life in the slow lane

No one ever won a ‘who blinked first?’ contest with tuatara.

This is a creature for whom slow motion is a way of life — a conclusion most people arrive at spontaneously as they stare at a tuatara through the glass port­hole of a zoo enclosure. If it weren’t for an occasional, al­most imperceptible throat move­ment, the specimen they are looking at could almost be a stuffed trophy.

Behind the tuatara’s penchant for a leisurely life lies a funda­mental truth about reptiles: they are cold-blooded, and life ticks over slowly at cold tempera­tures. If ever a creature could be described as cold-blooded, the tuatara is it. On islands in Cook Strait, average monthly air tem­peratures range from a tropical 16°C in summer to a bracing 9°C in winter. Combine this with the wind-chill factor produced by 40-knot southerly winds which regularly rake Cook Strait and you can quickly end up at -20°C. Wrapped up like mum­mies in parkas, over-trousers and balaclavas, we often wonder who are the crazier: we for being out in conditions like this, or the animals we are studying.

Tuatara are most active at night, thereby choosing the coolest parts of an already cool climate. Admittedly, activity is greatest on ‘warm’ nights (12 ­18°C), but even at temperatures as low as 6°C, a few large males can be seen sluggishly guarding the entrance to their burrows.

‘Cold-blooded’ is actually a misnomer, as the temperature of a reptile’s blood fluctuates with the temperature of its immediate environment. Many lizards live in deserts where their blood temperature rises as high as 45°C. Such species often cannot be found below temperatures of 20°C, because they have hidden to await warmer, more congenial conditions.

Everything about a reptile speeds up or slows down ac­cording to temperature. Over winter, tuatara can survive for up to six months without feeding, and their oxygen re­quirements are equally low. In 1924 a scientist observed a tuatara closely for one hour at 9°C, and it didn’t breathe once!

Warm temperatures actually present a problem to tuatara. If the body temperature exceeds 30°C — still a cool temperature for a desert reptile — adult tuatara die within a few hours. Their heartbeat (usually a sedate nine or ten beats per minute) speeds up to 100 beats per minute at such temperatures ­double the rate of a lizard under similar conditions.

Given the tuatara’s preference for cool conditions, it is not sur­prising that reproduction in tua­tara is enormously slow in com­parison with most other ani­mals. The process of egg forma­tion, for example, takes a female four years to complete — some­times more — and is longer than in any other reptile.

Every year, around January and February, males establish territories and begin their courtship display. Typically, a territory will be an area of about 25 square metres, with the male’s residence burrow near the centre. A territorial male emerges at dusk and sits for much of the night near the entrance to his residence bur­row, head up, ‘advertising’ his possession of the territory. Levels of his sex hormone, testosterone, are high, and he be­comes more aggressive in ap­pearance and behaviour. He puffs out his cheeks and holds the spiny crests on his neck and back fully erect, increasing the intensity of display. Should an­other male violate territorial boundaries, the resident attacks the intruder. Scars from vicious bites are visible on most older males, and many have jaw inju­ries and regrown tails, possibly from fighting.

Females lay a clutch of eggs only about once every four years, but males can mate annually. Because the number of males is similar to that of females on an island, in most years the number of males capable of mating far exceeds that of females. Courtship begins when a female ap­proaches a displaying male. He slowly circles her in a stiff-legged walk. At any time she may lose interest and run away, but if not, copulation ensues. Male tuatara lack the evertible genital organs found in other reptiles, so sperm transfer depends on close contact of the vents of the male and female. Copulation lasts up to an hour and ends when the female struggles to escape.

Within a month of mating the large, yolky eggs, that have re­quired, on average, just over three years to produce, burst out of the ovary and pass into the oviduct, where they are fertil­ised. Over the next seven months, from about April to No­vember, a shell is slowly depos­ited around the fertilised egg.

Around mid-November, fe­males gather in open, sunny areas to nest. Warm soil tem­peratures are probably impor­tant, as eggs placed by research­ers in canopied forest, where soil temperatures are lower than in exposed areas, develop slowly for a while but never hatch.

Nesting females have no re­spect for another female’s nest. Not infrequently, a female exca­vates a recently completed, but unguarded, nest for her own use, with fatal results for its eggs. We have seen the heart­breaking result many times ­eggs lying scattered and some­times broken on the ground, where they will invariably die.

Surviving eggs hatch in sum­mer after 11-16 months of incu­bation. During incubation, the egg absorbs moisture from the ground and swells. When it is ready to leave the egg, the young tuatara ruptures the shell using a special ‘egg tooth’ on the tip of its nose. It gradually corkscrews its way through the soil to the surface, where it confronts many dangers, especially drying out, overheating and predators, including possibly its own par­ents. Hatchlings reach sexual maturity only after another 10 or more years, but the rewards are great: they may continue repro­ducing for at least 50 years, and probably more.

The fight for survival

Until about a thousand years ago, tuatara existed in great numbers throughout the two largest islands of New Zealand and on many offshore islands. But fires, land clearing, and predation by humans, rats, cats, pigs, and dogs extermi­nated tuatara from land they had occupied for 80 million or more years. As early as 1877, scientists were noting their absence. “Tuatara … [are] now only found on the off-shore islets, the pigs having eaten them on the main-land,” wrote A.K.Newman.

Dr Gunther, of the British Museum, went further: “Nar­rowly restricted in its distribu­tion, exposed to easy capture by its sluggish habits, esteemed as food by the natives, pursued by pigs, it is one of the rarest objects in zoological and ana­tomical collections, and may one day be enumerated among the forms which have become extinct within the memory of man.”

Naturalists themselves may well have had a hand in the decline of tuatara. Sir Walter Buller noted in 1894 that the tuatara “has been exposed to the persecution of travelling natu­ral-biology collectors, one of whom is said to have forwarded at one time to Europe no less than three hundred specimens preserved in spirits.”

Apart from a few captive populations in zoos, tuatara are known to survive on only about 30 offshore islands. On one of these, Little Barrier, tuatara have not been seen in several years, and may already be extinct.

At least nine populations, all on offshore islands, have be­come extinct this century. Most of these are linked with the in­troduction of rats. Norway and ship rats probably eat both adult and young tuatara, and no tuatara survive on islands with these species. The most recent confirmed extinction occurred between 1981 and 1984, when Norway rats found their way to Whenuakura Island, off the coast of Whangamata. This island of only two hectares had been home to some 200 tuatara, but in just three years all tuatara disappeared.

The kiore, or Polynesian rat, was introduced to mainland New Zealand and many offshore islands by the Maori for use as food. Although direct evidence is limited, kiore probably include eggs and juvenile tuatara in their diet, but do not eat adult tuatara. At least one tuatara population — on East Island, off East Cape — has become extinct in the presence of kiore. What makes this ex­tinction all the more upsetting is that this population seems to have been different from most others: in 1878 Sir Walter Buller described the tuatara there as unusually stocky and bright olive-green in colour, and for a while considered the possibility of naming them as a new spe­cies.

The nesting behaviour of tua­tara is a dead give-away to an omnivorous animal like a rat. By aggregating at nesting areas and remaining there for days while digging the nest, laying eggs and guarding the completed nest, female tuatara are providing a rat with every possible clue to the site of a feast of tuatara eggs. And even if a few eggs manage to hatch, kiore are there to snap up the hatchlings.

At least seven and possibly eight tuatara populations still survive in the presence of kiore, but the future for some of these looks grim unless kiore are eradicated.

On Stanley Island, in the Mercury Islands group, off the coast of Whitianga, only 18 tuatara have been found during repeated searches in the past two years. This island is about 100 hectares in size and must once have been home to thou­sands of tuatara. It has a luxuri­ant canopy of bush, and looks to be an ideal habitat, but the only survivors are large adults, old and battle-scarred. Introduced rabbits on the island make matters worse: rabbits eat the vegetation on which insects live, reducing the abundance of food available to tuatara. On Red Mercury and Cuvier Island tuatara numbers appear to be as depleted as on Stanley.

Of the 22 rat-free tuatara is­lands, 15 are smaller than ten hectares. Some of these have tuatara populations numbering many hundreds, but the small­est islands (some less than a hectare) have populations that probably do not exceed a few dozen. The geological future of the tiniest islands is very short: in a few thousand years they may have crumbled into the sea.

Only seven tuatara islands are larger than ten hectares and free of rats. By far the largest population occurs on Stephens Island in western Cook Strait, where at least 30,000 tuatara (possibly several times that!) share the 150 hectare island with lizards, a tiny population of native frog, giant wetas, a giant weevil and tens of thou­sands of seabirds, mostly fairy prions.

While extinction of tuatara on mainland New Zealand is un­doubtedly due to human activ­ity, Stephens Island shows that humans can be quite compatible with tuatara. The enormous tua­tara population on Stephens Is­land seems to be the result of removal of much of the forest cover and conversion of the is­land to a sheep farm during the past century. The limiting factor for tuatara on many unmodified islands may be nest sites. The soil under a forest canopy is simply too cold for eggs to develop sufficiently to hatch.

Open sheep pastures, however, provide abundant nesting sites for tuatara, although undoubt­edly many nests and hatchlings were trampled by stock. Num­bers of tuatara on Stephens have probably increased dramatically during the past century as a result of increased nesting space.

Removal of predators from the island probably helped numbers too. Early this century, a government bounty was placed on harriers, and hun­dreds were claimed from Stephens Island. Domestic cats. released at the time of light­house construction, soon posed a threat to tuatara (as well as eliminating other species alto­gether). Lighthouse keepers earned a princely £13 by killing 511 cats on the island.

Last year the lighthouse on Stephens was automated, and the Department of Conservation is planning to allow much of the sheep pasture to revegetate. The result is likely to be far fewer nest sites for tuatara. Thus, over several centuries — because of the long lifespan of tuatara ­numbers on Stephens Island may decline to match those on other, less modified islands. Even so, Stephens should remain home to thousands of these ancient reptiles.


CT scans reveal that dinosaurs were airheads

(PhysOrg.com) -- Paleontologists have long known that dinosaurs had tiny brains, but they had no idea the beasts were such airheads.

A new study by Ohio University researchers Lawrence Witmer and Ryan Ridgely found that dinosaurs had more air cavities in their heads than expected. By using CT scans, the scientists were able to develop 3-D images of the dinosaur skulls that show a clearer picture of the physiology of the airways.

"I've been looking at sinuses for a long time, and indeed people would kid me about studying nothing—looking at the empty spaces in the skull. But what's emerged is that these air spaces have certain properties and functions," said Witmer, Chang Professor of Paleontology in Ohio University's College of Osteopathic Medicine.

Witmer and Ridgely examined skulls from two predators, Tyrannosaurus rex and Majungasaurus, and two ankylosaurian dinosaurs, Panoplosaurus and Euoplocephalus, both plant eaters with armored bodies and short snouts. For comparison, the scientists also studied scans of crocodiles and ostriches, which are modern day relatives of dinosaurs, as well as humans.

The analysis of the predatory dinosaurs revealed large olfactory areas, an arching airway that went from the nostrils to the throat, and many sinuses—the same cavities that give us sinus headaches. Overall, the amount of air space was much greater than the brain cavity.

The CT scans also allowed Witmer and Ridgely to calculate the volume of the bone, air space, muscle and other soft tissues to make an accurate estimate of how much these heads weighed when the animals were alive. A fully fleshed-out T. rex head, for example, weighed more than 1,100 pounds.

"That's more than the combined weight of the whole starting lineup of the Cleveland Cavaliers," Witmer said.

Witmer suggests that the air spaces helped lighten the load of the head, making it about 18 percent lighter than it would have been without all the air. That savings in weight could have allowed the predators to put on more bone-crushing muscle or even to take larger prey.

These sinus cavities also may have played a biomechanical role by making the bones hollow, similar to the hollow beams used in construction — both are incredibly strong but don't weigh as much their solid counterparts. A light but strong skull enabled these predators to move their heads more quickly and helped them hold their large heads up on cantilevered necks, explained Witmer, who published the findings in a recent issue of The Anatomical Record.

Though most researchers have assumed that the nasal passages in armored dinosaurs would mimic the simple airways of the predators, Witmer and Ridgely found that these spaces actually were convoluted and complex. The passages were twisted and corkscrewed in the beasts' snouts and didn't funnel directly to the lungs or air pockets.

"Not only do these guys have nasal cavities like crazy straws, they also have highly vascular snouts. The nasal passages run right next to large blood vessels, and so there's the potential for heat transfer. As the animal breathes in, the air passed over the moist surfaces and cooled the blood, and the blood simultaneously warmed the inspired air," said Witmer, whose research is funded by the National Science Foundation. "These are the same kinds of physiological mechanisms we find all the time in warm-blooded animals today."

These twisty nasal passages also acted as resonating chambers that affected how the ankylosaurs vocalized. The complex airways would have been somewhat different in each animal and might have given the dinosaurs subtle differences in their voices.

"It's possible that these armored dinosaurs could recognize individuals based on the voice," said Witmer, who noted that his research team's studies of the inner ear revealed a hearing organ that probably had the capability to discriminate these subtle vocal nuances.

Though Witmer found few similarities between the dinosaur and human sinuses — our brain cavities take up much more space relative to our sinuses — the scientist did find a resemblance between the air spaces of the crocodiles and ostriches and the ancient beasts under study.

"Extra air space turns out to be a family characteristic," he said, "but the sinuses may be performing different roles in different species. Scientists have tended to focus on things such as bones and muscle, and ignored these air spaces. If we're going to decipher the mysteries of these extinct animals, maybe we need to figure out just why it is that these guys were such airheads."


12 Answers 12

I think it would boost 'intelligence' but as people have stated, it's a hard to define concept.. they might be just as easy to fool but have really vivid imaginations, they might be inclined to meditate extensively, drifting off into another world, forgetting the real one.. they might have immense reasoning facility's but lack the focus to get anything done, being constantly bombarded with mental stimulus..

How about super clever but driven mad with the lack of reletivly deep environmental stimulus.

If your universe has magic then they'd probably get psy powers, a deep gaze that unnerves people but becomes softer an wiser with age..

IMO, a large variety of extremes.. ranging from total madness to sentient supreme.

The brain is very complex part of our anatomy and scientists still struggle very much to fully understand it.

One thing that is for sure is that there is a correlation between brain size and intelligence because we (mammals) have the hippocampus and hypothalamus and what not unlike reptilians who only have a triune brain.

So adding more volume and parts to the brain CAN have a positive impact on intelligence but will it necessarily ?

Whales and elephants have much bigger brains than humans, and we have about the same brain-to-body mass ratio as mice. source

But whales have not yet mastered nuclear fission and harnessed its power to possibly blow up entire countries now, did they ? (Humans 1 - Whales 0)

Since it would be against human nature to admit defeat, scientists have crafted a third measure of brain size called the encephalization quotient, which is the ratio of actual brain mass relative to the predicted brain mass for an animal’s size (based off the assumption that larger animals require slightly less brain matter relative to their size compared to very small animals)

Some studies claim the answer is yes.

Long story short, it is not impossible but we honestly have no clue.

If anything, your super-sized humans could be super slow to react because the impulse speed inside a neuron scales with size up to maximum cap and making super-sized humans will extend the distance they have to travel through neurons and nerves.

I do not know the threshold size at which speed caps but I do know that very large dinosaurs like the diplodocus were in that case. If you don't make your super-sized humans that big it shouldn't be a problem but you went for 20ft tall which is 6 meters tall and funnily matches the height of a diplodocus. Hopefully you did not also make your soldiers 25 meters long as well but keep in mind that they should be in that zone where impulse speed is capped and they are slower to react. (Making them pretty bad soldiers actually)

They could be intelligent or maybe not but they will be very slow to react and think if you make them too big.

what can the scientist do in order to meet the required (evil genius) level of intelligence ?

Train them from birth like any dictatorship. You take the babies from their parents and put them in a facility where they are taught to follow whatever orders the dictator gives.

Have them be taught science by the best scientists, trained by the best military.

Add a bit of gene selection or if you don't have that kind of technology make the tests deadly so environmental pressure will select the best soldiers for you.

The answer here really depends on exactly how the soldiers have been supersized. By that, I mean that there would be vastly different consequences if the cells themselves were supersized, or if it was on the level of the tissues.

As has been pointed out above, neurons reach a certain size cap at which they start to drop off in efficiency due to the distance between synapses (interestingly enough this same principle of maximum size efficiency applies to all of your cells. They become less effective at eliminating waste due to a decrease of surface area relative to volume)

Intelligence, as difficult as it may be to define, has been strongly correlated not with encephalization quotient, but rather with neuronal density. Humans have been noted to have a much higher density of neurons and synapses relative to brain size. Other advanced species have also ranked high on the curve.

In summary, if the cells themselves got bigger, your soldiers are broken. If the tissues have adapted to the new size by increasing in density and connectivity, there could reasonably be some expectation of a greater potential for intelligence.

There's a very rough estimate of "intelligence" (an already quite fuzzy concept) via "encephalization quotient" (quotient between brain mass and average body mass), but it's not universally accepted and I'm very unsure if it would apply to OGM soldiers.

Truth is we only have a vague idea of what is considered "intelligence" and where it resides.

Experts tend to divide different "components" of what we commonly refer as intelligence and stress fact they seem unrelated but synergic (which looks like an oxymoron, but isn't).

Reasoning behind the "encephalization quotient" is a large part of brain is used for "normal maintenance" and generic body control (simple acts as walking require a lot of precise regulations of almost all muscles we own integrated with continuous feedback of literally billions of sensors) and the larger the body (we speak about lean mass, a fat person does not became more stupid) the more "objects" you need to monitor and control only the "excess brain mass" may contribute to "exotic" functions like language for humans or sonar for dolphins.

Bottom line: without specific interventions your "super-soldiers" would be about as intelligent as the next man or fractionally brighter.

Truth is current neuroscience is still unable to pinpoint (in a scientific way) what and where is what makes us "intelligent", so it's difficult to say what would increase it. Actually doing such a thing is yet another level again.

Question why a dictator would want super-intelligent soldiers who would more easily see through propaganda and refuse to become cannon fodder is, of course, another matter.

No, I don't think they'll be super-intelligent. I think the key is in your question. You say your scientist has

developed a way of extending the natural growth of humans

Not using a growing/shrinking ray or anything exotic I don't think you have to worry about cells being too big to function, so I think this would result in big people with normal sized cells (FYI, all animals have similar sized cells). So they'd just have more brain cells, so they'd at least have the potential to be smarter or remember more, but I suspect they'd be relatively normal, but big people.

Looking at real animals that are different sizes, like horses that can range from Miniature to Clydesdales (about double height & maybe 4x mass)

or felines like tigers & cats

I think they all behave generally like their bigger/smaller counterparts, a little cat & a big cat are generally "cats", and the same for horses.

So, again I think you'll just end up with fairly normal, big people.

But, since it takes normal people about 18yrs to grow up, extending their natural growth could take an extra 18 or 36 more years too, unless it's specifically accelerated growth. Or it could result in a condition where growth just doesn't stop, like Acromegaly like Andre the Giant had
He was definitely a big guy, and I think he was of average intelligence. So once again, I think you'll just have average "big people.

Actually, that's probably a relatively easy way to make "big people":

Acromegaly is typically due to the pituitary gland producing too much growth hormone. In more than 95% of cases the excess production is due to a benign tumor, known as a pituitary adenoma.

I'd imagine creating tumors would be right in a mad scientist's wheelhouse, not much genetic engineering required either, maybe even an artificial or surgically implanted "tumor" might work. Though it has definite disadvantages, including heart & kidney failure.

Note: This was a really fun question to answer, Big +1 to the OP. Getting to read about animal cells, big & tiny cats & horses, and Andre the Giant, with pictures of a tiger & a cat, and Andre the Giant is awesome! Even guessing how to "make" giants too with relatively "discount bin mad science surgery" is cool

Short answer: No

Long answer: As far as we know there is no linear correlation between volume or surface area of the brain and intelligence.

As far as we know there is no linear correlation between volume or surface area of the brain and intelligence in animals, and in humans the correlation, albeit statistically significant, is very weak. As always, correlation != causation, and certainly one shouldn't extrapolate linear correlations (interpolation is fine). I strongly encourage OP to read at least the section 4 of the second publication the @BlindKungFuMaster linked in the comments ( the 2015 Pietschnig et al in Neuroscience and Biobehavioral Reviews ).

A counterexample I wanted to present is homo neandertalensis. If the size of the brain directly, LINEARLY correlated with greater intelligence, homo neanderthalensis would be smarter than us and it is we who would've gone extinct. Check Wikipedia's Homo Neanderthalensis article as first shot.

CAVEAT: As commentators correctly point out, the matters of evolution of Homo in general, and Homo Neanderthalensis extinction in particular, are complicated and far from being resolved. It may be worth to underscore that I meant that there is no LINEAR CORRELATION (which you question seems to implicitly assume), and only that.

Arguably, there probably IS some minimum volume/mass required to reach sentience, seeing as we don't see mosquitos evolving civilisation every now and then, but this probably in turn depends on how effective a given tissue is effective at computation. People tend to forget that not only we have large heads, it's also that our neurons are generally better - well, actually their expensive myelin coating.

So what can a scientist do? Well, this is a realm of very nebulous speculations. Intelligence is not a single scalar variable like height or body mass or bicep's strenght and in fact we have little clue on how it actually works. My favourite hypothesis essentially states that we have a generator of random thoughts in our heads which are then filtered and the ones which pass the filter are what actually occurs to our consciousness. The trick is, the generator is not completely random, it is skewed toward generating thoughts similar to the ones which had passed the test in the past and also the filtering is far from perfect and it is constantly recalibrated by our experiences of the outside world.

That being said, if You want to build more intelligent people, You could assume this hypothesis is true and use the additional cranial space their thoughts generator a lot more computing power to say, generate 10 thoughts per milisecond instead of 1, up the connection the generator has to the filter and then upgrade the filter two times, one time to handle all those additional input (otherwise the consciousness would be flooded by random noise) and also to use better tests to make the filter better - more logical, consistent and 'creative' (the last one in the sense better at letting through a seemingly crazy thoughts which nevertheless hold promise - genius and madness are differentiated by the quality of the filter).

I'm far from being an expert on intelligence and neurobiology, I advise You STRONGLY to read more about the topic, it is MUCH more complicated than people realise - and consequently so much more interesting and rewarding :)

Most likely not. Like our own transistors in real life, Human neurons have already evolved to the very edge of being as small as they can be and still function without being overwhelmed by electrical noise (noise causes errors) and evolution preserves this tiny size (and myelin coating) for the same reason we prefer tiny transistors: It makes communications between parts faster, getting more done in less time.

If everything in the giants is multiplied by 3, their brains internal communications would run 3 times slower than that of a normal human making them very slow dullards.

If their neurons are small like ours, they still have this problem: Without a complete brain reorganization, they will inevitably have communications between remote parts of the brain that take 3 times what our communication takes. On top of that, their neural signals to muscles will take three times as long to reach the muscles making reaction times slower, and inputs (ears, eyes, touch) will take three times as long to reach their neural centers, also contributing to making reaction times much slower.

Also, most of their larger brain will be taken up by having to process a much larger volume of body, skin sensors (pain, cold, warmth, pressure) and other operations there is a strong correlation between brain size and body size for that reason.

Finally, you need some working definition of what super-intelligent means. Borrowing from the artificial intelligence field one such working definition would be what most of us think of as a generalization of Sherlock Holmes type abilities, when investigating crimes. To solve crimes, Sherlock typically spots tiny obscure clues and translates them into what must have happened: In one case, the Dog that Didn't Bark, he deduces that because a dog did NOT bark at whomever committed a crime, the dog must have known the perpetrator, which with other clues narrowed the list of suspects to one.

Similarly, intelligence is the ability to solve puzzles, extrapolate from clues, and arrive at theories or models of reality that have a high probability of being correct. This includes "prediction" about the past and present, not just the future: Geologists study patterns in rocks and deduce what must have happened (volcanoes, earthquakes, floods). Astronomers study patterns in the light of stars and deduce supernova must have happened hundreds of millions of years ago. Archaeologists study patterns of fossils to deduce what must have gone on hundreds of millions of years ago, here. We have patterns that let us deduce what must be happening now: a column of smoke indicates a probable fire, even if we do not sense any fire directly. We have patterns to deduce what will happen in the weather tomorrow, in politics next month, in our health, in our economy, in our sciences.

As a working definition of higher intelligence, we can measure it as better pattern interpretation with a higher probability of being correct when deducing what most likely happened, is happening or will happen. So better deductions, or being better at finding obscure patterns that are useful in such deductions, or have meaning.

"Meaning" is about ramifications or constraints when somebody says "Do you know what this means?", they are saying they have identified a pattern that will most likely have specific consequences in the future, which may be good or bad, but are in their mind are highly likely. "Meaning" is about a distinct difference e.g. if I want my work to have "meaning" it should mean the world is different (and presumably better) because I did that work, it had impact I consider positive, etc. If somebody says something is "meaningless", they consider it to have no impact and create no difference in any outcomes they care about. (of course due to butterfly effects everything can make some difference in the future, but in human terms "meaningless" and "makes no difference" are talking about the same idea "meaning" and "made a difference" are the flip sides.)

Back to your story: It is not clear that neural mechanisms can get much better than the best of what we have now. For soldiers, that is not likely to be a good outcome: If they are more intelligent than their creator, they are unlikely to take orders from their creator for very long, and are likely to outsmart their creator's attempts to control them, control him instead, and implement their own agenda rather quickly and effectively: That is what greater intelligence means: Better anticipation of outcomes and reactions, better predictions of what strategies will work, and thus fewer mistakes and greater successes.

When we build a trap and bait it we are anticipating the behavior and reactions of an animal, and the animal's lower intelligence is failing to anticipate that taking the bait will have various consequences (mechanical for a trap, or biological in the case of spiked bait). It is our ability to see correctly predict what will happen (and because of that ability, devise a way to make something happen) that costs the animal its life and produces our dinner.

If your giants truly are far more intelligent than ordinary humans and can predict outcomes with 3 times the accuracy of humans, then your "genius creator" will be no match for them like a monkey charging a man with a shotgun.


The First Dinosaur was Named What now?

The first scientific name attributed to a dinosaur is, technically, Scrotum.

No, you did not read that wrong.

The year is 1677. Western civilization, while far more advanced than in the centuries prior, is still rather clueless in terms of general scientific knowledge. Over half the population was illiterate and basic biological concepts such as evolution and extinction would not be theorized until over a century later. What little understanding people did have of the world came from the Catholic Church, whose teachings, which included that the world was only a few thousand years old and that the earth was the center of the universe, were… shall we say dated. Most importantly, nobody knew what a Dinosaur was – nor would they for the next 165 odd years.

So, when massive bones were unearthed across the globe, humanity had no idea what to make of them. Some societies crafted myths and legends to make sense of these oddities, such as Chinese dragons or the Greek Cyclops (perhaps inspired by dwarf elephant skulls). Others used pre-existing myths to explain these fossils the idea that the bones belonged to Biblical giants was an ever-popular theory in Christian Europe. Recollections of “giant bones” appear in medieval literature with some regularity, albeit with unclear descriptions and no illustrations that have left paleontologists clueless as to what animals the remains could have belonged to.

This lack of adequate depiction changed in 1677 with Robert Plot’s book The Natural History of Oxfordshire. While the book focused on the flora and fauna of the Oxfordshire county of central England, there are a few exceptions – most notably the description and illustration of a massive, fossilized thighbone. The size of the bone led Plot to two conclusions. First, he theorized that the bone had belonged to an elephant, specifically one utilized by the Roman armies in their conquests of England. His other guess was that it was another one of those pesky old giant bones, straight out of the Old Testament. In the end, Plot favoured the giant bone theory and included it within the book alongside the first illustration of a dinosaur.

Unfortunately for the fossil, its shape is rather… unconventional. More than half the bone is missing, with only the lower extremity (joint) of the femur being present. For those unfamiliar with anatomy, the lower end of the femur ends in two circular structures, the lateral and medial condyle. To the untrained eye, these two circular structures take the shape of… (sigh) human testicles, a fact that did not go unnoticed by English physician Richard Brookes in 1763. After examining Plot’s illustration, Brookes chose to re-publish the fossil using the modern binomial naming system under the name “Scrotum Humanum.” How ironic is that a man named “Richard” would choose to call the giant fossils Scrotum? Truly a match made in immature 12-year-old heaven (or immature 18-year-old in my case).

If the first dinosaur was named Scrotum, then why isn’t the first dinosaur and subsequently the entire field of paleontology deemed a massive joke? Luckily for paleontology, there were a few issues associated with the naming of Scrotum. First, its name was published as a caption of the illustration and not in a formal piece of literature. Second, the caption came without any form of formal description of the fossil material. Lastly, the fossil was lost to time and paleontologists cannot confidently say which species it belonged to, though it probably belonged to a theropod along the lines of Megalosaurus. These reasons were enough for the International Commission of Zoological Naming to deem it invalid in the late 20 th century, thus ending the legend of Scrotum Humanum.

Presently, it is a well-known fact that the first named dinosaur species is the theropod Megalosaurus bucklandii, named in 1824 by British theologian William Buckland. While Megalosaurus is a pretty good (albeit overused) name, it will never be as NUTS as Scrotum Humanum.

Works Cited:

I do not take credit for any images found in this article.

Cyclops next to an elephant skull found here

Old School Megalosaurus found here

Prothero, Donald R. Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them. Columbia University Press, 2021.


Richard Dawkins and the crappy 'humanoid dinosaurs' that just won't die

Regular readers will know that I'm not exactly a fan of the idea - discussed here and there in the technical (Russell & Séguin 1982, Russell 1987), popular (Hecht 2007, Socha 2008, Naish 2008) and speculative literature (McLoughlin 1984, Magee 1993) - that non-avian theropod dinosaurs might have evolved into humanoids had they not bought the farm 65 million years ago [image below by Matt Collins].

The hypothetical (emphasis: hypothetical) evolution of big brains, intelligence and so on among imaginary post-Cretaceous deinonychosaurs is not (in my opinion) all that unreasonable, and I base this assertion on what birds have been doing over the past 65 million years. Look at parrots and corvids. Parrots overlap with primates in brain : body size ratio, intelligence and abilities, and evidence suggests that they (and corvids) have sophisticated emotions that aren't much different from ours (or from those of other primates humans are not magic animals different from all the others, but part of a spectrum). You probably heard the recent reports about funeral rites in magpies. This was in the news thanks to the publication of Bekoff's paper (Bekoff 2009), but stuff like this has been widely reported anecdotally and there's every reason to take it seriously [Alex the grey parrot (1976-2007) shown below, from wikipedia].

However. as for the idea that those bird-like dinosaurs might have evolved into bolt upright, tailless humanoids. well, it's a thoroughly stupid idea and I'm sure you don't need me to go through the arguments again (see the links below if you're unfamiliar with them). To put it as succinctly as possible, our body shape is the product of our very specific evolutionary history, and can we be absolutely sure that it's 'the best' body shape for the evolution of big brains or intelligence? Yes or no (I think no), there doesn't seem to be any indication (either from fossils, or from actual post-Cretaceous dinosaurs, by which I mean birds) that dinosaurs would go this way, big brain or no.

So it's slightly surprising to see well known evolutionary biologist and author Richard Dawkins take up the mantle of 'humanoid dinosaur' supporter in an article Michael Shermer has written for Scientific American. Things started with Shermer's argument that aliens - if real - will not resemble bipedal primates (he put this forward in a brief youtube video). Dawkins mostly agreed, but also responded with the argument that perhaps the odds aren't so vanishingly small after all, citing Simon Conway Morris's opinions and the dinosauroids of the speculative literature in his defence!

An interpretation of Conway Morris's argument is that (1) the human body shape really is the best shape for intelligence and sentience, and (2) convergence is so rampant throughout life on Earth that it very likely extends to life on other planets too. Point (2) may be reasonable, but point (1) seems less so. Dawkins is quoted as saying that Conway Morris's argument "is not to be dismissed". No, sorry, that's not how it works. It doesn't matter if Conway Morris is the world's bestest ever expert on. whatever he's the world's bestest ever expert on: he can still be wrong, or hold questionable opinions, just like the rest of us. If I may use a Carl Sagan quote, there are no authorities, only experts, and there are many who think that Conway Morris's argument about the inevitability of humans or humanoids is only an opinion, and a dodgy, biased one at that. Our body shape clearly works well for an intelligent, tool-using, sentient animal, but where is the convincing evidence that it is the only possible body shape for such a creature, or the most likely one to evolve in distantly related, or unrelated, organisms? I'm afraid I can't help but see promotion of 'magic human syndrome' in Conway Morris's arguments (this being the widespread belief that humans are the most wonderful, most perfect creatures in all of existence).

To make it clear, however, Dawkins doesn't necessarily support or endorse the possibility that non-avian dinosaurs might have become humanoid. Rather, he is merely pointing to the fact that at least a few scientists have speculated on this possibility. But I thought he would have known better, given that these speculations do not really seem justifiable.

For previous articles on 'smart dinosaurs', please see.

More on Libya soon, plus more toads and so on. Thanks to Nathan Myers for the heads-up. On the subject of dinosaurs, congrats to Adam Yates on Aardonyx, and to Herman Pontzer and colleagues for their PLoS ONE paper on dinosaur physiology. Empirical support for dinosaur endothermy: what a surprise :)

Bekoff, M. 2009. Animal emotions, wild justice and why they matter: grieving magpies, a pissy baboon, and empathic elephants. Emotion, Space and Society doi: 10.1016/j.emospa.2009.08.001

Hecht, J. 2007. Smartasaurus. Cosmos 15, 40-41.

Magee, M. 1993. Who Lies Sleeping: the Dinosaur Heritage and the Extinction of Man. AskWhy! Publications, Frome.

McLoughlin, J. 1984. Evolutionary bioparanoia. Animal Kingdom April/May 1984, 24-30.

Naish, D. 2008. Intelligent dinosaurs. Fortean Times 239, 52-53.

Russell, D. A. 1987. Models and paintings of North American dinosaurs. In Czerkas, S. J. & Olson, E. C. (eds) Dinosaurs Past and Present, Volume I. Natural History Museum of Los Angeles County/University of Washington Press (Seattle and Washington), pp. 114-131.

- . & Séguin, R. 1982. Reconstruction of the small Cretaceous theropod Stenonychosaurus inequalis and a hypothetical dinosauroid. Syllogeus 37, 1-43.

Socha, V. 2008. DinosauÅi: hlupáci, nebo géniové? SvÄt 3/2008, 14-16.


BIOL 1001 - EXAM 4 (Ch.14-17)

Part B: You find a stray dog while out walking. Which of the following would convince you that it is a Carolina dog?

Part C: You are a reproductive biologist interested in the mating behavior of dogs. How many times a year can you study the Carolina dog?

Part D: You are interested in adopting a dog and want it to be an ancient breed. Which of the following should you pick?

Part B: **It has a fishhook tail and it digs snout pits.

Part A: Which of the following events could NOT be caused by a population bottleneck?

Part B: Which of the following statements about the amoeba population described at the end of the tutorial is true?

(By definition, a population bottleneck dramatically reduces the size of a population.)

Part B: ** It is more vulnerable to extinction due to lack of genetic variation.

(The amoebas might not have the variation necessary to adapt to future changes in the environment.)

Part A: In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat, which type of selection would act on shell color in these snails?

(Disruptive selection causes both extreme phenotypes (light and dark shells) to be favored over the intermediate phenotype.)

Part B: ** Stabilizing selection

Part A: You are a cattle rancher and will abide by the new legislation. Which of the following will you be allowed to do?

Part B: What does the FDA think drug companies will do regarding voluntary label changes on antibiotics for livestock?

Part C: Which of the following people is most likely to be against the new antibiotics legislation?

Part D: Which of the following prompted the passing of the new legislation regarding antibiotic use in livestock?

Part B: ** They will comply with the new recommendations.

Part C: ** The CEO of the National Pork Producers Council.

Part D: ** The decreasing effectiveness of antibiotics in humans.

Part A: The evolution of populations due to chance is?

Part B: If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,

Part C: In a population with brown and green alleles for color, genetic drift

Part D: Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?

Part B: ** the frequency of the green allele will increase.

Part C: ** has more effect on the evolution of a small population.

Part D: **Gene flow causes the frequency of the brown allele to increase.


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National corporate funding for NOVA is provided by Draper. Major funding for NOVA is provided by the David H. Koch Fund for Science, the Corporation for Public Broadcasting, and PBS viewers. Additional funding is provided by the NOVA Science Trust.

Major funding for Polar Extremes is provided by the National Science Foundation. Additional funding is provided by the Heising-Simons Foundation, The Kendeda Fund, the George D. Smith Fund, and the Richard Saltonstall Charitable Foundation.

This material is based upon work supported by the National Science Foundation under Grant No. 1713552. Any opinions, findings, and conclusions or recommendations expressed are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


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