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Some motivational speakers may say that regrets are only useful to learn something from.
What are the other advantages?
Very interesting question.
First I'd like to highlight that this question relates to a very hypothetical field of evolutionary biology which is evolutionary psychology. This wikipedia article on evolutionary approaches to depression might be of interest as well. One sentence says: "Feelings of regret associated with depression also cause individuals to reflect and analyze past events in order to determine why they happened and how they could have been prevented". It basically says the same thing than you said in your question.
What other advantages might "regrets" have? Before trying to answer it, I'd like to ask : is it necessary that it has advantages? A behavior or a feeling might as well be a by-product of selection for big brains. It might therefore not be selected for but it exists only because there is not much selection against this by-product trait.
Our brain are often considered to have evolved for social purposes. I would hypothesize that if someone express "regrets", he might benefit from other's care and pity. And the best way to express "regrets" is to feel the "regrets". Robert Trivers would maybe say that in order to fool someone else (make someone else think we regret) the best thing to do is to fool ourself (make ourself feel "regrets"). See his book, the folly of fools.
Do cheaters have an evolutionary advantage?
Anyone who has crawled along in the left lane while other drivers raced up the right lane, which was clearly marked "lane ends, merge left," has experienced social cheating, a maddening and fascinating behavior common to many species.
Although it won't help with road rage, scientists are beginning to understand cheating in simpler "model systems," such as the social amoeba, Dictyostelium discoideum.
At one stage in their life cycle thousands of the normally solitary Dicty converge to form a multicellular slug and then a fruiting body, consisting of a stalk holding aloft a ball of spores. It is during this cooperative act that the opportunity for cheating arises.
Some amoebae ultimately become cells in the stalk of the fruiting body and die, while others rise to the top, and form spores that pass their genes to the next generation. When unrelated amoebae gather to form a fruiting body, some strains may overcontribute to the spores and undercontribute to the stalk. These are the cheaters.
Scientists knew that cheaters could be found in wild populations of Dicty, but whether this was a successful strategy in the game of natural selection was anyone's guess.
Now the ease and low cost of genome sequencing has finally made it possible to answer the question. "By looking at the genetic variation in or near Dicty's 'social genes,' scientists are able to tell whether variants of these genes that made cooperators into cheaters had swept through populations, fought to maintain a toehold, or been given a pass because they didn't affect survival," said Elizabeth Ostrowski, PhD, assistant professor of biology and biochemistry at the University of Houston.
"The genome signatures we found suggest neither the cheating nor the cooperating variants of the social genes was able to take over the populations and that the variants had battled to a standstill," said David C. Queller, PhD, the Spencer T. Olin Professor of Biology in Arts & Sciences at Washington University in St. Louis.
"A stalemate is maintained only in a complex environment where it's unclear which strategy will win," said Joan Strassmann, PhD, the Charles Rebstock Professor of Biology in Arts & Sciences. "If the rules never change, the gene that is best on average will eventually drive out the other variant."
The findings suggest the benefits of cheating change with its frequency, or prevalence, in a population. Cheaters may succeed, for example, only when they are rare, and fail when they become so numerous they push out cooperators or put pressure on cooperators to find ways to defeat cheating.
Many social behaviors are like this, Queller said the success of one individual's strategy depends on how many others are also employing it.
The study, described in the June 4 issue of Current Biology, is the work of a collaboration of scientists from Washington University, the University of Houston and the Baylor College of Medicine. Ostrowski is the first author on the paper and Queller and Strassman are senior authors.
An arms race or trench warfare?
"For this project, we sequenced 20 Dicty strains we had isolated from the soil in the eastern U.S. We then looked for variation in 140 genes implicated in social behavior, comparing them to the rest of the genome to see if the social genes were evolving differently," Strassmann said.
"We originally got enough funding to sequence two genomes," she said. "But by the time we had cleaned the clones up, the price of sequencing had dropped so much we were able to sequence many more."
The 140 genes, Queller said, were ones that had been located during an earlier genome-wide screen for genes, that when they are disabled, turn a cooperating amoeba into a cheater.
The scientists framed their study by defining several hypothetical scenarios for the evolutionary dynamics of cheating behaviors in Dicty (see illustrtaion), each of which makes different, testable predictions about DNA diversity in and near the social genes.
"We thought we were going to see the signature of an arms race in the DNA," Queller said, "because the cheater/cooperator conflict seems analogous with other kinds of conflict, such as host/pathogen conflict, that produce escalating battles between adaptations."
An arms race, technically a series of "selective sweeps," would have shown up as a lack of variation in the DNA in or near the social genes, because a highly advantageous gene "sweeps" through a population. "What we found was kind of the opposite," Queller said. "Instead of diminished variation, there was more variation in the social genes than average, which is consistent with a prolonged stalemate at these locations."
The scientists found more evidence for a stalemate when they compared strains from two different populations, one in Texas and the other in Virginia, Queller said.
In an arms race, the Dicty at these geographically separated locations would probably have undergone different selective sweeps, which in turn would make the two populations less similar. In fact, however, the populations differed less at the social gene locations than at other genes, suggesting that some selective force was working to maintain the same variants of the social genes in both the Texas and Virginia populations.
Both the increased genetic diversity near the social genes and the failure of separated populations to drift apart at those genetic locations support the stalemate scenario.
"We failed to observe the genetic signatures of a simple arms race: a reduction in genetic diversity and long-term divergence of populations,"Ostrowski said. "Rather, the genetic signatures suggests there is trench warfare among variants of the social genes, and neither the cheaters or the cooperators are able to gain the upper hand."
But why is that? Ostrowski said. "What limits the spread of cheaters? Are they suppressed by better cheaters or by a resistant population? And conversely what limits cooperators? Why don't the cooperators completely shut down the cheaters?"
Scientists Discover Evolutionary Advantage For Homosexuality
It’s an evolutionary paradox that’s frustratingly difficult for biologists to explain, but researchers may have just found a benefit conferred by homosexual sex that could offer an explanation as to why this behavior has persevered, at least in one species. According to a new study in fruit flies, not only does same-sex sexual behavior seem to be heritable, but females with a genetic makeup associated with this trait actually display higher reproductive rates, which is an evolutionary advantage. These fascinating findings have been published in Proceedings of the Royal Society B.
If a certain trait or behavior is detrimental to the reproductive success, or fitness, of an organism, you wouldn’t expect it to persist in the population as natural selection should get rid of it. After all, the aim of the reproductive game is to keep your genes going. Why, then, do members of the same sex cop off with each other in so many species? And we’re not just talking about homosexual behaviors (observed in more than 1,500 species, since you asked) we mean the whole shebang.
Scientists have long pondered this and have struggled to come to any consensus. Although there are a few different ideas, two prevailing hypotheses that resulted from theoretical work suggest that same-sex sexual behaviors (SSB) could persist for two reasons: overdominance and sexual antagonism. The former proposes that SSB could persist in the population if genes for this behavior confer a harmonizing reproductive advantage in individuals only possessing one copy of the gene, or heterozygotes, as opposed to those in possession of two (homozygotes). The latter suggests that a gene that is detrimental to fitness in one sex could be maintained so long as it is beneficial to the other sex.
So how do researchers work out which hypothesis seems to better explain this behavior that is seemingly harmful to reproduction? The method chosen by scientists behind the latest study, based at the University of St. Andrews, involved a combination of genetic and behavioral tests. First, they screened inbred fruit fly lines in search of gene variations that could account for SSB.
They did this by both examining the genomes of male fruit flies and observing how they behaved with other males. This involved quantifying the amount of courtship behaviors males would display towards other males—such as licking, singing or attempted mounting𠅊nd then looking for genetic differences present in males displaying high levels of these behaviors. This information was then used to identify genetic lines of flies that either consistently showed high levels of SSB, or low levels of SSB.
The final stage of the investigation involved performing experimental crosses of flies from both of these identified lines and examining the resulting offspring. More specifically, they wanted to see whether coming from a genetic background associated with high levels of SSB affected reproductive rates in female offspring.
The researchers found that while their data lent more weight to the overdominance hypothesis, their results did not exclusively support one over the other. In fact, they think that both could be contributing to the maintenance of SSB in the gene pool. But that wasn’t the most interesting find of the study: Males with a genetic makeup associated with high levels of SSB produced female offspring with higher rates of reproduction, or fecundity. This suggests that genes associated with SSB could be persisting in the population because they actually confer a fitness advantage in females, despite being reproductively harmful to males.
Why do humans laugh? The evolutionary biology of laughter.
Teeth by Creatas/Thinkstock photo illustration by Natalie Matthews-Ramo
On Jan. 30, 1962, three schoolgirls started giggling in a boarding school classroom in the northeastern corner of what is now Tanzania—and touched off a very strange epidemic. The three couldn’t stop laughing—and soon the uncontrollable cackles spread to their classmates. The laughing attacks lasted from a few minutes up to a few hours one poor girl reportedly experienced symptoms for 16 straight days. Victims couldn’t focus on their schoolwork, and would lash out if others tried to restrain them.
When 95 of the school’s 159 pupils had come down with what came to be known as omuneepo, the Swahili word for laughing disease, the school shut down. The students returned to their villages, taking omuneepo with them. The affliction spread from person to person, school to school, village to village. “The education of the children is being seriously interfered with and there is considerable fear among the village communities,” noted local medical officers in a 1963 report in the Central African Journal of Medicine. They could find no explanation for the matter. When the epidemic finally died down months later, roughly a thousand people had been struck by the “laughing disease.”
As part of our effort to understand what makes people laugh, we traveled to northeastern Tanzania, tracing omuneepo’s spread across the region more than a half-century ago. We tracked down teachers, students, and medical experts who experienced the phenomenon firsthand. We learned there was nothing funny at all about the situation at the time. The religious boarding school where the laughter began was marked by strict rules, windowless dorms, and devilishly uncomfortably chairs designed to promote correct posture. Investigators found similar conditions at other locations where the omuneepo later erupted: Serious overcrowding, poor food quality.
“It’s a form of complaint,” Kroeber Rugliyama, a longtime local psychiatrist said of the mysterious laughter. “They had no alternative form of expression.”
Laughter is a vexing subject even when it’s not spreading through the countryside like a virulent disease. Take the work of Robert Provine, a neuroscientist and psychology professor at the University of Maryland, Baltimore County. For his book, Laughter: A Scientific Investigation, Provine engaged in what he called “sidewalk neuroscience,” tracking and observing real-world laughter. He and his collaborators used tape recorders to capture more than a thousand “laugh episodes” in bars, shopping malls, cocktail parties, and class reunions. And he had dozens of student volunteers note in a “laugh log” the circumstances around every time they tittered, chuckled, or guffawed.
The results were surprising, even to Provine: Less than 20 percent of the real-world laughter incidents he cataloged were in response to anything resembling something funny. Far more often, people were giggling or chuckling at innocuous statements such as “I’ll see you guys later,” “I see your point,” and “Look, it’s Andre!” What’s more, in all of these cases, the person who produced the laugh-provoking statement was 46 percent more likely to be the one chuckling than the person listening. And while laughter might seem like something that can erupt at any point in response to something funny, in only eight of the 1,200 laugh episodes Provine cataloged did the laughter interrupt what somebody was saying. Instead, 99.9 percent of the time, laughter occurred in tidy, natural breaks in the conversation, punctuating the speech like a period or exclamation point.
Provine discovered that the laughter of our everyday lives isn’t for the most part in response to anything resembling jokes. Instead, most of it occurs in conversations that, out of context, don’t seem funny at all. Provine’s discoveries suggest that laughter is inherently social, that at its core it’s a form of communication and not just a byproduct of finding something funny. Sure enough, when Provine went through the laugh logs he’d collected, he found his participants were 30 times more likely to laugh in the presence of others than when they were alone. Among the few solitary instances of laughter, nearly all occurred in response to TV shows or other media—that is, electronic proxies for other people. When people noted in their journals that they were truly alone, they hardly recorded any laughter at all.
So why would we have evolved the odd and powerful vocal mannerism of laughter? Why do we have an innate need to share what we find funny with others, and why can it can resemble an out-of-control disease?
Evolutionary theory is rife with possible explanations, but one of the most compelling was put forward in a 2005 Quarterly Review of Biology article by an undergrad named Matthew Gervais and his adviser, evolutionary biologist David Sloan Wilson. It’s based on the efforts of a quirky 19 th -century French physician named Guillaume Duchenne, who went around zapping people’s faces with electrodes. Luckily for Duchenne, he worked at an old woman’s hospice, so he had access to a lot of prone bodies. He must have been quite the charmer. According to articles on Duchenne, all the ladies wanted to be electrocuted by the “little old man with his mischief box.”
Applying the prongs of his box to people’s faces, Duchenne evoked one kind of smiling—the voluntary kind, the type of expression we produce when we a grin to be polite. This mannerism, he discovered, involves the face’s zygomatic major muscles raising the corners of the mouth. But Duchenne discovered there was a second variety of smiling and laughing, one that occurs when we find something truly entertaining or funny. This expression was more complex, utilizing both the zygomatic major muscles and the orbicularis oculi muscles that form crow’s feet around your eyes. It’s why people say a real smile is in the eyes. Duchenne was never able to reproduce with his electrodes this second form of expression—now known as a Duchenne smile or Duchenne laughter—and he came to believe it was “only put at play by the sweet emotion of the soul.”
More than a century later, Gervais and Wilson saw Duchenne’s discovery as evidence that laughter evolved at two different points in human development. First, they posited, at a point sometime between 2 million and 4 million years ago, came Duchenne laughter, the kind triggered by something funny. An outgrowth of the breathy panting emitted by primates during play fighting, it likely appeared before the emergence of language. This sort of laughter was a signal that things at the moment were OK, that danger was low and basic needs were met, and now was as good a time as any to explore, to play, to socialize. “What the humor is indexing and the laughter is signaling is, ‘this is an opportunity for learning,’” Gervais told us. “It signals this is a non-serious novelty, and recruits others to play and explore cognitively, emotionally and socially with the implications of this novelty.”
But then, sometime in the hundreds of thousands of years after that, theorized Gervais and Wilson, the other sort of laughter emerged—the non-Duchenne sort, the kind that isn’t dependent on something being funny. As people developed cognitively and behaviorally, they learned to mimic the spontaneous behavior of laughter to take advantage of its effects. They couldn’t get it right—they couldn’t simulate the eye-muscle movements of real laughter and smiling—but it was close. Mimicked laughter was a way to manipulate others—sometimes for mutually beneficial purposes, sometimes for more devious reasons. As Gervais and Wilson put it in their paper, “non-Duchenne laughter came to occur in aggressive, nervous, or hierarchical contexts, functioning to signal, to appease, to manipulate, to deride, or to subvert.”
Laughter, in other words, is more than just a response to humor. It’s a primal human tool, one of the building blocks of society. It taps into the core of what we are as social creatures, expressing from one person to another what often cannot be said in any other way: either that everything is in good fun—or, as in the case of omuneepo, that something is very, very wrong.
What is the evolutionary advantage of cancer?
Like, it's clearly bad for the individual that gets it but is there or could there be an advantage for the species/group?
And what would that situation/s look like?
Ok, the idea of cancer in particular doesn't matter here so much, what would a situation where a disease that increases the mortality of an individual but has a net positive effect on that individual's group look like?
The thing about evolution is that it doesn't care about the good of the species. Reproduction is rewarded with more reproduction. Cancer cells, and cancers themselves, are in evolutionary terms, independent organisms that reproduce extremely well. They evolve to reproduce rapidly at the expense of the body in which they reside ignorant to the fact that they may burn themselves out if they kill the host. Cancer is evolution played out at our time scale. In fact, we have evolved tumor suppressors, the most famous of which is called p53, to prevent runaway developmental processes, and in many cancers with hereditary components, these are what are broken. We also have mechanisms such as programmed cell death, called apoptosis, that destroy cells when their DNA is no longer reliable. Sometimes this doesn't work. Many viruses, such as HPV, reproduce successfully as cancers by inserting themselves into the genome of cells which then reproduce. Cancers do all kinds of things like vascularize themselves using our developmental pathways, convert connective tissue matrix to more easily distributed mesenchymal tissue so they can seed the rest of the body (metastasis), and other sneaky tactics. Basically, they are mutineers.
So, in terms of the species, they are a detriment. But evolution at the scale of the cancer cell doesn't care because it can't predict the future. It just reproduces, and basically does so by screwing over the rest of the body by subverting its developmental processes.
Hacked out on a phone, so likely lacking, but you get the gist.
Right, but on the scale of the species cancer could plausibly be of a net benefit yes? Like the rate of cancer incidence within a species could be subject to natural selection.
None, but it typically doesn't arrive until after reproduction so it's not deleted from the gene pool, by the time it kills you you've had kids so there is no evolutionary pressure for a counter measure
That's sort of like asking "What's the evolutionary advantage of gushing chest wounds?".
Cancer is obviously something gone wrong with the body, much like a spear protruding from your chest. Our body has defenses against both. For the spear to the chest, we have ribcages, blood that clots, sophisticated healing mechanisms, an immune system to fight off infection while healing. You've even got a nice instinctual response to run away from scary pointy sticks.
For cancer, we have a good number of molecular switches that tell which cells to divide and when. For example, the p53 tumor suppressor gene is a critical anticancer gene that stops cells from dividing willy-nilly, and if things get too hairy with the cell, it plays a role in killing it outright. Further, your immune system can detect precancerous cells and kill them off before they become a problem. You get precancerous cells showing up on a daily basis, they're just killed before it's an issue.
However, your defenses to being impaled and to cancer can both be overwhelmed. For the spear, make it big enough and stick it somewhere important and your body is out of options. For cancer, a whole hell of a lot has to get wrecked. An individual cell has to be damaged, perhaps by radiation. Then your immune system has to fuck up and not kill it. Then your circulatory system needs to fuck up and start giving the cancer blood. Then the tumor needs to be really scary and start invading other tissues. Once all that goes wrong, well, the cancer spear is protruding from your chest. Your body tried its best, but now it's fucked.
Why Cry? Evolutionary Biologists Show Crying Can Strengthen Relationships
Medically, crying is known to be a symptom of physical pain or stress. But now a Tel Aviv University evolutionary biologist looks to empirical evidence showing that tears have emotional benefits and can make interpersonal relationships stronger.
New analysis by Dr. Oren Hasson of TAU's Department of Zoology shows that tears still signal physiological distress, but they also function as an evolution-based mechanism to bring people closer together.
"Crying is a highly evolved behavior," explains Dr. Hasson. "Tears give clues and reliable information about submission, needs and social attachments between one another. My research is trying to answer what the evolutionary reasons are for having emotional tears.
"My analysis suggests that by blurring vision, tears lower defences and reliably function as signals of submission, a cry for help, and even in a mutual display of attachment and as a group display of cohesion," he reports.
His research, published recently in Evolutionary Psychology, investigates the different kinds of tears we shed &mdash tears of joy, sadness and grief &mdash as well as the authenticity or sincerity of the tears. Crying, Dr. Hasson says, has unique benefits among friends and others in our various communities.
For crying out loud (and behind closed doors)
Approaching the topic with the deductive tools of an evolutionary biologist, Dr. Hasson investigated the use of tears in various emotional and social circumstances. Tears are used to elicit mercy from an antagonistic enemy, he claims. They are also useful in eliciting the sympathy &mdash and perhaps more importantly the strategic assistance &mdash of people who were not part of the enemy group.
"This is strictly human," reasons Dr. Hasson. "Emotional tears also signal appeasement, a need for attachment in times of grief, and a validation of emotions among family, friends and members of a group."
Crying enhances attachments and friendships, says Dr. Hasson, but taboos are still there in certain cases. In some cultures, societies or circumstances, the expression of emotions is received as a weakness and the production of tears is suppressed. For example, it is rarely acceptable to cry in front of your boss at work &mdash especially if you are a man, he says.
Streets awash with tears?
Multiple studies across cultures show that crying helps us bond with our families, loved ones and allies, Dr. Hasson says. By blurring vision, tears reliably signal your vulnerability and that you love someone, a good evolutionary strategy to emotionally bind people closer to you.
"Of course," Dr. Hasson adds, "the efficacy of this evolutionary behavior always depends on who you're with when you cry those buckets of tears, and it probably won't be effective in places, like at work, when emotions should be hidden."
Dr. Hasson, a marriage therapist, uses his conclusions in his clinic. "It is important to legitimize emotional tears in relationships," he says. "Too often, women who cry feel ashamed, silly or weak, when in reality they are simply connected with their feelings, and want sympathy and hugs from their partners."
Materials provided by Tel Aviv University. Note: Content may be edited for style and length.
Is There An Evolutionary Advantage To Grief?
A woman mourns on March 1, 2016 at the site where a woman suspected of killing a child aged three or . [+] four was detained on February 29, near Oktyabrskoye Pole metro station in Moscow. (DMITRY SEREBRYAKOV/AFP/Getty Images)
Is there an evolutionary advantage to grief? originally appeared on Quora - the knowledge sharing network where compelling questions are answered by people with unique insights.
Answer by Adriana Heguy, molecular biologist and genomics researcher, on Quora:
Grief is a side-effect of evolution. The behavior and emotion that was selected for is attachment (humans call it love). Animals that raise their babies are invariably attached to them birds too. Both filial bonds and pair (mates) bonds are very important. They are key to the survival of the offspring. And anything that is key to reproduction (including caring for the young, forming a strong bond with the mate, as is the case in some birds and some mammals) is of course heavily subjected to evolutionary pressures. Attachment is a fascinating mechanism that is heavily studied from a neurobiological point of view . In social animals, such as humans, there are strong bonds not just with our babies (I would argue that it is the strongest love we can experience), our mates, and our immediate family, but also with friends and members of our social group with whom we share many experiences and values. Humans are prepared to die for love: not just to protect our children (that makes total evolutionary sense) but also to protect other loved ones, including our fellow countrymen (as in the situation of war), most of whom we've never even met!
Thus, with such strong attachments, how can we not grieve when those we love die or leave us? Loss is an extremely negative emotion, even when not directed towards human losses, but instead to material losses. Just the thought itself of losing someone we love makes us incredibly sad. This leads us to strive to be good parents, good friends, or patriotic people. It is good for group cohesion, and in social species, this is key to the survival of the group.
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5 Answers 5
There are some traits in the animal kingdom that tend to be reasonably correlated (although not necessarily linear). Among those are size, birth rate, and longevity. Anecdotally, the mouse is small, lives just a couple of years, and has a big litter of pups every few months. The elephant is large, lives up to 70 years, and have one calf every five or six years. Blue Whales are enormous, live 80 to 110 years, and have one calf every couple of years. Humans seem to fall somewhere in the middle of the size range, live 70-100 years, and can have one baby every year, with occasional multiples. Note that the bigger-older-lower birth rate relationship is not perfect, but an overall pattern emerges.
Now we have a problem, as elves and humans are comparable in size, for them to follow this pattern they should also have comparable longevity and birth rate. However, if there was some event in the ancient elven past that made it part of their mores to not have as many children (for example, due to reduced resources to have to share with an increasing population), then evolution would have gradually favored longevity as well. This same scarcity of resources would also have favored not growing larger.
Here, Will's answer comes in, as those elves who are best able stick around to care for the few children they do have, will fare better in the long-term survival of the society. Thus, the long-lived more frequently pass on their genes for longevity.
In conclusion, have the ancient split between elves and humans happen in such a way that the humans got the lush forest, and the elves got the scrub at the edge of a desert, or something like that.
What advantages would extreme longevity need to provide for it to develop in a human subspecies/humanoid species without outside tampering/
Fitness (often denoted w w or ω in population genetics models) is the quantitative representation of natural and sexual selection within evolutionary biology. It can be defined either with respect to a genotype or to a phenotype in a given environment. In either case, it describes individual reproductive success and is equal to the average contribution to the gene pool of the next generation that is made by individuals of the specified genotype or phenotype.
It is somewhat unusual that this has not evolved. Consider
Man A lives 65 years. He fathers 5 children between ages 20 and 40. He contributes to the welfare and survival of his children and grandchildren from ages 40 to 65.
Man B lives 195 years. He fathers 5 children between ages 20 and 40, 5 more from 40 to 60, 5 more from 60 to 80, 5 more from 80 to 100, 5 more from 100 to 120, 5 more from 120 to 140, 5 more from 140 to 160. For his last 35 years he contributes to the welfare and survival of his many descendants.
Man B lives 3 times longer and fathers 7 times as many children as man A. His genetic fitness is far superior.
In fact, you would need to build in some sort of low reproductive rate for the long lived elves or they would quickly overwhelm and out-compete the humans with their cumulative numbers.
ADDENDUM I am a little perplexed by the comments and horrified by the downvote, and so I thought I would add more mechanism to the fitness advantage of longetivity than just the weight of numbers.
Suppose there is a selective event - a plague, or a famine, or a toxin in the water. Man A and Man B are resistant and survive. Man A fathers one more child and then comes to the end of his natural life. Man B continues contributing his resistant genes to many subsequent generations. This is how it works for lots of lower animals like fish or sea urchins. Very long lived creatures who escape the mortality risks in their environments contribute offspring season after season.
When in doubt use sexual selection.
If you have already included magic then you can use that as a indirect selective pressure. Magic is how elves choose mates (or it is at least a huge part of it), based on power or displays with magic. since you set the rules for magic you can say the longer you live the stronger your magic becomes and the better you can use it, works even better if magical ability also takes a long time to develop. Now age is roughly equal magical power which is basically how sexy you are to an elf, and evolution will create all kinds of stupid conditions in the name of mate attraction. so pushing longevity as far as it can makes sense.
This is pretty easy to see with your set up if humans can also use magic, magic is ancestral. Elves split off early by focussing on magic, where as faster breeding humans focused more on new ideas, aka technological development. I imagine elves to also be highly reliant on magic with stone age technology otherwise. Humans may have less power but may be more creative with it. Perhaps Humans don't just push the rock with magic like elves with abundant magic do, they use magic like a lever to roll it accomplishing the same thing with far less raw magical power.
this could also explain why magic in animals is rare if you so desire, most are too short lived.
Depression's Evolutionary Roots
This paradox could be resolved if depression were a problem of growing old. The functioning of all body systems and organs, including the brain, tends to deteriorate with age. This is not a satisfactory explanation for depression, however, as people are most likely to experience their first bout in adolescence and young adulthood.
Or, perhaps, depression might be like obesity &mdash a problem that arises because modern conditions are so different from those in which we evolved. Homo sapiens did not evolve with cookies and soda at the fingertips. Yet this is not a satisfactory explanation either. The symptoms of depression have been found in every culture which has been carefully examined, including small-scale societies, such as the Ache of Paraguay and the !Kung of southern Africa &mdash societies where people are thought to live in environments similar to those that prevailed in our evolutionary past.
There is another possibility: that, in most instances, depression should not be thought of as a disorder at all. In an article recently published in Psychological Review, we argue that depression is in fact an adaptation, a state of mind which brings real costs, but also brings real benefits.
One reason to suspect that depression is an adaptation, not a malfunction, comes from research into a molecule in the brain known as the 5HT1A receptor. The 5HT1A receptor binds to serotonin, another brain molecule that is highly implicated in depression and is the target of most current antidepressant medications. Rodents lacking this receptor show fewer depressive symptoms in response to stress, which suggests that it is somehow involved in promoting depression. (Pharmaceutical companies, in fact, are designing the next generation of antidepressant medications to target this receptor.) When scientists have compared the composition of the functional part of the rat 5HT1A receptor to that of humans, it is 99 percent similar, which suggests that it is so important that natural selection has preserved it. The ability to &ldquoturn on&rdquo depression would seem to be important, then, not an accident.
This is not to say that depression is not a problem. Depressed people often have trouble performing everyday activities, they can&rsquot concentrate on their work, they tend to socially isolate themselves, they are lethargic, and they often lose the ability to take pleasure from such activities such as eating and sex. Some can plunge into severe, lengthy, and even life-threatening bouts of depression.
So what could be so useful about depression? Depressed people often think intensely about their problems. These thoughts are called ruminations they are persistent and depressed people have difficulty thinking about anything else. Numerous studies have also shown that this thinking style is often highly analytical. They dwell on a complex problem, breaking it down into smaller components, which are considered one at a time.
This analytical style of thought, of course, can be very productive. Each component is not as difficult, so the problem becomes more tractable. Indeed, when you are faced with a difficult problem, such as a math problem, feeling depressed is often a useful response that may help you analyze and solve it. For instance, in some of our research, we have found evidence that people who get more depressed while they are working on complex problems in an intelligence test tend to score higher on the test.
Analysis requires a lot of uninterrupted thought, and depression coordinates many changes in the body to help people analyze their problems without getting distracted. In a region of the brain known as the ventrolateral prefrontal cortex (VLPFC), neurons must fire continuously for people to avoid being distracted. But this is very energetically demanding for VLPFC neurons, just as a car&rsquos engine eats up fuel when going up a mountain road. Moreover, continuous firing can cause neurons to break down, just as the car&rsquos engine is more likely to break down when stressed. Studies of depression in rats show that the 5HT1A receptor is involved in supplying neurons with the fuel they need to fire, as well as preventing them from breaking down. These important processes allow depressive rumination to continue uninterrupted with minimal neuronal damage, which may explain why the 5HT1A receptor is so evolutionarily important.
Many other symptoms of depression make sense in light of the idea that analysis must be uninterrupted. The desire for social isolation, for instance, helps the depressed person avoid situations that would require thinking about other things. Similarly, the inability to derive pleasure from sex or other activities prevents the depressed person from engaging in activities that could distract him or her from the problem. Even the loss of appetite often seen in depression could be viewed as promoting analysis because chewing and other oral activity interferes with the brain&rsquos ability to process information.
But is there any evidence that depression is useful in analyzing complex problems? For one thing, if depressive rumination were harmful, as most clinicians and researchers assume, then bouts of depression should be slower to resolve when people are given interventions that encourage rumination, such as having them write about their strongest thoughts and feelings. However, the opposite appears to be true. Several studies have found that expressive writing promotes quicker resolution of depression, and they suggest that this is because depressed people gain insight into their problems.
There is another suggestive line of evidence. Various studies have found that people in depressed mood states are better at solving social dilemmas. Yet these would seem to have been precisely the kind of problems difficult enough to require analysis and important enough to drive the evolution of such a costly emotion. Consider a woman with young children who discovers her husband is having an affair. Is the wife&rsquos best strategy to ignore it, or force him to choose between her and the other woman, and risk abandonment? Laboratory experiments indicate that depressed people are better at solving social dilemmas by better analysis of the costs and benefits of the different options that they might take.
Sometimes people are reluctant to disclose the reason for their depression because it is embarrassing or sensitive, they find it painful, they believe they must soldier on and ignore them, or they have difficulty putting their complex internal struggles into words.
But depression is nature&rsquos way of telling you that you&rsquove got complex social problems that the mind is intent on solving. Therapies should try to encourage depressive rumination rather than try to stop it, and they should focus on trying to help people solve the problems that trigger their bouts of depression. (There are several effective therapies that focus on just this.) It is also essential, in instances where there is resistance to discussing ruminations, that the therapist try to identify and dismantle those barriers.
When one considers all the evidence, depression seems less like a disorder where the brain is operating in a haphazard way, or malfunctioning. Instead, depression seems more like the vertebrate eye&mdashan intricate, highly organized piece of machinery that performs a specific function.
Are you a scientist? Have you recently read a peer-reviewed paper that you want to write about? Then contact Mind Matters co-editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe, where he edits the Sunday Ideas section.
The genes that code for homosexuality do other things too
The allele - or group of genes - that sometimes codes for homosexual orientation may at other times have a strong reproductive benefit. This would compensate for gay people's lack of reproduction and ensure the continuation of the trait, as non-gay carriers of the gene pass it down.
There are two or more ways this might happen. One possibility is that the allele confers a psychological trait that makes straight men more attractive to women, or straight women more attractive to men. "We know that women tend to like more feminine behavioural features and facial features in their men, and that might be associated with things like good parenting skills or greater empathy," says Qazi Rahman, co-author of Born Gay The Psychobiology of Sex Orientation. Therefore, the theory goes, a low "dose" of these alleles enhances the carrier's chances of reproductive success. Every now and then a family member receives a larger dose that affects his or her sexual orientation, but the allele still has an overall reproductive advantage.
Another way a "gay allele" might be able to compensate for a reproductive deficit is by having the converse effect in the opposite sex. For example, an allele which makes the bearer attracted to men has an obvious reproductive advantage to women. If it appears in a man's genetic code it will code for same-sex attraction, but so long as this happens rarely the allele still has a net evolutionary benefit.
There is some evidence for this second theory. Andrea Camperio-Ciani, at the University of Padova in Italy, found that maternal female relatives of gay men have more children than maternal female relatives of straight men. The implication is that there is an unknown mechanism in the X chromosome of men's genetic code which helps women in the family have more babies, but can lead to homosexuality in men. These results haven't been replicated in some ethnic groups - but that doesn't mean they are wrong with regards to the Italian population in Camperio-Ciani's study.