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Is amphibians being descended from fish reflected in the animalia taxonomy?

Is amphibians being descended from fish reflected in the animalia taxonomy?


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I think it is common knowledge that amphibians are descended from fish. At some point there was a transition from sea to land.

But when I try to confirm this through the Animalia taxonomy, the scientific classification of fish goes

https://en.wikipedia.org/wiki/Fish

while the scientific classification of amphibians go

https://en.wikipedia.org/wiki/Amphibian

If we draw this as a tree of sorts, we end up with

it seems to be quite obvious that fish and amphibians belong to the same phylum but different clades, but I'm not sure how that proves that amphibians are directly descended from fish?

I'm interested in a tree that shows amphibians branching off of the fish lineage.


Fish are a paraphyletic group: that is, any clade containing all fish also contains the tetrapods, which are not fish. For this reason, groups such as the class Pisces seen in older reference works are no longer used in formal classifications.

You got something completely wrong. In evolution one can not say that one taxonomical group evolved from the other. We say that two taxonomical groups have common distant relative. With that said all vertebrates have common distant relatives. Important is to know when did the branching in speciation happened.

Proto-amphibians evolved in Devonian by further speciation from relative that was sarcopterygiian (fish). It was a fish with some properties of amphibians (lungs and bones in appendages).


Is amphibians being descended from fish reflected in the animalia taxonomy? - Biology

Contents: Human taxomony | Domain - Phylum Table | History | Terms | Books | links
Bacteria | Protozoa | fungi | Plants | Animals (invertebrates | vertebrates) | Mammals | Primates Taxonomy is the classification of similar organisms into a group called a taxon (plural taxa).
The traditional classification of living organisms established by Swedish Naturalist, Carolus Linnaeus, in 1758 had two kingdoms, animal and vegitable, and a seven level hirearchy down to genus and species. Darwin's theory of evolution in 1859, and DNA analysis since 1960 have resulted in many proposals for new systems such as Systematics & Cladistics. Around 1990 a three level domain system above the traditional kingdoms was proposed after the discovery of archaea (ancient bacteria) by Carl Woese. See more in the Introduction below.

Kingdom Archaea - Single celled organisms (prokaryotes [no nucleus]) with distinctive cell membranes. Archaea were initially viewed as extremophiles living in harsh environments, such as hot springs and salt lakes, but they have since been found in a broad range of habitats, including soils, oceans, marshlands and the human colon and navel.

Kingdom Plantae - e.g. Mosses, grasses, flowering plants, shrubs, vegetables, fruit trees, conifers, .

Kingdom Animalia - e.g. Sponges, jellyfish, coral, worms, oysters, fish, reptiles, insects, birds, mammals, .

Kingdom Fungi - Mushrooms, Penicillium (from which Penicillin is derived) molds, athlete's foot, rusts, yeasts

Kingdom Chromista - Diatoms, kelps, golden algae, yellow-green algae, downy mildew

In the 108 years from 1898 to 2006, 57 kinds of freshwater fish declined to extinction in North America. The causes include damming of rivers and streams, the draining of ponds and lakes, the filling in of springheads, and pollution, all due to human activity.
Paleontologists and biodiversity experts estimate that since the existence of modern humans (200,000 years ago) the rate of extinction is between 100 to 1,000 times higher than it was before humans.
Source: A Biologist's Manifesto for Preserving Life on Earth - E.O. Wilson | Sierra Club Example of Human Classification : (Items in parenthesis were not part of original 7 level system):
Some of the groups come from new methods of classification (e.g. Cladistics) and would not be included in the traditional scientific classification system. Although there are 7 main taxa in the original model, we see above a total of 22 taxa from sub-divisions added over time to further distinguish different branches.

Domain: Eukaryota Kingdom: Metazoa Eumetazoa Bilateria Coelomata Deuterostomia Phylum: Chordata subphylum: Craniata Vertebrata superclass:Gnathostomata Teleostomi Euteleostomi (bony vertebrates) Sarcopterygii Tetrapoda Amniota (amniotes) Class: Mammalia Theria Eutheria (placentals) SuperOrder: Euarchontoglires Order: Primates Suborder: Haplorrhini Infraorder: Simiiformes Parvorder: Catarrhini Superfamily: Hominoidea Family: Hominidae Homo/Pan/Gorilla group Genus: Homo Species: Homo sapiens

Evolution of classifications
The Binomial Nomenclature (Genus, Species) introduced by Swedish Naturalist Carolus Linnaeus (Karl von Linné), the father of modern taxonomy, in the mid-1700's lasted for 200 years. Taxonomy has changed technologically as the field of biology has progressed.

The classifications of living organisms has evolved from two kingdoms (animal and vegitable) to six kingdoms to the current (2004) system of three Domains. As recently as 2000 35 new species were defined just for primates. See History below.

Historically, classification has been by comparison of anatomy since 1960, use of molecular tools has allowed classification based on differences in DNA (and proteins) to identify common ancestries (a shared genetic heritage).
See history below.

Major redesigns of the classification system, using PhyloCodes, are being proposed based on Systematics & Cladistics. See Phylogenetic Tree and Cladistic classification at the evolution page. .

Unfortunatly Zoologists and Botanists have different views on how things should be classified.

The following has the most common Phylums but it is not complete. There is little consistency in the reference books and web pages in this area. The following it an attempt to list the most common classification as of 2006, but it seems to be a moving target.
There are currently proposals to replace the Linnean System with a new PhyloCode.
Note: Viruses are made up of genetic material not complete cells, so are not considered living organisms.

Common Phylums :

Domain Kingdom Phylum
BACTERIA Bacteria
(Eubacteria)
Proteobacteria Nitrogen-fixing bacteria, such as rhizobium, in the root nodules of legumes, as well as enteric bacteria that live in the intestinal tract of animals (including E. Coli). Includes both Chemoautotrophic (free living) and Chemoheterotrophic (parasitic), like Salmonella.
Cyanobacteria Includes most bacterial photosynthesizers. Originally they were called blue-green algae because of their ability to photosynthesize, but were reclassified when it was found that they are more similar to bacteria, existing as prokaryotic cells. Produced the oxygen in early Earth.
Gram-Positive Eubacteria Display unique staining patterns when exposed to certain gram stains. Includes species of streptococci that causes strep throat.
Spirochetes Helical bacteria that all are chemoheterotrophs (parasitic). Includes Treponema pallidum, which causes syphilis.
Chlamydiae Intracellular parasites that get vitamins, amino acids, ATP, and other vital cellular molecules from their host cell. Some cause venereal disease others a type of pneumonia.
ARCHAEA CRENARCHAEOTA Pyrodictium, Thermoproteus A new group of micro-organisms were discovered in the Open Sea in 1970 and assigned their own domain in 1994.
They live in extremes of heat/cold, salinity and acidity.
EURYARCHAEOTA Methanogens
Thermoacidophiles
Halophiles
Korarchaeota
EUKARYA
Plants & Animals
PROTISTA
(single-celled organisms)

Classification sche-
mes for the protists
are numerous.
Some divide the kingdom into subkingdoms then
phila some into classes.


Zoomastigophora
Rhizopoda
Ciliophora
Protozoa
flagellates
Amoeba
Paramecium
Chlorophyta Green Algae
Dinoflagellata
Euglenophyta
Algal Protozoans

Rhodophyta
Phaeophyta
Seaweeds
Red Algae
Brown Algae
Pyrrhophyta
Chrysophyta
dinoflagellates (Red tides)
Golden Algae
Myxomycota
Acrasiomycota
Fungus-like Protists
(slime molds)
Kingdom Division  
FUNGI
(Mycota)
Zygomycota tube fungi, including some rusts, bread molds, water molds and others
Ascomycota sac fungi including yeasts, powdery mildews, cup fungi, blue and green molds, some bread molds and others
Basidiomycota club fungi, including most mushrooms, toadstools, bracket fungi, shelf fungi, puffballs, smuts and rusts.
Chytridiomycota chytrids
lichens are not a single organism, but rather a symbiotic association between a fungus and an alga.
Deuteromycota A miscellaneous junk category for forms of uncertain affinity, including those fungi in which sexual reproduction is unknown. It is not treated formally in more recent systems, although it is still used widely by plant pathologists.
CHROMISTA Phaeophyta kelp
Bacillariophyta Diatoms
Haptomonada haptophytes
Oomycota rusts and mildews
PLANTAE Bryophyta nonvascular (no roots, stems, or leaves) e.g. mosses and liverworts
Pterophyta ferns and relatives
Coniferophyta cone-forming seed plants, conifers (gymnosperms)
Anthophyta fruit-forming seed plants - flowering plants (angiosperms), trees, Maple, Oak, Roses, tulips, sunflower, water lilie
DomainKingdom Sub-
Kingdom
Superphylum Phylum Sub-Phylum
EUKARYA
(Cont.)
Plants & Animals
Animalia Parazoa Porifera (sponges )
Metazoa DEUTEROSTOMIA
(deuterostome
"mouth second") 2
Chordata 1 (with a nerve cord) (fish, reptiles, birds, amphibians, mammals) VERTE-
BRATA
Hemichordata (Acorn worms, graptolites)
Echinodermata (starfish, sea urchins, sand dollars, sea cucumbers, etc. ) Inverte-
brata
ECDYSOZOA
(molting animals)
Arthropoda (Insects, Spiders, lobster, crab, shrimp, scorpions )
Cephaloryncha (radialian worm )
Nematoda (roundworms )
Nematomorpha (gordian horsehair worms )
Onychophora (velvet worms )
LOPHOTROCHOZOA
(worms, molluscs, & lophophorates)
mollusca (oysters, snails, slugs, scallop, octopus, squid and clams )
Annelida (Segmented worms, leeches )
Brachiopoda (lamp shells )
Bryozoa ("moss animals")
Cnidaria (jellyfish, coral and sea anemones, and hydra. )
Platyzoa Platyhelminthes (flatworms )
Vendian Animals (the First animals )
1. There are two Cordata sub-phylums which are not vertebrates:
Urchordata - Sea squirts
Cephalochordata - Jawless Fish - Lamprey, Hagfish, Lancelets

2. Deuterostome means "mouth second" which refers to early embryo development. The other major group of bilateria animals, protostomia, develops the mouth first. See below.

See Eukarya for a 9 Kingdom model and list of 33 Phylums for Animalia.

There are estimated to be a total of 5-9 million species.
A team including Dr Derek Tittensor, who is based at the UN Environment Programme's World Conservation Monitoring Centre (Unep-WCMC) and Microsoft Research in Cambridge, UK, and peers from Dalhousie University in Canada and the University of Hawaii placed the number at 8.7 million from studying relationships between the branches and leaves of the "family tree of life".
The figure excludes bacteria and some other types of micro-organism.

About 1.2 million species have been formally described.

[ ] - Number of Species
* DOMAIN BACTERIA (Eubacteria) (formerly Monera or Prokaryota See history.) [4,800 known, est. up to 5 Million]

  • Thermofilum
  • Methanogens (Live in anaerobic environments such the muck of swamps and marshes, the rumen of cattle, sludge)
  • Halophiles (These are found in extremely saline environments such as the Great Salt Lake in the U.S. and the Dead Sea.)
  • Thermoacidophiles (Like acid and hot environments. Live in acidic sulfur springs (e.g., in Yellowstone National Park) and undersea vents ("black smokers").
  • Others: Methanococci, Methanopyri, Archeoglobi, Thermococci
  • Protozoa - Divisions Sarcodina/Rhizopoda (e.g. amoebas), Sporozoa/Apicomplexa (e.g.Plasmodium vivax, which causes malaria), Mastigophora/Zoomastigophora (e.g. Trypanosoma gambiense, which causes African sleeping sickness), Ciliophora (fresh water organisms and use cilia to move)
  • Algae - Divisions Rhodophyta (red algae), Phaeophyta (brown algae, kelp) and Chlorophyta (green algae, spirogyra), Chrysophyta (golden algae, Diatoms), Pyrophyta (Dioflagellates),
  • Fungus-like Protists - Division Myxomycota ( slime molds )
  • Division Bryophyta-- nonvascular (no roots, stems, or leaves) e.g. mosses and liverworts
  • Division Pterophyta--ferns and relatives
  • Division Coniferophyta-- cone-forming seed plants conifers (gymnosperms)
  • Division Anthophyta-- fruit-forming seed plants - flowering plants (angiosperms)
    • Class Dicotyledonae- plants with one seed leaf e.g., geranium, carrot, maple
    • Class Monocotyledonae- plants with two seed leaves e.g., lily, grass, bamboo, palm
    • Phylum Chordata (animals with a nerve chord) [45,820]
      - Sub-Phylum: Vertebrata [52,000 ?]
        Vertebrates also differ from all the other animals by having quadrupled their HOX gene cluster that is, vertebrates have 4 clusters of HOX genes located on 4 different chromosomes.
    • Fish [21,723]
    • Class Agnatha - Jawless fish/lamprey
    • Class Chondrichthyes - Sharks, skates, rays
    • Class Osteichthyes - bony fishes: bass, tuna, salmon
      • Class Amphibia Amphibians [4,334] - frogs, toads and salamanders
      • Class Aves Avians [>9,000] - Birds
      • Class Reptilia Reptiles [6,778] - snakes, crocodiles and alligators
        subclass Archosauria - Dinosars
      • Class Synapsida - (extinct) Early (300 mya) predecessor to mammals (looked like reptiles)
        Order: Therapsida - Therapsids became the dominant land animals during
        the Middle Permian. Mammals evolved from them.
      • Class Mammalia Mammals [5,400]
        - Sub-Class - Eutheria (Placentals: Mammals in which the young develop in a placenta inside the uterus.)
        • Order: Insectivora - Insect eating - Shrews, moles
        • Order: Carnivora - Meat eating - dog, cat, lion, bear, racoon, seal
        • Order: Chiroptera - bat
        • Order: Primates [310*]- monkeys, apes
          In older classifications, the Primates were divided into two suborders: Prosimii (lemurs and tarsiers) and Anthropoidea (Anthropod - monkeys, apes, humans). See primates at Wikipedia
          Sub-Order - Haplorrhini
          • Infraorder Tariiformes (Tarsiers)
          • Infraorder Simiiformes
            Family: Hylobatidae
          • SuperFamily: Catarrhini
          • SuperFamily: Hominoidea (hominoids) (Apes)
            Family: Hylobatidae: Gibbons
            Family: Hominidae 1 (Great apes)
            Subfamily: Ponginae - orangutans
            Subfamily: Homininae
            Genus: Gorilla - Gorilla
            Genus: Pan - chimpanzees, Bonobo (pygmy chimp)
            Hominid (Tribe Hominini)
            Genus: Australopithecus (extinct)
            Genus: Homo
            Species: H. sapiens - man/humans 3
            Species: Others (all extinct) neanderthalensis, floresiensis, erectus, habilis, .
            Neanderthal's are sometimes classified as a subspecies .
          • Phylum Porifera - sponges [5,000 known]
          • Phylum Cnidaria (Coelenterata) [9,000 known] - hydra, jellyfish, sea anemone, and the coral
          • Phylum Platyhelmintes [20,000 known] - worms with flattened bodies, such as the planarian, tapeworm and liver fluke
          • Phylum Nematoda [25,000 known] - roundworms such as the ascaris, pinworm, hookworm, stomach worm and the trichina or pork worm.
          • Phylum Annelida [12,000 known] - worms with bodies made of segments such as the sandworm, leech and the earthworm.
          • Phylum Mollusca [50,000 known] - oysters, snails, slugs, scallop, octopus and clams
          • Phylum Arthropoda [est. 6 Million - 75-84% of all known animal species]
            • Subphyla (or SuperClass) Hexapoda
              Class Insecta [>1 Million known] --butterflies, grasshoppers, beetles, fly, mosquito, moth. 90% of anthropod species, 65-75% of all species.
              (Estimates of total insect species range from 2 to 30 million.)
              See aquatic insects under fly-fishing.
              Non-insect (Entognatha): Collembola, Protura, and Diplura - Minute arthropods mostly found in leaf litter and soil. e.g. Springtails
            • Class Crustacea [50,000] --shrimp, crayfish, crabs
            • Subphyla Myriapoda [13,000]
              Class Chilopoda--centipedes
              Class Diplopoda--millipedes
            • Subphyla Chelicerata [75,000]
              Class Arachnida [75,000]--spiders, scorpions, ticks, mites
              Class Merostomata [1]--horseshoe "crab"

            1. Until recently, most classifications included only humans in the family Hominidae other apes were put in the family Pongidae. The evidence linking humans to gorillas and chimps has grown dramatically in the past two decades, especially with increased use of molecular techniques. It now appears that chimps, gorillas, and humans form a clade of closely related species See Hominidae at Primates.com

            The the chimpanzee/human split occurred between five and seven million years ago. Subspecies are animal groups that are related, can interbreed, and yet have characteristics that make them distinct from one another. Two basic ingredients are critical to the development of separate subspecies: isolation and time. Unlike most animals, humans are a relatively young species and we are extremely mobile, so we simply haven't evolved into different subspecies.

            Many other animal species have been around much longer or they have shorter life spans, so they've had many more opportunities to accumulate genetic variants.

            Domesticated animals such as dogs also have a lot of genetic diversity, but this is mostly due to selective breeding under controlled conditions.

            Race:
            Many articles refer to Neanderthal as a race. I think they are using race to distinguish from the "human race" not the what we refer to as different races today.

            When it comes to using "race" as a classification, race is not a scientifically-precise term. Genetically speaking, there is less than a 1% difference between negroids, caucasoids and mongoloids. Humans of different races are more than 99% alike genetically. Race is more of a political and quasi-biological term.
            Source The Politics of Egyptology and the History Kemet (Egypt)

            • 350 BC - Aristotle - living things were animated by a vital force different from anything found in nonliving matter. This force was interpreted as a perfecting principle, operating to improve the living world. Out of this concept was developed the "scale of nature" idea that suggested living things were arranged on a scale of perfection, with man at the top.
              He originated the concept of genera (used in a much broader sense than present-day biologists use the term) and then distinguished the species.
            • 300 BC - Theophrastus, a student of Aristotle, classifies 500 plants under herbs, shrubs, pre-shrubs & trees.
            • Middle Ages - Early Christian theologians (Augustine 354-430 and Thomas Aquinas 1225-1275) rejected a literal interpretation of the story of special creation (which is common to most religions) and suggested instead a naturalistic interpretation patterned after Aristotle. A refutation of Augustine and Thomas Aquinas, and an insistence on a literal interpretation of Genesis began in the 13th century with a banning of Arabian science and philosophy (most of it translated Greek books) and this continued to the middle of the 19th century.
            • 1758 - Carolus Linnaeus (Karl von Linné) Swedish Naturalist- ( Linnean System ) - Introduced Class, Order, Genus & Species and Binomial Nomenclature (A system in which two names are employed. The first name represents the genus the second a specific name.) in " Systema naturae ". His system, the Linnaen System , which included the 7 level taxonomy (Kingdom, Philum, . ) was based on the most evident characteristics of organisms - their morphology.
            • 1859 - Charles Darwin "The Origin of Species by means of natural selection"
              This started a new effort to classify groups which had descended from a common ancestor.
            • 1866 - Ernst Haeckel Organized a " tree of life " and proposed new kingdom Protista for protozoa and most algae.
            • Early 20th century - The systematics movement was characterized by the detailed sutdy of organisims as members of populations
            • 1942 - Ernst Mayr publishes " Systematics and the Origin of Species from the Viewpoint of a Zoologist " - The major problem with the evolution of taxonomy is that it was created before Darwin and was too slow in adopting the evolutionary relationship between species.

            Books/Papers:
            "The Growth of Biological Thought", Ernst Mayr
            "Principles of Systematic Zoology", Ernst Mayr
            Systematics and the Origin of Species, 1995, Ernst Mayr
            "Full House", 1996, Steven Gould
            "International Code of Zoological Nomenclature (ICZN)"
            "Life Evolving", 2002, Christian de Duve
            Life: The Science of Biology, by Purves et al., from Sinauer Associates


            Phylum Chordata – Chordates

            This phylum has some of the most familiar animals, including mammals such as humans. It has vertebrates such as reptiles, birds, and mammals marine invertebrates such as sea squirts and sea tulips and segmented marine animals (such as lancelets) with elongated bodies. Along with hagfish, vertebrates comprise the subdivision Craniata. Others include tunicates (Urochordata) and lancelets (Cephalochordata). Characteristic features of chordates include a notochord, a hollow dorsal nerve cord, pharyngeal slits, and a post-anal tail. Most of these animals are found to have one or more of these features, at least for a short period during their life cycles.

            Class Mammalia – Mammals

            These animals have hair or fur, and are capable of regulating body temperature, give birth to fully-formed babies, and produce milk to feed their young ones. Examples of mammals are monkeys, dogs, elephants, hippopotamuses, squirrels and other rodents, koalas, kangaroos, and humans. Marine mammals include whales and dolphins.

            Class Amphibia – Amphibians

            Amphibians lay eggs, usually in water. Most of them breathe through the lungs and skin. While some have gills, there are certain amphibians that breathe only through the skin as they lack lungs. These animals cannot regulate their body temperatures and can live both on land and in water. While some species are arboreal, there are some fossorial amphibians too.

            Class Reptilia – Reptiles

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            Reptiles have roamed the Earth before the age of dinosaurs, and these animals adapt well to changes in the environment. Dinosaurs were actually a clade of reptiles known as Dinosauria. Examples of extant reptiles are alligators, crocodiles, lizards, snakes, tortoises, etc. These animals cannot regulate body temperature on their own. Other features include dry skin covered with scales and amniotic eggs.

            Class Aves – Birds

            There are over 8000 different species of birds that include parrots, sparrows, pigeons, geese, sea gulls, etc. They have feathered wings, which enable them to fly beaks without teeth and light bones that make their flight easy. Birds can breathe even at high altitudes, and they lay hard-shelled eggs.

            Water is home to more than 20,000 different types of fish. They have gills and lack limbs. Earlier fish belonged to the class Pisces, but this classification is not in use anymore. Some examples of fish are sharks, goldfish, and herring.

            Phylum Echinodermata – Echinoderms

            The echinodermata phylum consists of animals such as star fish, sea urchin, sea cucumber, etc. The phylum has around 7000 species of marine animals with pentamerous (five-point) symmetry. Most of these animals are star-shaped, spherical, or elongated. Most of them have a spiny exoskeleton and lack a distinct head. Locomotion is achieved with the help of tubed feet.

            Phylum Hemichordata – Hemichordates

            The phylum has around 100 species that possess some of the characteristics of chordates. This is why the phylum is named Hemichordata. The characteristic feature of these marine animals is that their bodies are divided into three parts – the anterior part with a preoral lobe, a collar, and the trunk. Acorn worms are among the prominent members of this phylum. They are solitary, worm-like organisms that live in burrows. Others include pterobranchs (seen in colonies) and graptolites.

            Phylum Xenacoelomorpha

            This is a new phylum that has xenoturbellids and acoelomorphs. It has been discovered that these simple marine worms are closely related to sea urchins and even humans. So, it was decided to classify them under the infrakingdom Deuterostomia. Though xenoturbellids and acoelomorphs have a simple body structure, scientists believe that they have a common ancestor. It is also believed that the other complex deuterostomes descended from this ancestor.

            Phylum Cnidaria – Jellyfish, Sea Anemones …

            Commonly known as Cnidarians, there are around 9000 species of aquatic animals in this phylum. Most of them are found in marine water, and many have specialized stinging organelles. The most popular Cnidarians are jellyfish, sea anemones, corals, and Portuguese man-of-war. This group usually consists of two types of animals, namely the polyps (fixed, solitary, or colonial life) and medusae (free-swimming). Reproduction is asexual (budding) in polyps and sexual in medusae.

            Phylum Ctenophora – Comb Jellies

            Otherwise known as comb jellies or sea walnuts, Ctenophores are marine animals with gelatinous bodies. They have hair-like cilia that help them swim. These tufts of cilia have a comb-like appearance, and so, the animal got the name comb jelly. There are around 100 to 150 species of Ctenophores, and most of them are hermaphrodites.

            Phylum Placozoa

            Placozoans are non-parasitic, multicellular animals that are considered as the most simplest form of invertebrates. The body of a Placozoan is made of thousands of cells that are arranged as a plate with two layers. The flattened body of a Placozoan has a thickness of around a millimeter, and it moves with the help of cilia. Though it is believed that the phylum has a single genus Trichoplax, with a single species Trichoplax adhaerens, it has been speculated that there are more placozoans in the world. Treptoplax reptans is another species that was described in 1896. However, the organism was not seen after that year.

            Phylum Porifera – Sponges

            This phylum consists of simple multicellular animals that are mostly found in aquatic habitats. A typical sponge has pores known as ostia, found all over the body, and a large opening on the top, called the osculum. The body cells are held together so loosely that they do not form tissues. Food and oxygen are circulated through the numerous channels in the body. Reproduction can be sexual or asexual. There are around 15,000 extant species that are categorized into three classes. There is a fourth class that consists of some extinct species.

            Phylum Arthropoda – Insects, Arachnids, Crustaceans …

            With more than a million described species, Arthropoda is considered the largest phylum in the animal kingdom. All arthropods have jointed legs and visible exoskeletons that are shed periodically. Examples of arthropods include arachnids (scorpions, spiders, etc.) insects such as wasps and weevils crustaceans (crabs and lobsters) and myriapods such as centipedes and millipedes. Arthropods have a bilaterally symmetrical body, that is segmented into the head, thorax, and abdomen. The jointed legs enable easy walking, swimming, feeding, and feeling. Book lungs form the respiratory organ in these animals.

            Phylum Kinorhyncha – Mud Dragons

            This phylum is made up of around 15 species of marine invertebrates that dwell in mud or sand. Commonly known as mud dragons, these animals have a length of less than one millimeter. The body of a Kinorhynch has 13 segments with numerous spines. The outer membrane secretes a tough cuticle, which is shed several times, till the organism turns into an adult.

            Phylum Loricifera

            There are around 100 species of Lorciferans that are microscopic animals which are found in marine sediments. Though a Lorciferan is microscopic, its body is made up of around 10,000 cells, and it has a brain, digestive system, excretory organs, and a host of specialized organs. It has a protective outer covering that helps the organism to attach itself to gravel.

            Phylum Nematoda – Roundworms

            This phylum consists of numerous species with varying habitats. Many of them are parasitic in nature. Ascaris, filarias, hookworms, pinworms, and whipworms, are some nematodes that are parasitic on humans. Some are beneficial for pest control, and they are used for biologic elimination of certain insects. They have tube-like bodies with a round cross-section longitudinal muscles and a tough cuticle.

            Phylum Nematomorpha – Horsehair Worms

            This phylum has around 200 species of long, slender worms that are found in different parts of the world. While most of them inhabit fresh-water habitats, some are found in marine waters too. They are endoparasitic in aquatic crustaceans and arthropods during their larval and juvenile stages. They look similar to nematodes and hence, the name Nematomorpha. These organisms have a length of around 50 to 100 centimeters, and they are found to tie themselves in knots. So, they are also termed as Gordian worms (derived from the Gordian knot).

            Phylum Onychophora – Velvet Worms

            There are more than 100 species of terrestrial, worm-like organisms in the phylum Onychophora. They have slightly flat cylindrical bodies and multiple stub feet that are hollow. They have slime glands which produce adhesives that harden rapidly. These organisms squirt the slime at their prey and entangle the latter.

            Phylum Priapulida – Penis Worms

            These marine worms are named after their eversible proboscis, which is shaped like a penis. So, the phylum is named after the Greek God of fertility – Priapus. These worms are mostly seen in shallow waters and mud. They can be seen in varying sizes that may range from 1 mm to 40 cm. A penis worm has a cylindrical body, and its proboscis has longitudinal ridges.

            Phylum Tardigrada – Water Bears

            As the name rightly suggests, the organisms that make up this phylum live in water. These organisms can tolerate a wide range of extreme temperature and pressure. They can also withstand strong radiations that are more than lethal for humans. A Tardigrada has a segmented body and eight legs. There are around 1200 species in this phylum.

            Phylum Annelida – Segmented Worms

            This group consists of segmented worms, such as earthworms and leeches. There are around 17,000 species of annelids that are found in a wide range of habitats. While some are terrestrial, others can be found in freshwater as well as the marine environment. Most of the segmented worms have soft bodies that are bilaterally symmetrical. Each segment has bristles (known as chaetae) which help them move. While reproduction is usually sexual, they can also regrow broken body segments.

            Phylum Brachiopoda – Lamp Shells

            These marine organisms resemble clams in appearance. There are around 300 species of Brachiopods which are usually found in the extreme cold waters in the depth of oceans. Each individual has two unequal shells that are located on the upper and lower sides of its body. The shells are joined at the rear part, while the front remains open. There are two types of Brachiopods – articulate and inarticulate. Articulates have toothed hinges, whereas inarticulates have untoothed hinges.

            Phylum Bryozoa – Sea Mats

            This phylum has around 4000 aquatic invertebrate animals that are often found to live in colonies, that are attached to substrates. The members of each colony are found to be genetically identical. Each individual has a length of around 0.5 mm, and has a specialized structure (called lophophore) that helps it in filter feeding. The retractible lophophore has tentacles with cilia. While most of the species are colonial, the phylum has some solitary species too. Certain species discovered recently, float instead of attaching themselves to substrates.

            Phylum Kamptozoa (Entoprocta) – Goblet Worms

            These tiny, transparent aquatic animals have goblet-shaped bodies with long stalks. The goblet-shaped part has tentacles with cilia. These tentacles move and generate water currants, so that food particles can be drawn into the mouth. Both the anus as well as the mouth are located in this part. While most of them grow in colonies, certain species are solitary. There are around 200 species in this phylum.

            Phylum Mollusca – Molluscs

            With around 100,000 species, Mollusca is the largest phylum of marine animals. This phylum includes slugs, snails, squids, mussels, clams, and even octopuses. Slugs and snails make up 80% of the phylum. Most of the molluscs have a strong, muscular foot that helps them to swim, attach themselves to substrate, and burrow. They possess a rasping tongue that can rip off materials. While a majority of them are marine, some are terrestrial and others live in freshwater. Those living in water breathe through gills, while those living on the land have fully developed lungs.

            Phylum Nemertea – Ribbon Worms

            Also known as proboscis worms, there are around 1200 species in the phylum Nemertea. Members of this phylum are found across the world, and many of them inhabit marine waters. They have long, thin bodies with the mouth at one end, and the anus at the other. They have a proboscis that is almost as long as their bodies. It is kept inside the cavity called rhynchocoel. The organism ejects its proboscis so as to catch prey.

            Phylum Phoronida – Horseshoe Worms

            Like Bryozoans, Phoronids are marine animals that indulge in filter feeding, using their lophophores. The body of a horseshoe worm has three parts – the lophophore (with tentacles) located near the mouth, the tube-like trunk, and a flask-shaped bottom (ampulla). Food is drawn into the mouth by the lophophore, which is also responsible for gaseous exchange. Digestion happens in the ampulla. When threatened, the animal may retract into the ampulla.

            Phylum Sipuncula – Peanut Worms

            This phylum has around 150 to 200 marine worms that are mostly found in deep oceans. These unsegmented worms have cylindrical trunks, and a retractible anterior part called the introvert. The mouth, which is located at the tip of the introvert, is mostly surrounded with tentacles. When threatened, these worms retract their bodies and resemble peanut kernels in shape. So, they are also called peanut worms.

            Phylum Acanthocephala – Spiny-headed Worms

            There are around 1150 species of parasitic worms in this phylum. They have a retractible proboscis which is globular or cylindrical in shape. The proboscis has spines that are used for burrowing into the gut of the host. The spines are also beneficial for holding on to the gut wall. Even the body of this worm may have spines. During the early stage of their lives, these worms live inside invertebrates, and later they inhabit the gut of vertebrates.

            Phylum Gastrotricha – Gastrotrichs

            This phylum has around 700 species of small, worm-like organisms that are found in both marine and freshwater habitats. Some species are terrestrial and can be found on land. The body of a gastrotrich is covered with spines, bristles, or scales. Most of them have adhesive glands, which help them get attached to substrates. The cilia on their bodies aid movement. The body is spindle-shaped and ventrally flat, and the head is less distinct.

            Phylum Gnathostomulida – Jaw Worms

            This phylum has a few species of microscopic marine worms that inhabit the mud and sand in shallow coastal waters. Most of them have a maximum body length of 1 mm, and are slender. They have a ciliated covering and the cilia help them in movement. The mouth is located beneath the head. The characteristic feature of these worms is their muscular pharynx with strong jaws that are shaped like forceps. Hence the name jaw worms.

            Phylum Micrognathozoa

            This phylum has a single genus that has only one species – Limnognathia maerski. These microscopic animals are found in the homothermic springs located in Disko Island, Greenland. They are among the smallest animals on the Earth, as they have a length of around one-tenth of a millimeter. Though minute, this organism has a large brain and a jaw that has 15 separate segments,

            Phylum Orthonectida – Orthonectids

            This is also a small phylum with a few small parasitic animals. They are multicellular animals that are parasitic on marine invertebrates. These ciliated animals move freely inside the bodies of their hosts. The phylum has around 20 species that are classified into two families.

            Phylum Platyhelminthes – Flatworms

            This phylum has around 30,000 species with unsegmented, flat, soft bodies. While some species are free-living, many are parasitic in nature. Parasitic flatworms have a complex life cycle with multiple hosts. Flatworms derive nutrients and oxygen through their body surfaces, and they lack body cavities. Flukes and tapeworms belong to this phylum.

            Phylum Rhombozoa (Dicyemida)

            This phylum has tiny parasites with simple body structures. The body of a Rhombozoan is made up of an axial cell that is covered with ciliated cells. The organism uses the anterior part of its body to attach itself to the renal appendages of cephalopods. In short, Rhombozoans are parasitic on cephalopods.

            Phylum Rotifera – Rotifers

            Rotifers are free-living, aquatic animals that are microscopic in size. The phylum has around 1700 species, and most of them are found in freshwater bodies. While some are sessile, other move freely. These animals have varying body shapes, but are mostly cylindrical. Their characteristic feature is the corona with a ring of cilia, on the head.

            Phylum Chaetognatha – Arrow Worms

            The phylum has around 125 species of predatory marine species. Most of them have long, transparent bodies. The body of an arrow worm has a distinct head, trunk, and tail. It has hooks and spines on both sides of its head. These carnivorous animals use these hooks and spines for catching prey.

            This is only a brief overview about classification of animal species. With millions of animal species on the Earth, it is difficult to describe each class, order, family, genus, and species. Hope the article has helped you understand how different types of animals are classified under different phyla.

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            Is amphibians being descended from fish reflected in the animalia taxonomy? - Biology

            After spelling out the rationale for taxonomy, an annotated classification of living primates is given.

            Taxonomy is the study of the principles and practice of classification, and is commonly used as a synonym for systematics, although the latter is, in principle, broader, covering all aspects of relationships among organisms.

            The basis of taxonomy is the taxon (plural taxa). A taxon is any classificatory group, and there is a hierarchy of them: species, genus (plural genera), family, order, class, phylum (plural phyla), kingdom. The kingdom Animalia (the animals) is divided into a number of different phyla, including Chordata (more or less, the backboned animals). Each phylum is split into different classes one of the classes of the Chordata is the Mammalia (the mammals). Each class is split into different orders one of the orders of the Mammalia is the Order Primates. Each order is split into different families, each family into different genera, each genus into different species. (It may also happen that there is only one known species in a particular genus, only one known genus in a particular family, and so on.) The hierarchy is thus a nested one.

            These seven ranks of the taxonomic hierarchy are known as the obligatory ranks: every animal species is classified into a genus, each genus into a family, and so on up. If finer degrees of classification are required, the obligatory ranks can be subdivided: suborders, then infraorders, then parvorders can be inserted below the rank of order, subfamilies can be inserted to split up large families which contain many genera, and the rank “tribe” can be inserted below subfamily, and other subordinate ranks can be inserted. Groups of families can be combined in a superfamily. Note that these “sub-” and other subordinate categories are inserted only when needed but it is mandatory to list the seven ranks mentioned earlier.

            But on what basis are organisms classified? For the palaeontologist Simpson, who was the leading mammalian taxonomist of the mid-twentieth century, the main purpose of a classification is “simply to provide a convenient, practical means by which zoologists may know what they are talking about and others may find out”—that is to say, a classification is an aide-mémoire and filing system—but “it is also a secondary but still essential aim that classification should be consistent with the most important thing that evolutionary taxonomists have to talk about, that is, with animal affinities” (Simpson 1945 , 13).

            Simpson was representative of most, perhaps all, zoological taxonomists of his day, but it was not long before a revolution spread through the field with the work of the entomologist Hennig (1950/1966), who rejected Simpson's argument that a classification is primarily a mnemonic and filing system, and insisted that its overwhelming task is to represent affinities. Curiously, the question of what precisely is meant by “affinities” had never previously been approached in a rigorous way, and it is clear that Simpson and others used the term rather loosely, to express not only phylogeny but also general resemblances: Hennig argued that “affinity” should mean relatedness, that is to say, recency of common ancestry. Thus two taxa should be classified together in an exclusive higher taxon for no other reason than that they share an exclusive common ancestor. A taxon whose members are all descended from an exclusive common ancestor is said to be monophyletic, and in the Hennigian scheme all taxa are therefore monophyletic. Two taxa that are each other's closest relatives, in other words that arose at the same time from a common ancestor, are called sister groups.

            The Hennigian scheme, known as phylogenetic systematics, has swept the board, and it is probable that all specialists in animal taxonomy basically adhere to it. In some respects, therefore, a taxonomic scheme is a representation of a phylogeny.

            There are some practical limitations. The most obvious is that whereas most evolutionary splits in the past are thought to have been dichotomous (giving rise to a pair of sister groups), it is not always practicable to erect dichotomous taxonomic groups—either because a given sequence of evolutionary splits may have occurred quite rapidly (or, indeed, there may actually have been a polytomy rather than a simple dichotomy), or simply because we run out of ranks! “Running out of ranks” has been quite a problem in the past, and has been the stimulus for the invention of yet more intermediate ranks in the hierarchy: the parv-rank, below the infra- rank, is one example, so we get, for instance, parvorders. Even before the coming of phylogenetic systematics, Simpson and others grouped related orders into a cohort. Some taxonomists object strongly to this proliferation of ranks, and point out that they mean different things in different phyla, and some would like to do away with ranks altogether and name only phylogenetic nodes, by a phylocode. This is a minority view, although it has a certain rationale but there are ways of making the higher ranks work for us.

            As described, in taxonomy the principle of monophyly reigns supreme. An example is the classification of the human species. In the past, it was usual to split the superfamily Hominoidea into three families: Hylobatidae (for the lessor apes), Pongidae (for the great apes), and Hominidae (for humans and their ancestors). After all, as argued by Simpson and his contemporaries, do not chimpanzees and gorillas physically resemble orangutans, while humans stand apart in their morphology? However, ever since the middle of the twentieth century it has been acknowledged that some great apes (gorillas and chimpanzees) are evolutionarily closer to humans than they are to other great apes (orangutans), so the family Pongidae is clearly nonmonophyletic. This does not conform to the requirements of phylogenetic systematics, so gorillas and chimpanzees are nowadays classified in a grouping with humans, and orangutans are placed in a separate group (see below, in the classification). While the Hennigian scheme is, as noted earlier, adopted by taxonomic specialists, it must be admitted that outside the specialist field there are still a few holdouts who are devoted to the ways of the early twentieth century and continue to reserve the family Hominidae for humans alone, and to recognize the nonmonophyletic family Pongidae!

            Of the ranks in the taxonomic hierarchy, only species can be shown to have a real existence. The objective existence of species contrasts with the arbitrary nature of the other ranks, but unless we abolish rankings altogether we can introduce some degree of objectivity into them. Monophyly tells us which taxa should be grouped together at any given level, but obviously some other criterion must be invoked to tell us at what level they should be grouped: a genus, a family, an order?

            It was Hennig himself who asked this question: under what circumstances should we classify a given taxon at a particular rank in the hierarchy? He proposed that the criterion for assessing what taxonomic rank is appropriate should be time: the time since a given taxon separated from its sister group. If the separation was in the Eocene, it should be classified at one rank, if in the Jurassic, at a higher rank—and so on. However, Hennig immediately recognized that this is not possible, if the whole of the animal kingdom is to be classified consistently: as currently recognized, families of insects are far older than families of mammals, and indeed the insect genus Drosophila (the fruit flies of genetics fame) is probably as old as most orders of mammals! Goodman et al. in 1998 , followed by Groves in 2001 , suggested that we organize taxonomic rankings only within particular classes, acknowledging that the time/rank associations in mammals and birds would be very different from those in amphibians, and these in turn would be very different from those in insects. They proposed that within mammals we should recognize as orders those taxa that separated from their closest relatives around the Cretaceous–Tertiary (K/T) boundary as families, those that separated about the Oligocene/Miocene boundary and as genera, those that separated around the Miocene/Pliocene boundary. Whether we should assign time ranking to suborders, infraorders, subfamilies, and so on is questionable: after all, these subdivisions are not part of the obligatory hierarchy (as described) but inserted as needed, so it is arguable whether they have the same sort of potential reality as the obligatory ranks. Be that as it may, the time/rank proposal seems to be gradually gaining some acceptance in primatology, though too many taxonomists still seem content to operate on a subjective basis.

            The naming of families, genera, and species is regulated by the International Code of Zoological Nomenclature. The rules, as laid down in the Code, bring order where there has been considerable chaos in the past, and have stabilized nomenclature. The name of a genus is a Latin or latinized singular word, and is always written in italics (like the name of a species), and always begins with a capital letter. The name of a species is also Latin or latinized it may be an adjective, a noun in apposition, or a genitive (like katanganus (of Katanga), or schmidti (of Schmidt), and always begins with a small letter and, in combination with the generic name, forms a binomial which uniquely designates the species in question (Macaca fascicularis, Eulemur mongoz).

            Sometimes what is in effect the same taxon turns out to have been described more than once, under two or more names. These names are called synonyms, and the rules of nomenclature enable taxonomists to decide which of the synonyms should be used (in principle, the one described earliest).

            The name of a family is derived from the name of one of its included genera, and ends with -idae (such as Cercopithecidae, the family that designates the Old World monkeys, the name being derived from Cercopithecus, one of its included genera). The names of subfamilies, if they are needed, end in -inae if still further subdivision is required, tribes are recognized within subfamilies, and they end in -ini. The names of superfamilies end in -oidea. There are no standard endings for orders (or suborders) or any higher categories.

            The codified rules of nomenclature must be followed by all biologists, as they are designed to provide standardized names for potentially valid taxa. If a taxonomist finds evidence that two genera, formerly thought to be distinct, are actually the same (i.e., they are synonymous), then the rules of nomenclature tell the taxonomist which name to use for the newly combined genus. If a taxonomist finds that a single genus ought to be split into two, then again the rules of nomenclature tell the taxonomist which of the two must bear the name of the old, pre-split genus, and what the name of the other genus should be. As a general rule, “priority” is the watchword: the earliest name (called the senior synonym) should be used, although sometimes for one reason or another the International Commission on Zoological Nomenclature rules that one of the junior synonyms should be used. The International Code of Zoological Nomenclature is now in its fourth edition (which came into force at the beginning of the year 2000).

            Fossils also need to be incorporated into this scheme. Whereas some fossil taxa (the Proconsulidae, for example) have a considerable time depth and have their own clearly defined derived features, and can be slotted in alongside the families thought to be their closest relatives in the living fauna, others (such as Morotopithecus) were of very limited time duration and, having no detectable derived features, could even be common ancestors to two or more living (or long-lasting) taxa. It has been suggested that these short-lived and potentially ancestral taxa should be left unranked and given the status of “Plesion.”

            If there is evidence to suggest that some ranking “universally accepted” is wrong, then the classification has to be changed—as long as this new evidence is good, and it does not look as if any future discoveries will alter things. The Notes given in Table 1 draw attention to instances where it does seem that the “accepted” classification is incorrect, or may be, and so deserves further study.

            Notes
            Suborder Strepsirrhini Up to the time of Simpson (1945), taxonomists would divide primates into Prosimii (or Lemuroidea) and Anthropoidea. The difference between this division and the one nowadays adopted, into Strepsirrhini and Haplorrhini, is the position of the tarsiers and their extinct relatives. A group that includes tarsiers in the same suborder as lemurs and lorises is clearly nonmonophyletic, so the concept of a suborder Prosimii must be rejected.
            Infraorder Lemuriformes Family Lemuridae Genera: Lemur, Eulemur, Hapalemur, Prolemur, Varecia Prolemur used to be regarded as a synonym of Hapalemur, but the two are not sister groups (Hapalemur is sister to Lemur).
            Family Cheirogaleidae Subfamily Cheirogaleinae Genera: Cheirogaleus, Microcebus, Mirza, Allocebus There are some very deep (Middle Miocene) divisions within Microcebus, so extra genera will probably have to be recognized within what is at present a single genus.
            Subfamily Phanerinae Genus: Phaner
            Subfamily Lepilemurinae Genus: Lepilemur DNA studies sometimes associate Phaner with the dwarf lemurs (Cheirogaleus and its relatives), sometimes with Lepilemur. As Lepilemur shares a common stem with dwarf lemurs, subsequent to their separation from Lemuridae and Indriidae, it has been suggested by Masters et al. (2014) that we regard it as a member of the Cheirogaleidae, rather than as representing a family by itself, and, given the lack of resolution of the relationships of Phaner, we should recognize three more or less equal subfamilies in the Cheirogaleidae.
            Family Indriidae Genera: Indri, Propithecus, Avahi
            Infraorder Lorisiformes Family Lorisidae Genera: Loris, Nycticebus, Perodicticus, Arctocebus
            Family Galagidae Genera: Galago, Galagoides, Euoticus, Sciurocheirus, Otolemur
            Suborder Haplorrhini
            Infraorder Tarsiiformes Family Tarsiidae Genera: Tarsius, Cephalopachus, Carlito
            Infraorder Simiiformes (or Anthropoidea) It has been pointed out that the name Anthropoidea, more especially in the form of its vernacular derivative “anthropoids,” has been used in a variety of ways, and risks confusion. For this reason, some authors prefer the name Simiiformes.
            Parvorder Platyrrhini Family Cebidae Subfamily Cebinae Genera: Cebus, Sapajus, Saimiri
            Subfamily Aotinae Genus: Aotus
            Subfamily Callitrichinae Genera: Callithrix, Mico, Callimico, Saguinus, Leontopithecus The proposed genera Cebuella and Callibella seem to have separated from Mico only during the Pliocene, or even the Pleistocene, so under a time/rank association system they cannot stand (Schneider et al. 2011 ).
            Family Atelidae Subfamily Atelinae Genera: Ateles, Lagothrix, Brachyteles It has been proposed that a further genus, Oreonax, should be recognized in the subfamily, but the species it represents (O. flavicauda) separated from conventional species of Lagothrix only in the Earliest Pleistocene (Di Fiore et al. 2015 ).
            Subfamily Alouattinae Genus: Alouatta
            Family Pitheciidae Subfamily Pitheciinae Genera: Pithecia, Chiropotes, Cacajao
            Subfamily Callicebinae Genus: Callicebus
            Parvorder Catarrhini Superfamily Cercopithecoidea Family Cercopithecidae The time division between the two subfamilies of this family may be older than has previously been appreciated, such that they should be separated at family rank.
            Subfamily Cercopithecinae Tribe Cercopithecini Genera: Cercopithecus, Erythrocebus, Chlorocebus, Allochrocebus, Miopithecus, Allenopithecus
            Tribe Papionini Genera: Macaca, Papio, Theropithecus, Lophocebus, Mandrillus, Cercocebus These genera fall into three groups which are often recognized as tribes, but no tribes are recognized here because some of the genera may not be valid for example, Theropithecus and Lophocebus may have separated from Papio only in the Pliocene, while Mandrillus may be nested within Cercocebus. On the other hand, time depths between some species-groups within Macaca may well be greater than between traditional genera.
            Subfamily Colobidae Genera: Colobus, Piliocolobus, Procolobus, Semnopithecus, Trachypithecus, Pygathrix, Nasalis, Rhinopithecus The separation between Cercopithecidae and Colobidae appears to be around the Oligocene/Miocene boundary, so they should be separated at family level. Relationships among the genera are difficult to disentangle, in part because there appears to have been a great deal of hybridization and consequent gene exchange between some of the Asian genera in their early stages (Roos et al. 2011 ). A genus Simias is usually recognized, but the species it represents (S. concolor) separated from (the single species of) Nasalis only in the Early Pleistocene (Liedigk et al. 2012 ).
            Superfamily Hominoidea Family Hylobatidae Genera: Hylobates, Hoolock, Nomascus, Symphalangus Some data suggest that the Hylobatidae separated from the Hominidae only in the Early Miocene, in which case the division between these two families should be abolished (the prior available name for a united family would be Hominidae).
            Family Hominidae Subfamily Ponginae Genus: Pongo
            Subfamily Homininae Genera: Homo, Pan, Gorilla There are some purely fossil genera allocated to the human lineage most of them have a very shallow time depth, so should probably be synonymized with Homo, but if there are indeed any valid genera involved, then the three modern genera should each be made to typify a separate tribe (Hominini, Panini, Gorillini).

            Taxonomy is a specialized field of endeavor, and although it is perfectly possible for nonspecialists to practice the science, training in the field is required. In particular, the rules of nomenclature are poorly understood outside the field, as is species theory.


            The Linnaean system

            Carolus Linnaeus, who is usually regarded as the founder of modern taxonomy and whose books are considered the beginning of modern botanical and zoological nomenclature, drew up rules for assigning names to plants and animals and was the first to use binomial nomenclature consistently (1758). Although he introduced the standard hierarchy of class, order, genus, and species, his main success in his own day was providing workable keys, making it possible to identify plants and animals from his books. For plants he made use of the hitherto neglected smaller parts of the flower.

            Linnaeus attempted a natural classification but did not get far. His concept of a natural classification was Aristotelian i.e., it was based on Aristotle’s idea of the essential features of living things and on his logic. He was less accurate than Aristotle in his classification of animals, breaking them up into mammals, birds, reptiles, fishes, insects, and worms. The first four, as he defined them, are obvious groups and generally recognized the last two incorporate about seven of Aristotle’s groups.

            The standard Aristotelian definition of a form was by genus and differentia. The genus defined the general kind of thing being described, and the differentia gave its special character. A genus, for example, might be “Bird” and the species “Feeding in water,” or the genus might be “Animal” and the species “Bird.” The two together made up the definition, which could be used as a name. Unfortunately, when many species of a genus became known, the differentia became longer and longer. In some of his books Linnaeus printed in the margin a catch name, the name of the genus and one word from the differentia or from some former name. In this way he created the binomial, or binary, nomenclature. Thus, modern humans are Homo sapiens, Neanderthals are Homo neanderthalensis, the gorilla is Gorilla gorilla, and so on.


            Diversity in Living Organisms Class 9 Extra Questions Science Chapter 7

            Extra Questions for Class 9 Science Chapter 7 Diversity in Living Organisms

            Diversity in Living Organisms Class 9 Extra Questions Very Short Answer Questions

            Question 1.
            Which organisms are called primitive?
            Answer:
            Primitive organisms are those which have ancient body design and have not changed very much with the passage of time.

            Question 2.
            Name the branch of science that deals with classification.
            Answer:
            Taxonomy

            Question 3.
            What is biological classification?
            Answer:
            The system of arrangement of different plants and animals in different groups on the basis of their similarities and differences is called biological classification.

            Question 4.
            Who was the first to classify animals according to their habitats?
            Answer:
            Aristotle was the first one to classify animals according to whether they lived on land, in water or in air.

            Question 5.
            What is ‘binomial nomenclature’?
            Answer:
            It is the system of naming in which the scientific name of an organism hasTwo components, i.e., genus and species.

            Question 6.
            What is evolution?
            Answer:
            The life forms that exist today have risen because of changes in their body design over a course of time to adapt themselves in the changing conditions. This is called evolution.

            Question 7.
            Who gave the idea of evolution for the first time in the book ‘Origin of Species’?
            Answer:
            Charles Darwin

            Question 8.
            What is a genus?
            Answer:
            A genus is a group of related species.

            Question 9.
            Which groups of organisms do not have a defined nucleus or organelles?
            Answer:
            Monera

            Question 10.
            Name the largest animal on the planet.
            Answer:
            Blue whale (30 metres)

            Question 11.
            Name the largest tree on the Earth.
            Answer:
            Redwood (100 metres)

            Question 12.
            Which plant has life span of more than one thousand years?
            Answer:
            Pine trees

            Question 13.
            What are the three aspects of systematics?
            Answer:
            Identification, nomenclature and classification.

            Question 14.
            Name a coelenterate that occurs singly and is commonly found in freshwater ponds.
            Answer:
            Hydra

            Question 15.
            Name the group of sessile animals.
            Answer:
            Porifera

            Question 16.
            Name an organism that possesses flagella.
            Answer:
            Euglena

            Question 17.
            What are corals?
            Answer:
            Corals are marine coelenterates that live in colonies firmly attached to rocks.

            Question 18.
            Name two marine solitary coelenterates.
            Answer:
            Jelly fish and sea anemone.

            Question 19.
            Name the group of animals, which developed nervous system for the first time.
            Answer:
            Coelenterates

            Question 20.
            In which sub-division does xylem possess vessels?
            Answer:
            Angiosperms

            Question 21.
            Name the organism which has nervous system but no brain.
            Answer:
            Hydra

            Question 22.
            Which plants are perennial, evergreen and woody?
            Answer:
            Gymnosperms

            Question 23.
            Name the reproductive organs of gymnosperms.
            Answer:
            Cone

            Question 24.
            Name free living and parasitic flatworms.
            Answer:
            Free living: Planaria Parasitic: Tapeworm and liver fluke.

            Question 25.
            What are hermaphrodites?
            Answer:
            The animal that possess both male and female reproductive organ is called hermaphrodite, e.g., earthworm.

            Question 26.
            Name the group of animals, which has primitive nervous system but with brain which is developed for the first time.
            Answer:
            Platyhelminthes

            Question 27.
            Name the first group of animals with true coelom.
            Answer:
            Annelida

            Question 28.
            Define metameric segmentation.
            Answer:
            Metameric segmentation is a type of segmentation where external divisions correspond to internal divisions.

            Question 29.
            Name the cavity present in the coelenterates.
            Answer:
            Coelenteron

            Question 30.
            What is haemocoel?
            Answer:
            When a well-defined cavity is absent and the spaces present contain colourless blood, i.e., haemolymph, it is called haemocoel.

            Question 31.
            Give the names of two groups of animals that are haemocoelomate.
            Answer:
            Molluscs and arthropods

            Question 32.
            What are the skeletal elements in sponges?
            Answer:
            Needles called spicules and spongin fibres are the skeletal elements in sponges.

            Question 33.
            What are the excretory organs in flatworm?
            Answer:
            Protonephridia or flame cells.

            Question 34.
            What are cnidoblasts?
            Answer:
            The stinging cells present on the tentacles of coelenterates like Hydra, which inject hypnotoxin into the prey to hypnotise it.

            Question 35.
            What is the name given to the body cavity of nematodes?
            Answer:
            Pseudocoel

            Question 36.
            Name a parasitic annelid.
            Answer:
            Leech

            Question 37.
            What is polymorphism? Give an example.
            Answer:
            The presence of more than two types of individuals in a colony which differ in their structure as well as function is called polymorphism. E.g., honey bees.

            Question 38.
            Name two phyla which have open circulation.
            Answer:
            Mollusca and echinodermata

            Question 39.
            Name two phyla which have radial symmetry.
            Answer:
            Echinodermata and coelenterata

            Question 40.
            Why do amphibians do not possess exoskeleton?
            Answer:
            Amphibians do not possess exoskeleton as their skin is thin, moist and act as a respiratory organ.

            Question 41.
            Why do birds possess hollow bones?
            Answer:
            To make their body light in weight so as to make flying easier.

            Question 42.
            In which phylum are pharyngeal gill slits present?
            Answer:
            Phylum chordata

            Question 43.
            What do you mean by ‘characteristics’?
            Answer:
            Characteristics means a particular form or a particular function of any organism. For example, the presence of five fingers on each hand of a human being is a characteristic.

            Diversity in Living Organisms Class 9 Extra Questions Short Answer Questions-I

            Question 1.
            Why was the method of classification of animals proposed by Aristotle not accepted?
            Answer:
            Aristotle classified animals on the basis of their habitat, i.e., whether they live on land or in water. But these animals, otherwise are very different from each other in many respects and such a classification does not prove much helpful. So, the method of classification by Aristotle was not accepted.

            Question 2.
            Describe the hierarchical system of classification currently followed.
            Answer:
            Hierarchy of classification categories was established and designed by Linnaeus. Hierarchy of classification is a system of arrangement of a framework in order of logical sequence. The currently followed hierarchical system for all organisms is

            • Kingdom
            • Phylum/Division
            • Class
            • Order
            • Family
            • Genus
            • Species.

            Question 3.
            What are phanerogams?
            Answer:
            Phanerogams or spermatophyta are the most advanced type of plants bearing seeds. They have roots, stems, leaves and flowers. They include gymnosperms and angiosperms.

            Question 4.
            What are mycoplasma?
            Answer:
            Mycoplasmas are the smallest and the simplest organisms. They are prokaryotes having nucleoid. They have heterotrophic mode of nutrition and their body can change forms easily. They are also called as MLO, i.e., Mycoplasma Like Organisms.

            Question 5.
            List in tabular form, two distinguishing features of dicot plants with monocot plants.
            Answer:

            Question 6.
            What are lichens?
            Answer:
            Lichens are compound plants as algae and fungi live together in close association, as a result of which both are benefited. This relationship is called symbiosis. They occur as greyish green growths on rocks, bark of the tree or on the ground.

            Question 7.
            On which basis is the plant kingdom classified?
            Answer:
            The plants have been classified on the following basis:

            • Phylogeny and evolution.
            • Presence or absence of vascular tissue for transport of food and water.
            • Presence or absence of seeds.
            • Presence or absence of fruits.

            Question 8.
            Why are bryophytes called the amphibians of the plant kingdom?
            Answer:
            The plant bodies of bryophytes are devoid of vascular tissues and roots. So they live in moist habitats in order to obtain water directly or through rhizoids. Moreover, like the amphibians of animal kingdom, the sperms of bryophytes require an external water medium for reaching the eggs. Due to this reason, bryophytes are called the amphibians of the plant kingdom.

            Question 9.
            What are amphibians?
            Answer:
            Amphibians are the vertebrates that can live both on land and in water. That is why they are also called the vertebrates leading two lives. Their body varies in form and the skin is not covered with scales. They lay eggs in water and their larval forms always live in water. Also, amphibians are cold blooded animals having a three-chambered heart. They breathe through lungs or gills or skin.

            Question 10.
            What are reptiles?
            Answer:
            Reptiles are the crawling vertebrates that are cold-blooded and have dry horn scales. They are mostly terrestrial and live in warmer regions. They breathe through lungs. The heart is three-chambered, except for crocodiles which have four-chambered heart. Reptiles lay eggs with thick coverings.
            Examples: Snakes, lizards, crocodiles, turtles, etc.

            Question 11.
            What is notochord? What is its function?
            Answer:
            Notochord is a long rod-like support structure that runs along the back of the animals, separating the nervous tissue from the gut. It acts as a supporting structure by providing a place for muscles to attach for the ease of movement.

            Question 12.
            Why do we keep both snake and turtle in the same class? [NCERT Exemplar]
            Answer:
            Both snake and turtle are kept in the same class because both are

            • cold-blooded,
            • have scales,
            • breathe through lungs
            • have three-chambered hearts, and
            • lay eggs with thick covering.

            Question 13.
            Give reasons why mosses are found in humid and moist areas.
            Answer:
            The entire body of moss in damp humid places can absorb water. Moreover, sperms in mosses are flagellated and so they can reach the archegonia only in presence of water. Thus, water is indispensable in the life cycle of mosses for reproduction as well as for performing other physiological functions.

            Question 14.
            What is binomial nomenclature?
            Answer:
            In binomial nomenclature, name of every organism is composed of two components—the first one is generic (genus) and the second one is specific (species). Also, the generic name starts with a capital letter whereas the specific name starts with small letter. For example, the scientific name of man is “Homo sapiens”. Here “Homo” is the generic and “sapiens” is the specific name.

            Question 15.
            Which organism is more complex and evolved among bacteria, mushroom and mango tree? Give reasons. [NCERT Exemplar]
            Answer:
            Mango tree is more complex and evolved because, it is eukaryotic, autotrophic, terrestrial and a sporophyte with covered seed. The bacteria is a unicellular prokaryote and fungi is heterotrophic, simple thallophyte with no tissue system.

            Question 16.
            Endoskeleton of fishes are made up of cartilage and bone. Classify the following fishes as cartilagenous or bony:
            Torpedo, Sting ray, Dog fish, Rohu, Angler fish, Exocoetus [NCERT Exemplar]
            Answer:
            Torpedo — Cartilagenous,
            Dog fish — Cartilagenous
            Angler fish — Cartilagenous
            Sting ray — Cartilagenous
            Rohu — Bony
            Exocoetus — Bony

            Diversity in Living Organisms Class 9 Extra Questions Short Answer Questions-II

            Question 1.
            What is a species? Give its main features.
            Answer:
            Species is defined as a dynamic group of organisms, which resemble each other in all essential aspects, i.e., structure and function, and interbreed to produce fertile young ones of their own kind. The members of a species are reproductively isolated from other groups. They have descended from a common ancestor and have similar genetic material.

            Question 2.
            State reasons for each of the following:

            • Echidna and platypus lay eggs but are considered as mammals.
            • Forelimbs of birds are modified.
            • Crocodiles have four-chambered heart but are still reptiles.
            • They have mammary glands for the production of milk to nourish their young ones.
            • To reduce body weight for flight, forelimbs of birds are modified.
            • Crocodiles are cold blooded, lay eggs and have scale on their body. These characteristics make them reptile.

            Question 3.
            Differentiate between species and taxon.
            Answer:
            Species and taxon differ in the following ways:

            • Species represents the basic taxonomic category while the taxon represents any level of taxonomic category.
            • Species is always monophyletic while a taxon may be monophyletic or polyphyletic.
            • Species, being a rank, is an abstract term while a taxon represents a group of various living beings.

            Question 4.
            Give the general characters of kingdom Animalia.
            Answer:

            • In kingdom Animalia, all the members are multicellular eukaryotes with tissue differentiation.
            • They are heterotrophic with ingestive mode of intake of food.
            • They possess a well developed nervous system.
            • Muscular system is also well developed for locomotion.
            • They exhibit sexual reproduction.
              Sponge, molluscs, fishes, birds, reptiles and mammals all belong to kingdom Animalia.

            Question 5.
            Enlist the main features of organisms placed under Protista.
            Answer:

            • Most of the members are unicellular and primarily aquatic.
            • They have nucleus and typical eukaryotic cell organelles.
            • Most of the organisms bear flagella or cilia for movements.
            • Mode of nutrition is absorptive, ingestive or photo-autotrophic.
            • Reproduction may be asexual or sexual.

            Question 6.
            Give the main features of kingdom Fungi.
            Answer:

            • They are non-green because of the absence of chlorophyll.
            • They are heterotrophic and obtain food from dead and decaying organic matter by absorption.
            • The body organisation is mycelial or secondarily unicellular.
            • Cell wall is chitinous and cellulosic.
            • Asexual reproduction is by spore formation. Some also exhibit sexual reproduction.

            Question 7.
            Write the main characteristics of kingdom Plantae.
            Answer:

            • They are all complex multicellular plants which prepare their own food by photosynthesis.
            • They possess cell wall made of cellulose.
            • Plants are immobile and do not show locomotion.
            • They have unlimited growth and grow throughout their lives.

            Question 8.
            Write similarities between plants and animals.
            Answer:

            • Plants and animals are both made up of cells.
            • Both contain protoplasm and the genetic material, DNA.
            • Both plants and animals show growth.
            • Both show response to external stimuli.
            • Both plants and animals reproduce and pass on their characters to the offspring by the same mechanism.

            Question 9.
            Give the main features of algae.
            Answer:

            • They are autotrophic as they possess chlorophyll.
            • They are mainly aquatic but some also grow in moist places.
            • The body is not divided into root, stem and leaves.

            Question 10.
            Give the important features of division Bryophyta.
            Answer:

            • Bryophytes are called the amphibians of the plant kingdom.
            • The plant body is commonly differentiated to form stem and leaf-like structures. But there is no specific tissue for conduction of water and other substances.
            • Vegetative reproduction is very common.
            • Sexual reproduction is of oogamous type, i.e., the male gamete is small and motile and female gamete is non-motile and large, e.g., moss, Funaria and Marchantia.

            Question 11.
            Give the main features of Pteridophyta.
            Answer:
            Following are the main features of Pteridophyta:

            • The plant body is divided into root, stem and leaves.
            • The fertilised eggs form embryo.
            • They are also called vascular cryptogams as they have a developed vascular system.
            • They have multicellular reproductive system.

            Question 12.
            Give the important features of class Mammalia.
            Answer:
            The important features of class Mammalia are:

            • They are warm-blooded animals.
            • Their heart is four-chambered.
            • They have mammary glands which produce milk with which they nourish their young ones.
            • They give birth to young ones, with the exception of platypus and echidna. Kangaroos give birth to very poorly developed young ones.

            Question 13.
            Blue green algae have been included under the group Monera and not under Plantae. Why?
            Answer:
            Monera is a kingdom of prokaryotes while organisms of kingdom Plantae are eukaryotes with definite nucleus, membrane-bound organelles and multicellular body design. Blue-green algae are prokaryotes having nucleoid with naked DNA. The cell organelles are also not enclosed in membrane. As they also do not possess multicellular body design, these characters bring them closer to Monera and exclude them from the kingdom Plantae.

            Question 14.
            What is the difference between bilateral and radial symmetry?
            Answer:
            An animal is said to have bilateral symmetry if it has two equal but opposite right and left halves when cut lengthwise in the middle vertical plane, e.g., frog. On the other hand, an animal is said to have radial symmetry, if it is symmetrical with respect to any plane passing through its longitudinal axis. In other words, any plane passing longitudinally through any diameter divides the body into equal halves, e.g., Hydra.

            Question 15.
            How is notochord different from nerve cord?
            Answer:
            Notochord is the skeletal rod which lies lengthwise between the central nervous system and the alimentary canal or the gut and the chordates possess it at young stage of development. In adult vertebrates, it is replaced by vertebral column. On the other hand, a nerve cord is a solid strand of nervous tissue, forming part of central nervous system, especially of invertebrates. The main difference between the two is that notochord is a part of skeleton system whereas nerve cord is a part of nervous system.

            Question 16.
            Write names of few thallophytes. Draw a labelled diagram of Spirogyra. [NCERT Exemplar]
            Answer:
            Ulothrix, Spirogyra, Cladophora, Ulva and Chara are few thallophytes.

            Question 17.
            Define the terms and give one example of each.
            (i) Coelom
            (ii) Triploblastic [NCERT Exemplar]
            Answer:
            (i) Coelom is the internal body cavity between visceral organs and body wall in which well ‘ developed organs can be accommodated, e.g., in butterfly.
            (ii) Animals having three layers of cells from which differentiated tissue can be made are called triploblastic, e.g., star fish.

            Question 18.
            You are given leech, Nereis, Scolopendra, prawn and scorpion and all have segmented body organisations. Will you classify them in one group? If no, give the important characters based on which you will separate these organisms into different groups. [NCERT Exemplar]
            Answer:
            All organisms given in the question do not belong to same group. Leech and Nereis belong to phylum annelida because they have metamerically segmented body, i.e., body is divided into many segments internally by septa. Body segments are lined up one after the other from head to tail. But Scolopendra, prawn and scorpion belong to phylum arthropoda as these have jointed legs and open circulatory system.

            Question 19.
            Classify the following organisms based on the absence/presence of true coelom (i.e., acoelomate, pseudocoelomate and coelomate):
            Spongilla, Sea anemone, Planaria, Liver fluke, Wuchereria,Ascaris, Nereis, Earthworm, Scorpion,Birds, Fishes, Horse.
            Answer:
            Spongilla — Acoelomate
            Planaria — Acoelomate
            Wuchereria — Pseudocoelomate
            Nereis — Coelomate
            Earthworm — Coelomate
            Sea anemone — Acoelomate
            Liver fluke — Acoelomate
            Ascaris — Pseudocoelomate
            Scorpion — Coelomate
            Birds, Fishes and Horse — Coelomate

            Question 20.
            Fill in the boxes given in figure with appropriate characteristics/plant group(s). [NCERT Exemplar].

            Answer:
            (a) Thallophyta
            (b) Without specialised vascular tissue
            (c) Pteridophyta
            (d) Phanerogams
            (e) Bear naked seeds
            (f) Angiosperms
            (g) Have seeds with two cotyledons
            (h) Monocots

            Question 21.
            Label a,b,c and d given in figure. Give the function of part (b).

            Answer:
            (a) Dorsal fin
            (b) Caudal fin
            (c) Pelvic fin
            (d) Pectoral fin
            Function of caudal fin: Caudal fin helps in streamlined movement in water.

            Question 22.
            List out some common features in cat, rat and bat.
            Answer:
            Bat, rat and cat belong to the class mammalia and all have following common features:

            • have notochord at some stage of life cycle.
            • are warm-blooded.
            • have four-chambered heart.
            • have skin covered with hair and sweat and oil glands.

            Diversity in Living Organisms Class 9 Extra Questions Long Answer Questions

            Question 1.
            Describe the three main characteristics that are used for a hierarchical classification.
            Answer:
            The three main characteristics used for a hierarchical classification are:
            (i) Complexity of cell structure, i.e., type of cell—prokaryotic or eukaryotic. As a eukaryotic cell has membrane-bound organelles including a nucleus, the cellular processes can be carried out efficiently in isolation from other cells. On the other hand, the organisms without a clearly demarcated nucleus and other organelles need to have very different biochemical pathways. This would naturally have a great effect on every aspect of cell design. Moreover, the nucleated cells would have the capacity to participate in making a multicellular organism as they are capable of taking up specialised functions.

            (ii) Body organisation, i.e., whether the organism is unicellular or multicellular. In a eukaryotic multicellular organism, cells that group together to form a single organism use the principle of division of labour. In this type of body design, all cells would not be identical. Rather, groups of cells will carry out specialised functions. Thus, this makes a very basic distinction in the body designs of organisms. As a result, an amoeba will be very different in its body design from a fish.

            (iii) Mode of nutrition: autotrophic or heterotrophic. Plants make their own food while animals depend on plants or other animals for their food. For this they will definitely have different body design.

            Question 2.
            Give the main features of the phylum Porifera.
            Answer:

            • They are primitive animals.
            • They are generally multicellular organisms with specialised cells but these cells do not group together to form tissues.
            • Most of them are marine, i.e., found in the seas. Some of them are also found in ponds and rivers.
            • They possess pores all over the body.
            • Reproduction can be by both sexual and asexual methods.
            • Sensory system is absent.
            • Mouth and anus are absent.
            • A distinct canal system with inlets and outlets for water circulation inside the body is present. They obtain food and oxygen by means of water. The collar cells filter out food particles from the water current flowing through the canal system.
              Examples are: Sycon, Spongilla and Euplectella.

            Question 3.
            Give the main features of coelenterates.
            Answer:

            • Diploblastic animals with tissue level organisation in the body.
            • The body is radially symmetrical.
            • The body bears tentacles supplied with special stinging cells called cnidoblasts.
            • There is a cavity in the body.
            • Body is made of two layers of cells.
            • Simple gonads without gonoducts are present.
            • Reproduction is usually asexual (budding) in polyp form and sexual in medusae form.
            • They show polymorphism.
              Examples: Hydra, Obelia and jelly fish.

            Question 4.
            (i) List three characteristics which help us to distinguish amphibians from pisces.
            (ii) Classify the following living organisms as cold-blooded and warm- blooded animals:
            Shark, Lizard, Sparrow, Rohu.
            Answer:
            (i) Following characteristics distinguish amphibians from pisces:

            • Amphibians lack scales whereas skin of pisces are covered with scales.
            • Amphibians have mucous glands.
            • Amphibians have a three-chambered heart unlike pisces, their hearts have only two chambers.

            (ii) Cold-blooded: Shark, Rohu, Lizard
            Warm-blooded: Sparrow

            Question 5.
            Describe the features of phylum Platyhelminthes.
            Answer:

            • They show bilateral body symmetry.
            • Their body is dorsoventrally flattened like a ribbon. So they are also called flatworms.
            • Most of them are parasitic, only a few are free living.
            • They are mostly hermaphrodites.
            • There are three embryonic layers of cells in their body. So, they are triploblastic.
            • The body does not have any pore or cavity.
            • They have power of regeneration.
              Examples: Fasciola (Liver fluke), and Taenia solium.

            Question 6.
            Write the important features of phylum Aschelminthes (Nematoda).
            Answer:

            • Most of them are small and cylindrical. So they are also called as round worms.
            • The body size ranges from microscopic to a few centimetres in length.
            • They all are mainly heterotrophic animals.
            • They are triploblastic.
            • Body cavity has a true coelom.
            • Respiratory and circulatory systems are absent.
            • They have a complete alimentary canal.
            • Sexes are separate.
              Examples: Ascaris (roundworm), Enterobius, and Wuchereria (filarial worm).

            Question 7.
            Enlist the main features of phylum Annelida. Give examples.
            Answer:

            • Body of annelids are bilaterally symmetrical.
            • They are triploblastic.
            • Metameric segmentation is present.
            • Closed circulatory system with respiratory pigment dissolved in the plasma.
            • Nephridia for excretion and osmoregulation are present.
            • These animals are found in a variety of habitats like fresh water, marine water as well as on land.
              Examples are: Nereis (sand worm or clam worm), Aphrodite (sea mouse), Pheretima (earthworm).

            Question 8.
            Give the important distinguishing features of Arthropoda.
            Answer:

            • These animals are bilaterally symmetrical and segmented.
            • Body is covered with chitinous exoskeleton.
            • One or two pairs of jointed legs are present.
            • The body cavity is blood-filled and is called haemocoel.
            • Body bears jointed appendages, and is divided into head, thorax and abdomen.
            • Circulatory system is open, i.e., blood doesn’t flow in blood vessels.
              Examples: Palaemon, cockroach and butterfly.

            Question 9.
            Give the main distinguishing features of phylum Mollusca.
            Answer:
            Following are the main distinguishing features of phylum Mollusca:

            • The animal shows bilateral symmetry.
            • They have soft bodies, so they are also called soft bodied animals.
            • Body is segmented and divided into head, foot and visceral mass.
            • A glandular fold, the mantle, is present over the body.
            • There is a calcareous shell around the body in some molluscs.
            • They have open circulatory system.
            • Kidney-like organs for excretion are present.
              Examples: Pila, Sepia, octopus.

            Question 10.
            What are vertebrates? What are their main features?
            Answer:
            Vertebrates are the animals included in the phylum chordata in which the spinal chord is made of small vertebrae.
            There are five classes of vertebrates:

            The main features of vertebrates are given as under:

            • They possess a solid notochord.
            • The body has bilateral symmetry.
            • They have a true vertebral column.
            • They have a dorsal hollow nerve cord.
            • They are triploblastic.
            • The terrestrial forms respire through lungs and the aquatic forms through gills.
            • They are coelomate.

            Question 11.
            Give the point of differences between non-chordates and chordates.
            Answer:

            Question 12.
            What are the characteristics of kingdom Monera?
            Answer:
            Following are the characteristics of kingdom Monera:

            • The organisms do not possess a clearly defined nucleus, i.e., the nucleus is not enclosed by a nuclear membrane.
            • Cell organelles are also not covered with a membrane.
            • Organisms are unicellular, microscopic prokaryotes living in moist conditions.
            • Cell wall may or may not be present.
            • The mode of nutrition may be autotrophic or heterotrophic.
            • Reproduction is primarily asexual by binary fission or budding.

            Question 13.
            Thallophyta, Bryophyta and Pteridophyta are called as ‘Cryptogams’. Gymnosperms and Angiosperms are called as ‘Phanerogams’. Discuss why. Draw one example of a gymnosperm. [NCERT Exemplar]
            Answer:
            The thallophyta, bryophyta and pteridophyta are called as ‘cryptogams’ because the reproductive organs of these groups are inconspicuous or hidden. Seeds are absent. On the other hand ‘Phanerogams’ include gymnosperms and angiosperms which have well differentiated reproductive tissue and the embryo with stored food. Their embryo develops into seed.

            Question 14.
            Give the salient features of class Pisces.
            Answer:
            The main features of Pisces are:

            • They are exclusively water living animals and include the fishes.
            • Their skin is covered with scales/plates.
            • They obtain oxygen dissolved in water by using gills.
            • Their body is streamlined, and a muscular tail is used for movement.
            • They are cold-blooded and their hearts have only two chambers.
            • They lay eggs.
            • Some fish varieties have their skeletons made of both bone and cartilage, such as Anabas, Sea horse, Rohu, and some have their skeletons made entirely of bone, e.g., Torpedo fish and Sting ray (Trygon).

            Question 15.
            Differentiate between flying lizard and bird. Draw the diagram. [NCERT Exemplar]
            Answer:
            Flying lizard belongs to the group ‘reptiles’ and is characterised as cold blooded, body covered with scales and have three chambered heart. Whereas the birds belong to the group ‘aves’ and have characteristics of being warm blooded, having feather covered body, forelimbs modified as wings and four chambered heart.

            Question 16.
            Distinguish between the five classes of vertebrates on the basis of characters like habitat, kind of exoskeleton, respiratory organs and other distinct features.
            Answer:
            Differences between Pisces, Amphibia, Reptilia, Aves and Mammals are as follows:

            Question 17.
            How are the phanerogams classified?
            Answer:
            Phanerogams are classified depending on the presence or absence of fruits. They are of two types:

            • Gymnosperm possesses naked seeds, i.e., not enclosed by fruits.
            • Angiosperms, in which the seeds are enclosed within the fruit.

            Angiosperms are further divided into two types:

            • Monocotyledons, which have a single cotyledon in their seeds, e.g., wheat, rice, etc.
            • Dicotyledons, which have two cotyledons in their seeds, e.g., gram, pea, etc.

            Diversity in Living Organisms Class 9 Extra Questions HOTS (Higher Order Thinking Skills)

            Question 1
            Meena and Hari observed an animal in their garden. Hari called it an insect while Meena said it was an earthworm. Choose the character from the following which confirms that it is an insect.
            (a) Bilateral symmetrical body
            (b) Body with jointed legs
            (c) Cylindrical body
            (d) Body with little segmentation [NCERT Exemplar]
            Answer:
            (b)

            Question 2.
            You are provided with the seeds of gram, wheat, rice, pumpkin, maize and pea. Classify them whether they are monocot or dicot.
            Answer:
            Monocots — wheat, rice, maize
            Dicots — gram, pumpkin, pea

            Question 3.
            Classify the following based on number of chambers in their heart: Rohu, Scoliodon, Frog, Salamander, Flying lizard, King Cobra, Crocodile, Ostrich, Pigeon, Bat, Whale. [NCERT Exemplar]
            Answer:
            Rohu, Scoliodon — 2-chambered.
            Frog, Salamander, Flying lizard, King Cobra — 3-chambered.
            Crocodile, Ostrich, Pigeon, Bat, Whale — 4-chambered.

            Question 4.
            Classify Rohu, Scoliodon, Flying lizard, King Cobra, Frog, Salamander, Ostrich, Pigeon, Bat, Crocodile and Whale into cold-blooded or warm-blooded animals. [NCERT Exemplar]
            Answer:
            Cold-blooded — Rohu, Scoliodon, Frog, Salamander, Flying Lizard, King Cobra, Crocodile. Warm-blooded — Ostrich, Pigeon, Bat, Whale.

            Question 5.
            Match items of column (A) with items of column (B). [NCERT Exemplar]

            Answer:
            (a)—C (b)—B (c)—F (d)— A (e)—E (f)—D

            Question 6.
            Match items of column (A) with items of column (B). [NCERT Exemplar]

            Answer:
            (a)—B (b)—A (c)—D (d)—C (e)—F (f)—E (g)—G


            The Living World Class 11 Biology Chapter 1 Notes

            The earth serves as a home for diverse living organisms. The organisms live in various habitats like forests, mountains, deserts, oceans, freshwater bodies, hot springs, polar regions and almost every place of the earth. Living things possess certain characteristics, which makes
            Some of these important characteristics are shown in the flowchart given below:

            Major Characteristics of Living Organisms:
            Major characteristics of living organisms are given below
            1 Growth
            Living things grow by increase in mass and increase in number of individuals/cells. In multi cellular organisms in particular, growth occur by cell division or increase in number of cells. Growth occurs continuously throughout life in plants, whereas, in animals, it occurs up to a certain age only. However, growing in certain body parts like nails, hair and replacement of lost cells, occurs throughout the life.
            In unicellular organisms, growth can be observed under the microscope by simply counting the number of cells via in vitro experiment.
            Non-living things like mountains, boulders, sand dunes also grow in size, but just by accumulating the material on their external surface. Thus, growth in living things is internal, while in non-living things, it is external. It is to be noted that a dead organism do not grow.
            2. Reproduction
            Reproduction, a characteristic of living organisms is the process of producing offsprings, possessing features similar to those of parents. In multicellular organisms, the mode of reproduction is generally sexual. Living organisms also reproduce by asexual means.
            Some examples are given below
            (i) Fungi spread and multiply fast by producing millions of asexual spores. Some fungi, the filamentous algae and the protonema of mosses multiply by fragmentation.
            (ii) In yeast and Hydra, budding occurs to produce new organisms. While, in Planaria (flatworm),
            regeneration of fragmented body parts occur. These parts inturn grow as a new organism.
            (iii) Unicellular organisms like bacteria, algae and Amoeba reproduce by increasing the number of cells, i.e., through cell division (growth is synonymous with reproduction).
            Some organisms like mules, sterile worker bees, infertile human couples, etc., do not reproduce. Hence, reproduction also cannot be an all-inclusive defining characteristic of living organisms.
            3 Metabolism
            Metabolism is an another characteristic and defining feature of all living things. The sum total of anabolic or constructive reactions (anabolism) and catabolic or destructive reactions (catabolism) continuously occurring inside the body is called metabolism.
            Metabolism —> Anabolism + Catabolism Metabolism occurs in all unicellular and multi cellular organisms. Its two stages include, i.e., anabolism, the process of building up or synthesis of complex substances from simpler ones, e.g., Photo synthesis and catabolism, the process of breakdown of complex substances into simpler substances, e.g., Respiration, releasing waste outside.
            Metabolic reactions can also be demonstrated outside the body in cell free systems, which are neither living nor non-living. Thus, these reactions in vitro are surely living reactions not living things. Hence, metabolism can be considered as a defining feature of all living organisms without exception.
            The important differences between anabolism and catabolism are

            Viruses are considered as non-living because they don’t need energy for their activities, i.e., metabolic activities are altogether absent in them.
            4 Cellular Organisation
            The cells are the building blocks of all living things whether plants, animals or humans. The unicellular organisms are made of a single cell, while multi cellular organisms are formed by millions of cells. The cells contain protoplasm (living matter) and cell organelles (inside the cells) which perform several activities at the cellular level and result into various life processes.
            5 Consciousness
            All living organisms have excellent ability to sense their environment. They respond to various physical, chemical and biological stimuli.
            The various external factors to which living organisms respond are light, water, temperature, pollutants, other organisms, etc. Light duration or photo period affects many seasonal breeders, plants as well as animals. All living things respond to chemicals, entering their * bodies.
            Humans are superior to all living things as they have an additional ability of self-consciousness. Therefore, consciousness can also said to be a defining property of living organisms.
            However, in human beings, it is more difficult to define living state, e.g., Patients lying in coma supported by machines that replace heart and lungs, are brain-dead with no self-consciousness.
            6 Body Organisation
            The body of living organisms is organised, i.e., several component and sub-components cooperate with each other for the functioning of whole body.

            Physical and Biological Hierarchies
            There is a physical (non-living) hierarchy and biological hierarchy in the organisation of living body. In physical hierarchy, various non-living components aggregate to form compounds, which finally enter the living world in the form of cells. These cells organise to form tissues, that form organs and several organs combustive to form organ-systems. Finally, many organ systems organise and form a living organism.
            The properties of tissues are not present in the constituent cells but arise as a result of interactions among the constituent cells. For example, bone is a hard tissue, which provides framework to the body. But, the cells present inside it do not have this property. This phenomenon of interactions between various components of the body results in the hierarchy of organisation.
            The various life processes are the result of this interaction and coordination. The complexity in organisation enable living organisms as to be self-replicating, evolving, self-regulating and responding to external stimuli. All living organisms along with their ancestors and descendants are linked to one another by sharing of common genetic material in the form of DNA in varying degrees. This DNA is responsible for the expression of specific traits in organisms. Thus, Biology is the story of life on earth. It is the story of evolution of living organisms on the earth.
            Some Other Characteristics of Living Organisms
            We have discussed some important and defining characteristics of living things. However, organisms . also have many other features that differentiate them from non-living things, such as, shape & size, life cycle, movement, self-regulation, variations, adaptations, healing & repair, excretion and death.

            2.Living World : Diversity and Taxonomy

            The earth hosts an immense variety of living organisms. According to a survey, the number of species that are known and described are between 1.7-1.8 million.
            This number refers to the biodiversity on the earth. The term Biodiversity or Biological diversity means the number and types of organisms present on the earth, forms of life in the living world. The living world includes all the living organisms, such as microorganisms, plants, animals and humans.
            Biodiversity is not limited to the existing life forms. If we explore new areas and even old ones, new organisms are continuously being added. This huge available variety cannot be studied and identified without having a proper system of classification and nomenclature.
            Systematics
            The word ‘Systematics’ is derived from the Latin word Systema, which means systematic arrangement of organisms. Linnaeus used Systema Naturae as the title of his book. He. coined the term Systematics in 1751.
            Systematics is the branch of science that deals with unique properties of species and groups to recognise, describe, name and arrange the diverse organisms according to an organised plan.

            In 1961, Simpson, defined systematics as the study of diversity of organisms and all their comparative and evolutionary relationships based on comparative’ anatomy, physiology, biochemistry and ecology. The word ‘Systematics’ and ‘Taxonomy’ are often used interchangeably by the biologists. Systematics includes the following:
            Identification
            It aims at finding the correct name and appropriate position of an organism. The morphological and anatomical characters are examined for proper identification.
            Classification
            It is almost impossible to study all the living organisms. So, it is necessary to devise some means to make this possible. This can be done by classifying the organisms.
            Thus, classification is the process by which organisms are grouped into categories based on some easily observable characters.
            Biological classification is the scientific arrangement of organisms in a hierarchy of groups and sub-groups on the basis of similarities and differences in their traits.
            Advantages of Classification
            (a) It helps to identify an organism easily.
            (b) New organisms easily get correct place in their respective groups.
            (c) It makes study of fossils easy.
            (d) It also helps in building evolutionary pathways.
            (e) It becomes easy to know the features of whole group by studying one or two organisms of the group.

            Thus, based on these characteristics, all living organisms are classified into different taxa.
            Nomenclature
            Nomenclature is the system of naming living organism in a way that a particular organism is known by the same name all over the world.
            i. Common Names
            The common names or vernacular names are the local names given to an organism in a specific language in a particular region. There are different names of a same organism in different regions even with in a country.

            Advantages of Common Names
            (a) Common names are easy to pronounce and are short, e.g., Cat or billi.
            (b) People are familiar to these names since childhood.
            (c) They are based on some features of organisms, e.g., Cowa (crow—Caawn-Caawn sound).
            Dis-Advantages of Common Names
            (a) All the organisms cannot be named by this method as there are organism of different sizes and shapes.
            e.g., Microbes.
            (b) An organism may have several names in a given language, e.g., 8 Hindi names of prickly poppy and water lily has 15 English names.
            (c) A common names may have different meanings in different countries, e.g., Maize, means wheat and other grains in USA and it is called corn in common wealth countries.

            (d) Common names may have little relevance, e.g., Lady’s finger (okra), widows tears (Tradescantia-Rhoeo), etc.
            (e) Common names may be incorrect, e.g., Jelly fish (a coelenterate), silverfish (an arthropod), starfish (an echinoderm) are not real fishes.
            (f) These names are not useful for scientific studies.
            ii- Scientific Names
            A scientific name is given by biologists. These names represent a particular organism in every part of the world. The system of providing scientific names is called binomial nomenclature.
            The scientific names must be
            (a) acceptable in every part of the world.
            (b) assigned on agreed principles and criteria.
            (c) different for each species and not used for other organisms earlier.
            Binomial Nomenclature
            Binomial nomenclature was developed by Carolus Linnaeus in 1751 (Philosphica Botanica). All scientific names for animals under binomial nomenclature were given by Linnaeus in the tenth edition of his book Systerna Naturae (1758). Linnaeus named plants according to binomial nomenclature in his book Species Plantarum (1753). Binomial nomenclature is the system of providing distinct and appropriate names to organisms, each consisting of two words, first generic name
            For example, Scientific name of mango is written as Mangifera indica. In this name, Mangifera represents the genus and indica is a particular species or specific epithet.

            Rules of Binomial Nomenclature
            Rules of binomial nomenclature were initially framed by Linnaeus in his books, Species Plantarum and Systema Naturae.
            The rules were revised again by the following nomenclature codes

            (i) International Code for Botanical Nomenclature (ICBN).
            (ii) International Code of Zoological Nomenclature (ICZN).
            (iii) International Code of Bacteriological Nomenclature (ICBN).
            (iv) International Code of Viral Nomenclature (ICVN).
            (v) International Code of Nomenclature for Cultivated Plants (ICNCP).
            The rules framed by Linnaeus and by these codes are as follows
            (i) The names are generally in Latin and written in italics. They are Latinised or derived from Latin irrespective of their origin.
            (ii) The first word in a biological name represent the genus while, the second component denotes the specific epithet.
            (iii) Both the words in a biological name, when handwritten are separately underlined or printed in italics to indicate their Latin origin.
            (iv) The first word denoting the genus starts with capital letter while, the specific epithet starts with a small letter, e.g., Mangifera indica.
            (v) Generic and common names may be same, e.g., Gorilla gorilla.
            (vi) No names are recognised prior to those used by Linnaeus in 1753 for plants in Species Plantarum and in 1758 for animals in the 10th edition of Systema Naturae.
            (vii) The name of categories higher than the rank of genus are not printed in italics. Bold letters can, however be used.
            (viii) When a species is transferred or revised, the name of the original worker is retained but in parenthesis, e.g., Syzygium cumini (L) Skeels.
            Advantages of Binomial Nomenclature
            (i) Binomial names are universally acceptable and recognised.
            (ii) They remain same in all languages.
            (iii) The names are small and comprehensive.
            (iv) There is a mechanism to provide a scientific name to every newly discovered organism.
            (v) The names indicate relationship of a species with other species present in the same genus.
            (vi) A new organism can be easily provided with a new scientific name.
            Taxonomy
            It is the science of identification, classification and nomenclature. Based on their special / characteristics, all living organisms can be classified into different taxa. This process of classification is called taxonomy. Carolus Linnaeus is known as father of taxonomy.
            The basis of modern taxonomy studies are external and internal structure (comparative morphology), along with the structure of cells (cytology), development process (embryology) and ecological information of organisms (ecology). It provide information according to similarities, dissimilarities and evolutionary relationships of various organisms.
            The basic processes for taxonomic studies are
            (i) Organisms are described on the basis of morphology and other characteristics.
            (ii) The description of characteristics helps in the placement of the organism in various taxa.
            (iii) A new taxon can be framed if the organism is different from the existing taxa.
            (iv) The correct naming of an organism can be done after placing it in various taxon. A new organism can be given a new name after following the standardized rules.

            Classical Taxonomy (Old Taxonomy)
            The concept of classical or old taxonomy exists since, the time of Aristotle and Theophrastus and continued up to Linnaeus. It states that 4 .
            (i) Species is the basic unit of taxonomy, that can be described on the basis of one or few preserved specimens.
            (ii) Species are fixed and do not change with time.
            (iii) A species is delimited based on morphological features.
            (iv) Organisms are classified on the basis of some limited features such as root modification, leaf venation, floral structures, number of cotyledons in case of plants.
            Due to the limited number of groups, many organisms could not be classified correctly. This finally led to artificial system of classification.
            Modern Taxonomy (New Taxonomy)
            The concept of modern taxonomy was given by Julian Huxley (1940). It uses evidences from all the areas of biology like morphology, anatomy, biochemistry, cell biology, physiology, genetics, evolution, etc.
            The modem taxonomy is based on the following features
            (i) The studies are done on a huge number of organisms based on all the variations.
            (ii) Study is also focused on sub-species, varieties, races and populations.
            (iii) Species are not isolated. They are related by common descent and vary from them due to accumulation of variations.
            (iv) Species is considered as dynamic and ever-changing entity.
            (v) Biological delimitation includes various branches of systematics, e.g., Cytotaxonomy, experimental taxonomy, numerical taxonomy, chemotaxonomy, etc. This led to the development of phylogenetic system or cladistics of classification.
            Taxonomic Categories
            Classification is not a single step process. It involves hierarchy of steps in which each step represents a rank or category. Since, the category is a part of overall taxonomic arrangement, it is called the taxonomic category and all categories together constitute the taxonomic hierarchy.

            Taxon
            Each category, referred to as a unit of classification, in fact, represents a rank and is commonly termed as taxon (Pi. taxa). The term Taxon was first introduced by ICBN during 1956.
            According to Mayr (1964) taxon is a group of any rank that is sufficiently distinct to be worthy of being assigned a definite category. In simple words, taxon refers to a group of similar, genetically related individuals having certain characters distinct from those of other groups.
            A taxon that includes a common ancestral species and all the species descended from it is called a clade or a monophyletic taxon.

            Taxonomic Hierarchy
            The taxonomic hierarchy is the system of arranging taxonomic categories in a descending order. It was first introduced by Linnaeus (1751) and hence, it is also known as Linnaen hierarchy.
            Groups represent category and category further denotes rank. Each rank or taxon represents a unit of classification.
            These taxonomic groups/categories are distinct biological entities and not merely morphological aggregates.
            Obligate/Common Categories
            The taxonomic categories, which are always used in hierarchical classification of organisms are called obligate or common categories.
            They are seven in number. In descending order, these are kingdom, phylum or division, class, order, family, genus and species.
            All the members of taxonomic categories possess some similar characters, which are different from those of others. The maximum similarity occurs in species, which is also the lowest category in the hierarchy of categories. Similarity of characters decreases with the rise in hierarchy.
            i. Species
            Taxonomic studies consider a group of individual organisms with fundamental similarities as a species (John Ray).

            Species is considered as the lowest or basic taxonomic category, which consists of one or more individuals of a populations that resemble one another more closely than individuals of other species. The members of species interbreed freely and are reproductively isolated from others. For example, Mangifera indica (mango), Solarium tuberosum (potato) and Panthera leo (lion).
            All the three names indica, tuberosum and leo represent the specific epithets while, the first words Mangifera, Solanum and Panthera are genera and represents another higher level of taxon or category.
            Each genus may have one or more than one specific epithets representing different organisms, but having morphological similarities. For example, Panthera has another specific epithet called tigris and Solanum includes species like nigrum and melongena.
            ii.Genus
            Genus (John Ray) comprises a group of related species, which has more characters common in comparison to species of other genera. In other words, genera are aggregates of closely related species.

            iii. Family
            Family (John Ray) is a group of related genera with less number of similarities as compared to genus and species. All the genera of a family have some common or correlated features. They are separable from genera of a related family by important differences in both vegetative and reproductive features.
            A plant family ends in a suffix -aeae and sub-family -oideae. While, an animal family has a suffix -idae and sub-family -inae.
            iv. Order
            An order (Linnaeus) is a group of one or more related families that possess some similar correlated characters, which are lesser in number as compared to a family or genera.
            Plants and Animal Orders with their Respective Families
            Order Animals and Families
            Carnivora Canidae (dog, wolf and fox), Felidae (cat, leopard, tiger and lion), Ursidae (bear) and Hyaenidae (hyaena)
            Polemoniales Solanaceae (potato and tomato), Convolvucaceae (sweet potato and morning glory), Polemoniaceae (herbs, shrubs and small trees) and Hydrophyllaceae (water leaf).
            Primates Lemuridae (lemurs), Cebidae (new world monkeys), Pongidae (apes) and Hominidae (humans).

            v. Class
            Class (Linnaeus) is a major category, which includes related orders. For example, order-Primata comprises monkey, gorilla & gibbon and is placed in class—Mammalia along with order—Carnivora that includes animals like tiger, cat and dog.
            Class-Mammalia has other orders also.
            vi.Phylum or Division
            Phylum or Division (Cuvier, Eichler) is a taxonomic category higher than class and lower” in rank to kingdom. The term Phylum is used for animals, while division is commonly employed for plants.
            It consists of more than one class having some similar corelated characters.
            For example, Phylum— Chordata of animals contain following classes, e.g., Pisces, amphibians, reptiles, aves and mammals.
            vii. Kingdom
            It is known to be the highest category in taxonomy. This includes all the organisms, which share a set of distinguished characters. For example, all the animals belonging to various phyla are assigned the highest category called kingdom.
            For example, Animalia in the classification system of animals. Similarly, all the plants are kept in kingdom—Plantae.
            RH Whittaker. (1969) assigned five kingdom classification of organisms.
            These are Monera, Protista, Fungi, Plantae and Animalia.
            Intermediate Categories
            The taxonomic categories from species to kingdom are broad categories or obligate categories. However, taxonomists have also developed sub-categories in this hierarchy to facilitate more sound and scientific placement of various taxa. These sub-categories are sub-species (or varieties), sub-genera, sub-families, sub-orders, sub-classes and sub-phyla.
            These sub-categories are referred to as intermediate categories.
            Taxonomical Aids
            Taxonomical aids are techniques and procedures to store information as well as specimens or identification and classification of organisms.
            The taxonomic studies of various plants, animals and other organisms are useful in areas like agriculture, forestry, industry and knowing our bioresources. All these studies need correct identification and classification of organisms. Identification of organisms requires intensive laboratory and field studies. The collection of actual specimens of plants and animal species, knowing their habitats and other traits are essential and are the prime source of taxonomic studies. All this information is used in classification of an organism and is also stored along with the specimens. Sometimes, specimens are also preserved for future studies.
            Some of the taxonomical aids developed by Biologists include Herbarium, Botanical gardens, Museum, Zoological parks, Key, etc.
            1 Herbarium
            Herbarium (Pi. Herbaria) is a store house of collected plant specimens that are dried, pressed and preserved on sheets. These sheets are arranged further according to a universally accepted system of classification. The institutes and universities maintain their own herbarium by collecting specimens from local and far away places.


            Uses of Herbaria
            The uses of herbaria are listed below
            (a) These are used for identification of plants.
            (b) Compilation of floras, monographs and manuals are mainly based on the specimens in herbaria.
            (c) Herbaria are useful in locating wild varieties and relatives of economically important plants.
            (d) They help in knowing the morphological variations found in species.
            (e) Herbaria are useful for research in plant taxonomy, morphology, ecological distribution, etc.
            2. Botanical Gardens
            Botanical gardens are specialised gardens that have collections of living plants for reference. These gardens generally have facilities like library, laboratory, herbarium and museum. The botanical gardens are maintained by government, semi-government and other private organisations. Botanists and gardeners look after plants in botanical gardens.

            Role of Botanical Gardens
            A botanical garden has following important roles
            (a) Botanical gardens have aesthetic appeal and provide recreation facility to people.
            (b) A wide variety of plant species grow there, so they provide ready material for research.
            (c) These gardens also play an important role in conservation of endangered plant species and genetic diversity.
            (d) There are more than 500 botanical gardens all over the world. These provide free exchange of seeds.
            (e) These improve the environment, provide greenery, help in creating pollution free environment and some serves as habitat for animals.
            Knowledge Plus
            Indian Botanical Garden-Largest Botanical Garden of Asia.
            First Botanical Garden-Pisa Botanical Garden, Italy established by Luca Glini (1490-1556).
            3. Museums
            Museum is a place for collections of preserved plants and animal specimens for study and reference. The universities and educational institutes maintain their own museums in their botany and zoology departments. Plants, which cannot be kept in herbaria are preserved in museums.
            For example, algae, fungi, mosses, ferns, fruits, etc. Specimens are preserves in containers or jars in preservative solutions. Plant and animal specimens may also be preserved as dry specimens. Insects are preserved in insect boxes after collecting killing and pinning. While, the larger animals are stuffed and preserved in skeletal forms.

            4. Zoological Parks
            Zoological parks or zoo are the places where wild animals are kept in protected environments under human care and which enable us to learn about their food habits and behaviour. Zoological parks provide natural habitat to the animals.
            In India there are about 200 zoological parks. These zoos are managed by the Central Zoo Authority of India. The World Zoo Conservation Strategy (WZCS) refer to all these zoological institutions as zoos.
            Role of Zoological Parks
            (a) The zoological parks increase understanding of wildlife.
            (b) These are the centres for recreation and education.
            (c) Zoos are the centres for conservation of threatened and rare animal species.
            (d) These provide sites for ex situ breeding of endangered animals. conservation through captive breeding of endangered animals.

            5. Key
            Key is also a taxonomical aid used for identification of plants and animals based on the similarities and dissimilarities.
            It helps in the identification of plants and animals by selecting and eliminating the characters according to their presence or absence in the organism under study.
            The keys generally use two contrasting characters called couplet. This results in acceptance of one present in organism and rejection of the other. Each statement in the key is called a lead.
            These taxonomic keys are of two types
            Indented Key
            The indented key or yolked key provides a sequence of choices between two or more characteristics. By careful selection of characters at each sub-division, the exact name of the organism can be arrived at.
            Bracketed Key
            The bracketed key also uses contrasting characters like the indented key. But in, these characters are not separated by intervening sub-dividing characters. Each character in this case is given a number in brackets.
            Other Means of Recording Descriptions
            Apart from the all mentioned means of keeping records of description. Some other means are also present.
            These are of following types
            Flora
            Floras are the important resource that provide information on the taxonomy, nomenclature and descriptive data for the taxa covered.
            The floras also include information on the biology, distribution and habitat preferences of the taxa, as well as illustrations, identification keys and other notes. These provide index to the plant species found in a particular area.
            Manuals and Catalogues
            These are other means of recording descriptions. They also help in correct identification. Manuals are useful in providing information for identification of names of species found in an area.
            Monograph
            A monograph is a comprehensive treatment of a taxon in biological taxonomic studies. These contain information on any one taxon. Monographs revise all known species within a group, add any newly discovered species, collect and organise available information on the ecological associations, geographic distributions and morphological variations within the group.
            The first ever monograph of a plant taxon was given in Robert Morison (1672) Plantarum Umbelliferarum Distributio Nova.


            Taxonomic Term Confusion

            Taxonomy, the classification of living things, is really complicated. For example, anyone who's worked in a record store and had to fit every band into one neat little category or other has an idea as to why: Many organisms defy traditional or obvious categories in the absence of genetic studies. This is why there is such a wide variety of terms for organizing living things (and theoreticians regularly come up with new ones).

            Writers of fiction tend to tidy things up a bit. They regularly come up with creative ways of employing normal classification terms in ways that are incredibly inappropriate. Primarily, what seems to be at fault is a failure to recognize that the terms for taxonomic categories have specific meanings, and are not just interchangeable synonyms for "a big group of similar things". Sometimes they do know better it's just that they couldn't resist the Beast Fable pun of having an Animal Kingdom. You know, where the lion is the King.

            For the record, any group of related organisms, regardless of the degree of relatedness, is called a taxon. The major recognized taxonomic ranks are:

            • Domain
            • Kingdom
            • Phylum/Division
            • Class
            • Order
            • Family
            • Genus
            • Species

            (If you're having trouble remembering, remember this simple mnemonic: "Danny Kaye, Please Come Over For Good Strawberries" or, if you prefer, "Dear King Phillip Came Over For Good Soup". A commonly-used one is "Dumb kids playing catch on freeways get squashed". Before "Domain" was added to the top of the list, mnemonics were "Kings Play Cards Only For Gold and Silver" and "Kings Play Chess on Fine Glass Surfaces.")

            Compound variations on these terms such as "subspecies" and "superfamily" are in common use. Some taxonomists also make use of the term "tribe" for a rank intermediate between subfamily and genus. This is not just limited to fiction in a strictly factual sense birds are technically reptiles, and the whole animal, plant, fungus distinction is being rewritten of late so more often than not, it's hard to know the correct terminology because it always is changing. It doesn't help matters that the current system was invented before evolution was understood, and that the ranks are pretty arbitrary. One "genus" might be older and more diverse than another "family." Some scientists even want to abolish taxonomic ranks, though that's not likely to happen soon.

            The scientific Latin name for a species consists of the genus name (capitalized), followed by the species name (in all lower case), both italicised. Tyrannosaurus rex is genus Tyrannosaurus, species rex Homo sapiens is genus Homo, species sapiens. If the species is well known, or has already been mentioned earlier in the same work, the genus name will frequently be abbreviated to a single letter, e.g. T. rex or H. sapiens. If more hairsplitting is needed, the subspecies or variety name can be appended as a third word, e.g. Homo sapiens sapiens.

            Frankly, it's not surprising that writers are sometimes ignorant or confused. Though this can also turn into a case of Fan Wank as many of these words also have different less precise meanings in regular English as in family and class are both used to refer to groups of similar things, a class of ships, the t-series family of trucks so a lot of these errors are just people using the words with their regular meanings. But there's really no excuse for the examples under "General", especially by scientists.

            Of course, things are also more complicated than even this. Cladistics, Dendrograms, Phylogenetics. We'll just leave it at this lest Your Head Asplode .


            Is amphibians being descended from fish reflected in the animalia taxonomy? - Biology

            The legless condition that is observed in several groups of extant reptiles is the result of
            A) their common ancestor having been legless.
            B) a shared adaptation to an arboreal (living in trees) lifestyle.
            C) several instances of the legless condition arising independently of each other.
            D) individual lizards adapting to a fossorial (living in burrows) lifestyle during their
            lifetimes

            The scientific discipline concerned with naming organisms is called
            A) taxonomy.
            B) cladistics.
            C) binomial nomenclature.
            D) systematics.
            E) phylocode

            ) The various taxonomic levels (viz, genera, classes, etc.) of the hierarchical classification
            system differ from each other on the basis of
            A) how widely the organisms assigned to each are distributed throughout the
            environment.
            B) the body sizes of the organisms assigned to each.
            C) their inclusiveness.
            D) the relative genome sizes of the organisms assigned to each.
            E) morphological characters that are applicable to all organisms.

            Which of these illustrates the correct representation of the binomial scientific name for the
            African lion?
            A) Panthera leo
            B) panthera leo
            C) Panthera leo
            D) Panthera Leo
            E) Panthera leo

            A phylogenetic tree that is ʺrootedʺ is one
            A) that extends back to the origin of life on Earth.
            B) at whose base is located the common ancestor of all taxa depicted on that tree.
            C) that illustrates the rampant gene swapping that occurred early in lifeʹs history.
            D) that indicates our uncertainty about the evolutionary relationships of the taxa
            depicted on the tree.
            E) with very few branch points.

            The correct sequence, from the most to the least comprehensive, of the taxonomic levels
            listed here is
            A) family, phylum, class, kingdom, order, species, and genus.
            B) kingdom, phylum, class, order, family, genus, and species.
            C) kingdom, phylum, order, class, family, genus, and species.
            D) phylum, kingdom, order, class, species, family, and genus.
            E) phylum, family, class, order, kingdom, genus, and species.

            The common housefly belongs to all of the following taxa. Assuming you had access to
            textbooks or other scientific literature, knowing which of the following should provide you
            with the most specific information about the common housefly?
            A) order Diptera
            B) family Muscidae
            C) genus Musca
            D) class Hexapoda
            E) phylum Arthropoda

            If organisms A, B, and C belong to the same class but to different orders and if organisms
            D, E, and F belong to the same order but to different families, which of the following pairs
            of organisms would be expected to show the greatest degree of structural homology?
            A) A and B
            B) A and C
            C) B and D
            D) C and F
            E) D and F

            Darwin analogized the effects of evolution as the above-ground portion of a
            many-branched tree, with extant species being the tips of the twigs. The common ancestor
            of two species is most analogous to which anatomical tree part?
            A) a single twig that gets longer with time
            B) a node where two twigs diverge
            C) a twig that branches with time
            D) the trunk
            E) neighboring twigs attached to the same stem

            Dozens of potato varieties exist, differing from each other in potato-tuber size, skin color,
            flesh color, and shape. One might construct a classification of potatoes based on these
            morphological traits. Which of these criticisms of such a classification scheme is most likely
            to come from an adherent of the phylocode method of classification?
            A) Flesh color, rather than skin color, is a valid trait to use for classification because it is
            less susceptible to change with the age of the tuber.
            B) Flower color is a better classification criterion, because below-ground tubers can be
            influenced by minerals in the soil as much as by their genes.
            C) A more useful classification would codify potatoes based on the texture and flavor of
            their flesh, because this is what humans are concerned with.
            D) The most accurate phylogenetic code is that of Linnaeus. Classify potatoes based on
            Linnaean principles not according to their color.
            E) The only biologically valid classification of potato varieties is one that accurately
            reflects their genetic and evolutionary relatedness.

            The term ʺhomoplasyʺ is most applicable to which of these features?
            A) the legless condition found in various types of extant lizards
            B) the 5-digit condition of human hands and bat wings
            C) the beta-hemoglobin genes of mice and of humans
            D) the fur that covers Australian moles and North American moles
            E) the basic skeletal features of dog forelimbs and cat forelimbs

            If, someday, an archaean cell is discovered whose SSU-rRNA sequence is more similar to
            that of humans than the sequence of mouse SSU-rRNA is to that of humans, the best
            explanation for this apparent discrepancy would be
            A) homology.
            B) homoplasy.
            C) common ancestry.
            D) retro-evolution by humans.
            E) co-evolution of humans and that archaean.

            ) The best classification system is that which most closely
            A) unites organisms that possess similar morphologies.
            B) conforms to traditional, Linnaean taxonomic practices.
            C) reflects evolutionary history.
            D) corroborates the classification scheme in use at the time of Charles Darwin.
            E) reflects the basic separation of prokaryotes from eukaryotes.

            Which of the following pairs are the best examples of homologous structures?
            A) bat wing and human hand
            B) owl wing and hornet wing
            C) porcupine quill and cactus spine
            D) bat forelimb and bird wing
            E) Australian mole and North American mole

            ) Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser
            panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of
            these two species are probably due to
            A) inheritance of acquired characteristics.
            B) sexual selection.
            C) inheritance of shared derived characters.
            D) possession of analogous structures.
            E) possession of shared primitive characters.

            In angiosperm plants, flower morphology can be very intricate. If a tree, such as a New
            Mexico locust, has flowers that share many morphological intricacies with flowers of the
            sweet pea vine, then the most likely explanation for these floral similarities is the same
            general explanation for the similarities between the
            A) dorsal fins of sharks and of dolphins.
            B) reduced eyes of Australian moles and North American moles.
            C) scales on moth wings and the scales of fish skin.
            D) cranial bones of humans and those of chimpanzees.
            E) adaptations for flight in birds and adaptations for flight in bats.

            The importance of computers and of computer software to modern cladistics is most closely
            linked to advances in
            A) light microscopy.
            B) radiometric dating.
            C) fossil discovery techniques.
            D) Linnaean classification.
            E) molecular genetics.

            ) Which mutation should least require realignment of homologous regions of a gene that is
            common to several related species?
            A) 3-base insertion
            B) 1-base substitution
            C) 4-base insertion
            D) 1-base deletion
            E) 3-base deletion

            The common ancestors of birds and mammals were very early (stem) reptiles, which almost
            certainly possessed 3-chambered hearts (2 atria, 1 ventricle). Birds and mammals, however,
            are alike in having 4-chambered hearts (2 atria, 2 ventricles). The 4-chambered hearts of
            birds and mammals are best described as
            A) structural homologies.
            B) vestiges.
            C) homoplasies.
            D) the result of shared ancestry.
            E) molecular homologies.


            Examples of Changes Made to the Linnaean Classification System

            Many adjustments have been made to the Linnaean classification system over time as scientists have made discoveries about fossils, DNA sequencing and molecular biology, among others. Linnaeus focused mostly on the physical characteristics of species, which is considered insufficient now.

            As scientists have discovered new species and evolutionary history has come into sharper focus, many levels have been added to the Linnaean system of classification, such as phylum, superclass, subclass, family and tribe. Regardless of the level, when a group of organisms is being described, they are now called a taxon, or taxa for plural groups.

            Most recently, a level called domain was added to the top of the hierarchy above kingdom. The three domains are Archaea, Bacteria and Eukarya. The four kingdoms Protista, Animalia, Fungi and Plantae fit within the Eukarya domain.

            Although Linnaeus provided a framework for classifying living creatures, his own system was not limited to organisms. For instance, in his quest to classify the natural world, he created a kingdom of minerals. He also created a scientific name for Homo anthropomorpha, a proposed species that included all human-like mythical creatures, which he believed truly existed. These included the satyr, phoenix and hydra.


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