classification of animals
DESCRIPTION
Classification is done clearlyTRANSCRIPT
Mukunda Priya
Classification of animals"The arrangement of entities in a hierarchical series of nested classes, in which similar or related classes at one hierarchical level are combined comprehensively into more inclusive classes at the next higher level." A class is defined as "a collection of similar entities"
COELENTERATA/CNIDARIANS
All coelenterates are aquatic, mostly marine. The bodyform is radially symmetrical with a tissue grade of organisation. The body has a single opening hypostome surrounded by sensory tentacles leading into a spacious cavity called the gastrovascular cavity or coelenteron. Digestion is both intracellular and extracellular. Respiration and excretion are accomplished by simple diffusion. A network of nerves is spread throughout the body.
Coelenterata is an obsolete term encompassing two animal phyla, the Ctenophora (comb jellies) and the Cnidaria (coral animals, true jellies, sea anemones, sea pens, and their allies). The name comes from the Greek "koilos" ("full bellied"), referring to the hollow body cavity common to these two phyla. They have very simple tissue organization, with only two layers of cells, external and internal and radial symmetry. Some of the examples are corals, sea anemone which are colonial and hydra, jelly fish which are solitary. History of classificationThe term coelenterate is no longer recognized as scientifically valid, as the Cnidaria and Ctenophora have less in common than previously assumed.[1] Any group containing the two but excluding other phyla would be paraphyletic. Nonetheless, the term coelenterate is still used in informal settings to refer to the Cnidaria and Ctenophora.Complicating the issue is the 1997 work of Lynn Margulis (revising an earlier model by Thomas Cavalier-Smith) that placed the Cnidaria and Ctenophora alone in the branch Radiata within Eumetazoa.[2] (The latter refers to all the animals except the sponges, Trichoplax, and the still poorly understood Mesozoa.) Neither grouping is accepted universally;[3] however, both are commonly encountered in taxonomic literature.The Coelenterata hypothesis has been more recently revived, based on molecular data, placing the Coelenterates as a monophyletic sister-group to the Bilateria
MOLLUSCA
The molluscs or mollusks compose the large phylum of invertebrate animals known as the Mollusca. Around 85,000 extant species of molluscs are recognized. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms.
Gastropods, the group of mollusks that include the terrestrial snails and slugs and the marine limpets, periwinkles, abalones, whelks, and their relatives, are the largest and most varied class of mollusks, with more than 75,000 extant species in addition to 15,000 fossil forms that are known. These successful animals are the only class of mollusks to occupy both marine, fresh-water, and terrestrial environments. In the sea, most species are epibenthic, crawling on the surface, but there are some swimming forms as well (some types of Opisthobranchia). Although many gastropods are herbivorous grazers, several groups are active carnivores able to drill through the shell of their victim, or in the case of predatory forms like the Conidae (Neogastropoda) cases swallow it whole through a proboscis.Most of the gastropods are classified on the characteristics the gill structures and other soft-bodied features. Few distinguishing characters of the shell are used in classification as many are the result of convergent evolution. Although the differences in the shell form may be difficult to recognize, different morphologic groups can generally can be differentiated on characteristics of ornamentation, shell shape, and aperture. The shell of many gastropods can either be external or, less commonly, internal. The difference can often be deduced by the luster of shell material and the presence of other features such as deviations of a structural shell form.
VERTEBRATE
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1. Fish
Scales- Fins - Eyes & lateral Lines - Gills.
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2.Amphibians
Moist scaleless skin - Eye & Ears - 4 limbs.
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3. Reptiles
Dry scaly skin - Eyes & Ears - 4 legs (apart from snakes).
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4. Birds
Beak - Feathers - Scales on legs - Wings - 2 legs.
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5. Mammals
Fur - 4 limbs.
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Mammals
1.Land mammals2.Marines
mammals3.Flying mammals
1.Land mammals
Outer ears four limbs(arms/legs)a.Marsupialsb.Primatesc.Rodents
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a.MarsupialsCommonly known as marsupials, members are divided into seven orders; Didelphimorphia, Paucituberculata, Microbiotheria, Dasyuromorphia, Peramelemorphia, Notoryctemorphia, and Diprotodontia. the members of the order Marsupialia are pouch-bearing mammals who give birth to underdeveloped offspring( Koalas, Possums, Kangaroo, Wallabies )
b.PrimatesThe mammalian order Primates contains over 230 species and includes the prosimians, monkeys and apes. All primates are omnivorous, although many who live in rain forests eat vegetation almost exclusively. Primate eyes face forward which allows for binocular vision ( Prosimians, Monkeys, Apes and Humans )
c.Rodentshe order Rodentia consist of nearly 2000 species or mice, rats, squirrels, gophers, porcupines and various other rodents, and is the largest mammalian order. The worlds largest rodent is the capybara while the smallest is the pygmy mouse. Rodents naturally occur everywhere around the world with the exception of Antarctica and New Zealand, but have been introduced there as well. ( Rodents )
Marine mammal
Marine mammals, which include seals, whales, dolphins, otters and walruses, form a diverse group of 129 species that rely on the ocean for their existence.[1] They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding.[2] The level of dependence on the marine environment for existence varies considerably with species. For example, dolphins and whales are completely dependent on the marine environment for all stages of their life, whereas seals feed in the ocean
Flying MammalsThe bats are the representative animal of this group. Bats have many unusual characteristics. They cannot walk very well because skin that reaches over its front and back legs. It flies at night and stays in caves and other dark places during the day., Hanging upside down by the claws of its back legs. They look like flying mice.Bats eat insects, although the vampire bat drinks blood. Bats fly in total darkness and have keen hearing. They listen for sounds and echoes to guide their flight. Bats can be helpful in eating insects but can be harmful as they can carry such germs as rabies.
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