Question

Write a short note echinodermata

Answer 1

phylum of exclusively marine bottom-dwelling invertebrates having external skeletons of calcareous plates just beneath the skin. The plates may be solidly fused together, as in sea urchins, loosely articulated to facilitate movement, as in sea stars(starfish), or reduced to minute spicules in the skin, as in sea cucumbers. The skin usually has warty projections or spines, or both. Echinoderms display pentamerous radial symmetry, that is, the body can be divided into five more or less similar portions around a central axis. Unlike other radially symmetrical animals, they develop from a bilaterally symmetrical larva and retain some degree of bilateral symmetry as adults. There is no head; the surface containing the mouth (the underside, in sea stars and most others) is called the oral surface, and the opposite side, which usually bears the anus, the aboral surface. There are five living classes of echinoderms. 

Answer 2

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➧ Some Phylum in Animal Kingdoms are:-
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❶❭ Porifera:-━━━━━━━━━━━━━━━☟

❱ Body is cylindrical & asymmetrical.

❱ Canal system is present.

❱ Cellular level of organisation.

❱ It is diploblastic.

❱ They reproduce by budding in Asexual Reproduction.

❱ Special cells are choanocytes.

❱ Skeleton is in the form of spicules.

▶Ex:- Sycon & Sponges

❷❭ Coelenterata:-━━━━━━━━━━━━━━━☟

❱ Body is Radially symmetrical.

❱ Canal system is absent.

❱ Tissue grade level of organisation.

❱ Body wall is diploblastic.

❱ Opening served by mouth & anus.

❱ Special Cell or Cnidoblasts.

❱ It occurs in the form of polyp & Medusa.

❱ It have gastrovascular cavity.

❱ It poses tentacles called Nematoblasts.

▶Ex:-  Hydra & Jellyfish

❸❭ Platyhelminthes:-━━━━━━━━━━━━━━━☟

❱ Body is bilaterally symmetrical, flattened & Ribbon shaped.

❱ Digestive system is absent or incomplete.

❱ Body cavity is absent.

❱ Body is triploblastic.

❱ It is bisexual or Hermaphrodite.

❱ Respiration is an aerobic.

❱ They possess sućker.

❱ Circulatory or respiratory system is absent.

▶Ex:-  Planaria & Tape worm

❹❭ Nematoda:-━━━━━━━━━━━━━━━☟

❱ Body is bilaterally symmetrical or cylindrical.

❱ Body has tissue level of organisation.

❱ It is mostly parasites organism.

❱ Body is triploblastic.

❱ Respiratory or circulatory system is absent.

❱ Sex are separate.

❱ They have tissue but no real organ.

▶Ex:-  Ascaris & Hook worm

❺❭ Annelida:-━━━━━━━━━━━━━━━☟

❱ Body is cylindrical, bilaterally symmetrical & metamerically.

❱ Body structure ring-like segment.

❱ Respiration by gills or moist skin.

❱ Body is triploblastic.

❱ Excretory organs are nephridia.

❱ Digestive & circulatory system are well developed.

❱ Locomotory organs are parapodia.

❱ They have true body cavity.

▶Ex:-  Earthworm & Leech

❻❭ Arthropoda:-━━━━━━━━━━━━━━━☟

❱ Body is bilaterally symmetrical & segmented.

❱ Exoskeleton shed periodically during growth.

❱ Body is covered with non living exoskeleton.

❱ Body wall is triploblastic.

❱ Body divided into head, Thorax & abdomen.

❱ It have jointed appendages.

❱ It possess compound eyes & antennae.

❱ Respiration by gills, trachea & book lungs.

▶Ex:-  Cockroach & Spider

❼❭ Mollusca:-━━━━━━━━━━━━━━━☟

❱ Body is bilaterally symmetrical.

❱ Shell formed of calcium carbonate.

❱ Body covered with mantal & hard shell.

❱ Body is triploblastic & Coelomate.

❱ Body divided into head, foot & visceral mass.

❱ Foot is ventral & muscular.

❱ Respiration by gills or ctenida.

❱ Blood may be Black - blue.

▶Ex:-  Octopus & Unio

❽❭ Echinodermata:-━━━━━━━━━━━━━━━☟

❱ Body is radially symmetrical.

❱ Body size is spherical or cylindrical.

❱ Body surface covered with spines.

❱ Body is triploblastic & have coelomic cavity.

❱ It possess power of regeneration.

❱ No head tail right & left side.

❱ Body differentiated into oral & aboral surface.

❱ It have water vascular system.

▶Ex:-  Starfish & Antedon

❾❭ Chordata:-━━━━━━━━━━━━━━━☟

❱ Nerve cord hollow tubular & dorsal.

❱ Notochord is present.

❱ Heart is ventral.

❱ Circulatory system is always closed.

❱ RBCs are present.

❱ Endoskeleton is present.

❱ A series of pharyngeal gill-silts present in the pharyngeal wall.

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