Question

Give an account on the classification of invertebrates with few general features and examples.

Answer 1

Invertebrates are animals without a backbone. The invertebrates have been classified into various phyla as follows:

S.No	Division	Examples	General Characters
1.	Phylum Protozoa	Eg. Amoeba, Euglena p	Microscopic unicellular, pseudopodia, flagella and cilia for locomotion, reproduce by fission or conjugation.
2.	Phylum Porifera	Eg. Leucosolenia, Sycon.	Multicellular organisms with holes in the body. Skeleton formed of spicules, asexual and sexual reproduction.
3.	Phylum Coelenterata	Eg. Hydra, Jelly fish.	Multicellular organisms Diploblastic, sessile or free swimming, solitary or colonial, asexual and sexual reproduction
4.	Phylum Platyhelminthes	Eg. Planaria, Liver fuke	Acoelomates, parasites inside the body of animals and human beings, mostly hermaphrodite (bisexual).
5.	Phylum Aschelminthes or Nematoda	Eg. Ascaris lumbricoides	Unsegmented body, mostly parasites in human beings and animals, causing diseases, asexual reproduction.
6.	Phylum Annelida	Eg. Earthworm, Leech.	Triploblastic, segmented body, mostly hermaphrodite (bisexual and unisexual).
7.	Phylum Arthropoda	Eg. Crab, Prawn	Segmented body, thick chitinous cuticle forming an exoskeleton, paired and jointed legs, unisexual exhibits sexual dimorphism.
8.	Phylum Mollusca	Eg. Cuttle fish, Snail	Soft bodied, unsegmented, muscular head, foot and visceral mass, mantle, a calcareous shell, sexual reproduction.
9.	Phylum Echinodermata	Eg. Starfsh, Sea – Urchin	Exclusively marine, spines and spicules over the body, water vascular system, tube feet, for feeding, respiration and locomotion sexual reproduction.