22. Give answer in detail III

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

 

a. Invertebrates are animals that lack a vertebral columnhave a vertebral column. The invertebrates have been classified into various phyla.

 

b. Phylum Protozoa are microscopic, unicellularmulticellular organisms. They have flagella and ciliaspicules for locomotion, and reproduce by sexual reproductionfission or conjugation. Examples include Amoeba, euglena and paramoeciumLeucosolenia, spongilla and sycon.

  

c. Phylum Porifera are multicellularmicroscopic, unicellular organisms that have holes or pores in their bodies. They are externally covered by a rigid skeleton made of flagella and ciliaspicules composed of spongin protein and calcium carbonate. They reproduce through sexual reproductionasexual and sexual reproduction. Examples include Leucosolenia, spongilla and syconAmoeba, euglena and paramoecium.

 

d. Phylum Coelentrata are also known as cnidarianssponges. They are multicellular, diploblastictriploblastic  organisms that lack organs. They are sessile or free-swimming, solitary or colonial. They reproduce through sexual reproductionasexual and sexual reproduction. Examples include Hydra, Sea anemonePlanaria, Liver fluke.

 

e. Phylum Platyhelminthes are commonly known as flatwormscnidarians. They are multicellular, triploblasticdiploblastic animals. They are sessile or free-swimming animals, and are found as either solitary or colonial. They reproduce through sexual reproductionasexual and sexual reproduction. Examples include Planaria, Liver flukeHydra, Sea anemone.

 

f. Phylum Aschelminthes are commonly known as roundwormsflatworms. They have an unsegmented body, and are diploblastictriploblastic animals. They are mostly parasites in human beings and animals, causing diseases such as elephantiasis and filariasis. They reproduce through asexual and sexual reproductionasexual reproduction and are sexually dimorphic. Examples include Ascaris lumbricoides.

 

g. Phylum Annelida are triploblasticdiploblastic animals, which have a body that is segmented from head to tail. They have locomotory structures known as cuticleparapodia for locomotion. Examples include Earthworm and Nereis.

 

h. Phylum Arthropoda are triploblastic animals which have unsegmented bodiessegmented bodies. Their body has a thick chitinous parapodiacuticle which forms an exoskeleton. Examples include crab, prawn.

 

i. Phylum Mollusca are triploblastic soft-bodied animals which have unsegmented bodiessegmented bodies. These organisms have a muscular head, foot, visceral mass, mantle, and a calcareous shell. They undergo  sexual reproductionasexual reproduction. Examples include cuttle fish, snail.

 

j. Phylum Echinodermata are marine, triploblastic animals which have unsegmented bodiessegmented bodies, and definite organs. They use water vascular systems for the transport of food, gases, and water throughout their body. Locomotion and feeding take place through tube feetparapodia. Examples include starfish, sea cucumber.