Question

PHYLUM ANNELIDA :Compare and contrast Oligochaeta, Polychaeta and Hirudinea. What traits do they share (as annelids) and what traits distinguish each class? ( Similarity vs Difference)

PHYLUM PLATYHELMINTHES (FLATWORMS): compare and contrast the three Platyhelminthes classes( Turbellaria, Trematoda and Cestoda). What traits do they share (as Platyhelminthes) and what traits distinguish each class? ( Similarity vs Difference)

Answer 1

polychaetae	oligochaetae	Hirudinea
Marine	terrestrial and freshwater	ectoparasite and freshwater organisms
Clitellum absent	clitellum present	clitellum is not distinct ,it appears only in breeding season
body has setae/parapodia for locomotion	parapodia absent setae in few in number	setae /parapodia absent.suckers present
they are dioecious	they are hermaphrodite	hermaphrodite
external ferlitization	cross fertilization	cross fertilization

similarity- bilateral symmetry, tube with in tube body plan,triploblastic,digestive system complete,extracellular digestion,closed circulation, excretion through nephridia,

Turbellaria	Trematoda	Cestoda
aquatic ,free swimming organisms	ecto and endoparasite with leaf like body	endoparasite with tape like body
ciliated epidermis without cuticle	devoid epidermis with thick cuticle	thick and living cuticle called tagumen
suckers are rare	one or more suckers	head has hook and suckers
mouth is ventral	mouth is anterior	body is divisible in to proglottis
numerous tesis and ovaries are two in number	testis 2 or more and ovary is single	single set of reproductive organ
simple life history	complex life history	complicated life history
eg: Planaria	Eg:Polystomum	Eg:Gyrocotyle

similarity-organ system level of organisation, bilateral symmetry, blind sac body plan,Acoelomates,respiration through general body surface, triploblastic organisms,circulation through parenchymal tissue fluid