Write a short notes on a) …

Echinodermata(Spiny skinned animals)

1)They are star like,spherical or elongated. 2)Body is triploblastic,coelomate,unsegmented,radially symmetrical. 3)Body lacks heads but has oral surfaces. 4)The body w 4)The body wall is co all is covered by spiny hard calcium carbonate plates forming a rigid y hard calcium carbonate plates forming a rigid endoskeleton. 5)Excretory organs absent. 6)Sexes are separate. 7)Reproduction is asexual and sexual. 8)They have a peculiar vascular system that they use for moving. For Ex:Starfish,Echinus,sea cucumber.

Protochordata

1)Animals are bilaterally symmetrical, triploblastic, have coelom. 2)They show a feature of body design named notochord. 3)They do not have proper notochord at all stages of their lives. 4)They are marine animals. For Ex: Balanoglossus, herdemania, amphioxus.

Platyhelminthes

• The organisms belonging to this group are complexly designed.
• The body of these organisms has bilaterally symmetrical shape. This means that the design of the left and the right halves of the body are alike.
• These organisms have three layers of cells that makes up differentiated tissues due to which such animals are called triploblastic.
• These organisms have no true internal body cavity or coelom.

Nematode 1)The organism have bilaterally symmetrical and triploblastic body. 2)Body is cylindrical rather than flattened. 3)Body has tissues but no real organs. 4)Parasitic nematodes are pathogenic means they produce diseases in host. 5)For Ex:Roundworm lives in human intestine and cause ascariasis. 6)Sexes are separate. 7)Alimentary canal is straight,complete mouth and ****. For Ex: Ascaris,pinworm,hookworm.

Mollusca 1)Body is soft,bilaterally symmetrical,segmented. 2)Circulatory system is open. 3)The coelomic cavity is blood filled and reduced. 4)They have kidney like organs for excretion. 5)Sexes are usually separate. 6)There is little segmentation. 7)They is a foot that is used for moving around. 8)They are aquatic and some are terrestrial. For Ex:Chiton,pila,Unio