Question

1.    What is the significance of metanephridium thickness in the earthworm? Be specific.

2.    Compare and contrast the exoskeleton of the grasshopper and the crayfish. How might they be used differently for osmoregulation?

3.    The green gland of lobsters does not have any convoluted tubules associated with it as it does with the crayfish. What might be the significance of this difference?

Answer 1

Answer-(1)There is one pair of metanephridia in each segment of Lumbricus terrestris which has one pair of metanephridia per segment. The head of nephrostome of each nephridium passes through the intersegmental septum to project into the coelome. Nephrostome is open funnel which uses hair-style cilia to draw coelomic fluid inside it which pumped through a coiled tube by cilia.

Metanephridium also help in the osmoregulation.

Answer -2 Uric acid is synthesized by tissues of insects like grasshopper and released in soluble form into the hemocoel of grasshopper exoskeleton through malpghian tubules.

In crayfish the Green gland is used as excretory organ through exoskeleton.

Convoluted tubules is found in crayfish however not present in grasshopper.

Answer- 3 Soft green substance found in the body cavity of lobsters.which is used as the liver and pancreas more fast than the organism which have convoluted tubules.