Question

Phylum Nematoda Discussion:

1. What distinguishes nematodes?

2. What is the function of the cuticle?

3. What serves as a support for the body of these worms?

4. How does gas exchange takes place?

5. Speculate on why this group is so successful.

Answer 1

1. Nematodes( Round worms) :- triploblastic, bilatetal, unsegmented, round, long, slender body. The body cavity is pseudocoel, which is a false coelom derived from blastocoel. The body wll is having only longitudinal muscles and the body has no distinct head, and it has complete alimentary canal. The nematodes show sexual dimorphism. these are parasitic in nature.

2. The function of cuticle is to protect the body from mechanical injury and from digestive enzymes of the host.

3. The wall of nematodes have cuticle and longitudinal muscles separated by a thin layer of hypodermis, all these layers which supports its body and allows side to side movement.

4.The respiratory absent is absent, respiration is anaerobic. The essential gases are simply diffused through skin.

5. This group is so successful may be due to the following reasons;

First thing they are parasitic in nature and feeds on the host so no need to perform any tough work for this. Feeds on stored food such as glycogen nd digestion is extracellular. Next thing is in the host they do easily survive from the attack of digestive enzymes with the help of cuticle.

The egg of nematodes have a chitinous shell which protects it from the outside envoenvironmental hazards, problems, like temperature, heat etc. This shows aberrant migration inside the host which adds another feature for great survival inside the host.its respiration is anaerobic so less or no oxygen is needed. The sense organs such as amphids , papillae are there. Such features and body plan makes it to sustain more and continue life successfully.