The coelom is a fluid-filled space between the body wall and digestive tract that acts as a cavity for other organs. The presence or absence of body cavity or coelom plays a very important role in the classification of animals as it decides the complexity for any animal at the organ level. Based on the nature and presence of the body cavity the animals can be classified into:
1. Coelomates: These are the animals that possess a fluid-filled cavity between the body wall and digestive tract. Annelids, mollusks, arthropods, echinoderms, and chordates are examples of coelomates.
2. Pseudocoelomates: These are the animals in which the body cavity is not lined by the mesoderm and remains scattered in between the ectoderm and endoderm. Aschelminthes is an example of pseudocoelomates.
3. Acoelomates: These are the animals in which the body cavity is absent. Platyhelminthes is an example of acoelomates.
Answered by Pragya Singh | 1 year agoPrepare a list of some animals that are found parasitic on human beings.
Match the following:
| Column I | Column II |
| (a) Operculum | (i) Ctenophora |
| (b) Parapodia | (ii) Mollusca |
| (c) Scales | (iii) Porifera |
| (d) Comb plates | (iv) Reptilia |
| (e) Radula | (v) Annelida |
| (f) Hairs | (vi) Cyclostomata and Chondrichthyes |
| (g) Choanocytes | (vii) Mammalia |
| (h) Gill slits | (viii) Osteichthyes |
Segmentation in the body is first observed in which of the following:
(a) Platyhelminthes
(b) Aschelminthes
(c) Annelida
(d) Arthropoda
Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
What are the modifications that are observed in birds that help them fly?