Page 8 - 11-Bio-10 Kingdom plantae

10. Kingdom Animalia eLearn.Punjab

Pseudocoelomates

In Aschelminthes the space between the body wall and the digestive tube is called pseudocoelom
(false body cavity). Pseudocoelom is not homologous to true coelom because: it is not lined by
coelomic epithelium. It has no relation with the reproductive and excretory organs. It develops
from the blastocoel of the embryo and it is bounded externally by the muscles and internally by the
cuticle of the intestine. The animals having pseudocoelom are called pseudocoelomates

Coelomates

Coelom is cavity present between the body wall and the alimentary canal and is lined by mesoderm.
The mesoderm splits into outer parietal layer which under lines the body wall and the visceral
layer which covers the alimentary canal and the cavity between them is the true coelom. It is filled
with fluid called coelomic fluid. The animals which possess coelom or true body cavity are called
coelomates e.g. animals from annelids to chordates.

In coelomates gut attains more complexity and neuro-sensory system is well developed along with
excretory system, circulatory system, respiratory and reproductive systems.

Fig. 10.3 General body plan of acoefomate, pseudocoelomate and coelomate.

PARAZOA

Phylum: Porifera the most primitive animals V: 1.1

The name porifera is derived from Latin porus = pore, ferra = to bear

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