Animal Kingdom

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FÜÑÇTÏØÑS ØF ÇØËLØM

It acts as shock

absorber.

Coelomic fluid reduces

friction between

visceral organs.

2

1

5. MËTÅMËRÏSM (SËGMËÑTÅTÏØÑ)



It is the phenomenon in which the body or organs is externally and

internally divided into repeated segments (metameres). E.g. Annelids

(earthworm, etc.), Arthropods. (AIPMT 2006)

6. ÑØTØÇHØRD



It is a mesodermally derived supporting rod formed on the dorsal

side during embryonic development in some animals. Animals with

notochord are called chordates and those without notochord are called

non-chordates.

Features

Porifera

(Sponges)

Cnidaria

(Coelenterata)

Ctenophora

(Comb jellies or

Sea walnuts)

Levels of

organisation

Cellular

Tissue

Tissue

Symmetry

Asymmetrical,

some are radial

Radial

Radial

Germ layers

Diploblastic

Diploblastic

Diploblastic

Coelom

Acoelomate

Acoelomate

Acoelomate

Habit and

habitat

Aquatic (mostly

marine),

sedentary,

solitary/colonial

Aquatic (mostly

marine), sessile/

free swimming,

solitary/colonial

Exclusively marine,

solitary & pelagic

Digestive

system

Absent,

intracellular

digestion

Incomplete,

intracellular &

extracellular

digestion

Incomplete,

intracellular and

extracellular

digestion

Respiratory

system

Absent

Absent

Absent

Circulatory

system

Absent

Absent

Absent