Animal Kingdom 3

Question 1

what are common features of molluscs

Answer 1

This is the second largest animal phylum
(Figure 4.13). Molluscs are terrestrial or aquatic
(marine or fresh water) having an organ-system
level of organisation. They are bilaterally
symmetrical, triploblastic and coelomate
animals.

Question 2

exclusive features of molluscs

Answer 2

Body is covered by a calcareous shell
and is unsegmented with a distinct head,
muscular foot and visceral hump.

A soft and
spongy layer of skin forms a mantle over the
visceral hump which encloses most of the organs.

The space between the hump
and the mantle is called the mantle cavity in
which feather like gills are present. They have
respiratory and excretory functions.
The
anterior head region has sensory tentacles.

The
mouth contains a file-like rasping organ for
feeding, called radula.

Question 3

whata re the sexes of these animals

Answer 3

fertilisation is internal
development is indirect
diecious
oviparous

Pila (Apple snail), Pinctada (Pearl oyster), Sepia
(Cuttlefish), Loligo (Squid), Octopus (Devil fish), Aplysia (Seahare), Dentalium (Tusk shell) and Chaetopleura (Chiton).

Question 4

what is the structue of echinodermata

Answer 4

These animals have an endoskeleton of calcareous ossicles
and, hence, the name Echinodermata (Spiny bodied, Figure
4.14). All are marine with organ-system level of organisation.
The adult echinoderms are radially symmetrical but larvae
are bilaterally symmetrical. They are triploblastic and
coelomate animals.

Question 5

what are the organs of the exhniodermata

Question 6

what is the most exclusive feature of hemicorhdate

Answer 6

Hemichordates have a rudimentary
structure in the collar region called stomochord, a structure
similar to notochord.

Question 7

what are the organs of the exhniodermata

Answer 7

Digestive system is complete with mouth
on the lower (ventral) side and anus on the upper (dorsal)
side. The most distinctive feature of echinoderms is the
presence of water vascular system which helps in
locomotion, capture and transport of food and respiration.
An excretory system is absent.

Question 8

what is the fertlisation of exhinoderm

Answer 8

Sexes are separate.
Reproduction is sexual. Fertilisation is usually external.
Development is indirect with free-swimming larva.
Examples: Asterias (Star fish), Echinus (Sea urchin), Antedon
(Sea lily), Cucumaria (Sea cucumber) and Ophiura (Brittle star).

Question 9

what are the hemichordate s

Answer 9

This phylum consists of a small group of worm-like
marine animals with organ-system level of organisation. They
are bilaterally symmetrical, triploblastic and coelomate
animals.

Question 10

whata re the organ systems of hemichordates

Answer 10

The body is cylindrical and is composed of an
anterior proboscis, a collar and a long trunk (Figure 4.15).
Circulatory system is of open type. Respiration takes place
through gills. Excretory organ is proboscis gland.
Sexes are
separate. Fertilisation is external. Development is indirect.
Examples: Balanoglossus and Saccoglossus.