Question

Answer the following questions for :
(a) Sycon
(b) Pheretima
(c) Sepia

(i) Write their common names.
(ii) The phylum to which they belong.
(iii) Type of digestive system they possess.
(iv) Type of fertilisation they undergo.
(v) Type of development they undergo.

Answer 1

Bonjour!

(a) Sycon :
(i) Common name : Crown sponge/ Urn sponge.
(ii) Phylum : Porifera
(iii) Digestive system : It does not possess a digestive system. It is a sponge and exhibits cellular level of organisation. Organ-systems are not formed in sponges. Digestion in sponges is intracellular, occurs
in choanocytes and phagocytes not in spongocoel.
(iv) Fertilisation : Fertilisation is internal. The fusion of sperms and ova takes place inside the body of
animal.
(v) Development : Development is indirect. A larval stage is present which is morphologically distinct from
the adult.

(b) Pheretima :
(i) Common name : Earthworm
(ii) Phylum : Annelida
(iii) Digestive system : Complete digestive system is present which bears two separate openings mouth and anus.
(iv) Fertilisation : Fertilisation is external in earthworm.
(v) Development : Development is direct, i.e., no larva is formed in the life history of earthworm.

(c) Sepia :
(i) Common name : Cuttlefish
(ii) Phylum : Mollusca
(iii) Digestive system : Digestive system is complete with a characteristic rasping organ radula for feeding.
(iv) Fertilisation : Fertilisation is internal; the fusion of sperms and ova takes place inside the female genital tract.
(v) Development : Development is direct with no intervening larval stage.

Hope this helps...:)

Answer 2

Olá User.
Here's ur answer.

⭐SYCON⭐
a) Common name:Crown sponge.
b) Phylum:Porifera.
c) Digestive System: It isn't present.It consumes it's food with sponge like structures.
d) Fertilisation: Internal.
(It's organisation is of cellular level)

⭐PHERETIMA⭐
a) Common name:Earthworm.
b) Phylum:Annelida.
c) Digestive system: Well-developed and with proper mouth and anus.
d) Fertisation:Internal.

⭐SEPIA⭐
a) Common name:Cuttlefish.
b) Phylum:Mollusca
c) Digestive system:Developed.
d) Fertilisation:Internal.

HOPE IT HELPS!!
@Charlie16.