Mode Of Food & Feeding In Porifera.ppt

food nd feeding of porifera phylum and protozoa animals

1. Mode of Food & Feeding in
Porifera
Dinesh parihar
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2. Porifera
The phylum Porifera (the sponges) includes
about 5000 species almost all of which are
marine.
Range in size from a few millimeters to 2 meters
across.
Porifera means “pore-bearing” and refers to the
numerous pores and channels that permeate a
sponge’s body.

3. Barrel sponge
Yellow tube sponge

4. Porifera
Sponges are the simplest multi-cellular
organisms, but they lack the germ layers
of more complex metazoans.
Have a cellular level of organization lacking
true tissues and organs.
Body is a mass of cells imbedded in a
gelatinous matrix (mesohyl) which is
supported by a framework of spicules, as well
as collagen and spongin fibers.

5. Glass sponge spicules

6. Groups of sponges
There are three classes of sponges on the
basis of formation of exoskeleton:
Class Calcarea
Class Hexactinellida
Class Demospongiae

7. Clathrina canariensis (Calcarea):

8. Marine Demospongiae on a Caribbean Coral Reef :

9. Porifera feeding
Sponges are sessile (they don’t move) and
depend on water movement to bring in
food and oxygen and remove wastes.
Sponges feeds on small food particles
present in the water.
Sponges generate their own flow of water
having a unique water current system.

10. Canal systems
Most sponges have one of three types of
canal system which help them in feeding:
Asconoid
Syconoid
Leuconoid
These systems differ from in each other in
the increasing complexity.

11. Porifera feeding
Water enters through many small pores
called ostiaand exits through larger
oscula.

12. Oscula

14. Porifera feeding
Openings are connected by a series of
canals, which are lined by choanocytes
(the flagellated collar cells) that maintain
the current of water and filter out food
particles.
Choanocytes

15. Porifera feeding
The choanocyte’s collar consists of microvilli
joined together by delicate microfibrils,which
filter out tiny food particles.
The beating of the flagellum draws water
through the collar and out the top.
Particles too big to pass through the collar get
trapped in mucus and slide down the collar to
the base where they are phagocytized.

17. Porifera feeding
Sponges can filter enormous volumes of
water as much as 20,000 times the
volume of the sponge in 24 hours.
Sponges mostly consume bacteria and
may filter as much as 90% of those
passing through.
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18. Porifera feeding
Some sponges also supplement their filter
feeding by hosting symbionts such as
green algae, dinoflagellates or
cyanobacteria that provide nutrients to the
sponge.
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