1. Phylum Porifera includes sponges, which are the simplest multicellular animals. 2. Sponges have no true tissues and rely on diffusion for digestion, respiration, and excretion. They feed by filtering water through pores in their bodies. 3. There are over 5,000 living sponge species divided among three classes: Calcarea, Hexactinellida, and Demospongiae. They differ in the material that makes up their skeletons (calcium carbonate, silica, or spongin) and canal structure.

1. Phylum Porifera
“Sponges”
Kingdom: Animalia
Phylum: Porifera
Classes: Hexactinellida
Demospongia
Calcarea
By
Dr. Priti D.Diwan
AssistantProfessor
Department of Zoology
J.D.Patil Sangludkar Mahavidyalay Daryapur.

2. Phylum Porifera
 Pronounced (po-rif'-er-a)
 The name means
“bearing pores”
• 5,000 living species
• Most primitive of all
animals

3. Phylum Porifera
 Sponges are sessile, meaning they have a
stationary, inactive lifestyle can move up
to 4 mm per day
 Because they are sessile, they are highly
dependent on ocean currents to bring
food to them and eliminate waste
products.
 Embryos are free-swimming.

4. Major Characteristics:
 They have no organs or true tissues.
 Digestion, respiration, and excretion all
occur by simple diffusion directly into and
out of the cells.
 No nervous system.
 Most sponges are asymmetrical.
Occasionally radial

5. Major Characteristics:
 Their bodies are made up of thousands of
cells mixed together in a gel-like mixture,
supported by small skeletal structures
called spicules.

6. Major Characteristics:
• Feed by filtering water through their outer
walls and pumping it out of body
• Flow of water is uni-directional
 Sponges are made up of a system of tiny
pores and canals that make up a intricate
filter feeding system.

7. Structure/General Anatomy:
• Opening at top called
the osculum
• Gelatinous interior
called the mesohyl
• The interior cavity
called the
spongocoel
OSCULUM - opening
MESOHYL
SPONGOCOEL

8. Sponge Skeletons
 Thin strands of collagen are found
throughout the bodies of sponges.
 The class of Demospongiae produces a
form of collagen known as spongin.

9. Sponge Skeleton
 Spicules on the left
 Spongin on the right

10. Spicules:

11. Structure / Anatomy:

13. Structure / Anatomy:
• No tissues or organs
• Each type of sponge
cell is responsible for
a specific function
• The outer surface is
covered by tiny
openings called ostia

14. Cellular Structure of Sponges
 The inner material that makes up the main body (a
type of connective tissue) of a sponge consists of a
loose gel-like mixture called Mesohyl.
 Porocytes make up the ostia that allow the
passage of water into the sponge.

15.  The epithelial cells of sponges are called
Pinacocytes. These cells play a role in trapping
food particles.

16.  Amoebocytes are cells in the mesohyl that perform
a variety of functions. The primary functions are
digestion (archaeocytes) and production of spicules
and collagen.

17. • The spongocoel is lined with flagellated
cells called choanocytes or collar cells.
• The flagella beat to cause a current –
drawing water in through the ostia
• The collar traps food particles

18. Cellular Structure of a Sponge

19. Structure / Anatomy:

20. Feeding:
• Flow of water through the
sponge allows for
feeding, waste removal,
and the intake of oxygen
• Sponges filter bacteria as
a food source
 Some sponges filter as
much as 1500 liters/day
(that is equivalent to
about 400 gallons/day).
Moving Water/Current = Low
Pressure
Water pumped in through the walls

21. Sponge Digestion

22. Digestive:
• Filter feeders
• NO GVC – food
is digested
intracellularly
• Collar cells engulf
and digest food
vacuoles
• Use amoeboid
cells to distribute
nutrients

23. Circulatory:
• Amoeboid Cells in
the wall transport
food and
nutrients

24. Excretory:
• All wastes are
purged through
the main pore
called the
osculum

25. Respiratory
• Various cells take in oxygen through
diffusion

26. Sponge Sexual Reproduction
 Most sponges are monoecious. Meaning a
single sponge can have both male and female sex
cells.
 Sperm cells develop from choanocytes. Egg cells
can develop from choanocytes in some species
and from archaeocytes in others.
 After fertilization, the a free-swimming flagellated
larva called a parenchymula breaks off from the
adult sponge and are carried away by ocean
currents.

27. Sponge Asexual Reproduction
 fragmentation and by external budding.
 Fragmentation occurs when a fragment is broken off
from the main body of the sponge.
 Budding occurs when a small sponge grows off of the
adult sponge. Eventually these can break off and
regenerate.

28. Sponge Asexual Reproduction
 Gemmules are internal buds that usually remain
dormant and contain archaeocytes.
 Gemmules are usually formed during unfavorable
conditions
 After the unfavorable conditions pass, the
archaeocytes can then be released - regenerate into
a new adult sponge.

29. Parenchymula and Gemmules
 Gemmules on
the left
 Parenchymula
on the right.

30. Sponge Ecology
 Adults are always attached to other
objects. (rocks, corals, submerged objects
etc.)
 Many other organisms such as crab and
fish live symbiotically in or on sponges.
 Some sponges live on other organisms
like mollusk shells and corals.

31. Class Calcarea
 Spicules made of
calcium carbonate
(calcite and
limestone)
 All three types of
canals represented
(asconoid, syconoid,
and leuconoid).
 All marine
Example (Clathrina)

32. Class Hexactinellida
 Six-rayed spicules
made of silica
(same substance
as glass)
 Body often
cylindrical and
funnel shaped
 Syconoid or
leuconoid
 All Marine
Example, Venus Flower
Basket (Euplectella)

33. Class Demospongiae
 Skeleton made of
silica spicules that
are not six-rayed, or
a skeleton made of
spongin, or both.
 Leuconoid type canal
systems only.
 One family
freshwater, all others
are marine.
Very diverse group of
sponges