1. Phylum Porifera

2. General Characteristics
SPONGES!
Simplest of all animals
Cellular level organization
Specialized cells, but no tissues (bodies are a loose aggregation of cells)
No true tissues or organs
Radial or asymmetrical
Marine and Freshwater
Saltwater are colorful
Freshwater are dull green color

3. General Characteristics Cont.
Sponges are sessile (not free moving) as adults
Free swimming larval stage called dipleurula
Porifera means pore-bearing
Water enters through pores (ostia) bringing in food and oxygen
Sexual & Asexual Reproduction
Osculum- large opening at the top where excess water leaves

4. Water Flow Through the Sponge
WATER OUT
Water Flow Through the Sponge
WATER IN
Osculum

5. 3 Basic Cell Types
Pinacocytes
Mesenchyme Cells
Choanocytes

6. 3 Basic Cell Types
1. Pinacocytes- flat cells that line the outer surface of the sponge.
May be slightly contractile
Porocyte: a specialized type of pinacocyte; are tube-like in shape; contractile; and can regulate water circulation.

7. 2. Mesenchyme Cells- move around in the mesohyl layer; are specialized for reproduction, secreting the skeleton, transporting/storing food.
Amoebocyte: jelly-like layer just underneath the pinacocyte layer.
(makes spicules – skeletal)

8. 3. Choanocytes- flagellated cells that line the inner chamber of the sponge; called collar cells.
Flagellum: flagella spins to create water currents to pull in water and food
Collar: “trap” plankton and other fine particles from the water

9. Choanocyte
Choanocyte

10. Structural Skeleton Consists of either one or all of the following:
Spicule: microscopic needle-like spikes that are made of Calcium carbonate (CaCO3) or silica (glass).
Spongin: a fibrous protein made of collagen

11. Sponge Skeletons
Silica Spicules
Limestone Spicules
SPONGIN

12. Sponge Body Types
3 Kinds-
Ascon
Sycon
Leucon

13. Ascon Simple tube perforated by pores
Open internal part of tube is called the spongocoel (coel = gut)
Are vase-like
Least common type of sponge
Single opening to the
outside called the osculum

14. Sycon
Sponge wall is folded into canals
Choanocytes line the
radial canals to
move water
osculum

15. Leucon Have an extensively branched canal system.
Multiple canals lined with flagellated cells
Multiple ostia
for water to exit
Increased surface
area means more
water can move
through sponge

16. Body Forms Summary

17. Reproduction
Sexual Reproduction- sponges are monoecious (male and female in the same body)
Release sperm and eggs into the water from the Osculum
Cross-Fertilization takes place in the ocean
Fertilized eggs form larvae which swim off looking for a place to settle

18. Sponge Releasing Eggs & Sperm
Reproduction
Sponge Releasing Eggs & Sperm

19. Reproduction Cont’
Sponges can regenerate (regrow) lost body parts through mitotic cell division (asexual)
Sponges also reproduce asexually by (budding)

20. Reproduction Cont’d
gemmule
Asexual Reproduction- involves the formation of gemmules
gemmules: resistant capsules that sponges release to survive unfavorable conditions.
When conditions become favorable, the gemmules sprout into sponges.

21. CLASSES Phylum Porifera 3 Classes Class Calcarea Class Hexactinellida
Class Demospongiae

22. Class Calcarea Spicules made of Calcium Carbonate
Can have all three body forms
Most primative
Ex. Grantia

23. Class Hexactinellida Deep sea sponges
Can have syncon or leucon body forms
Often fused into an intricate lattice
Glass sponges
(silica)

24. Class Demospongiae Spicules made of silica, spongin, or both.
Most common (fresh (green) & salt)
All are Leuconoid
Ex: bath sponge