1. Chapter 9: Phylum Porifera
The Sponges

2. Classification Phylum Porifera Animal phylum whose members are:
Sessile and either asymmetrical or radially symmetrical
Body organized around a system of water canals and chambers
Cells not organized into tissues or organs.

3. Characteristics Asymmetrical Three cell types
Pinacocytes, mesenchyme and choanocytes
Division of Labor
Central cavity or branching chambers for water circulation
Filter feeders
No tissues or organs

4. Characteristics Live worldwide: polar regionstropics
Quiet, clear waters because sediment stirred up could clog their pores
Difficult to feed and/or breathe

5. Sponge Structure Central cavity (spongocoel) or branching chambers
Osculum
Inhalant pore
Central cavity (spongocoel) or branching chambers
Filter feeders
Water exits out a large opening at the top (osculum)

6. Cell Layers Pinacoderm: outer layer Mesohyl: jellylike middle layer
Choanoderm: inner layer

7. Specialized Cells: Outer Layer
Pinacocytes: thin, flat cells the line the outer surface
Porocytes: specialized pinacocytes
Openings for water movement
Also called ostia or pore cells

8. Pinacocytes

9. Porocytes
Dermal
ostia

10. Specialized Cells: Middle Layer (Mesohyl)
Mesenchyme cells
Amoebocytes
Specialized for reproduction, secreting skeletal elements, forming contractile rings and transporting and storing food
Archaeocytes
Can change to other types of cells
Responsible for ingesting and digesting food caught by the choanocytes and transporting the food to other types of cells.

11. Specialized Cells: Middle Layer (Mesohyl)
Mesenchyme cells
Collencyte: produce collagen
Creates spongin for skeletal support
Spongin (protein), non-allerginic
Commercial sponges
Sclerocytes: produce spicules
Skeleton of needlelike spikes
CaCO3 or Silica
Used for defense (some can be poisonous)

13. Specialized Cells: Inner Layer (Choanoderm)
Choanocytes (collar cells)
Flagellated cells that beat and create current
Collar will
filter food
particles
from the
water

14. Obtaining Food
Food moves through the base of the cell, incorporated into a food vacuole (phagocytosis), and passed to the amoebocytes for digestion.

15. Life of a sponge
The life of a sponge depends on the water currents that the choanocytes make.
Food
Gas exchange
Getting rid of wastes

16. Three Body Forms Ascon Sycon Leucon Vase-like Folded walls
Extensively branched canal system

17. Asconoid Sponges
Incurrent pore
Spongocoel
Osculum
Porocyte

18. Sycon Osculum Spongocoel Choanocyte Radial canal Incurrent pore
Incurrent canal
Choanocyte

19. Leucon Osculum Excurrent canal Incurrent pore Incurrent canal
Choanocyte
chamber
Osculum
Incurrent canal
Excurrent canal
Incurrent pore

20. Class Calcarea Spicules composed of calcium carbonate
Spicules are needle-shaped or have 3 or 4 rays
Ascon, Leucon, or Sycon body forms
All marine
Leucosolenia eleanor – Calcareous Sponge

21. Class Hexactinellida Spicules composed of silica and six rayed
Spicules often fused into an intricate lattice
Cup or vase shaped
Sycon or Leucon body form
Found at m depths in tropical West Indies and eastern Pacific

22. Class Demospongiae
Brilliantly colored sponges with needle-shaped or four-rayed spicules or spongin (or both)
Leucon body form
Up to 1m in height and diameter

23. A B C D E F

24. Nutrition Filter Feeders
Bacteria, algae, other microorganisms
A few are carnivorous
Important source of nutrition for some snails, sea stars and fish
Respiration and excretion (ammonia) by diffusion

25. Reproduction Most hermaphroditic (monoecious) Do not self fertilize
Produce eggs and sperm at different times
Form from choanocytes or amoebocytes

26. Reproduction Larva develop within wall
Larva breaks free and swims for no more than two days
Settles and begins to develop into adult body form.

27. Asexual Reproduction Budding Fragmentation Creating gemmules
Weather resistant capsules of archaeocytes surrounded by spicules
Released in winter (can survive freezing/drying)
When conditions are favorable, amoeboid cells stream out and organize into a sponge.

28. Ecological
Home to many other species

29. Euplectella (Venus Flower Basket)
vase shaped sponge
When it reaches a certain size, a shrimp will enter the sponge through the osculum. If a male shrimp is already “in residence,” and another males tries to enter, the resident will prevent him. He will allow another female shrimp to enter. Eventually, the two shrimp grow to a size such that they cannot exit the osculum of the sponge. They will spend their entire life within the sponge, and dried specimens of Euplectella and the resident shrimp are sometimes given as a wedding present in Asian countries, as a symbol of marriage “till death do us part!”