1. Porifera
The Sponges

2. General Characteristics
“Pore-bearer”
Sessile
9000 species
Mostly marine, some fresh water
Range from mm to meters
Acoelomate
Ectothermic
Not metameric
Filter feeders-up to 1500 L/day

3. Symmetry and Shape Often asymmetrical Can have radial symmetry
Ball, vase, disc, shrub, tree

4. Development Neither protosome or deuterosome
Doesn’t have mouth or anus
Diploblastic vs. Triploblastic
No tissues
Specialized cells

5. Skeleton
Spicules
Needle-like
Spongin
Mainly collagen

6. Specialized Cells
3 cell layers
Pinacoderm
Mesohyl
Choanoderm

7. Pinacoderm Outer layer Cells are pinacocytes (Flat)
Porocyte (ostia) is opening for water

8. Mesohyl Gelatinous middle layer Amoebocytes Archeocytes Reproduction
Spicule formation
Transport and store food
Archeocytes

9. Choanoderm Inner layer Choanocytes Nutrient absorption
Beating flagella create current
Possibly from choanoflagellates
Nutrient absorption

10. Ascon
Simplest
Least common
Porocyte -> spongocoel
-> osculum

11. Sycon
Folded walls
Porocyte -> incurrent canal -> radial canal -> spongocoel -> osculum

12. Leucon Loss of spongocoel Multiple oscula
Porocyte -> incurrent canal ->radial canal -> excurrent canal -> osculum

13. Sexual Reproduction Monoecious Release gametes through osculum
Larva settles and develops
Sperm transported by amoebocytes
Fertilization in mesohyl

14. Asexual Reproduction
Fragmentation
Budding
Gemmules

15. Uses and Importance Spongin used in sponges
Food source for snails, sea stars, fish
Protection for small fish