1. Phylum Porifera: The Sponges
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2. Sponge Basics
Sponges are filter feeders that get their food (mostly unicellular organisms) and oxygen by filtering them from a flow of water.

3. Flagella Powered!

4. Are you Looking at my Osculum?
In this picture, a yellow dye has been placed around the bottom of the sponge, to illustrate water flow through the pores and out the osculum

5. Cell Types of Sponges

7. Sponge Cells

8. Spicules: Sponge bones…
One of the ways sponges are classified is by careful examination of their microscopic spicules.
Often, this is the only way to be sure of sponge identification

10. Sponge Diversity

11. Porifera by the Numbers
There are three recognized classes within Porifera.
Over 7,000 individual species have been described.

12. Sponge Life Cycle Sponges can reproduce asexually, by regeneration
Sponges can also reproduce sexually; most sponges are hermaphrodites, having the capability to produce either eggs or sperm.

13. Sponge Reproduction
Larva becomes mobile for short time, finds new location, develops into new sponge
“male” releases sperm. Eggs in “female” spongocoel are fertilized
Diploid larva develops inside female for short time

14. Sponge Evolution
The oldest animal fossils ever found are sponges. (550 MYA)
Sponges are also the “basal” or bottom branch of the phylogenetic tree of the animals.
For these 2 reasons, sponges are thought to be the MRCA of the animals.

15. 18s rRNA Relatedness

16. Sponge Ecology
Almost all sponges (95% +) live in marine environments. Very few are freshwater.
Sponges are found in every ocean, from pole to pole.
Sponges are low-level consumers, and are sometimes food for other species.
They are an important part of coral reef ecosystems.