Phylum Porifera: The Sponges

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Sponge Basics• Sponges are

filter feeders that get their food (mostly unicellular organisms) and oxygen by filtering them from a flow of water.

Flagella Powered!

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

Cell Types of Sponges

Sponge Cells

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

Sponge Diversity

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

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.

Sponge Reproduction

“male” releases sperm. Eggs in “female” spongocoel are fertilized

Diploid larva develops inside female for short time

Larva becomes mobile for short time, finds new location, develops into new sponge

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.

18s rRNA Relatedness

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.