Sponges Cnidarians 2BIbDF09 10/11

What are Sponges?

Sponges, from the Latin pore bearers, are very primitive animals of the phylum Porifera, more precisely they are the first multicellular animals.They evolved very early from colonial protists. They are loosely organized and lack true tissues. There are between 8'000 and 9'000 species of sponges, depending of the textbook. Their sizes are from a few millimeters to more than 2 meters in diameter. The body of a sponge looks similar to a vase pierced with small holes and pores. Sponges do not have nervous, digestive or circulatory systems. Their ancestors are the choanoflagellates (group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals).

• see Appendix Sponges 1

What are Cnidarians?

Cnidarians (phylum Cnidaria) are mostly marine species (more than 10'000).