are there also one-cellular animals, or are they all classified as Protista? AxelBoldt
I don't know for sure, but I would imagine so. Perhaps I should make the article more unclear on that subject? (also, I actually didn't see the PBS show myself, but someone I was chatting with on IRC was watching it and I was aghast to discover no sponge article here on Wikipedia. Had to fix that quick. :) Bryan Derksen
All sponges are in the kingdom animalia and are therefore multi-cellular (protista are single-celled organisms that sometimes form colonies). Although the interaction of those cells is very primitive compared to the cells in your body or even in a worm. As a side note, some groups of sponges are little more than collections of cells that work together on a higher level than colonial organisms do. --maveric149