BIOL 1101 Lecture Notes - Lecture 94: Opisthokont, The Sponge, Eumetazoa
27 Jun 2016
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You are probably aware that we have reached the kingdom animalia. But just like the fungi, the animalia are opisthokont eukaryotes. We will not be through with the opisthokonts until we reach the plants. The 10,000 or so species of sponges are among the simplest animals. They are the only animals we will study that are asymmetrical. Sponges have no organ systems, nerves or muscles. They have some specialized cells, but these are only weakly dependent on one another. A sponge is more a colony than a multicellular animal. Thus they do not qualify for inclusion in the true multicellular animals, the eumetazoa. The colonial nature of sponges was confirmed by a spectacular early experiment. An investigator squeezed a sponge through a silk cloth, disassociating it into small clumps of cells. In a short time, the cells reassembled themselves into several smaller sponges.
