BIOL 1202 : TEST 4
Document Summary
Most recent hypothesis about animal phylogeny: figure 32. 11, chordata contains vertebrates. Concept 33. 1: sponges are basal animals that lack true tissues: porifera: phyla calcarea and silicea, live in both fresh and marine waters, lack true tissues and organs, asymmetrical body. Sponges: sponges are suspension feeders (draw water through their body, filter water passing through their bodies, have an outer intradermal layer, figure 33. 4. Water movement through a sponge would follow what path: pore spongeocoel osculum, blastopore gastrovascular cavity protosome, choanocypte mesohyl spongecoel, pore choanocte mesohyl. Concept 33. 2: cnidarians are an ancient phylum of eumetazoans. Cnidarian body plans: polyp form is generally sessile, medusa form moves freely in water by passive drifting and contractions of the bell, figure 33. 5. Defining feature of cnidarians: cnidocytes, unique cells that function in defense and the capture of prey, stimulus causes the cell to evert releasing thread, some cnidocytes sting, others just entangle prey, figure 33. 6.
