BIOL 1202 : EXAM 4 Notes
Document Summary
Most recent hypothesis about animal phylogeny [figure 32. 11] 33. 1 sponges are basal animals that lack true tissues: porifera: phyla calcarea & silicea, live in both fresh and marine waters, lack true tissues and organs, asymmetrical body. Sponges [figure 33. 4: sponges are suspension feeders, filter water passing through their bodies. Water movement through a sponge would follow what path: pore spongocoel osculum, blastopore gastrovascular cavity protostome, choanocyte mesohyl spongocoel, pore choanocyte mesohyl. 33. 2 cnidarians are an ancient phylum of eumetazoans. Cnidarian body plans [figure 33. 5: polyp form is generally sessile, medusa form moves freely in water by passive drifting and contractions of the bell. Defining feature of cnidarians [figure 33. 6: 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. Which of the following animals is responsible for more lethal attacks on humans each year: sharks, killer whales, snakes, cubozoans.
