BIOL 1202 : EXAM 4 NOTES
Document Summary
Concept 33. 1: sponges are basal animals that lack true tissues. Water movement through a sponge would follow what path: pore spongocoel osculum, blastopore gastrovascular cavity protostome, choanocyte mesohyl spongocoel, pore choanocyte mesohyl. Concept 33. 2: cnidarians are an ancient phylum of eumetazoans. *wide range of sessile and floating forms including jellyfish, corals, and hydras. *medusa form moves freely in water by passive drifting and contractions of the bell. *cnidocytes unique cells that function in defense and the capture of prey. *stimulus causes the cell to evert releasing thread. *hydrozoa most marine, a few freshwater; both polyp and medusa stages in most species polyp stage often colonial. *scyphozoa all marine; polyp stage reduced; free-swimming; medusa up to 2 m in diameter. *anthozoa all marine; medusa stage completely absent; most sessile; many colonial. Which of the following animals is responsible for more lethal attacks on humans each year: sharks, killer whales, snakes. -body plan is a sac w/ a central gastrovascular cavity.
