BIOL 211 Lecture Notes - Lecture 10: Cnidaria, Sea Anemone, Osculum
Document Summary
Animal groups (phyla) are defined by a body plan: symmetry, organization of tissues, type of body cavity, pattern of embryonic development (blastopore fate) Body wall consists of 2 layers of cells separated by a gelatinous regions. Body is like a sac perforated with holes (pores) Water flows in through the pores in the spongoceol and out the osculum (this is not a body cavity) Sponges are filter feeders (suspension feeders) ex: prokaryotes, protists. To grow 100g a sponge must filter 1000 kg of water. A unique cell type found only in porifera (has long flagellum) Structurally similar to the choanoflagellates (protists) that may be the ancestor to all animals. Water is drawn through the collar and food particles are trapped. Engulfed by phagocytosis; digested by amoebocytes who carry it to other cells. Most species are hermaphrodites (one individual produce both egg and sperm) Sperm are release into the water, brought into another sponge (internal fertilization)
