BIOL 2030 Study Guide - Calcareous Sponge, Spongin, Siphonophorae
Document Summary
Lab 2 phylum porifera and phylum cnidaria. Skeleton made of collagen and spicules (calcareous or siliceous) Digestion is intracellular (no mouth , anus or digestive system) Asexual (budding or formation of gem mules) Sexual (eggs and sperm produce ciliated larvae) Water enters via small pores (incurrent pores)and exists via large pore (osculum) Outer surface covered in flat cells (pinacocytes),inner choanocyte layer and the middle is mesohyl (gelatinous protein matrix) Pinacocoytes at base of sponge secrete a substance that attached sponge to its substrate. Water flow;incurrent pores> incurrent canals >radial canal (flagellated choanocytes)>central cavity/spongocoel > osculum. Skeletal components (non-living)-spongin fibers,spicules of calcium carbonate/silicon dioxide. Body wall composed of two cell layers: outer ectoderm. Inner endoderm: structure-less layer between them(mesoglea)- contains cells derived from primary cells. Nervous system is a network of cells. No specialized organs for excretion(its by diffusion) Sexual (planula larva- ovoidal and uniformlyciliated is produced) Class hydrozoa :-polyp and medusoid body forms occur in successive stages of life cycle.
