BIO 1106 Study Guide - Midterm Guide: Choanocyte, Spongin, Planula
28 Nov 2016
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Document Summary
Simplest of major animal phyla; most live in ocean. lack tissues and organs and are asymmetrical assemblages of cells. saclike body consists of two layers breached by pores; internal cavity lined with choanocytes ( lter-feeding heterotrophs w/o photosynthetic pigments) Grantia: one of the simplest sponges. tubular, sessile open-ended chamber surrounded by a thin, porous, folded wall of cells; wall contains spicules. Spongia: more complex arrangement of chambers than grantia. skeleton made of proteinaceous spongin bers which are exible. Euplectella: spicules are siliceous and fuse together to form a delicate lattice; wedding present in. Reproduction: medusae produce and release gametes into water. zygote develops into planula larva which settles and develops into a polyp, which may reproduce asexually by budding or sexually by budding ephyrae that develop into mature medusae. Hydra: live in shallow freshwater, no medusa stage solitary polyps. extracellular digestion. hang from waters surface w basal disks. swim by somersaulting along the substrate.
