BIO 3334 Lecture Notes - Lecture 4: Retina, Chitin, Cephalization
12 Apr 2017
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Document Summary
Carnivores, sting, entangle, or poison prey using cnidae(nematocysts) fired from cnidocyte triggered by cniocil. Dimorphic life cycle minus anthozoa - sessile polyp and then motile medusa. Diploblastic outer epidermis/ ectoderm and inner gastrodermis/ endoderm. No circulatory system, and gas exchange and elimination of metabolic wastes diffusion. Organisms formed from only the two primitive cell layers. May be some type of matrix between the two layers: mesoglea or mesenchyme. Not a true tissue layer two layers formed during gastrulation. Outermost cell layer that forms the epithelium and nervous system of an animal. Endoderm innermost layer of cells that form digestive tract and other associated organs. During embryological development stage results in the blastula is converted to gastrula cells migrate toward the inside of the embryo. Away from where blastopore will form to create second germ layer. Goes from having one cell layer, to two cell layers.
