BIO 124 Lecture Notes - Lecture 10: Gastrovascular Cavity, Cambrian Explosion, Eumetazoa
6 Apr 2016
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Document Summary
Heterotrophy- obtain energy & organic molecules by ingesting other organisms. Filter feeders: internal choanocytes (collar cells) used to feed. Cnidarians: sea jellies & anemones; gastrovascular cavity- digestive compartment w/ single mouth/anus. Radial symmetry- arranged around central axis (2 equal halves) Bilateral symmetry- right and left halves are mirror images. Cephalization- evolution of a nervous system in a concentrated area. Diploblastic- outer ectoderm (body covering & nervous system) and inner ectoderm (digestive organs) Circulatory system- allows nutrient low & waste removal. Open system- blood passes from vessels into sinuses, mixes w/ body luids & reenters the vessels. Closed system- blood moves continuously through vessels that are separated from body luids. Blastula indents (gastrulates) to form a two layered ball, gastrula w/ blastopore- opening to outside & archenteron- primitive body cavity. Notochord- luid illed cells that go down dorsal part. Tunicates- ilter feeding chordates w/ highly derived adult phases. Gnathostomes- jaws, paired pectoral & pelvic ilms, mineralized skeleton.
