Lecture 3 - Development of Digestive...

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Development of Digestive System --Blastocoel—inside cavity --Archenteron—outside cavity (primitive gut) --Blastopore—single opening in front of Archenteron --During Development, initially, the digestive system has only 1 opening --Start with a zygote that undergoes many mitotic divisions --End up with a hollow ball of cells which has a cavity in the middle --Endoderm goes inward and forms the Archenteron --Will eventually have 2 openings, but starts out with 1 opening Fate of the Blastopore in a Complete Digestive System --Protostomes —Blastopore develops into the mouth Mosaic Development—Each cell in the early stages has its fate determined If one cell dies, a section of the organism will be missing --Deuterostomes —Blastopore develops into the anus If you kill one cell…the organism develops normally If two cells are separated…each cell will develop into an organism Phylum Platyhelminthes—flatworms “helminthes”-worm --Bilaterally Symmetrical --Ganglia—concentration of nerve cell bodies --Eyespot—photoreceptors—used to avoid light --Digestive System has only 1 opening—subdivided so that nutrients can be carried to the entire body --“Protostome-like” --Acoelomate --May have evolved from ancestors that had coelomes
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This note was uploaded on 04/06/2010 for the course BIO 01-119-10 taught by Professor D'arville during the Fall '09 term at Rutgers.

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Lecture 3 - Development of Digestive...

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