BIOL 101 Lecture Notes - Lecture 16: Parthenogenesis, External Fertilization, Closed System
13 Jan 2016
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Document Summary
Monophyly of protostomes confirmed by genetic data. Protostomy is just not a useful identifying character. Toothed throat everts, grabs prey & retracts. Protostomes (mouth first) show schizocoely (splitting of. Deuterostomes (mouth second) show enterocoely mesoderm) (outpockets form) Covered by thin layers of skin & muscle. Intermediate larval stage grows 3 adhesive arms & Original mouth & anus disappear, new mouth on left sucker side. Transformation from egg to newly formed starfish takes 2 months. Used for locomotion, feeding, excretion, gas exchange. Arms may be dropped & regenerated to: escape predation, decrease chance of infection, reproduce. Can be induced artificially in sea urchins by exposing eggs to appropriate salt solution. Evert stomach, secrete enzymes to digest prey & engulf partially digested prey. Responsible for periodic coral destruction on great. Aristotle"s lantern for scraping algae off of rocks. Pharyngeal gill slits, dorsal hollow nerve chord, notochord, muscular, post-anal tail.
