BIOL 1108 Lecture Notes - Lecture 17: Seta, Leech, Subcutaneous Tissue
Document Summary
Animal evolution and diversity (ecdysozoa through chordata) (ch. 44) Bilateria is divided between the protostomes and deuterostomes: lophotrochozoa and ecdysozoa make up the protostomes. Protostomes: mouth forms first, spiral cleavage, determinate cleavage cell fate determined early in embryonic development. Lophophore: tentacle lined organ for filter feeding, found in 3 phyla: Trochophore: a ciliated larval form, found in 2 phyla: Subphylum: neodermata: new skin , syncytial tegument, parasites of vertebrates, examples: Vertebrate definitive hosts: cows, sheep, humans, etc. Many vertebrate hosts: sharks, cows, pigs, humans, etc. Eggs or tapeworm segments in feces are passed into the environment. Eggs or segments are ingested by pigs or humans. Tapeworm embryos hatch, penetrate the intestinal wall, and circulate to musculature in pigs or humans. Embryos develop into larvae in muscles of pigs or humans: cysts may develop in any organ, and are most common in subcutaneous tissue as well as in the brain and eyes.
