BIOL 1101 Lecture Notes - Lecture 9: Crustacean, Chitin, Rocky Mountain Spotted Fever
10 May 2016
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Document Summary
Lobsters, crabs, shrimp and crayfish are deliciously edible, and south carolina has a large shrimp fishery. Spiders do an immense amount of good in keeping down the numbers of harmful insects. Spiders and scorpions are among the most venomous of organisms. Ticks are vectors of such devastating diseases as rocky mountain spotted fever and lyme disease. Mites are serious agricultural pests, on animals (chickens and turkeys particularly) as well as plants. There is controversy about the origin of the arthropods, but the traditional view says that they probably arose from segmented annelid ancestors, perhaps through a transitional form like an onychophoran. However, now molecular data are making us think that the lophotrochozoan protostomes (annelids) and the ecdysozoan protostomes (arthropods) arose from different ancestors. The new theory is that the phylum tartigrada (the water bears) is most closely related to the arthropods.
