BIOL-UA 12 Lecture 8: Lecture 8
31 May 2016
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Lecture 8: introduction to animal biology ii: ecdysozoans: nematodes, arthropods. It is made of chitin: nematodes (refer last lecture), arthropods: Segmented coelomates- segmented like annelids, however after evolution, segments became specialized: body plan dates back to cambrian period (cambrian explosion). After massive extinctions, new predator-prey relationships occurred due to new species arising. Genes for the development of the embryo arose- hox gene complex. Hox genes control the identity of the body parts. Hox family are highly conserved, yet produce a wide diversity of morphologies. ubx is a hox gene. Usually gives drosophila one set of wings, yet a mutation can give it two. (ultrabithorax) Antennapedia arises in legs developing where antenna grow: arthropod evolution: Regulation of hox genes resulted in segments becoming specialized. Have an open circulatory system, with hemolymph (no blood), and a heart: 4 subphyla: Crustaceans: crabs, lobsters: chelicerates: (chelios: lips, cheir: arm) Two part bodies: abdomen and cephalothorax, and the head is fused to the body.
