BIOLOGY 1M03 Lecture Notes - Lecture 5: Resistance 3, Ulna, Humerus
22 Sep 2015
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Bio 1m03 lecture 5 evolution by natural selection (part 2) Eye homology: genes are homologous but the eyes themselves are very different, genes make a gene product, gene taken from a mouse and controlled to be expressed at a certain time. Instructed cell in the location of the limb to activate the genes. Developmental homology: similarity among embryonic traits, example: gill pouches are found during embryonic development in chicks, humans, and house cats. In humans, the gill pouches develop to become part of the jaw. Structural homology: refers to similarities in adult morphologies, example: in vertebrates, the structural plan found in the bones of their limbs. In many cases, traits are similar in different species because the species were related to each other by common descent: these similarities might not occur if the species were created independently of each other.
