BIOL359 Chapter Notes - Chapter 4: Convergent Evolution, Synapomorphy, Monophyly
11 Jan 2014
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If convergent evolution has occurred, then similar traits are not homologous and do not qualify as synapomorphies: ex. Octopuses and vertebrates did not inherit their camera eyes from a common ancestor: the two lineages independently evolved camera eyes because both depend on eyesight to find food and avoid danger, ex. Wings of bats and birds, streamlined shapes of sharks and whales, the elongated, limbless bodies of snakes and legless lizards. If a reversal has occurred, then similar traits are not homologous and do not qualify as synapomorphies: convergence and reversal are lumped under the term homoplasy, similarities in traits that are not due to homology. Finding the best tree implied by the data. If the bootstrap support for a branch is low, under 50%, then the branching pattern is uncertain. Classification and nomenclature: is there such a thing as a fish: systematics: the effort to name and classify species, cladistic approaches: name schemes that are based on evolutionary relationships.
