BI111 Lecture Notes - Lecture 13: Pterosaur, Natural Selection, Parallel Evolution
Document Summary
Twin goals of systematics: reconstruction of evolutionary history and classification of species. Phylogenetic trees come about through successive events of speciation (branching) in which one species gives rise to two (or more) Reconstructing these trees requires comparison of traits (which shared genetic ancestry) in multiple ancestry. Binary nomenclature: genus and species (reflect the nested hierarchy of life) Name: what group does it belong to. Rank (where does it fit into phylogeny?) Resemblance due to similar selective pressures to fill niche (homoplasies) E. g. bones that support wings of bats and pterosaur all look like modifications of pentadactyl. When no homologies exist, traits are said to be analogues. Wings of insects are distinct analogous traits make you think species are related when they really are not. Insect pitfall trap pitcher structures developed in response to low soil nitrogen. Shaped by similar environments, independently from each other. Old world and new world porcupine ancestor did not have quills.
