BI111 Lecture : Chapter 19.docx
Document Summary
Twin goals of systematics: reconstruction of evolutionary history and classification of species (taxonomy, the idea that we are able to define species and put them in a relationship that matches their evolutionary history) Phylogenetic trees come about through successive events of speciation (branching), in which one species is given rise to two (or more) Reconstructing these trees requires comparison of traits (with shared genetic ancestry) in multiple species. Binary nomenclature: genus and species (reflect the nested hierarchy of life) Homologies tell us a bit about the ancestor, homoplasties tell us nothing about ancestry (only a little bit about natural selection) Bones the support wings of bat, bird, pterosaur all look like the modifications of pentadactyl limb. Develop from comparable embryonic structures embryology is important when we are trying to determine is the clumps of cells form homologous cells. Often development of an individual recreates" its evolutionary history: ontogeny recapitulates phylogeny .
