Biology 1002B Lecture Notes - Lecture 20: Divergent Evolution, Convergent Evolution, Cladistics
9 Apr 2016
School
Department
Course
Professor
Document Summary
May be a time scale, or a change scale. Nothing is more highly evolved , everything has been evolving for the same amount of time. Most recent common ancestor is closer, so more closely related: building phylogenies. How do we know which groups are closely related, and which are more distantly related: similarities two groups have in common, the more likely it is they shared a common ancestor, similarity vs. relatedness. Homology: similarity that reflects recent common ancestry. Same bones arranged in the same manor, but in different species, and used for different actions. Crocodiles and hippo"s have eyes atop their heads, not because they"re related, but because they both hang around in the water. Sometimes we can infer from structure or development. Only synapomorphous traits are important: traits shared by two or more species that are derived and modified from a common ancestor. Not symplesiomorphous traits: shared by two or more groups.
