BI111 Chapter Notes - Chapter 77: Polyphyly, Paraphyly, Monophyly
Document Summary
Clade: group of organism, common ancestor, & descendants. Must distinguish b/w homologous traits, indicating common ancestry and analogous traits (traits that are similar due to reasons other than relatedness-wings of butterfly & bat result of convergent evolution) Polyphyletic species & some of descendants group that includes species with different ancestors. Particular character that organism share with common ancestor. Trait unique to clade but absent from ancestor mammary gland in mammals (absent from ancestor) Branch length: time it took for species to diverge length dna mutation shows how long it took for species to diverge. Species/group/pop known to have diverged before lineage of in-group. *essential to choose correct outgroup known to have diverged prior to node of interest to obtain meaningful & accurate result. Investigator should consider simplest explanation that is consistent w/ existing information or facts. Rules on how gene sequences over time enable construction of tree that reflects the most likely series of evolutionary events.
