Biology 3466B Lecture : Evolution Notes

• School: Western University
• Department: Biology
• Course: Biology 3466B
• Professor: Yolanda Morbey

Document Summary

Humans are located at two places in the phylogenetic tree because we are eukaryotic and prokaryotic. Mitochondria are some kind of bacteria that have become part of eukaryotic cells through symbiosis. Observation: all species are related by common ancestry. Implication: a classification base on evolutionary history will be informative and permanent. Observation: as species change through time (anagenesis), differences accumulate within species (microevolution). As species split (cladogenesis), differences accumulate between species (macroevolution). The only difference between macro and micro is that they occur at different branches. Application: the current character states can be used to reconstruct that history. In phylogenetic classification, taxa should be monophyletic, which means that they are all derived from a single lineage (all taxa are nested sets). Reptiles without the birds are paraphyletic, which means a subset of lineage members is excluded. This is not good and should be avoided. Polyphyletic is a grouping that is made up of selected taxa from diverse lineages.