BIOLOGY 1M03 Lecture Notes - Lecture 15: Polytomy, Vertically Transmitted Infection, Shocked Quartz
14 Jun 2020
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Phylogeny: the evolutionary history of a group of organisms (represented by a phylogenetic tree), based on the idea that organisms are related by evolution, understanding these relationships is critical to our understanding of. Polytomies mean we don"t know which event happened rst. Monophyletic groups: a group de ned by a single common ancestor. All descendants of the ancestor must be in the group: monophyletic groups can also be called clades or taxa, as biologists, we should try to think in terms of clades. Not clades: apes (don"t include humans), reptiles, dinosaurs, sh. Outgroup: a species not directly in the group of interest, but is close in relation and is used for comparison; more distantly related than a monophyletic group. Reading phylogenetic trees: the tree indicates the pattern of branching of lineages (evolving lines, tips are assumed by the model to be monophyletic, a tree is a model of how evolution occurred.
