Biology 1001A Lecture Notes - Lecture 18: Mosaic Evolution, Evolutionary Taxonomy, Convergent Evolution
16 Aug 2017
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Document Summary
Phylogenies show the evolutionary history of a group of organisms. Phylogenies are presented as phylogenetic trees, which are formal hypotheses identifying likely relationships among groups of organisms. This phylogenetic tree for anthropoidea, the clade that includes monkeys, apes, and humans, illustrates properties shared by most phylogenetic trees. The relative positions of the nodes (branching points) define how recently sister clades diverged. Clades that emerge from a recent common node (near the tips of the branches) are more closely related to each other than clades that emerged from an older node (closer to the root of the tree). Until the mid-1900s, systematists classified organisms and developed phylogenies based mainly on morphological characters. Over the past 50 years, along with morphology, they considered patterns of behaviour and traits such as chromosomal anatomy, details of physiology, morphology of subcellular structures, cells, and organ systems. Modern systematists also use molecular sequences of nucleic acids and proteins as additional characters.
