BIOL 2200 Lecture Notes - Lecture 13: Microevolution, Tangled, Macroevolution
15 Feb 2017
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Use a nested clade approach, starting from the tip to the root. Determine the branch length using the molecular clock. Must be variation in a trait in a population for evolution. Novelties can arise through gradual change of simple to complex traits. Ex: transition from eye spots to human eyes. Exaptations = structures that evolved for one purpose can be co-opted for another function. Ex: feathers originally arose for the purpose of warmth, but then evolved to be suitable for flight. Classic classification system (kingdoms, classes, etc) is not the most suitable. Two of the three consist of prokaryotes. Phylogenetic data, particularly molecular data, has led biologists to expand classification to domains. Horizontal gene transfer = gene movement between organisms from different domains without the use of reproduction. Vertical gene transfer = inheritance of traits. Prokaryotic tree of life is much more tangled than we anticipated. Microevolution = changes in allele frequency from generation to generation in a population.
