BIOL 2200 Lecture Notes - Lecture 12: Molecular Clock, Tiktaalik, Absolute Time And Space
13 Feb 2017
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Used when morphology is not the most reliable sometimes because a change in a single change can change the phenotypic traits of an organism. Ex: protist, plant, and person all look different, yet they are somewhat related. Ex: looking at a group of species within a genus. Precambrian organisms and some current day organisms are soft- bodied or did not fossilize properly. Few people are highly informed about a specific group of organisms. Molecular methods are now fast, cheap, and relatively simple. The skills associated with sequencing are honed down into computer programs, so that now anyone can sequence. Can use a sequence from a specific gene and compare it among that of the other species. One of the first steps is to select a gene that is common to all the taxa in a tree. One of the species may lack the gene, and can then be considered the outgroup. Genes for essential function likely evolve slowly.
