Biology 1201A Lecture Notes - Lecture 9: Mosaic Evolution, Chloroplast Dna, Systematics
4 Jan 2018
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Phylogenetic trees illustrate: common ancestor, modern taxa, sequence of events, relative relatedness of species. If they differ, which ones differ: 3 is different from 1 and 2. Group species into increasing inclusive taxa: monophyletic group: all decedents of a single common ancestor, non-monophyletic groups, a common ancestor and only some of its descendants, members from diverse lineages. Other groups that are not monophyletic: naming of fish, for example, are not consistent with our naming of evolutionary species because they are non-monophyletic. Most closely related taxa should have most traits in common and more distantly related taxa should have more differences between them: homology: similar traits that are due to descent from a common ancestor. Be wary of homoplasy: similar traits not due to common ancestry, may be a consequence of convergent evolution, when you break down the bone structure of these species, they all display homology: All have humorous (white), radius (orange) carpels and phalanges (yellow and brown)
