BSCI 207 Lecture Notes - Lecture 3: Polyphyly, Paraphyly, Archaea
26 Jan 2016
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Paraphyly and polyphyly (finishing up phylogenetic trees/tree thinking from lecture. In practice, polyphyletic groupings are often the result of convergent (independently derived) similarities. Paraphyletic groupings are often the result of retained ancestral similarities. Groups with conspicuously derived traits are often informally separated out as distinct groups. E. g. lineage of flying dinosaurs = birds. Paraphyletic and polyphyletic groups lost formal recognition once their status is discovered, but informal use is still common. Bsci207 - lecture 3 - diversity of life & the origins of multicellularity. Similar characteristics among all 3 domains of life include: Bacteria & archaea is an example of a paraphyletic group since it includes the common ancestors and some, but not all of its descendents. Lateral gene transfer is widespread among prokaryotes. It is the transfer of genes across species. There are multiple protist groups (mostly unicellular) Cyanobacteria evolved into chloroplasts = photosynthetic algae. 1 lineage of multicellular green algae went terrestrial became land plants.
