BIOL 304 Lecture Notes - Lecture 16: Carpenter Ant, Lasius, Synapomorphy
5 Mar 2018
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Document Summary
The science and philosophy of building phylogenetic trees. Internal nodes = open circles: nodes, terminal nodes = closed circles, root node = open circle i, branches: Internal branches = dotted lines: terminal branches = solid lines. Rooted vs unrooted trees: rooted: shows ancestry, unrooted: no reference to where the ancestor was, just what the relationships are between the organisms. Scaled vs unscaled trees: scaled: scaled by some measurable unit time, genetic distance, unscaled: reflective of unit of change, not a measurable unit. How many possible rooted trees are there for 3 species: 3 possibilities: a related to b, exclusion of c, a related to c, exclusion of b. How many rooted trees for 4 species: 15 possibilities (see slide, phylogeneticists have a challenge to accurately construct trees: for 5 species, there are. 105 possibilities, for 6 species there are 954 possibilities, etc.
