BIOL 111 Lecture Notes - Lecture 2: Phylogenetic Tree, Homo Sapiens, Convergent Evolution

• School: McGill University
• Department: Biology
• Course: BIOL 111
• Professor: Rudiger Krahe

Document Summary

Biol 111 lecture 2 origin & evolution of life. Lecture date/time: sept 15th, 2015 / 10:35-11:25 am. Evolution: the genetic change in populations of organisms over successive generations. Scientists look for similarities and differences to work out evolutionary relationships by looking at fossil record, morphological comparisons, development, molecular analyses, behaviour. Phylogenetic tree = (like the tree of life that we saw in lecture 1) Clade: group with a common root; a monophyletic group (=includes ancestral group and all its descendants) Taxon: a named group of organisms at any level of a phylogenetic tree (ex. mammals, or homo sapiens) Sister groups: groups who are the closest relatives. Out group: often the base of a tree, a single taxon. Node: where a branch splits into more than one group. Polytomy: populations likely split very rapidly from each other, making it hard to resolve which split off earlier or later. No, because if it was, it would also include group a.