BIOL 2P92 Lecture Notes - Lecture 2: Species Problem, Continental Drift, Autapomorphy
6 Feb 2017
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Macroevolution: changes over long periods of time (eons) Microevolution: changes gradually (changes in allele frequencies) Leads to macroevolution (small changes that get passed on from generation to generation) that would eventually lead to lineage splitting (speciation to create new species) Biological species concept: all individuals that can produce viable offspring are members of the same species. Shares the same gene pool = same species = grouped together. Speciation results in increasing diversity over time: early ancestors at the top, and evolution flows down the stream, ancestral species: share the same gene pool (before lineage split) Lineage split glaciation, continental drift of pangea, etc. Common ancestor of a and b are more recent than b and c: allopathic speciation: different places. Autapomorphy: the only species that have the derived trait. Over long stretches of time, repeated speciation results in macroevolution. Two approaches to phylogenetic tree construction: cladistics: correct approach for morphology. Based on shared, evolutionarily derived characteristics (synapomorphy and autapomorphy)
