BIOLOGY 1M03 Chapter Notes - Chapter 27: Background Extinction Rate, Distance Matrix, Extinction Event
14 Sep 2016
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Tips: the end of the trees that refer to the taxa. Branches: connect nodes and connects nodes to tips. Characterized by: lactation, loss of egg laying, placenta: exchange boundary that allows oxygen and nutrients to transfer from the mother and the child, placenta and nipples are innovations. **mass extinctions occurring right now driven by human activities** For example, gorilla to humans, gorilla to chimps and chimps to humans: fundamental feature of phenetics is the distance matrix. Homology: similarities due to similar ancestors: similarity by descent/heredity, occurs more commonly (assumption) Homoplasy: similarities are due to other reasons other than a similar ancestor: derived from convergent evolution, convergent evolution can occur when natural selection imposes selective constraints on species. Mutations can cause convergence: creates problems in estimating phonologies because it gives us information that conflicts with the true evolutionary relationships. Homology and homoplasy both occur in nucleotides.
