Biology 3466B Lecture Notes - Lecture 10: Biogeography, Macroevolution, Anagenesis
25 Aug 2013
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Document Summary
All living organisms on earth are descendent from one common ancestor. Contains all the organisms for which the entire genome was sequenced. The homo sapiens genome contains both prokaryotic (mitochondrial) dna and eukaryotic (nuclear) dna. The phylogenetic structure is indicative of a hierarchy among species of the planet and in classifying monophyletic (single ancestry) species, there is stability and permanence of classification. Anagenesis describes how as species change through time, differences accumulate within species (a form of microevolution). Cladogenesis describes the accumulated differences between species (a form of macroevolution). Paraphyletic species is where a subset of lineage members is excluded; some lineages are missing. Polyphyletic species are made up of selected taxa from diverse lineages; missing origins. Ancestors are hardly available for study since only existing or surviving species can be examined for genome sequencing. For example, many of the earliest ancestors of planet earth"s lineages (prokaryotes) are microorganisms that don"t leave anything in the fossil record for studying purposes.
