BIOL 227 Lecture Notes - Lecture 2: Pilipili, Endospore, Carl Woese
3 May 2016
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Document Summary
Classification groups species by similar key character combinations into a taxonomic hierarchy. Carl woese molecular sequence (shortsubunitrrna) divided organisms into 2 broad domains: Whittaker"s 5 functional kingdoms remain as major clades: monera (bacteria, archaea), protists, fungi, Currently, most bacteria are identified in their environment by their sequence, or, most bacteria sequences are not from culture. This assumes that sequence variation (at some level) is a unique indicator of species differences. Enrichment cultures are based on setting up specific conditions in the laboratory (nutrients, temperature, oxygen etc). The cells that grow rapidly are isolated, providing a sample of bacteria that thrive under the specific nutrient and other conditions controlled in the enrichment culture. Time frame ~4 to 2 billion years ago, the only organisms were probably prokaryotes. Consensus is that eukaryote and eventually multicellular organisms evolved after the shift to a higher oxygen environment. The 1st organisms to inhabit earth were likely prokaryotes.
