MICR 221 Lecture 2: Microbial Diversity
28 Apr 2016
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Document Summary
Life falls into 3 primary groups based on phylogenetic features (sequence analysis of small ribosomal rna [16s rna or 18s rna]: eucarya (eucaryotes, bacteria, archaea, groups 2 and 3 are procaryotic. Archaea (chapter 20) third line of evolutionary descent procaryotic like bacteria but on a genetic level no more closely related to bacteria than eucaryotes based initially on 16s rrna sequence data. Walls lack murein, ether linked lipids translation/transcription like eukaryotes (much more like them than bacteria) Major groups are methanogens, extreme halophiles, sulfur-dependent thermophiles. Microbes are in far more niches than eukaryotes ph 0 to greater than 12 temps of <0oc to >100oc concentrated nacl deep sea hydrothermal vents cracks in rocks at depths of several km. Microbial numbers (don"t need to know the numebrs) 1031 viruses laid end to end would extend 100 million light years. More bacteria in ocean 1. 3 x 1029 than stars.
