Biology 1001A Lecture Notes - Lecture 4: Archaea, Carl Woese, Endoplasmic Reticulum
6 Dec 2017
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The first organisms may have been single celled methane-producing bacteria. Earliest known fossils are single-celled cyanobacteria that deposited. Methanogens and cyanobacteria modified earths atmosphere, raising oxygen levels and declining carbon dioxide levels. Two kingdoms of organisms: plants and animals. Two kingdoms of life: prokaryotes and eukaryotes (based on cellular characteristics. Life was reclassified into 3: eubacteria, archaea and eukarya. Creating a tree of life with prokaryotic organization is impossible because of horizontal gene transfer throughout life"s history. Prokaryotes, archaea and eubacteria are all small with no nuclear membrane. No cytoskeleton, no complex organelles, and divide by binary fission. Horizontal transfer of genes between prokaryotic lineages is now known to have been common, a finding that complicates finding a universal tree of. Recovering a tree of life for prokaryotes may be impossible. Classified in many ways: unicellular and multicellular, bacteria, plants and animals, prokaryotes and eukaryotes. Assignment depended on structure and function, type of metabolism (plants-
