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studyquestions3 - Microbes Chapter 21 History and Phylogeny...

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Microbes Chapter 21 - History and Phylogeny of Life In undisturbed strata of sedimentary rock, the oldest rocks lie at the bottom Carbon-14 can be used to determine the ages of fossil organisms because all organisms contain many carbon compounds, carbon-14 has a regular rate of decay to carbon-12, the ratio of C-14 to C-12 in living organisms is always the same as that in the atmosphere, the production of new C-14 in the atmosphere balances the natural radioactive decay of C-14 An important, generally unidirectional change in Earth during its history is a steady increase in they oxygen content of the atmosphere The total of all species of organisms in a given region is known as the region’s biota The coal beds we now mine for energy are the remains of trees that grew in swamps during the Carboniferous period Chapter 25 - Phylogenies A clade is a group of evolutionarily related species that share a common ancestor Phylogenetic trees may be reconstructed for genes, species, major evolutionary groups, viruses Animals, plants and fungi, bacteria, and viruses all have different sets of rules for nomenclature Chapter 26 - Bacteria and Archaea Most prokaryotes are chemoheterotrophs The division of the living world into three domains is strongly supported by data on rRNA sequences Many of the archeaeal genes have never been observed in bacteria or eukaryotes About nitrogen metabolism: Certain prokaryotes reduce atmospheric N2 to ammonia Some nitriFers are soil bacteria NitriFers obtain energy by oxidizing ammonia and nitrite Without the nitriFers, terrestrial organisms would lack a nitrogen supply DenitriFers are normally aerobic, but may use nitrate under anaerobic conditions All photosynthetic bacteria are photoautotrophs Gram negative bacteria are the most abundant of the bacterial groups Endospores are resting structures Chlamydias live on the surface of human skin Mycoplasma: lack cell walls, are they smallest known cellular organisms, contain half as much DNA as do other
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studyquestions3 - Microbes Chapter 21 History and Phylogeny...

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