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Domain archaea

extremophiles (halophiles, thermophiles); some live in more moderate environments such as methanogens


an organism that lives in an environment whose conditions are so extreme that few other species can survive there; these include extreme halophiles and extreme thermophiles

Extreme halophile

an organism that lives in a highly saline environment, such as the great salt lake or the deExtreme thermophilead sea

Extreme thermophile

an organism that thrives in hot environments (often 60-80 degrees celsius or hotter)


an organism that obtains energy by using carbon dioxide to oxidize hydrogen, producing methane as a waste product; all known are in teh domain archaea

Prokaryotes diversity of shape

cocci, bacilli, spirilli


rod-shaped prokaryotes


spherical prokaryotes


spiral prokaryotes

Prokaryotes diversity of form

mostly unicellular, but also colonial and filamentous


a type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides

Gram stain

a staining method that distinguishes between two different inds of bacterial cell walls (peptidoglycan)


describing the group of bacteria that have a cell wall that is structurally less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria; these bacteria are usually less toxic than gram-negative bacteria; appear purple


describing the group of bacteria that have a cell wall that is structurally more complex and contains less peptidoglycan thatn the cell wall of gram-positive bacteria; these bacteria are often more toxic than the gram-positive bacteria; cell appears pink or red

Prokaryotes diversity of extensions

some have flagella for movement, others have pili for attachment

Prokaryotes diversity of nutrition

photoautotroph, chemoautotroph, photoheterotroph, and chemoheterotroph


an organism that needs only carbon dioxide as a carbon source but obtains energy by oxidizing inorganic substances


an organism that must consume organic molecules for both energy and carbon


an organism that harnesses light energy to drive teh synthesis of organic compounds from carbon dioxide


an organisms that uses light to generate ATP but must obtain carbon in organic form

Prokaryotes metabolic diversity

prokaryotes "invented" photosynthesis (nonoxygen generating, oxygen generating (cyanobacteria = important for evolution of chloroplasts)); bacteria "invented aerobic respiration (eg. proteobacteria (important for the evolution of mitochondria))

Ecological importance of bacteria

decomposers; nutrients recycling (biogeochemical cycles); symibosis (mutualism, commensalism, parasitism); pathogens (causing diseases, releasing harmful toxins)


a symbiotic relationship in which both of the participants benefit


a symbiotic relationship in which one organism benefits but the other is neither helped nor harmed


a symbiotic relationship in which on erganism, the parasite, beneftis at the expense of another, the host, by living either within or on the host

Oxygen revolution

(2.2 - 2.7mya, near archaean/proterozoic boundary) cyanobacteria and O2 generating photosynthesis; rising O2 levels = major environmental changes (ozone layer (UV shield), toxic to many species, new selective pressures ( led to origin of eukaryotes around 2.1bya)

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