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An anaerobic organism or anaerobe is any organism that does not require molecular oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environment.
The Earth was formed at 4.54 Gya, and the earliest evidence of life on Earth dates from at least 3.8 Gya from Western Australia. Some studies have suggested that fossil micro-organisms may have lived within hydrothermal vent precipitates dated 3.77 to 4.28 Gya from Quebec , soon after ocean formation 4.4 Gya during the Hadean .
Anaerobic may also refer to: Anaerobic adhesive, a bonding agent that does not cure in the presence of air; Anaerobic respiration, respiration in the absence of oxygen, using some other molecule as the final electron acceptor Anaerobic organism, any organism whose redox metabolism does not depend on free oxygen
Numerous fermentation pathways exist such as lactic acid fermentation, mixed acid fermentation, 2-3 butanediol fermentation where organic compounds are reduced to organic acids and alcohol. [8] [4] The energy yield of anaerobic respiration and fermentation (i.e. the number of ATP molecules generated) is less than in aerobic respiration. [8]
A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. [1] [2] Some examples of facultatively anaerobic bacteria are Staphylococcus spp., [3] Escherichia coli, Salmonella, Listeria spp., [4] Shewanella oneidensis and Yersinia ...
The Oldest Living Organism Is Over 2 Billion Years Old Scientists have identified the oldest living species on Earth is a deep sea organism that hasn't evolved in more than two billion years.
There are over 150 described species of methanogens, [9] which do not form a monophyletic group in the phylum Euryarchaeota (see Taxonomy). They are exclusively anaerobic organisms that cannot function under aerobic conditions due to the extreme oxygen sensitivity of methanogenesis enzymes and FeS clusters involved in ATP production.
If an earlier civilization existed on Earth millions of years ago, we might have trouble finding evidence of it -- but that doesn't mean it didn't exist.