|
Lifeform
Life form (also spelled life-form or lifeform) is an entity that is living, such as plants (flora) and animals (fauna). It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, are extinct. Earth is the only celestial body known to harbor life forms. No form of extraterrestrial life has ever been discovered. Archaea * Archaea – a domain of single-celled microorganisms, morphologically similar to bacteria, but they possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably the enzymes involved in transcription and translation. Many archaea are extremophiles, which means living in harsh environments, such as hot springs and salt lakes, but they have since been found in a broad range of habitats. ** Thermoproteota – a phylum of the Archaea kingdom. Initially *** Thermoprotei **** Sulfolobales – grow in terrestrial volcanic hot springs with optimum grow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extraterrestrial Life
Extraterrestrial life, colloquially referred to as alien life, is life that may occur outside Earth and which did not originate on Earth. No extraterrestrial life has yet been conclusively detected, although efforts are underway. Such life might range from simple forms like prokaryotes to intelligent beings, possibly bringing forth civilizations that might be far more advanced than humankind. The Drake equation speculates about the existence of sapient life elsewhere in the universe. The science of extraterrestrial life is known as astrobiology. Speculation about the possibility of inhabited "worlds" outside the planet Earth dates back to antiquity. Multiple early Christian writers discussed the idea of a "plurality of worlds" as proposed by earlier thinkers such as Democritus; Augustine references Epicurus's idea of innumerable worlds "throughout the boundless immensity of space" (originally expressed in his Letter to Herodotus) in ''The City of God''. In his first century p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Life
Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from that which does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energy transformation, and reproduction. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. Biology is the science that studies life. The gene is the unit of heredity, whereas the Cell (biology), cell is the structural and functional unit of life. There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many biomolecules such as proteins and nucleic acids. Cells reproduce through a process of cell division, in which the parent cell divides into two or more daughter cells and passes its genes onto a new generation, sometimes producing genetic variation. Organisms, or the individual entities of life, are generally thought t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanococci
Methanococci is a class of methanogenic archaea in the phylum Euryarchaeota.See the NCBIbr>webpage on Methanococci Data extracted from the They can be mesophilic, thermophilic or hyperthermophilic A hyperthermophile is an organism that thrives in extremely hot environments—from 60 °C (140 °F) upwards. An optimal temperature for the existence of hyperthermophiles is often above 80 °C (176 °F). Hyperthermophiles are often within the doma .... References Further reading Scientific journals * * * Scientific books * * Scientific databases External links Archaea classes Euryarchaeota {{Euryarchaeota-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Korarchaeota
In alpha taxonomy, taxonomy, the Korarchaeota are a phylum (biology), phylum of the Archaea. The name is derived from the Greek noun koros or kore, meaning ''young man'' or ''young woman,'' and the Greek adjective archaios which means ''ancient.'' They are also known as Xenarchaeota. Taxonomy Korarchaeota is regarded as a phylum, which itself is part of the archaeal TACK superphylum which encompasses Thaumarchaeota (now Nitrososphaerota), "Aigarchaeota", Crenarchaeota (now Thermoproteota), and "Korarchaeota". Species * "''Candidatus'' Korarchaeum cryptofilum" Elkins et al. 2008 * "''Candidatus'' Methanodesulfokores washburnensis" McKay et al. 2019 Phylogeny Analysis of their 16S rRNA gene sequences suggests that they are a deeply branching lineage that does not belong to the main archaeal groups, Thermoproteota and Euryarchaeota. Analysis of the genome of one korarchaeote that was enriched from a mixed culture revealed a number of both Crenarchaeota- and Euryarchaeota-like feat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halophiles
The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, such as the alga ''Dunaliella salina'' and fungus '' Wallemia ichthyophaga''. Some well-known species give off a red color from carotenoid compounds, notably bacteriorhodopsin. Halophiles can be found in water bodies with salt concentration more than five times greater than that of the ocean, such as the Great Salt Lake in Utah, Owens Lake in California, the Urmia Lake in Iran, the Dead Sea, and in evaporation ponds. They are theorized to be a possible analogues for modeling extremophiles that might live in the salty subsurface water ocean of Jupiter's Europa and similar moons. Classification Halophiles are categorized by the extent of their halotolerance: slight, moderate, or extreme. Slight halophiles prefer 0.3 to 0.8 M (1.7 to 4.8% ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoplasmatales
In alpha taxonomy, taxonomy, the Thermoplasmatales are an order (biology), order of the Thermoplasmata. All are acidophiles, growing optimally at pH below 2. ''Picrophilus'' is currently the most acidophile, acidophilic of all known organisms, being capable of growing at a pH of -0.06. Many of these organisms do not contain a cell wall, although this is not true in the case of ''Picrophilus''. Most members of the Thermotoplasmata are thermophilic. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). See also * List of Archaea genera References * Further reading Scientific journals * * * * Scientific books * * Scientific databases External links Archaea taxonomic orders Euryarchaeota {{Euryarchaeota-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoplasmata
In taxonomy, the Thermoplasmata are a class of the Euryarchaeota. All are acidophiles, growing optimally at pH below 2. ''Picrophilus'' is currently the most acidophilic of all known organisms growing at a minimum pH of 0.06. Many of these organisms do not contain a cell wall, although this is not true in the case of ''Picrophilus''. Most members of Thermotoplasmata are thermophilic. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). See also * List of Archaea genera This article lists the genera of the Archaea. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). Phylogeny National Center for ... References Further reading Scientific journals * * * * Scientific books * * Scientific databases External links Archae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermococcales
In taxonomy, the Thermococcales are an order of microbes within the Thermococci. The species within the Thermococcales are used in laboratories as model organisms. All these species are strict anaerobes and can ferment sugars as sources of carbon, but they also need elemental sulfur. See also * List of Archaea genera This article lists the genera of the Archaea. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). Phylogeny National Center for ... References Further reading * * * * * External links Archaea taxonomic orders Euryarchaeota {{Euryarchaeota-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermococci
In taxonomy, the Thermococci are a class of microbes within the Euryarchaeota.See the NCBIbr>webpage on Thermococci Data extracted from the They live in extremely hot environments, such as hydrothermal vents, and they have optimal growth temperatures above 80 °C. '' Thermococcus'' and ''Pyrococcus'' (literally "balls of fire") are both obligately anaerobic organism, anaerobic chemoorganotrophs. ''Thermococcus'' prefers 70-95 °C and ''Pyrococcus'' 70-100 °C. '' Palaeococcus helgesonii'', recently discovered in the Tyrrhenian Sea, is an aerobic chemoheterotrophic that grows at temperatures of 45-85 °C with an optimal temperature of 80 °C. '' Thermococcus gammatolerans'' sp. nov. was recently discovered in the Guaymas Basin, and it grows at temperatures from 55-95 °C with an optimal temperaturearound 88 °C with an optimal pH of 6. It has pronounced radioresistance and can survive gamma radiation at 30 kGy. See also * List of Archae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanopyrales
In taxonomy, the Methanopyrales are an order of microbes within the class methanopyri. It contains only one family, Methanopyraceae, one genus, Methanopyrus, and one species, Methanopyrus kandleri. This species is chemolithoautotrophic and its cells are bacillus in form. It grows comfortably at temperatures of 98 °C and can survive at temperatures as high as 110 °C, making it the most thermophilic known methanogen. Strain 116 can survive at up to 122 °C. They live in hydrothermal vents and were first discovered on the walls of a black smoker in the Gulf of California, at the depth of 2000 metres. They are similar to Methanobacteriales, but unlike other methanogenic archaea, their cell walls contain pseudomurein Pseudopeptidoglycan (also known as pseudomurein;White, David. (1995) ''The Physiology and Biochemistry of Prokaryotes'', pages 6, 12-21. (Oxford: Oxford University Press). . PPG hereafter) is a major cell wall component of some Archaea that differs .... Refer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanopyri
In taxonomy, the Methanopyri are a class of the Euryarchaeota.See the NCBI The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...br>webpage on Methanopyri Data extracted from the References Further reading Scientific journals * * Scientific books * * Scientific databases External links Archaea classes Euryarchaeota {{Euryarchaeota-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
