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Do not fill this in! == Environmental conditions == [[File:20100422 235222 Cyanobacteria.jpg|thumb|upright=0.9|[[Cyanobacteria]] [[oxygen catastrophe|dramatically changed]] the composition of life forms on Earth by leading to the near-extinction of [[Anaerobic organism|oxygen-intolerant organisms]].]] The diversity of life on Earth is a result of the dynamic interplay between [[genetic opportunity]], metabolic capability, [[environment (biophysical)|environmental]] challenges,<ref name=astrobiology>{{cite web |url=http://astrobiology.arc.nasa.gov/roadmap/g5.html |archive-url=https://web.archive.org/web/20120329092237/http://astrobiology.arc.nasa.gov/roadmap/g5.html |archive-date=29 March 2012 |url-status=dead |title=Understand the evolutionary mechanisms and environmental limits of life |access-date=13 July 2009 |last=Rothschild |first=Lynn |author-link=Lynn J. Rothschild |date=September 2003 |publisher=NASA}}</ref> and [[symbiosis]].<ref>{{Cite journal |title=Symbiosis and the origin of life |journal=Origins of Life and Evolution of Biospheres |date=April 1977 |first=G.A.M. |last=King |volume=8 |issue=1 |pages=39–53 |doi=10.1007/BF00930938 |pmid=896191 |bibcode=1977OrLi....8...39K|s2cid=23615028 }}</ref><ref>{{Cite book |last=Margulis |first=Lynn |author-link=Lynn Margulis |title=The Symbiotic Planet: A New Look at Evolution |publisher=Orion Books |date=2001 |location=London|isbn=978-0-7538-0785-9}}</ref><ref>{{Cite book |last1=Futuyma |first1=D.J. |author1-link=Douglas J. Futuyma |author2=Janis Antonovics |title=Oxford surveys in evolutionary biology: Symbiosis in evolution |publisher=Oxford University Press |date=1992 |volume=8 |location=London, England |pages=347–374 |isbn=978-0-19-507623-3}}</ref> For most of its existence, Earth's habitable environment has been dominated by [[microorganism]]s and subjected to their metabolism and evolution. As a consequence of these microbial activities, the physical-chemical environment on Earth has been changing on a [[geologic time scale]], thereby affecting the path of evolution of subsequent life.<ref name=astrobiology/> For example, the release of molecular [[oxygen]] by [[cyanobacteria]] as a by-product of [[photosynthesis]] induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this posed novel evolutionary challenges, and ultimately resulted in the formation of Earth's major animal and plant species. This interplay between organisms and their environment is an inherent feature of living systems.<ref name=astrobiology/> === Biosphere === {{main|Biosphere}} [[File:Deinococcus geothermalis cells.jpg|thumb|''[[Deinococcus geothermalis]]'', a bacterium that thrives in [[geothermal springs]] and deep ocean subsurfaces<ref>{{Cite journal |last1=Liedert |first1=Christina |last2=Peltola |first2=Minna |last3=Bernhardt |first3=Jörg |last4=Neubauer |first4=Peter |last5=Salkinoja-Salonen |first5=Mirja |date=2012-03-15 |title=Physiology of Resistant Deinococcus geothermalis Bacterium Aerobically Cultivated in Low-Manganese Medium |journal=Journal of Bacteriology |language=en |volume=194 |issue=6 |pages=1552–1561 |doi=10.1128/JB.06429-11 |pmc=3294853 |pmid=22228732}}</ref>|left]] The [[biosphere]] is the global sum of all ecosystems. It can also be termed as the zone of life on Earth, a closed system (apart from solar and cosmic radiation and heat from the interior of the Earth), and largely self-regulating.<ref>{{Cite encyclopedia |encyclopedia=The Columbia Encyclopedia|edition=6th |publisher=Columbia University Press |year=2004 |url=https://www.questia.com/library/encyclopedia/biosphere.jsp |url-status= |archive-url=https://web.archive.org/web/20111027194858/http://www.questia.com/library/encyclopedia/biosphere.jsp |archive-date=27 October 2011 |title=Biosphere }}</ref> Organisms exist<!--not necessarily metabolising--> in every part of the biosphere, including [[soil]], [[hot spring]]s, [[endolith|inside rocks]] at least {{convert|12|mi|km|order=flip|abbr=on}} deep underground, the deepest parts of the ocean, and at least {{convert|40|mi|km|order=flip|abbr=on}} high in the atmosphere.<ref name="SD-19980625-UG">{{cite web |author=University of Georgia |title=First-Ever Scientific Estimate Of Total Bacteria On Earth Shows Far Greater Numbers Than Ever Known Before |url=https://www.sciencedaily.com/releases/1998/08/980825080732.htm |date=25 August 1998 |website=[[Science Daily]] |access-date=10 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20141110162101/https://www.sciencedaily.com/releases/1998/08/980825080732.htm |archive-date=10 November 2014 }}</ref><ref name="ABM-20150112">{{cite web |last=Hadhazy |first=Adam |title=Life Might Thrive a Dozen Miles Beneath Earth's Surface |url=http://www.astrobio.net/extreme-life/life-might-thrive-dozen-miles-beneath-earths-surface/ |date=12 January 2015 |website=[[Astrobiology Magazine]] |access-date=11 March 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170312065614/http://www.astrobio.net/extreme-life/life-might-thrive-dozen-miles-beneath-earths-surface/ |archive-date=12 March 2017 }}</ref><ref name="BBC-20151124">{{cite web |last=Fox-Skelly |first=Jasmin |title=The Strange Beasts That Live in Solid Rock Deep Underground |url=http://www.bbc.com/earth/story/20151124-meet-the-strange-creatures-that-live-in-solid-rock-deep-underground |date=24 November 2015 |publisher=[[BBC]] |access-date=11 March 2017 |url-status=live |archive-url=https://web.archive.org/web/20161125013248/http://www.bbc.com/earth/story/20151124-meet-the-strange-creatures-that-live-in-solid-rock-deep-underground |archive-date=25 November 2016 }}</ref> For example, spores of ''[[Aspergillus niger]]'' have been detected in the [[mesosphere]] at an altitude of 48 to 77 km.<ref>{{Cite journal |last1=Imshenetsky |first1=AA |last2=Lysenko |first2=SV |last3=Kazakov |first3=GA |date=June 1978 |title=Upper boundary of the biosphere |journal=Applied and Environmental Microbiology |volume=35 |issue=1 |pages=1–5 |doi=10.1128/aem.35.1.1-5.1978 |pmc=242768 |pmid=623455|bibcode=1978ApEnM..35....1I }}</ref> Under test conditions, life forms have been observed to thrive in the [[Weightlessness#Effects on non-human organisms|near-weightlessness]] of space<ref name="GZM-20170913">{{cite web |last=Dvorsky |first=George |title=Alarming Study Indicates Why Certain Bacteria Are More Resistant to Drugs in Space |url=https://gizmodo.com/alarming-study-indicates-why-certain-bacteria-are-more-1805666249 |date=13 September 2017 |website=[[Gizmodo]] |access-date=14 September 2017 |url-status=live |archive-url=https://web.archive.org/web/20170914011750/http://gizmodo.com/alarming-study-indicates-why-certain-bacteria-are-more-1805666249 |archive-date=14 September 2017 }}</ref><ref name="ASU-20070923">{{cite web |last=Caspermeyer |first=Joe |title=Space flight shown to alter ability of bacteria to cause disease |url=https://biodesign.asu.edu/news/space-flight-shown-alter-ability-bacteria-cause-disease |date=23 September 2007 |website=[[Arizona State University]] |access-date=14 September 2017 |url-status=live |archive-url=https://web.archive.org/web/20170914172718/https://biodesign.asu.edu/news/space-flight-shown-alter-ability-bacteria-cause-disease |archive-date=14 September 2017 }}</ref> and to survive in the vacuum of space.<ref name="Dose">{{cite journal |title=ERA-experiment "space biochemistry" |journal=Advances in Space Research |volume=16 |issue=8 |year=1995 |pages=119–129 |doi=10.1016/0273-1177(95)00280-R |pmid=11542696 |last1=Dose |first1=K. |last2=Bieger-Dose |first2=A. |last3=Dillmann |first3=R. |last4=Gill |first4=M. |last5=Kerz |first5=O. |last6=Klein |first6=A. |last7=Meinert |first7=H. |last8=Nawroth |first8=T. |last9=Risi |first9=S. | last10=Stridde | first10=C. |bibcode=1995AdSpR..16h.119D}}</ref><ref name="Horneck">{{cite journal |title=Biological responses to space: results of the experiment "Exobiological Unit" of ERA on EURECA I |journal=Adv. Space Res. |year=1995 |author1=Horneck G. |author2=Eschweiler, U. |author3=Reitz, G. |author4=Wehner, J. |author5=Willimek, R. |author6=Strauch, K. |volume=16 |issue=8 |pages=105–118 |pmid=11542695 |bibcode=1995AdSpR..16h.105H |doi=10.1016/0273-1177(95)00279-N}}</ref> Life forms thrive in the deep [[Mariana Trench]],<ref name="NG-20130317">{{cite journal |last1=Glud |first1=Ronnie |last2=Wenzhöfer |first2=Frank |last3=Middelboe |first3=Mathias |last4=Oguri |first4=Kazumasa |last5=Turnewitsch |first5=Robert |last6=Canfield |first6=Donald E. |last7=Kitazato |first7=Hiroshi |title=High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth |doi=10.1038/ngeo1773 |date=17 March 2013 |journal=[[Nature Geoscience]] |volume=6 |issue=4 |pages=284–288 |bibcode=2013NatGe...6..284G}}</ref> and inside rocks up to {{convert|580|m|ft mi|abbr=on}} below the sea floor under {{convert|2590|m|ft mi|abbr=on}} of ocean off the coast of the northwestern United States,<ref name="LS-20130317">{{cite web |last=Choi |first=Charles Q. |title=Microbes Thrive in Deepest Spot on Earth |url=http://www.livescience.com/27954-microbes-mariana-trench.html |date=17 March 2013 |publisher=[[LiveScience]] |access-date=17 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20130402234623/http://www.livescience.com/27954-microbes-mariana-trench.html |archive-date=2 April 2013 }}</ref><ref name="LS-20130314">{{cite web |last=Oskin |first=Becky |title=Intraterrestrials: Life Thrives in Ocean Floor |url=http://www.livescience.com/27899-ocean-subsurface-ecosystem-found.html |date=14 March 2013 |publisher=[[LiveScience]] |access-date=17 March 2013 |url-status=live |archive-url=https://web.archive.org/web/20130402235647/http://www.livescience.com/27899-ocean-subsurface-ecosystem-found.html |archive-date=2 April 2013 }}</ref> and {{convert|2400|m|ft mi|abbr=on}} beneath the seabed off Japan.<ref name="BBC-20141215-RM">{{cite news |last=Morelle |first=Rebecca |author-link=Rebecca Morelle |title=Microbes discovered by deepest marine drill analysed |url=https://www.bbc.com/news/science-environment-30489814 |date=15 December 2014 |work=[[BBC News]] |access-date=15 December 2014 |url-status=live |archive-url=https://web.archive.org/web/20141216185424/http://www.bbc.com/news/science-environment-30489814 |archive-date=16 December 2014 }}</ref> In 2014, life forms were found living {{convert|800|m|ft mi|abbr=on}} below the ice of Antarctica.<ref name="NAT-20140820">{{cite journal |last=Fox |first=Douglas |title=Lakes under the ice: Antarctica's secret garden |date=20 August 2014 |journal=[[Nature (journal)|Nature]] |volume=512 |issue=7514 |pages=244–246 |doi=10.1038/512244a |bibcode=2014Natur.512..244F |pmid=25143097 |doi-access=free }}</ref><ref name="FRB-20140820">{{cite web |last=Mack |first=Eric |title=Life Confirmed Under Antarctic Ice; Is Space Next? |url=https://www.forbes.com/sites/ericmack/2014/08/20/life-confirmed-under-antarctic-ice-is-space-next/ |date=20 August 2014 |website=[[Forbes]] |access-date=21 August 2014 |url-status=live |archive-url=https://web.archive.org/web/20140822002442/http://www.forbes.com/sites/ericmack/2014/08/20/life-confirmed-under-antarctic-ice-is-space-next/ |archive-date=22 August 2014 }}</ref> Expeditions of the [[International Ocean Discovery Program]] found [[Unicellular organism|unicellular]] life in 120 °C sediment 1.2 km below seafloor in the [[Nankai Trough]] [[subduction]] zone.<ref>{{Cite journal |last1=Heuer |first1=Verena B. |last2=Inagaki |first2=Fumio |last3=Morono |first3=Yuki |last4=Kubo |first4=Yusuke |last5=Spivack |first5=Arthur J. |last6=Viehweger |first6=Bernhard |last7=Treude |first7=Tina |last8=Beulig |first8=Felix |last9=Schubotz |first9=Florence |last10=Tonai |first10=Satoshi |last11=Bowden |first11=Stephen A.|date=4 December 2020 |title=Temperature limits to deep subseafloor life in the Nankai Trough subduction zone |journal=Science |volume=370 |issue=6521 |pages=1230–1234 |doi=10.1126/science.abd7934 |pmid=33273103 |bibcode=2020Sci...370.1230H |hdl=2164/15700 |s2cid=227257205 |url=https://escholarship.org/uc/item/5b65v425 |hdl-access=free |access-date=5 November 2023 |archive-date=26 September 2022 |archive-url=https://web.archive.org/web/20220926003958/https://escholarship.org/uc/item/5b65v425 |url-status=live }}</ref> According to one researcher, "You can find [[microbe]]s everywhere—they're extremely adaptable to conditions, and survive wherever they are."<ref name="LS-20130317" />{{-}} === Range of tolerance === The inert components of an ecosystem are the physical and chemical factors necessary for life—energy (sunlight or [[biochemistry|chemical energy]]), water, heat, [[Earth's atmosphere|atmosphere]], [[gravitational biology|gravity]], [[nutrient]]s, and [[ultraviolet]] [[ozone layer|solar radiation protection]].<ref>{{cite web |url=http://cmapsnasacmex.ihmc.us/servlet/SBReadResourceServlet?rid=1025200161109_2045745605_1714&partName=htmltext |title=Essential requirements for life |access-date=14 July 2009 |publisher=CMEX-NASA |url-status=dead |archive-url=https://web.archive.org/web/20090817100436/http://cmapsnasacmex.ihmc.us/servlet/SBReadResourceServlet?rid=1025200161109_2045745605_1714&partName=htmltext |archive-date=17 August 2009 }}</ref> In most ecosystems, the conditions vary during the day and from one season to the next. To live in most ecosystems, then, organisms must be able to survive a range of conditions, called the "range of tolerance".<ref name=tolerance>{{Cite book |last=Chiras |first=Daniel C. |edition=6th |title=Environmental Science – Creating a Sustainable Future |date=2001 |isbn=978-0-7637-1316-4 |url=https://archive.org/details/environmentalsci0000chir |publisher=Sudbury, MA : Jones and Bartlett }}</ref> Outside that are the "zones of physiological stress", where the survival and reproduction are possible but not optimal. Beyond these zones are the "zones of intolerance", where survival and reproduction of that organism is unlikely or impossible. Organisms that have a wide range of tolerance are more widely distributed than organisms with a narrow range of tolerance.<ref name=tolerance/> === Extremophiles === {{further|Extremophile}} [[File:Deinococcus radiodurans.jpg|thumb|upright|''[[Deinococcus radiodurans]]'' is an [[extremophile]] that can resist extremes of cold, dehydration, vacuum, acid, and radiation exposure.]] To survive, some microorganisms have evolved to withstand [[psychrophile|freezing]], [[xerophile|complete desiccation]], [[oligotroph|starvation]], high levels of [[radioresistance|radiation exposure]], and other physical or chemical challenges. These [[extremophile]] microorganisms may survive exposure to such conditions for long periods.<ref name=astrobiology/><ref name="NYT-20160912">{{cite news |last=Chang |first=Kenneth |title=Visions of Life on Mars in Earth's Depths |url=https://www.nytimes.com/2016/09/13/science/south-african-mine-life-on-mars.html |date=12 September 2016 |work=[[The New York Times]] |access-date=12 September 2016 |url-status=live |archive-url=https://web.archive.org/web/20160912225220/http://www.nytimes.com/2016/09/13/science/south-african-mine-life-on-mars.html |archive-date=12 September 2016 }}</ref> They excel at exploiting uncommon sources of energy. Characterization of the [[morphology (biology)|structure]] and metabolic diversity of microbial communities in such [[extreme environment]]s is ongoing.<ref>{{cite journal |first1=Pabulo Henrique |last1=Rampelotto |year=2010 |volume=2 |issue=6 |pages=1602–1623 |title=Resistance of microorganisms to extreme environmental conditions and its contribution to astrobiology |doi=10.3390/su2061602 |bibcode=2010Sust....2.1602R |journal=Sustainability|url=http://urlib.net/dpi.inpe.br/plutao@80/2010/06.29.20.11 |doi-access=free }}</ref> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! 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