Nature

==Ecosystems==<!-- This section is linked from Nature -->
[[File:View of loch lomond.JPG|thumb|left|[[Loch Lomond]] in Scotland forms a relatively isolated ecosystem. The fish community of this lake has remained unchanged over a very long period of time.<ref>{{cite journal|last=Adams|first=C.E.|title=The fish community of Loch Lomond, Scotland: its history and rapidly changing status|journal=Hydrobiologia|date=1994|volume=290|issue=1–3|pages=91–102|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=3302548|doi=10.1007/BF00008956|s2cid=6894397|access-date=January 5, 2007|archive-url=https://web.archive.org/web/20120114115347/http://cat.inist.fr/?aModele=afficheN&cpsidt=3302548|archive-date=January 14, 2012|url-status=live|df=mdy-all|doi-access=free}}</ref>]]
[[File:Aravalli.jpg|thumb|left|Lush green [[Aravalli Range|Aravalli Mountain Range]] in the Desert country – [[Rajasthan]], India.]]
[[File:Chicago Downtown Aerial View.jpg|thumb|An aerial view of a [[human ecosystem]]. Pictured is the city of Chicago.]]
{{Main|Ecology|Ecosystem}}
Ecosystems are composed of a variety of [[biotic component|biotic]] and [[abiotic component]]s that function in an interrelated way.<ref>{{cite web |last=Pidwirny |first=Michael |date=2006 |work=Fundamentals of Physical Geography (2nd Edition) |title=Introduction to the Biosphere: Introduction to the Ecosystem Concept |url=http://www.physicalgeography.net/fundamentals/9j.html |access-date=September 28, 2006 |archive-url=https://web.archive.org/web/20110718040429/http://www.physicalgeography.net/fundamentals/9j.html |archive-date=July 18, 2011 |url-status=live |df=mdy-all }}</ref> The structure and composition is determined by various environmental factors that are interrelated. Variations of these factors will initiate dynamic modifications to the ecosystem. Some of the more important components are [[soil]], [[atmosphere]], radiation from the [[sun]], water, and living organisms.
[[File:PenasBlancas, part of the Bosawas Reserve, Jinotega Department, Nicaragua.jpg|thumb|left|Peñas Blancas, part of the [[Bosawás Biosphere Reserve]]. Located northeast of the city of [[Jinotega]] in Northeastern Nicaragua]]
Central to the ecosystem concept is the idea that [[living organism]]s interact with every other element in their local [[environment (biophysical)|environment]]. Eugene Odum, a founder of ecology, stated: "Any unit that includes all of the organisms (ie: the "community") in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (i.e.: exchange of materials between living and nonliving parts) within the system is an ecosystem."<ref name="Odum1971">Odum, EP (1971) ''Fundamentals of ecology'', 3rd edition, Saunders New York</ref> Within the ecosystem, species are connected and dependent upon one another in the [[food chain]], and exchange energy and [[matter]] between themselves as well as with their environment.<ref>{{cite web |last=Pidwirny |first=Michael |date=2006 |work=Fundamentals of Physical Geography (2nd edition) |title=Introduction to the Biosphere: Organization of Life |url=http://www.physicalgeography.net/fundamentals/9d.html |access-date=September 28, 2006 |archive-url=https://web.archive.org/web/20110813100946/http://www.physicalgeography.net/fundamentals/9d.html |archive-date=August 13, 2011 |url-status=live |df=mdy-all }}</ref> The human ecosystem concept is based on the human/nature [[dichotomy]] and the idea that all species are ecologically dependent on each other, as well as with the abiotic constituents of their [[biotope]].<ref>{{Cite book|url=https://books.google.com/books?id=-s5oRDUuMSIC&pg=PA237|title=Biotechnology Fundamentals|last=Khan|first=Firdos Alam|date=2011|publisher=CRC Press|isbn=978-1-4398-2009-4}}</ref>

A smaller unit of size is called a [[microecosystem]]. For example, a microsystem can be a stone and all the life under it. A ''macroecosystem'' might involve a whole [[ecoregion]], with its [[drainage basin]].<ref>{{cite journal|last=Bailey |first=Robert G. |date=April 2004 |title=Identifying Ecoregion Boundaries |journal=Environmental Management |volume=34 |pmid=15883869 |issue=Supplement 1 |url=http://www.fs.fed.us/institute/news_info/Identifying_ecoregion_boundaries.pdf |doi=10.1007/s00267-003-0163-6 |pages=S14–S26 |s2cid=31998098 |url-status=dead |archive-url=https://web.archive.org/web/20091001013622/http://www.fs.fed.us/institute/news_info/Identifying_ecoregion_boundaries.pdf |archive-date=October 1, 2009 }}</ref>

===Wilderness===
[[File:Biogradska suma.jpg|thumb|[[Old-growth forest|Old growth]] [[European Beech]] forest in [[Biogradska Gora]] National Park, [[Montenegro]]]]
{{Main|Wilderness}}
'''Wilderness''' is generally defined as areas that have not been significantly modified by human activity. Wilderness areas can be found in preserves, estates, farms, conservation preserves, ranches, [[:Category:national forests|national forests]], [[national park]]s, and even in urban areas along rivers, gulches, or otherwise undeveloped areas. Wilderness areas and protected [[parks]] are considered important for the survival of certain [[species]], ecological studies, [[Habitat conservation|conservation]], and solitude. Some nature writers believe wilderness areas are vital for the human spirit and creativity,<ref name="Man p155-157">Botkin, Daniel B. (2000) ''No Man's Garden'', Island Press, pp. 155–157, {{ISBN|1-55963-465-0}}.</ref> and some ecologists consider wilderness areas to be an integral part of the Earth's self-sustaining natural [[ecosystem]] (the [[biosphere]]). They may also preserve historic [[genetics|genetic]] traits and that they provide [[habitat]] for wild [[flora (plants)|flora]] and [[fauna (animals)|fauna]] that may be difficult or impossible to recreate in [[zoo]]s, [[arboretum]]s, or [[laboratory|laboratories]].