View source for Ecophysiology

{{Short description|Study of adaptation of an organism's physiology to environmental conditions}}
{{Use dmy dates|date=July 2020}}
'''Ecophysiology''' (from [[Ancient Greek|Greek]] {{lang|grc|οἶκος}}, ''oikos'', "house(hold)"; {{lang|grc|φύσις}}, ''physis'', "nature, origin"; and {{lang|grc|-λογία}}, ''[[-logy|-logia]]''), '''environmental physiology''' or '''physiological ecology''' is a [[biology|biological]] [[List of academic disciplines|discipline]] that studies the response of an [[organism]]'s [[physiology]] to environmental conditions.  It is closely related to [[comparative physiology]] and [[evolutionary physiology]]. [[Ernst Haeckel]]'s coinage '''bionomy''' is sometimes employed as a synonym.<ref>Ernst Haeckel, ''The Wonders of Life'': "I proposed long ago to call this special part of biology œcology (the science of home-relations) or bionomy." "</ref>

== Plants ==

{{Further|Plant perception (physiology)| Plant stress measurement}}
Plant ecophysiology is concerned largely with two topics: mechanisms (how plants sense and respond to environmental change) and scaling or integration (how the responses to highly variable conditions—for example, gradients from full sunlight to 95% shade within tree canopies—are coordinated with one another), and how their collective effect on plant growth and gas exchange can be understood on this basis.{{cn|date=March 2024}}

In many cases, [[animal]]s are able to escape unfavourable and changing environmental factors such as heat, cold, drought or floods, while [[plant]]s are unable to move away and therefore must endure the adverse conditions or perish (animals go places, plants grow places). Plants are therefore [[phenotypic plasticity|phenotypically plastic]] and have an impressive array of [[gene]]s that aid in acclimating to changing conditions. It is hypothesized that this large number of genes can be partly explained by plant species' need to live in a wider range of conditions.

===Light===
{{See also|Photomorphogenesis|Photoperiodism}}
[[Light]] is the food of plants, i.e. the form of energy that plants use to build themselves and reproduce. The organs harvesting light in plants are [[Leaf|leaves]] and the process through which light is converted into biomass is [[photosynthesis]]. The response of photosynthesis to light is called light response curve of net photosynthesis ([[PI curve]]). The shape is typically described by a non-rectangular hyperbola. Three quantities of the light response curve are particularly useful in characterising a plant's response to light intensities. The inclined [[asymptote]] has a positive slope representing the efficiency of light use, and is called quantum efficiency; the x-intercept is the light intensity at which biochemical assimilation (gross assimilation) balances leaf respiration so that the net CO<sub>2</sub> exchange of the leaf is zero, called [[light compensation point]]; and a horizontal asymptote representing the maximum assimilation rate. Sometimes after reaching the maximum assimilation declines for processes collectively known as [[photoinhibition]].<ref>{{Citation |publisher=Elsevier |language=en |doi=10.1016/B978-0-12-816209-5.00002-7 |isbn=978-0-12-816209-5 |chapter=Radiation-Use Efficiency Under Different Climatic Conditions |title=Changing Climate and Resource Use Efficiency in Plants |date=2019 |last1=Bhattacharya |first1=Amitav |pages=51–109 }}</ref>

As with most abiotic factors, light intensity (irradiance) can be both suboptimal and excessive. Suboptimal light (shade) typically occurs at the base of a plant canopy or in an understory environment. [[Shade tolerant]] plants have a range of adaptations to help them survive the altered quantity and quality of light typical of shade environments.

Excess light occurs at the top of canopies and on open ground when cloud cover is low and the sun's zenith angle is low, typically this occurs in the tropics and at high altitudes. Excess light incident on a leaf can result in [[photoinhibition]] and [[photodestruction]]. Plants adapted to high light environments have a range of adaptations to avoid or dissipate the excess light energy, as well as mechanisms that reduce the amount of injury caused.<ref>{{Cite journal |last1=Zhang |first1=Man |last2=Ming |first2=Yu |last3=Wang |first3=Hong-Bin |last4=Jin |first4=Hong-Lei |date=2024-05-13 |title=Strategies for adaptation to high light in plants |journal=aBIOTECH |volume=5 |issue=3 |pages=381–393 |language=en |doi=10.1007/s42994-024-00164-6 |issn=2662-1738|doi-access=free |pmid=39279858 |pmc=11399379 }}</ref>

Light intensity is also an important component in determining the temperature of plant organs (energy budget).<ref>{{Cite journal |last1=Yang |first1=Jingli |last2=Song |first2=Jinnan |last3=Jeong |first3=Byoung Ryong |date=2022-02-23 |title=Lighting from Top and Side Enhances Photosynthesis and Plant Performance by Improving Light Usage Efficiency |journal=International Journal of Molecular Sciences |volume=23 |issue=5 |pages=2448 |doi=10.3390/ijms23052448 |doi-access=free |issn=1422-0067 |pmc=8910434 |pmid=35269590}}</ref>

===Temperature===
{{See also|Fire_ecology#Immediate_Biotic_responses_and_adaptations|l1=Plant adaptations to wildfires}}
In response to extremes of temperature, plants can produce various [[protein]]s. These protect them from the damaging effects of ice formation and falling rates of [[enzyme]] catalysis at low temperatures, and from enzyme [[Denaturation (biochemistry)|denaturation]] and increased [[photorespiration]] at high temperatures. As temperatures fall, production of [[antifreeze protein]]s and [[dehydrin]]s increases. As temperatures rise, production of [[heat shock protein]]s increases. Metabolic imbalances associated with temperature extremes result in the build-up of [[reactive oxygen species]], which can be countered by [[antioxidant]] systems. [[Cell membrane]]s are also affected by changes in temperature and can cause the membrane to lose its [[Fluid mosaic#Structure and the Fluid mosaic model|fluid properties]] and become a gel in cold conditions or to become leaky in hot conditions. This can affect the movement of compounds across the membrane. To prevent these changes, plants can change the composition of their membranes. In cold conditions, more [[Fatty acid#Unsaturated fatty acids|unsaturated fatty acids]] are placed in the membrane and in hot conditions, more [[saturated fatty acid]]s are inserted.
[[File:Leaf temperature- infrared image of tomato leaves.jpg|thumbnail|right|Infrared image showing the importance of transpiration in keeping leaves cool.]]
Plants can avoid overheating by minimising the amount of sunlight absorbed and by enhancing the cooling effects of wind and [[transpiration]]. Plants can reduce light absorption using reflective leaf hairs, scales, and waxes. These features are so common in warm dry regions that these habitats can be seen to form a 'silvery landscape' as the light scatters off the canopies.<ref name="Lee2010">{{cite book|author=David Lee|title=Nature's Palette: The Science of Plant Color|url=https://books.google.com/books?id=M3e5wyFJY-8C|year=2010|publisher=University of Chicago Press|isbn=978-0-226-47105-1}}</ref> Some species, such as ''Macroptilium purpureum'', can move their leaves throughout the day so that they are always orientated to avoid the sun (''[[paraheliotropism]]'').<ref name="Plant Ecology">{{cite book|title=Plant Ecology|url=https://books.google.com/books?id=rDo8hLWtWzgC|year=2005|publisher=Springer|isbn=978-3-540-20833-4}}</ref> Knowledge of these mechanisms has been key to [[breeding for heat stress tolerance]] in agricultural plants.{{cn|date=March 2024}}

Plants can avoid the full impact of low temperatures by altering their [[microclimate]]. For example, ''[[Raoulia]]'' plants found in the uplands of New Zealand are said to resemble 'vegetable sheep' as they form tight cushion-like clumps to insulate the most vulnerable plant parts and shield them from cooling winds. The same principle has been applied in agriculture by using [[plastic mulch]] to insulate the growing points of crops in cool climates in order to boost plant growth.<ref>{{Cite journal | last1 = Farrell | first1 = A. D. | last2 = Gilliland | first2 = T. J. | doi = 10.1111/j.1365-2494.2010.00778.x | title = Yield and quality of forage maize grown under marginal climatic conditions in Northern Ireland | journal = Grass and Forage Science | volume = 66 | issue = 2 | pages = 214 | year = 2011 | bibcode = 2011GForS..66..214F }}</ref>

===Water===
{{see also|Moisture stress}}
Too much or too little water can damage plants. If there is too little water then tissues will dehydrate and the plant may die. If the soil becomes waterlogged then the soil will become anoxic (low in oxygen), which can kill the roots of the plant.<ref>{{Cite journal |last1=Orsák |first1=Matyáš |last2=Kotíková |first2=Zora |last3=Hnilička |first3=František |last4=Lachman |first4=Jaromír |date=2023-04-25 |title=Effect of long-term drought and waterlogging stress on photosynthetic pigments in potato |journal=Plant, Soil and Environment |volume=69 |issue=4 |pages=152–160 |doi=10.17221/415/2022-pse |issn=1214-1178|doi-access=free }}</ref>

The ability of plants to access water depends on the structure of their roots and on the [[water potential]] of the root cells. When soil water content is low, plants can alter their water potential to maintain a flow of water into the roots and up to the leaves ([[Soil plant atmosphere continuum]]). This remarkable mechanism allows plants to lift water as high as 120 m by harnessing the gradient created by [[transpiration]] from the leaves.<ref>{{Cite web
| author1=George Koch
| author2=Stephen Sillett
| author3=Gregg Jennings
| author4= Stephen Davis
| title= How Water Climbs to the Top of a 112 Meter-Tall Tree
| url = http://5e.plantphys.net/article.php?ch=&id=100
| series= Plant Physiology Online, A Companion to Plant Physiology, Fifth Edition by Lincoln Taiz and Eduardo Zeiger
| date= May 2006
| archive-url=https://web.archive.org/web/20130914053947/http://5e.plantphys.net/article.php?ch=&id=100
| archive-date=14 September 2013
}}</ref>

In very dry soil, plants close their stomata to reduce transpiration and prevent water loss. The closing of the stomata is often mediated by chemical signals from the root (i.e., [[abscisic acid]]). In irrigated fields, the fact that plants close their stomata in response to drying of the roots can be exploited to 'trick' plants into using less water without reducing yields (see [[partial rootzone drying]]). The use of this technique was largely developed by Dr Peter Dry and colleagues in Australia<ref>{{Cite journal | last1 = Stoll | first1 = M. | last2 = Loveys | first2 = B. | last3 = Dry | first3 = P. | doi = 10.1093/jexbot/51.350.1627 | title = Hormonal changes induced by partial rootzone drying of irrigated grapevine | journal = Journal of Experimental Botany | volume = 51 | issue = 350 | pages = 1627–1634 | year = 2000 | pmid =  11006312| doi-access = free }}</ref>
{{further|Nominative determinism}}

If drought continues, the plant tissues will dehydrate, resulting in a loss of [[turgor pressure]] that is visible as [[wilting]]. As well as closing their stomata, most plants can also respond to drought by altering their water potential (osmotic adjustment) and increasing root growth. Plants that are adapted to dry environments ([[Xerophytes]]) have a range of more specialized mechanisms to maintain water and/or protect tissues when desiccation occurs.

Waterlogging reduces the supply of oxygen to the roots and can kill a plant within days. Plants cannot avoid waterlogging, but many species overcome the lack of oxygen in the soil by transporting oxygen to the root from tissues that are not submerged. Species that are tolerant of waterlogging develop specialised roots near the soil surface and [[aerenchyma]] to allow the diffusion of oxygen from the shoot to the root. Roots that are not killed outright may also switch to less oxygen-hungry forms of cellular respiration.<ref>{{Cite web|url=http://www.plantstress.com/Articles/index.asp|title=The Impact of Flooding Stress on Plants and Crops|access-date=29 April 2013|archive-date=3 May 2013|archive-url=https://web.archive.org/web/20130503124218/http://www.plantstress.com/Articles/index.asp|url-status=dead}}</ref> Species that are frequently submerged have evolved more elaborate mechanisms that maintain root oxygen levels, such as the aerial roots seen in [[mangrove]] forests.<ref>{{cite web
| url        = http://mangrove.nus.edu.sg/guidebooks/text/1043.htm
| title      = How plants cope in the mangroves
| work       = A Guide to the Mangroves of Singapore
| last1      = Ng
| first1     = Peter K.L.
| last2      = Sivasothi
| first2     = N
| date       = 2001
| access-date = 2019-04-19
}}</ref>

However, for many terminally overwatered houseplants, the initial symptoms of waterlogging can resemble those due to drought. This is particularly true for flood-sensitive plants that show drooping of their leaves due to [[epinasty]] (rather than wilting).

==={{co2}} concentration===
{{co2}} is vital for plant growth, as it is the substrate for photosynthesis. Plants take in {{co2}} through [[stomatal]] pores on their leaves. At the same time as {{co2}} enters the stomata, moisture escapes. This trade-off between {{co2}} gain and water loss is central to plant productivity. The trade-off is all the more critical as [[Rubisco]], the enzyme used to capture {{co2}}, is efficient only when there is a high concentration of {{co2}} in the leaf. Some plants overcome this difficulty by concentrating {{co2}} within their leaves using [[C4 carbon fixation|{{c4}} carbon fixation]] or [[Crassulacean acid metabolism]]. However, most species used [[C3 carbon fixation|{{c3}} carbon fixation]] and must open their stomata to take in {{co2}} whenever photosynthesis is taking place.{{cn|date=October 2024}}

[[File:Plant Productivity in a Warming World.ogv|thumb|Plant Productivity in a Warming World]] The concentration of [[Carbon dioxide in the Earth's atmosphere|{{co2}} in the atmosphere]] is rising due to [[deforestation]] and the combustion of [[fossil fuels]]. This would be expected to increase the efficiency of photosynthesis and possibly increase the overall rate of plant growth. This possibility has attracted considerable interest in recent years, as an increased rate of plant growth could absorb some of the excess {{co2}} and reduce the rate of [[global warming]]. Extensive experiments growing plants under elevated {{co2}} using [[Free-Air Concentration Enrichment]] have shown that photosynthetic efficiency does indeed increase. Plant growth rates also increase, by an average of 17% for above-ground tissue and 30% for below-ground tissue.<ref>{{Cite journal
| journal=Nature Education Knowledge
| volume= 3 | issue= 10 | at=21
| last= Taub | year= 2010 | first= Daniel R.
|title=Effects of Rising Atmospheric Concentrations of Carbon Dioxide on Plants |url=https://www.nature.com/scitable/knowledge/library/effects-of-rising-atmospheric-concentrations-of-carbon-13254108/|access-date=2023-02-08|publisher=www.nature.com|language=en}}</ref><ref>{{Cite journal | last1 = Ainsworth | first1 = E. A. | last2 = Long | first2 = S. P. | doi = 10.1111/j.1469-8137.2004.01224.x | title = What have we learned from 15 years of free-air CO2 enrichment (FACE)? A meta-analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2 | journal = New Phytologist | volume = 165 | issue = 2 | pages = 351–371 | year = 2004 | pmid =  15720649| doi-access = free }}</ref> However, detrimental impacts of global warming, such as increased instances of heat and drought stress, mean that the overall effect is likely to be a reduction in plant productivity.<ref name="Parry2007">{{cite book|author=Martin Lewis Parry|title=Climate Change 2007: Impacts, Adaptation and Vulnerability : Working Group II Contribution to the Fourth Assessment Report of the IPCC Intergovernmental Panel on Climate Change|url=https://books.google.com/books?id=TNo-SeGpn7wC&pg=PA214|year=2007|publisher=Cambridge University Press|isbn=978-0-521-88010-7|page=214}}</ref><ref>{{Cite journal | last1 = Long | first1 = S. P. | last2 = Ort | first2 = D. R. | doi = 10.1016/j.pbi.2010.04.008 | title = More than taking the heat: Crops and global change | journal = Current Opinion in Plant Biology | volume = 13 | issue = 3 | pages = 241–8 | year = 2010 | pmid =  20494611| bibcode = 2010COPB...13..240L }}</ref><ref>{{Cite journal | last1 = Lobell | first1 = D. B. | last2 = Schlenker | first2 = W. | last3 = Costa-Roberts | first3 = J. | doi = 10.1126/science.1204531 | title = Climate Trends and Global Crop Production Since 1980 | journal = Science | volume = 333 | issue = 6042 | pages = 616–620 | year = 2011 | pmid =  21551030| bibcode = 2011Sci...333..616L | s2cid = 19177121 | doi-access = free }}</ref> Reduced plant productivity would be expected to accelerate the rate of global warming. Overall, these observations point to the importance of avoiding further increases in atmospheric {{co2}} rather than risking [[runaway climate change]].<ref>{{Cite web |date=2022-01-27 |title=How Climate Change Will Affect Plants – State of the Planet |url=https://news.climate.columbia.edu/2022/01/27/how-climate-change-will-affect-plants/ |access-date=2024-09-02 |language=en-US}}</ref>

===Wind===
{{See also| wind pollination|seed dispersal}}

Wind has three very different effects on plants.<ref name=":0">{{Cite journal|last1=Gardiner|first1=Barry|last2=Berry|first2=Peter|last3=Moulia|first3=Bruno|title=Review: Wind impacts on plant growth, mechanics and damage|journal=Plant Science|volume=245|pages=94–118|doi=10.1016/j.plantsci.2016.01.006|pmid=26940495|year=2016|bibcode=2016PlnSc.245...94G }}</ref>
* It affects the exchanges of mass (water evaporation, {{co2}}) and of energy (heat) between the plant and the atmosphere by renewing the air at the contact with the leaves ([[convection]]).
* It is sensed as a signal driving a wind-acclimation syndrome by the plant known as [[thigmomorphogenesis]], leading to modified growth and development and eventually to wind hardening.
* Its [[Drag (physics)|drag force]] can damage the plant (leaf abrasion, wind ruptures in branches and stems and [[windthrow]]s and toppling in trees and [[Lodging (agriculture)|lodging]] in crops).<ref>{{Cite journal|last1=Moore|first1=J. R.|last2=Tombleson|first2=J. D.|last3=Turner|first3=J. A.|last4=van der Colff|first4=M.|date=2008-07-01|title=Wind effects on juvenile trees: a review with special reference to toppling of radiata pine growing in New Zealand|journal=Forestry|volume=81|issue=3|pages=377–387|doi=10.1093/forestry/cpn023|issn=0015-752X|doi-access=free}}</ref>

==== Exchange of mass and energy ====

Wind influences the way leaves regulate moisture, heat, and carbon dioxide. When no wind is present, a layer of still air builds up around each leaf. This is known as the [[boundary layer]] and in effect insulates the leaf from the environment, providing an atmosphere rich in moisture and less prone to convective heating or cooling. As wind speed increases, the leaf environment becomes more closely linked to the surrounding environment. It may become difficult for the plant to retain moisture as it is exposed to dry air. On the other hand, a moderately high wind allows the plant to cool its leaves more easily when exposed to full sunlight. Plants are not entirely passive in their interaction with wind. Plants can make their leaves less vulnerable to changes in wind speed, by coating their leaves in fine hairs ([[trichomes]]) to break up the airflow and increase the boundary layer. In fact, leaf and canopy dimensions are often finely controlled to manipulate the boundary layer depending on the prevailing environmental conditions.<ref>{{Cite journal | last1 = Vogel | first1 = S. | title = Leaves in the lowest and highest winds: temperature, force and shape | doi = 10.1111/j.1469-8137.2009.02854.x | journal = New Phytologist | volume = 183 | issue = 1 | pages = 13–26 | year = 2009 | pmid =  19413689| doi-access = free | bibcode = 2009NewPh.183...13V }}</ref>

==== Acclimation ====

Plants can sense the wind through the deformation of its tissues. This signal leads to inhibits the elongation and stimulates the radial expansion of their shoots, while increasing the development of their root system. This syndrome of responses known as [[thigmomorphogenesis]] results in shorter, stockier plants with strengthened stems, as well as to an improved anchorage.<ref>{{Cite journal|last=Jaffe|first=M. J.|date=1973-06-01|title=Thigmomorphogenesis: The response of plant growth and development to mechanical stimulation|journal=Planta|language=en|volume=114|issue=2|pages=143–157|doi=10.1007/bf00387472|pmid=24458719|bibcode=1973Plant.114..143J |s2cid=25308919|issn=0032-0935}}</ref> It was once believed that this occurs mostly in very windy areas. But it has been found that it happens even in areas with moderate winds, so that wind-induced signal were found to be a major ecological factor.<ref name=":0" /><ref>{{Cite journal|last=Ennos|first=A|title=Wind as an ecological factor|journal=Trends in Ecology & Evolution|volume=12|issue=3|pages=108–111|doi=10.1016/s0169-5347(96)10066-5|pmid=21237994|year=1997|bibcode=1997TEcoE..12..108E}}</ref>

Trees have a particularly well-developed capacity to reinforce their trunks when exposed to wind. From the practical side, this realisation prompted arboriculturalists in the UK in the 1960s to move away from the practice of staking young [[amenity tree]]s to offer artificial support.<ref>{{Cite journal|last1=Grace|first1=J.|year=1988|title=3. Plant response to wind|journal=Agriculture, Ecosystems & Environment|volume=22–23|pages=71–88|doi=10.1016/0167-8809(88)90008-4|bibcode=1988AgEE...22...71G }}</ref>

==== Wind damage ====

Wind can damage most of the organs of the plants. Leaf abrasion (due to the rubbing of leaves and branches or to the effect of airborne particles such as sand) and leaf of branch breakage are rather common phenomena, that plants have to accommodate. In the more extreme cases, plants can be mortally damaged or uprooted by wind. This has been a major selective pressure acting over terrestrial plants.<ref>{{Cite journal|last1=Rowe|first1=Nick|last2=Speck|first2=Thomas|date=2005-04-01|title=Plant growth forms: an ecological and evolutionary perspective|journal=New Phytologist|language=en|volume=166|issue=1|pages=61–72|doi=10.1111/j.1469-8137.2004.01309.x|pmid=15760351|issn=1469-8137|doi-access=free|bibcode=2005NewPh.166...61R }}</ref> Nowadays, it is one of the major threatening for agriculture and forestry even in temperate zones.<ref name=":0" /> It is worse for agriculture in hurricane-prone regions, such as the banana-growing Windward Islands in the Caribbean.<ref>{{Cite web|url=https://www.theguardian.com/global-development/poverty-matters/2010/dec/23/windward-islands-caribbean-farmers-bananas|title = We mustn't abandon the Windward Islands' farmers &#124; Renwick Rose and Nick Mathiason|website = [[TheGuardian.com]]|date = 23 December 2010}}</ref>

When this type of [[disturbance (ecology)|disturbance]] occurs in natural systems, the only solution is to ensure that there is an adequate stock of seeds or seedlings to quickly take the place of the mature plants that have been lost- although, in many cases, a [[Ecological succession|successional]] stage will be needed before the ecosystem can be restored to its former state.

== Animals ==

=== Humans ===

[[environment (biophysical)|The environment]] can have major influences on human [[physiology]]. Environmental effects on human physiology are numerous; one of the most carefully studied effects is the alterations in [[thermoregulation]] in the body due to outside [[stress (medicine)|stresses]]. This is necessary because in order for [[enzyme]]s to function, [[blood]] to flow, and for various body [[Organ (anatomy)|organ]]s to operate, [[temperature]] must remain at consistent, balanced levels.{{cn|date=March 2024}}

====Thermoregulation====
To achieve this, the body alters three main things to achieve a constant, normal body temperature:
* Heat transfer to the [[epidermis (skin)|epidermis]]
* The rate of [[evaporation]]
* The rate of heat production

The hypothalamus plays an important role in thermoregulation. It connects to thermal receptors in the [[dermis]], and detects changes in surrounding blood to make decisions of whether to stimulate internal heat production or to stimulate evaporation.

There are two main types of stresses that can be experienced due to extreme environmental temperatures: [[heat stress]] and [[cold stress]].

Heat stress is physiologically combated in four ways: [[thermal radiation|radiation]], [[heat conduction|conduction]], [[convection]], and [[evaporation]]. Cold stress is physiologically combated by shivering, accumulation of [[body fat]], circulatory adaptations (that provide an efficient transfer of heat to the epidermis), and increased blood flow to the extremities.

There is one part of the body fully equipped to deal with cold stress. The [[respiratory system]] protects itself against damage by warming the incoming air to 80-90 degrees Fahrenheit before it reaches the [[bronchi]]. This means that not even the most frigid of temperatures can damage the respiratory tract.

In both types of temperature-related stress, it is important to remain well-hydrated. Hydration reduces cardiovascular strain, enhances the ability of energy processes to occur, and reduces feelings of exhaustion.

====Altitude====
Extreme temperatures are not the only obstacles that humans face. [[High altitude]]s also pose serious physiological challenges on the body. Some of these effects are reduced [[Arterial blood gas|arterial <math>P_{{\mathrm{O}}_2}</math>]], the rebalancing of the [[acid-base content in body fluids]], increased [[hemoglobin]], increased [[Red blood cell|RBC]] synthesis, enhanced circulation, and increased levels of the [[glycolysis]] byproduct [[2,3 diphosphoglycerate]], which promotes off-loading of O<sub>2</sub> by [[hemoglobin]] in the [[hypoxic tissues]].<ref>{{Cite journal |last1=Płoszczyca |first1=Kamila |last2=Czuba |first2=Miłosz |last3=Chalimoniuk |first3=Małgorzata |last4=Gajda |first4=Robert |last5=Baranowski |first5=Marcin |date=2021-06-15 |title=Red Blood Cell 2,3-Diphosphoglycerate Decreases in Response to a 30 km Time Trial Under Hypoxia in Cyclists |journal=Frontiers in Physiology |volume=12 |pages=670977 |doi=10.3389/fphys.2021.670977 |doi-access=free |issn=1664-042X |pmc=8239298 |pmid=34211402}}</ref>

Environmental factors can play a huge role in the human body's fight for [[homeostasis]]. However, humans have found ways to adapt, both [[physiology|physiologically]] and tangibly.{{cn|date=March 2024}}

=== Scientists ===

[[George A. Bartholomew]] (1919–2006) was a founder of animal physiological ecology. He served on the faculty at [[UCLA]] from 1947 to 1989, and almost 1,200 individuals can trace their academic lineages to him.<ref name='bargentree'>[http://bartgen.bio.uci.edu/tree BartGen Tree] {{webarchive|url=https://archive.today/20120707042447/http://bartgen.bio.uci.edu/tree/ |date=7 July 2012 }}</ref> [[Knut Schmidt-Nielsen]] (1915–2007) was also an important contributor to this specific scientific field as well as [[comparative physiology]].<ref name=fne>{{Cite journal |last=Egerton |first=Frank N. |date=October 2019 |title=History of Ecological Sciences, Part 64: History of Physiological Ecology of Animals |journal=The Bulletin of the Ecological Society of America |language=en |volume=100 |issue=4 |doi=10.1002/bes2.1616 |bibcode=2019BuESA.100E1616E |issn=0012-9623|doi-access=free }}</ref>

[[Hermann Rahn]] (1912–1990) was an early leader in the field of environmental physiology. Starting out in the field of zoology with a Ph.D. from [[University of Rochester]] (1933), Rahn began teaching physiology at the [[University of Rochester]] in 1941.  It is there that he partnered with [[Wallace O. Fenn]] to publish ''A Graphical Analysis of the Respiratory Gas Exchange'' in 1955.  This paper included the landmark O<sub>2</sub>-CO<sub>2</sub> diagram, which formed the basis for much of Rahn's future work.  Rahn's research into applications of this diagram led to the development of aerospace medicine and advancements in hyperbaric breathing and high-altitude respiration.  Rahn later joined the [[University at Buffalo]] in 1956 as the Lawrence D. Bell Professor and Chairman of the Department of Physiology.  As Chairman, Rahn surrounded himself with outstanding faculty and made the University an international research center in environmental physiology.<ref name=fne/>

== See also ==
{{portal|Ecology|Biology|Environment}}
{{div col|colwidth=22em}}
* [[Comparative physiology]]
* [[Evolutionary physiology]]
* [[Ecology]]
* [[Phylogenetic comparative methods]]
* [[Plant physiology]]
* [[Raymond B. Huey]]
* [[Theodore Garland, Jr.]]
* [[Tyrone Hayes]]
{{div col end}}

== References ==
{{reflist|2}}

== Further reading ==
{{refbegin|2}}
* {{cite journal|last=Bennett|first=A. F.|author2=C. Lowe|year=2005|title=The academic genealogy of George A. Bartholomew|journal=[[Integrative and Comparative Biology]]|issn=1540-7063|volume=45|issue=2|pages=231–233|doi=10.1093/icb/45.2.231|pmid=21676766|doi-access=free|citeseerx=10.1.1.589.3158}}
* {{cite book|last=Bradshaw|first=Sidney Donald|title=Vertebrate ecophysiology: an introduction to its principles and applications|url=https://archive.org/details/vertebrateecophy0000brad|url-access=registration|year=2003|publisher=Cambridge University Press|location=Cambridge, U.K.|isbn=978-0-521-81797-4|page=xi + 287 pp}}
* {{cite book|last=Calow|first=P.|title=Evolutionary physiological ecology|publisher=Cambridge University Press|location=Cambridge|year=1987|isbn=978-0-521-32058-0|page=[https://archive.org/details/evolutionaryphys0000unse/page/239 239 pp]|url=https://archive.org/details/evolutionaryphys0000unse/page/239}}
* {{cite book|last=Karasov|first=W. H.|author2=C. Martinez del Rio |title=Physiological ecology: how animals process energy, nutrients, and toxins |publisher=Princeton University Press |location=Princeton, NJ |year=2007 |isbn= 978-0-691-07453-5|page=xv + 741 pp}}
* {{cite book|last=Lambers|first=H.|title=Plant physiological ecology|year=1998|publisher=Springer-Verlag|location=New York|isbn=978-0-387-98326-4}}
* {{cite book|last=Larcher|first=W.|title=Physiological plant ecology|edition=4th|year=2001|publisher=Springer|isbn=978-3-540-43516-7}}
* {{cite book|last=McNab|first=B. K.|title=The physiological ecology of vertebrates: a view from energetics|publisher=Comstock Publishing Associates|location=Ithaca and London|year=2002|isbn=978-0-8014-3913-1|no-pp=true|page=xxvii + 576 pp|url=https://archive.org/details/physiologicaleco00mcna|url-access=registration}}
* {{cite book|last=Sibly|first=R. M.|author2=P. Calow|title=Physiological ecology of animals: an evolutionary approach|publisher=Blackwell Scientific Publications|location=Oxford|year=1986|isbn=978-0-632-01494-1|page=[https://archive.org/details/physiologicaleco0044sibl/page/179 179 pp]|url=https://archive.org/details/physiologicaleco0044sibl/page/179}}
* Spicer, J. I., and K. J. Gaston. 1999. Physiological diversity and its ecological implications. Blackwell Science, Oxford, U.K. x + 241 pp.
* {{cite journal|last=Tracy|first=C. R.|author2=J. S. Turner|year=1982|title=What is physiological ecology?|journal=[[Bulletin of the Ecological Society of America]]  |issn=0012-9623|volume=63|issue=4 |pages=340–347|doi=10.2307/20166334 |jstor=20166334 |s2cid=86354445 }}. Definitions and Opinions by: G. A. Bartholomew, A. F. Bennett, W. D. Billings, B. F. Chabot, D. M. Gates, B. Heinrich, R. B. Huey, D. H. Janzen, J. R. King, P. A. McClure, B. K. McNab, P. C. Miller, P. S. Nobel, B. R. Strain.
{{refend}}
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