Organisms can live at high altitude, either on land, in water, or while flying. Decreased oxygen availability and decreased temperature make life at such altitudes challenging, though many species have been successfully adapted via considerable physiological changes. As opposed to short-term acclimatisation (immediate physiological response to changing environment), high-altitude adaptation means irreversible, evolved physiological responses to high-altitude environments, associated with heritable behavioural and genetic changes. Among vertebrates, only few mammals (such as yaks, ibexes, Tibetan gazelles, vicunas, llamas, mountain goats, etc.) and certain birds are known to have completely adapted to high-altitude environments.[1]
Human populations such as some Tibetans, South Americans and Ethiopians live in the otherwise uninhabitable high mountains of the Himalayas, Andes and Ethiopian Highlands respectively. The adaptation of humans to high altitude is an example of natural selection in action.[2]
High-altitude adaptations provide examples of convergent evolution, with adaptations occurring simultaneously on three continents. Tibetan humans and Tibetan domestic dogs share a genetic mutation in EPAS1, but it has not been seen in Andean humans.[3]
- ^ Storz JF, Scott GR, Cheviron ZA; Scott; Cheviron (2007). "Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates". J Exp Biol. 213 (pt 24): 4125–4136. doi:10.1242/jeb.048181. PMC 2992463. PMID 21112992.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Frisancho AR (1993). Human Adaptation and Accommodation. University of Michigan Press. pp. 175–301. ISBN 978-0472095117.
- ^ Wang, G.D; Fan, R.X; Zhai, W; Liu, F; Wang, L; Zhong, L; Wu, H (2014). "Genetic convergence in the adaptation of dogs and humans to the high-altitude environment of the tibetan plateau". Genome Biology and Evolution. 6 (8): 206–212. doi:10.1093/gbe/evu162. PMC 4231634. PMID 25091388.