Organisms at high altitude
[8][9] Other invertebrates with high-altitude habitats are Euophrys omnisuperstes, a spider that lives in the Himalaya range at altitudes of up to 6,700 m (22,000 ft);[10] it feeds on stray insects that are blown up the mountain by the wind.
[15] Ballooning is a term used for the mechanical kiting[16][17] that many spiders, especially small species such as Erigone atra,[18] as well as certain mites and some caterpillars use to disperse through the air.
Some spiders have been detected in atmospheric data balloons collecting air samples at slightly less than 5 km (16,000 ft) above sea level.
[23][24][25] These factors may decrease productivity in high altitude habitats, meaning there will be less energy available for consumption, growth, and activity, which provides an advantage to fish with lower metabolic demands.
[27] It is unclear whether this is a common characteristic in other high altitude dwelling fish or if gill remodelling and HIF-1 use for cold adaptation are limited to carp.
Mammals are also known to reside at high altitude and exhibit a striking number of adaptations in terms of morphology, physiology and behaviour.
Those that can survive a wide range of high-altitude regions are eurybarc and include yak, ibex, Tibetan gazelle of the Himalayas and vicuñas llamas of the Andes.
Stenobarc animals are those with lesser ability to endure a range of differences in altitude, such as rabbits, mountain goats, sheep, and cats.
Several mechanisms help them survive these harsh conditions, including altered genetics of the hemoglobin gene in guinea pigs and deer mice.
[33][34] Deer mice use a high percentage of fats as metabolic fuel to retain carbohydrates for small bursts of energy.
[35] Other physiological changes that occur in rodents at high altitude include increased breathing rate[36] and altered morphology of the lungs and heart, allowing more efficient gas exchange and delivery.
At high altitudes, some rodents even shift their thermal neutral zone so they may maintain normal basal metabolic rate at colder temperatures.
This shows that highland mice have evolved a metabolic process to economise oxygen usage for physical activities in the hypoxic conditions.
The yak is the most important domesticated animal for Tibet highlanders in Qinghai Province of China, as the primary source of milk, meat and fertilizer.
Their physiology is well-adapted to high altitudes, with proportionately larger lungs and heart than other cattle, as well as greater capacity for transporting oxygen through their blood.
[47] In yaks, hypoxia-inducible factor 1 (HIF-1) has high expression in the brain, lung and kidney, showing that it plays an important role in the adaptation to low oxygen environment.
[48] On 1 July 2012 the complete genomic sequence and analyses of a female domestic yak was announced, providing important insights into understanding mammalian divergence and adaptation at high altitude.
[49] In addition, researchers also found an enrichment of protein domains related to the extracellular environment and hypoxic stress that had undergone positive selection and rapid evolution.
[69][page needed] Birds also have a high capacity for oxygen delivery to the tissues because they have larger hearts and cardiac stroke volume compared to mammals of similar body size.
[72] The bar-headed goose (Anser indicus) is an iconic high-flyer that surmounts the Himalayas during migration,[73] and serves as a model system for derived physiological adaptations for high-altitude flight.
Rüppell's vultures, whooper swans, alpine chough, and common cranes all have flown more than 8 km (26,000 ft) above sea level.
[78] In 2013, the molecular mechanism of high-altitude adaptation was elucidated in the Tibetan ground tit (Pseudopodoces humilis) using a draft genome sequence.
[81] High-altitude plants must adapt to the harsh conditions of their environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.
