Temperature adaptation

Temperature adaptation

The ability of animals to survive and function at widely different temperatures as a result of specific physiological adaptations. Temperature is an all-pervasive attribute of the environment that limits the activity, distribution, and survival of animals.

Changes in temperature influence biological systems, both by determining the rate of chemical reactions and by specifying equilibria. Because temperature exerts a greater effect upon the percentage of molecules that possess sufficient energy to react (that is, to exceed the activation energy) than upon the average kinetic energy of the system, modest reductions in temperature (for example, from 77 to 59°F or from 25 to 15°C, corresponding to only a 3% reduction in average kinetic energy) produce a marked depression (two- to threefold) in reaction rate. In addition, temperature specifies the equilibria between the formation and disruption of the noncovalent (electrostatic, hydrophobic, and hydrogen-bonding) interactions that stabilize both the higher levels of protein structure and macromolecular aggregations such as biological membranes. Maintenance of an appropriate structural flexibility is a requirement for both enzyme catalysis and membrane function, yet cold temperatures constrain while warm temperatures relax the conformational flexibility of both proteins and membrane lipids, thereby perturbing biological function. See Cell membranes, Enzyme

Animals are classified into two broad groups depending on the factors that determine body temperature. For ectotherms, body temperature is determined by sources of heat external to the body; levels of resting metabolism (and heat production) are low, and mechanisms for retaining heat are limited. Such animals are frequently termed poikilothermic or cold-blooded, because the body temperature often conforms to the temperature of the environment. In contrast, endotherms produce more metabolic heat and possess specialized mechanisms for heat retention. Therefore, body temperature is elevated above ambient temperature; some endotherms (termed homeotherms or warm-blooded animals) maintain a relatively constant body temperature. There is no natural taxonomic division between ecto- and endotherms. Most invertebrates, fish, amphibians, and reptiles are ectotherms, while true homeothermy is restricted to birds and mammals. However, flying insects commonly elevate the temperature of their thoracic musculature prior to and during flight (to 96°F or 36°C), and several species of tuna retain metabolic heat in their locomotory musculature via a vascular countercurrent heat exchanger. See Hibernation, Thermoregulation

References in periodicals archive ?
Temperature adaptation in a changing climate; nature at risk.
The effects of climate change on low temperature adaptation has been an overlooked area in the worlds of research and policy.
kuehniella at temperatures of 18, 20, 25, 30 and 33[degrees]C for temperature adaptation.
The approach used here as a first step for determining whether temperature adaptation has occurred in the most southern part of the zebra mussel range in North America, was a comparison of heat-tolerance among populations from three sites along the Mississippi River.
Temperature adaptation in Phaeodactylum tricomutum Bohlin: Photosynthetic rate compensation and capacity.
The cultivation of many tropical japonicas in high-elevation areas of Southeast Asia, may have also placed an advantage on characteristics associated with low temperature adaptation.
They were also the ancestral genotypes used to found an evolutionary experiment on temperature adaptation (previously described in Bennett et al.
In addition, one would not expect homeoviscous adaptation to reduce the sensitivity to pressure, as is the case for enzymatic adaptations, but rather to shift the tolerated range of pressure in the same way that it does in temperature adaptation (Sinensky, 1974).
Evidently, correlated losses of fitness at dissimilar temperatures may sometimes occur during selection for thermal specialists, but such tradeoffs are not necessary outcomes of temperature adaptation in this system.
We all have the ability to make quick temperature adaptations.
There is an excellent discussion of temperature adaptations and acclimatization with several very good illustrations.