All organisms are sensitive to temperature, and have distinct temperature preferences. Some organisms have broad temperature tolerances while some have narrow temperature responses. The following are the ranges of body temperatures for various organisms.
The Antarctic fish Trematomus benacchi has a body temperature tolerance range of 4 degrees (from -2° to 2° C). The desert pupfish tolerates temperatures from 10° to 4° C, with a preference for temperatures about 20° C. Most cold blooded animals have low metabolic rates and body temperature of the air or water in which they are immersed. Reptiles on the other hand may have body temperatures that are regulated to remain within narrow limits except for some animals that hibernate, then they go into a cold blooded state. The normal body temperature for a human is about 37° C, but can survive with body temperature going as low as 22° and high as 43° C. Birds have the highest body temperature which ranges between 41° and 44° C.
Plants generally have temperatures close to air temperature except in strong sunlight, when the leaves may be 10° to 20° C above the air temperature, and under cold clear skies at night they can have temperatures of of 5° to 8° C below the air temperature. All plants and all blooded organisms have a behavioral and growth response that increases with increasing temperatures above some low temperature tolerance limit, the behavioral and growth response reaches a maximum at some optimum temperature and decreases sharply at higher temperatures until the thermal maximum is reached.
Many plants begin to sustain thermal damage when their tissue temperature exceeds 43 degrees Celsius. Some plants that adapt to high-temperature habitats have good resistance to thermal damage at the temperature likely to be encountered, thus they may have relatively poor cold resistance to low temperatures.
Algae usually optimize their photosynthesis and growth response to the temperature of the stream of lake which they are living, but because of temperature changes throughout a yearly cycle many bodies of water have organisms with different temperature levels.
