The degree of hotness or coldness of a body is called temperature. Temperature is one of the most essential and changeable environmental factors which influence all forms of life. Temperature influences the viral activities of organisms such as metabolism, reproduction, growth and development, behaviour and death. The environmental temperature fluctuates both daily and seasonally and also from place to place. The temperature fluctuates are comparatively less in the aquatic environment than the terrestrial environment due to the high specific heat capacity of water.
The deep lake shows different thermal stratifications. It has three strata:
The normal life process of organism goes on smoothly at a specific temperature or at the specific range of temperature called optimum temperature or optimum range of temperature. The enzymes show its highest activity in optimum temperature. It varies among organisms. However, the life in this universe can exist in the range of -200 to +100°C but the normal life can persist with a narrow range of temperature of about -10°C to 50°C.
On the basis of the temperature tolerance capacity, organisms are of two types:
The organisms which can tolerate a wide range of temperature are called eurythermal organisms. Eg: frog, toad, the wall lizard, grass snake, man etc.
The organisms which can tolerate a narrow range of temperature are called stenothermal organisms. Eg:fishes, snails etc.
Formation of a hard chitinous protective layer around the body called cyst.
Aestivation (summer sleep): It is the similar condition in which other species pass periods of heat or drought in warm latitudes. For example;Snails achieve a state of dormancy during the summer in tree trunks, under leaves or on stone walls.
Hibernation (winter sleep):State of inactivity and metabolic depression in endotherms is know as hibernation.An inactive state resembling deep sleep in which certain animals living in cold climates pass the winter is called hibernation. For example;Several mammals hibernate during the long, cold winters. Woodchucks are one example of true hibernators. During their hibernation, the woodchuck's heart goes from 80 beats per minute to only four or five. It also drops its body temperature to 60 degrees below normal.
The ability of organisms to maintain the body temperature constant is known as homeothermy.
Excessive low or high temperature compel the animals to migrate from one place to another.
Development of thick bark, dense hairy coat, thick leaves, thick cubical mucilage etc. in plants to protect from extreme temperatures.