Role of atmosphere
Air functions as a medium for Locomotion of insets, birds etc. Ozone layer of atmosphere protects the living organisms from harmful radiations of sun.
Air is the source of oxygen, carbon dioxide and nitrogen required for various metabolic activities of living beings. It helps in dispersal of spores, pollen, seeds etc. Air transmits sound for communication. Burning of fire takes place in presence of oxygen.
The gases present in the atmosphere are chiefly oxygen, carbon dioxide and nitrogen which greatly influence the living organisms. Atmosphere is the thick gaseous envelope around the earth. The composition of Atmospheric air is: Oxygen—20.84%, Nitrogen—-78.64%, Carbon dioxide—0.03%, Water vapors—0.1%
LIGHT (RADIATION FACTOR)
Light is a very important of the climatic factors which is directly responsible for the growth, development and differentiation of plants. Similarly, light as a complex physical factor, also affects the colour vision, eye-size, skin pigmentation, Migration, reproduction and biological periodicity of the animals. Thus, light is a Factor of physical and physiological importance.
EFFECTS OF LIGHT ON ANIMALS
Size of eye: Marine animals of 500-3,000 meters depth have larger eyes than those found in surface water.
Photo-periodism: It refers to the response of organisms to the duration of sunlight in a day (photoperiod).In many animals’ migration, hibernation and Reproductive behaviors are controlled by relative lengths of day and time. Metabolism: Light increases the enzymatic activities and general metabolic Rate. It also increases photo oxidation and respiration rates. Animals found in Caves have low rate of metabolism.