The nature of all aquatic environments depends upon the following factors which exert their effects in varying degree: i) The depth of water Has an important secondary effect by reducing the penetration of light and hence the degree of colonisation by plants. ii) Light Water absorbs light of long wavelengths, particularly the blue part of the visible spectrum. Since this would not normally be sufficient for photosynthesis, many freshwater plants possess adaptations so that light …showed first 75 words of 1256 total…

…showed last 75 words of 1256 total…flattening as well such as the large mayfly nymphs. v) Behavioural responses - In general, stream animals face and move upstream. This facilitates the use of gills in gas exchange and also the capture of food floating towards them. Another response is a tendency to cling to any surface with which the body comes into contact. This is particularly important for small molluscs whose powers of locomotion and avoidance of an excessive current are limited.