According to the theory of natural selection, as proposed by Darwin and Wallace, continuous interactions between changing genetic architecture of living organisms and changing environment lead to the formation of large number of different species. While enthusiastic Darwinists use the popular phrase “struggle for existence” to dramatize his theory of natural selection, it means survival of those which have genetic variations that are appropriate for a given environment. Evolution does not mean progress or improvement. It simply means change. The whole process is blind. Genetic variations occur randomly and their selection by nature is purely based on their adaptability in given time and space.
Nonetheless, “struggle for existence” has caught the imagination of naturalists, who extrapolated this to examine the effect of behavioral traits on natural selection and vice versa. With the better understanding of brain and consciousness, scientists started exploring to what extent behavioral adaptations influence innate interactions between morphological traits and environment. If we look around social behaviour of insects, fishes, birds, primates and many other species, it is clear that there has been natural selection not only at the levels of morphological phenotypes, but also at the levels of behaviour for better survival and reproduction abilities (together known as fitness. By their very nature, all behavioural traits are subjected to environmental influence much more than morphological and physiological traits.