The changes in the ecological system affect man human lives ad changes the course of his struggle for survival. But modern man has been able to overcome much of the instabilities through various means of gaining control over the environment such as domestication of species and other technological know-how. Human biological factors do affect social change in two ways in main the genetic character of a given population, and the quantity, density and composition of population. Although, the influence of genetic character has not been as important as the latter, it cannot be sidelined altogether. The intelligence level of Homo sapiens (human beings) from other lower animals (non-human beings) is enough indication of the capability and potential of human faculty that bears on socio-cultural development.
The human genetic character plays roles in the determination of numbers, composition and selection of population on one hand and hereditary quality of the successive generations. Human beings are changing all the time. We are different from our parents in our physical make-up, intelligence and behaviours. Every individual is not identical with the other either.
Nevertheless, it is the change of genetic character of the human beings, except for the process of mutation and variations in genetic combination that determine the physical and mental make-up of human beings. Population change, unlike genetic factors, is considered to be one of the most important factors of social change. Growth in population and also its composition have been affecting various aspects of socio-cultural lives. With the invention of new technologies and enhanced knowledge of health care and sanitation, the rate of death has decreased greatly over the past two centuries. The decrease in the death rate has caused an enormous increase in the size of population. Simultaneously, life expectancy and life span have also increased. Thus, population change has itself become a social change and factor of further social and cultural changes. Migration brings about further change by creating a new environment setting after the contact of two or more alien peoples and cultures with numerous new problems.
Migration could also effect to the processes of acculturation, cultural diffusion and/or social conflict. On the other hand, food productivity would not improve that fast to be able to catch up with the growing population. There is a general tendency in India that population increases faster than the food productivity or food supply. Such incompatible situation could lead to other consequences, such as, an attempt to improve food productivity by increasing the acreage under cultivation, farming technology or other sources on one hand and migration, famine, disease or war on the other. There would also be tendency for checking of population growth by possible means such as family planning among others. Thus, a population change has itself become a social change and a factor of further social and cultural changes.