Population studies and biology are also closely related. It must be remembered that population phenomena take place within the framework of physiology and that there are certain biological limits within which the variables of population change operate.
The study of fertility provides a good illustration of the relationship between population and biology. It is a biologically determined fact that only females can give birth to children and that, too, only during a certain age span.
Similarly, in the study of mortality, it is known that the age and sex differentials are biologically determined. Even the sex ratio among the new-born is biologically determined. Population genetics have been an important area of specialisation.
The knowledge of reproduction, so necessary for the study of fertility, is gained mainly from reproductive physiology. An effective regulation of fertility through improvements in contraceptive techniques has been the contribution of applied research workers in the field of reproductive physiology.
ADVERTISEMENTS:
It is also well-known that advances in the medical sciences and the adoption of widespread public health measures have been responsible for declining mortality rates even in developing countries, irrespective of the level of development in these countries.