Q.11. Name and discuss the major periods of
growth of human population. (AKTU. - 2008 - 09)
Ans. The
percentage growth in population during each decade is shown in the following
table:
Between 1911 and 1920, the birth and death
rates were almost equal: about 48 births and 48 deathz per 1,000 people. The
immense research in medical science led to the development of various curative
and preventive medicines and ensured a steady decline in the death rate. Due to
this, the estimated death rate fell to 10 per 1,000 people by mid 1990s; the
estimated birth rate also fell to 28per 1,000. Owing to the countinuous decline
in the death rate, it is clear that the future configuration of population in
India depends solely on the birth rate. Indian population has now crossed the 1
billion mark and comprises one sixth of the total world population.
Q.12. Discuss the effects of human activity on the
environment. (AKTU. - 2010-11)
Ans. In
a natural state, the earth’s life forms live in equilibrium with their
environment. The population and activities of every species are governed by the
resources available to them. Interaction among species is quite common, the
waste product of one species may form the food supply of another species.
Humans alone have the potential to gather resources from beyond their immediate
surroundings and process them into different and more versatile forms. This has
made humans to thrive and flourish beyond natural constraints. As a result of
which the anthropogenic (man-induced) pollutants have overloaded the system,
and the natural equilibrium is disturbed.
Primitive humans used natural
resources to satisfy their basic needs of air, water, food and shelter. These
natural and unprocessed resources were readily available in the biosphere, and
the residues produced by the use of these resources were generally compatible
with or easily assimilated by the environment. Even when use of fire became
common, the relatively small amounts of smoke generated were easily and rapidly
dispersed and assimilated by the atmosphere. Early human populations left
behind very few things which were not readily broken down and absorbed by the
environment. As these things were so few in number (quantity), no significant
impact was fell on the environment.
With the dawn of the industrial
revolution, humans were better able than ever to satisfy their needs for air,
water, food and shelter. So, humans turned their attention to other needs
beyond those associated with survival. Automobiles, household appliance,
processed foods and beverages, etc. have now become so popular as to seem
necessities, and meeting these acquired needs has become a major thrust of
modern industrial society. These acquired needs are usually met by items that
must be processed or manufactured or refined; and the production, distribution
and use of such items usually results in more complex residuals and/or wastes,
many of which are not compatible with or readily assimilated by the
environment. As the acquired needs (or luxuries) increase so will the
complexity of the production chain, and mass and complexity of the pollutants
generated.
Thus, the impact of modern humans upon the
environment is of major concern.
