Population Dynamics

Life expectancy is the statistical average age at death for a given population, calculated from mortality rate data.

The global total fertility rate (average children per woman) was approximately 2.59 around 2010-2012. This has since declined to about 2.3 in recent years (2020s), but 2.59 represents accurate demographic data from that earlier period.

The National Population Register (NPR) is conducted alongside the Census in India. While Census collects detailed demographic and socio-economic data, NPR maintains a register of usual residents, and both exercises are carried out during the same field visit.

Demographic relates to the study of human populations, particularly their statistics, structure, and distribution. Option A correctly identifies that this term pertains to population characteristics, balance, and statistical analysis of groups.

Fluctuations in natural population are affected by: birth and death rates, resources like food, water and space, natural calamities such as earthquake and volcanic eruptions, abiotic factors like temperature and rainfall, other organisms sharing habitat.

Population explosion occurs in the second stage of demographic transition when death rates decline sharply due to better healthcare, sanitation, and nutrition, while birth rates remain high. This creates a rapid population surge. First stage has high birth and death rates (stable population), third stage shows declining birth rates, and fourth stage achieves low birth and death rates (replacement level).

Emmigration is the permanent movement of individuals of same species out of the local population due to considerable reasons such as lack of food, scarcity of space (over crowding), etc. It decreases the size of local population.

Similar populations of a species amusing different geographical areas are called sister populations.

It is the period of slow increase in the population.

Yes, this is the correct option. Increase in birth rate, decrease in maternal mortality rate and decrease in death rate will obviously increase the population.

Population grows rapidly when birth rates remain high but death rates fall due to improvements in healthcare, sanitation, and nutrition. This creates a large gap between births and deaths. High death rates with high birth rates (option A) result in stable or slow-growing populations.

Population density measures how crowded a country is by calculating the average number of people living in each square kilometre of land area. This standard metric allows comparison between countries of different sizes. Option C incorrectly uses hectare instead of the standard square kilometre unit used in demographic measurements.

Natural selection has resulted in genetic differences between populations that allow them to be more or less successful in adapting to particular stresses. Populations that have been exposed to a stress generally have the best adaptation.

Birth-rate is conventionally expressed as births per 1000 people per year. This standardized measurement allows for easy comparison between different populations and is the universally accepted demographic indicator.

Population change in any region is determined by three fundamental factors: births (fertility), deaths (mortality), and migration (both immigration and emigration). Marriage affects births indirectly but is not a direct factor, and life expectancy is a consequence, not a cause.