CHARACTERISTICS OF POPULATION -
Each population envolves adaptations suited to its own locality.
Population is unit of evolution.
Population is also an ecological unit which plays important role in ecosystem.
1. Pattern of distribution -
Population is not uniform in whole country.
It is thick near river and lakes & thin in the deserts and at high altitudes.
2. Variation in number -
Population is not constant every time. This variation is expressed as population size and population density.
It requires three paramitere -
(i) Number and kind of individual.
(ii) Given area
(iii) Given time
e.g. population of India in 1999. population of lions in gir forest in 2001.
Total numbers of individuals of a species in a particular area of a specific time is population size. e.g. there were 40,000 asiatic elephants in 1991.
Density is number of individuals present per unit area.
D = n/a
n = number of individuals.
a = area in square killometers.
Increasing density of animals can eventually lead to shortages in food, living space & privacy.
Low density may be eliminated completely by a predator or unfavourable conditions.
In world 33 / km2.
Maximum in Bangladesh.
Minimum in Greenland i.e. 15/ km2.
3. Age structure -
It deals with % of individuals of diff. ages such as young, adult and old.
4. Sex ratio -
It refers to the no. of females and males per thousand individuals.
In 1991, there were 929 female per 1000 males in our country.
In 2001, there were 933 females per 1000 males in our country.
In Haryana, there were 861 females per 1000 males.