Question

(a) List the different attributes that a population has and not an individual organism.
(b) What is population density? Explain any three different ways the population density can be measured, with the help of an example each. [5]

Answer 1

(a) Following are the attributes that a population has but an individual organism does not (write any 2): [1]
Birth rate - Per capita Births
Death rate - Per capita deaths
Sex ratio - Ratio of number of males to females in a population.

(b) Population density refers to the number of individuals present per unit area at a given time/period. [1]

Different ways to measure population density are:

(i) By numbers : In order to determine the number of bacteria growing in a petri dish, their colonies are counted. [1]
(ii) By biomass or percentage cover : Biomass of one huge banyan tree is larger than hundreds of Parthenium plants. [1]
(iii) By indirect estimation : Tiger census is based on pugmarks and faecal pellets. [1]