Mention the different ways by which …

(a) Population density means number of individuals present per unit area. We can find out population density of a habitat by determining the population size. The different methods to study population size are as follows:-

(1) Total number: In this method the total number of organism in the population is counted. For example, in order to determine the number of bacteria growing in a Petri dish, their colonies are counted.

(2) Relative densities- In this method relative density of the population is taken into account rather than counting the total number. For example - The number fish caught per trap gives the measure of their total population density in the given water body.

(3) Percent cover or biomass cover: For example in a population of 200 Parthenium plants and a single huge Banyan tree the percent cover of both are taken into account.