Mention the different ways by which the population density of different species can be measured.
The population density of different species can be measured by:
(1) Quadrat method: It is a method that involves the use of a square of particular dimensions to measure the number of organisms.
Example: The number of Parthenium plants in a given area can be measured using the quadrat method.
(2) Direct observation: It involves the counting of organisms in the given area.
Example: In order to determine the number of bacteria growing in a Petri dish, their colonies are counted.
(3) Indirect method: In this method, there is no need to count the organisms individually.
Example: The number of fishes caught per trap gives the measure of their total density in a given water body.