(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.

Explanation

Following are the attributes that a population has·but an individual organism does not have: 1. Per capita birth·rate. 2. Per capita death rate.
3. Sex ratio : ,Ratio of number of males to females in a population
Population density means number of individuals present. per unit area, population density can be measured by determining the population: size. The different methods to study population size are as fallows:
( 1) Per cent cover or biomass : In an area with 200 parthenium plant and only one banyan tree with -large conopy, the denstiy of banyan tree is small but does not reflect its important role in the community. Here percent cover or biomass is a more meaningful method of assesseing population density.
( 2) Total Number : It involves the counting of organisms in the given area.
( 3) Relative Density :In this method m there is no need to count the organsms individually Example the nubmber of fishes caught per trap gives the measure of total density in a given water body.
( 4) Indirect Assesment: The tiger cenus is based on pug marks and faecal pellets.