Question

The population density can be calculated by
A. ${\text{D = }}\dfrac{{\text{S}}}{{\text{N}}}$
B. ${\text{D }} = \dfrac{{\text{N}}}{{\text{S}}}$
C. ${\text{D = }}\dfrac{{\text{S}}}{{\text{W}}}$
D. ${\text{D = }}\dfrac{{\text{W}}}{{\text{S}}}$

Answer 1

All the organisms belonging to the same group or species who live in a particular geographical area are known as a population. It is the sum total of all the organisms of the same species that reside in a geographical organism. The population of an area is estimated on the basis of including all the inhabitants of the area. It is an important tool in ecological and biological studies.

Complete answer:
A group of related organisms that inhabit a place is known as population. Population is a dynamic unit and is always under the influence of both ecological and evolutionary forces. The inhabitants of the population live and spend their lives in the specific environment. The ecology of the environment affects the different life processes of the organism such as growth, development and reproduction. It also affects the formation of fertile offspring to carry the generation of the organism. The population is also affected by several evolutionary forces such as mutation, natural selection etc. which brings about changes in the gene pool of the population.

The population is always changing by mainly three reasons which are the addition of new individuals by birth, death of the older individuals and movements of individuals in the form of migration and immigration.

The measurement of population in per unit area of ecological space is known as population density. It is a quantity that is described in type number density. In most common sense, it is applied to the density of living organisms, particularly humans. Thus, population density is the number of people living in a particular area per square kilometer. It is calculated as population or number of individuals in a population divided by total area of space which is land area in case of human population.

Mathematically, population density can be calculated by using the following formulae:
${\text{Population density}}\left( {\text{D}} \right){\text{ = }}\dfrac{{{\text{Number of individual}}\left( {\text{N}} \right)}}{{{\text{Surface area}}\left( {\text{S}} \right)}}$
$\Rightarrow$ ${\text{D}} = \dfrac{{\text{N}}}{{\text{S}}}$

Where,
D = Density of the population or Population Density.
N = Total number of individuals of the population.
S = Surface area or the land area in which the population inhabits.

Hence, the correct answer is option (B).

Note: Population represents the group of similar types of organism that reside together in an area. The population density is calculated as the total number of individuals of a population divided by the total area covered by the peoples. N denotes the total number of individuals in a population and S denotes the total surface area and D is the population density.