Question

For which of the following cases, population density can be easily determined by utilizing non-biological parameter?
A) Fish density
B) Density of bacteria in culture plate
C) Siberian cranes at Bharatpur wetlands
D) Tiger census

Answer 1

Population density is the number of individuals present in a given area with respect to the size of the are they occupy. For example, if 100 dogs live in 100 square kilometres then the population density is 1 dog per square kilometre. It can be calculated as arithmetic density, physiological density and agricultural density.

Complete answer:
The population density refers to the size of the population at a definite area. It is mostly applicable to the living organisms. The population density is dependent on the biological and non biological factors.
Biological factors include:
- Presence of sexual mates.
- Increased inbreeding.

Non biological factors include-temperature, water, pH, salt concentration, dissolved oxygen, mineral contents etc. The population density of the plants are heavily dependent on the non-biological parameters. The density of fish is also dependent on these factors like dissolved oxygen, pH, presence of water etc.

In the case of bacteria both biological and non-biological factors affect the population size as the bacteria. a biological factor means the presence of other organisms and the non biological factor is the nutrients, pH temperature etc.

For calculating the fish density, the non-biological features of water like pH, oxygen concentration, turbidity, salts, pollutants etc is enough for the same. If the water has any change in these parameters, the population of fish will not thrive or be reduced.

In case of Siberian cranes - presence of mate is the most important requirement for the density or the population size to increase. It is dependent on both biological as well as non-biological parameters. The temperature is very important in case of Siberian cranes. They mostly migrate during winters.

Tiger Census- It refers to the population of tigers. It is greatly dependent on mates and also external non biological factors like hunting, poaching, climate etc.

Thus, the answer of the above question is option A.

Note: Larger the population, the more stable it is. The larger population has more genetic variability so that they can adapt to the environmental changes and natural selection process. The population of low density will face problems of finding mates and therefore reproduction will be less.