NCERT Solution for Class 10 Science Chapter 9
Heredity and Evolution
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Intext Questions
Page No-150
Questions No-1
What are the different ways in which individuals with a particular trait may increase in a population?
Share
The different ways in which individual with a particular trait may increase are:
Natural selection:- Certain variations give survival advantages to individuals in a population in a changed situation resulting in increase of their population.
Genetic drift: accidents in small population even if they give no survival advantage also lead to increase of certain individuals in population.
When a beneficial trait appears, it can increase in a population. The example of blue beetles in the chapter shows this. Since blue beetles could not be spotted by the crows hence more blue beetles could survive. Sometimes, an accident can also lead to proliferation of a new trait in a population, as happened in the example of trampling of bushes by elephants. It can be said that sudden or gradual changes in the environment or some mutation in a species can lead to a particular trait being passed on through generations.
Different ways in which individuals with a particular trait may increase in a population are as follow :
1. An individual trait may increase in a population in the following two ways:-
The trait is beneficial to the population: if a trait is beneficial to a population, it will increase naturally. For example, green colour in beetles is favourable as it helps them in camouflage against the predators
2.By accident: if a population faces an accident such that majority of its members get killed, the remaining members will pass on their traits to the subsequent generations. This will lead to an increase of the trait in the population.
3. By mutation
4. Natural Selection: if a trait is useful to the population, it will increase naturally.
Individuals with a particular trait may increase in a population as a result of the following:
(i) Natural selection: When that trait offers some survival advantage.
(ii) Genetic drift: When some genes governing that trait become common in a population.
(iii) When that trait gets acquired during the individual’s lifetime.
For more answers visit to website:
https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-9/