Anyone using GBD's guide book please answer NCERT textbook page no.150 q2 of Science (biology)
Answers
Good Morning
Question 1. What are the different ways in which individuals with a particular trait may increase in a population ?
Answer: Different ways are : variation, natural selection and genetic drift (isolation).
Question 2. Why are traits acquired during the lifetime of an individual not inherited ?
Answer: Because acquired characters bring changes only in non-reproductive tissues and cannot change the genes of the germ cells. Thus, acquired traits cannot be passed to next generation.
Question 3. Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
Answer: (i) If any natural calamity occurs and kills these small number of surviving tigers, they can become extinct resulting in the loss of some genes forever.
(ii) Small number will lead to little recombination and, therefore, lesser variations. These both are very important for giving better survival chances to the species.
(iii) Less number of species means lesser extent of diversity and lesser number Of traits which reduces the chances of adaptability with respect to the change in the environment.