(a) Why is variation beneficial to the species but not necessarily for an individual?
Explain with help of a suitable example.
(b) What is meant by the term speciation? List four factors which could lead to
speciation.
Answers
Answer:
(i) Variation is useful for the survival of a species even in adverse environmental conditions. There may be some drastic changes like excessive heat or cold or shortage of water, etc., in the habitat. If all the organisms of a population that are identical, then there is danger that all of them may die. However, if some variations are present in some to tolerate excessive heat or cold or survive on meagre water supply, then there is a chance for them to survive and flourish even in adverse environment.
(ii)The process by which new species develop from the existing species is known as speciation.
Factors which could lead to the formation of new species are:
(1) Geographical isolation of population by various types of barriers (such as mountain ranges, rivers and sea).
(2) Genetic drift caused by drastic changes in the frequencies of particular genes by chance alone.
(3) Origin of new species.
(4) Reproductive isolation
Answer:
The reason why the variation is beneficial to the species than individuals is because sometimes the climatic changes have a drastic effect on the species which makes their survival difficult. For examples, if the temperature of the water body increases, then are might be certain species of microorganisms which might die. This may result in disturbance in the environment. So, variation is beneficial to species and not for the individuals.