Question

List any three factors and mention how they could lead to the rise of a new species. 

Answer 1

There are various factors that can lead to the rise of a new species. Three of them are as follows:

(i) Geographical isolation: Geographical barriers such as mountain ranges, seas or rivers may produce a barrier to gene flow. The inability of organisms or their gametes to meet leads to reproductive isolation and hence speciation.

(ii) Natural selection: The theory of 'Natural selection' states that there is "struggle for existence" within a population and variation exists within all populations of organisms. The continuous competition between individuals for environmental resources creates a 'struggle for existence' and this struggle makes sure that certain organisms would fail to survive or reproduce. This would eliminate less suited organisms and better adapted organisms would survive and pass on their traits to next generation, leading to evolution.

(iii) Genetic drift: Genetic drift is the variation in gene frequencies within populations that occur by chance (for example, by death of some members due to any natural calamity, or due to migration of some members to some different region). It leads to changes in allele and genotype frequencies of the remaining populations. After few generations, variations get accumulated in such populations, which may eventually lead to formation of new species.