Question

explain three factor of speciation?

Answer 1

geographical isolation is the isolation of the species or individuals from others by the means of physical factors like rivers,mountains,big glaciers etc

genetic drift is the change in the allele frequency in the population due to random selection which is the basic mechanism of evolution

natural selection is the selection of the organisms who are better adaptive to the particular kind if environment by the nature and eliminating the organisms which are less adaptive to that environment

Answer 2

(i)    Genetic variation between individuals: There is a large amount of variation in the genes within a population. This genetic variation arises from random mutations in the DNA sequence.
(ii)  Natural selection: All populations respond to changes in their environment. Individuals will respond in different ways depending on their genes. 
(iii)Genetic drift: It is caused due to drastic changes in the frequencies of particular genes by chance alone. Genetic drift with changes in the gene flow imposed by isolation mechanism acts as an agent of speciation which ultimately results in evolution.
(iv)Geographical isolation: It is a major factor in speciation since it interrupts with gene flow. It may be rivers , mountain ranges or any other barriers