Question

What do you understand by geographical isolation? How is this mechanism responsible for speciation?

Answer 1

Geographical isolation: It is the prevention of the gene flow among the group of population separated by a geographical barrier such as a river or a mountain.

Speciation: Speciation is the process through which new species arise from the existing species.

Geographical barrier causes speciation:

• The geographical barrier like the mountain acts as a barrier in reproduction.
• Since the populations on two sides of the mountain will not be able to physically meet each other, they will not interbreed either.
• There will be no sexual reproduction or gene flow between two populations present on two different sides of the mountain.
• Thus, reproductive isolation will eventually separate these two populations.
• The populations on either side will respond to the changes in the physical environment and develop new variations. This will lead to the formation of new species.
• After a long time, the members of these isolated populations cannot reproduce even if they meet again.