What are Variations?
Variations are the differences between cells, individual organisms, or groups of organisms of any species.
For example,
Variation in a single population of frogs gave rise to a yellow coloured frog. These frog species move and migrate to a new place, where numerous possibilities of an altogether different variation exist. When the existing species of the new place will mate with the migrant frog, they will produce offspring with vast DNA changes.
What is Isolation and Genetic Drift?
Isolation is a process by which two species are not able to interbreed. Several instances of cross-breeding led to a Genetic Drift.
For example,
The migrant frog brought in a set of genes which flowed into the population of a new place. As time passed by, these frogs were isolated and formed a new gene pool altogether. The genetic flow caused a great variation in the future generations and mating with frogs of the same area became impossible.
Process of natural selection started taking place differently in two sectors as they were separated by nature. These changes over a while gave rise to a new species of frogs. The genes and the DNA of the two frogs are very different from each other. They cannot breed with each other as their genes are not compatible anymore. Thus, a new species emerged after variation and isolation.
This phenomenon is called Genetic Drift which creates new species and this is called
Speciation.