Question

How does a population become ‘founders’ of a new species?

Answer 1

When a section of the population migrates to another place, gene frequencies change in both the original and the new populations. New genes/alleles are added to the new population, whereas those in the old population are lost. There would be a gene flow if this gene migration happened multiple times. Sometimes the change in allele frequency is so significant in a new population sample that it becomes a different species. The original population drifts, and the effect is called the founder effect.