Allopatric speciation occurs when a population is divided by a geographical barrier, leading to reproductive isolation and the formation of new species. Over time, genetic differences accumulate making interbreeding between the separated populations impossible even if they come back into contact.
Sympatric Speciation: Speciation that occurs without geographical separation within the same environment.
Reproductive Isolation: Mechanisms that prevent different species from interbreeding and producing fertile offspring.
Genetic Drift: A mechanism of evolution that causes random changes in allele frequencies in a population.