Final answer:
When two groups within a population become reproductively isolated within the same geographic area, this often leads to speciation, the formation of a new species through processes like allopatric or sympatric speciation.
Step-by-step explanation:
When two groups within a population become reproductively isolated within the same geographic area, it may result in speciation. Speciation can occur along two main pathways: allopatric speciation, which involves geographic separation, and sympatric speciation, which occurs without physical separation but through other mechanisms such as behavioral differences. Reproductive isolation is necessary for speciation to occur because it enables the populations to diverge and evolve independently of one another. One example is the divergence of a cricket population that was separated after a flood, leading it to reproductive isolation and eventually potential speciation over time due to natural selection, mutation, and genetic drift.