Occupying the same or overlapping geographic areas without interbreeding. Although they share the same geographic range, sympatric populations of related organisms become isolated from each other reproductively. This can happen by the development of subpopulations that become dependent on distinct food sources or that evolve distinct seasonal mating behavior. Flowering plants frequently become reproductively isolated through the development of polyploid hybrids (hybrids with three or more sets of chromosomes) that cannot backcross with either parent. ◇ The development of new species as a result of the reproductive isolation of populations that share the same geographic range is called sympatric speciation. Compare allopatric.