Which type of speciation occurs when new species form in populations that inhabit the same geographic area?

Sympatric speciation is the correct answer because it describes the process by which new species evolve from a single ancestral species while inhabiting the same geographic area. This type of speciation occurs without the physical separation of populations and is often driven by factors such as reproductive isolation due to behavioral changes, ecological niche differentiation, or polyploidy in plants.

In sympatric speciation, members of the same population can become genetically distinct as a result of changes in their mating preferences, feeding behaviors, or habitat use. This can ultimately lead to a divergence into separate species even though they occupy the same environment and are capable of interbreeding.

The other types of speciation involve physical barriers or distinct habitats that lead to genetic divergence. In peripatric speciation, a small population becomes isolated at the edge of a larger population's range. Allopatric speciation occurs when populations become geographically separated, leading to the development of distinct species due to isolation. Parapatric speciation happens when two populations are separated by a gradient or slightly different environments but still partially interbreed. In contrast to these, sympatric speciation illustrates how species can emerge and evolve in a shared geographic space through mechanisms other than geographic separation.