The phenomenon of evolution of different species in a given geographical area starting from a point and spreading to other habitats is called:

The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation. or When because of the competition for food and living space, a single ancestral species evolves into different species/forms which occupy different habitats (areas), it is called the adaptive radiation.

Example: Darwin finches and Australian marsupials