Lake victoria, in the african rift valley, is home to hundreds of species of cichlid fishes, each with slightly different diets and habits. all these fishes probably evolved from one or a few ancestors within the past 100,000 years, making them an example of

Adaptive radiation

Explanation:

Adaptive radiation is usually defined as a pattern of evolution that occurs in many of the organisms from a common ancestor. This type of evolution is faster than the usual evolution pattern. During the time of adaptive radiation, some type of living species leaves their habitat area and migrates into a new environment, resulting in some changes in them, that help them to survive in the new area.

For example, the cichlid fishes existing in the Lake Victoria, in the African Rift valley undergone evolution from a particular ancestor over the last 100,000 years. This shows an example of adaptive radiation.