Evolution — NCERT Solutions

One example of adaptive radiation is the case of Darwin’s finches on the Galapagos Islands. From an original seed-eating ancestor, many different finches evolved on the islands. Their beaks changed in different ways so that some became insect-eating and others plant-eating. This is adaptive radiation because one ancestral species gave rise to many species in a particular geographical area, each adapted to a different niche.

Human evolution is not called adaptive radiation in the chapter. Adaptive radiation means the evolution of different species from a common ancestor in a given geographical area to fit different habitats, as in Darwin’s finches or Australian marsupials. Human evolution is described as the evolution of one lineage leading to modern humans, not the branching into many different species adapted to different ecological niches in the same way.