Adaptive radiation refers to the process of diversification of ancestral line into different forms that occupy diverse ecological niche. The ancestral seed eating stock of Darwin’s finches diversified according to different types of food (plants, seeds, insects, cactus etc) available. They developed type of beak adapted to that food. The geographical isolation led reproductive isolation. Hence, many species of finches on the Galápagos Islands exhibit "adaptive radiation".
Answer; Adaptive radiation; The pattern of evolution that is shown by many species of finches on the Galapagos Islands is Adaptive radiation.
Explanation; Adaptive radiation is a pattern of evolution in which a single lineage undergoes multiple speciation events to fill divergent ecological niches. The result is a cluster of phenotypically distinct related species. A few million years ago, one species of finch migrated to the rocky Galapagos from mainland of Central or south America. From this one migrant species would come many species;-at least 13 species of finch, which exploit different niches, evolving from a single ancestor.
