Explain adaptive radiation with the help of a suitable example.

Adaptive radiation is the process of evolution of different species in a given geographical area from a point and spreading or radiating to other geographical area or habitats. For example Drawin's finches / black birds (on Galapagos islands), evolved from original seed eating features, into insectivorous & vegetarian features in different habitat / island.

Detailed Answer : 

Darwin during his journey to Galapagos Islands observed that there were many varieties of small black birds later called Darwin's finches. 

(i) All the varieties he conjectured, evolved on the island itself. 

(ii) From the original seed-eating features, many other forms with altered beaks arose, enabling them to become insectivorous and vegetarian finches. This 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.

Adaptive Radiation 

▪ It is the evolutionary process in which different species starting from a common point in a geographical area radiate to other geographical areas. Examples: 

i. Darwin’s finches 

• Darwin observed many varieties of finches in the same island. 

• All varieties had evolved from original seed-eating finches. 

• With alteration in beaks some became insectivorous and some vegetarian.