Select the incorrect statement regarding adaptive radiation.

The correct answer is Option (2) → All varieties of finches were evolved from different geographical areas.

Adaptive radiation is the evolution of different species from one common ancestor in the same geographical area, spreading out into different habitats.

(1) Darwin’s finches represent one of the best examples of this phenomenon. — Correct statement. From the original seed-eating finch, forms with different beaks arose.

(2) All varieties of finches were evolved from different geographical areas. — Incorrect statement. All the varieties evolved on the same island from one ancestor. They did not come from different areas.

(3) It is a process of evolution of different species in a given geographical area starting from a point and radiating to other habitats. — Correct statement. This is the definition.

(4) Placental mammals in Australia also exhibit adaptive radiation in evolving into varieties of mammals. — Correct statement. Besides the marsupials, the placental mammals of Australia also radiated into many forms.

NCERT Extract:
What Is Adaptive Radiation? – “… Of particular interest, small black birds later called Darwin’s Finches amazed him. He realised that there were many varieties of finches in the same island. All the varieties, he conjectured, evolved on the island itself. From the original seed-eating features, many other forms with altered beaks arose, enabling them to become insectivorous and vegetarian finches (Figure 6.5). 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. Darwin’s finches represent one of the best examples of this phenomenon. Another example is Australian marsupials. A number of marsupials, each different from the other (Figure 6.6) evolved from an ancestral stock, but all within the Australian island continent. When more than one adaptive radiation appeared to have occurred in an isolated geographical area (representing different habitats), one can call this convergent evolution. Placental mammals in Australia also exhibit adaptive radiation in evolving into varieties of such placental mammals each of which appears to be ‘similar’ to a corresponding marsupial (e.g., Placental wolf and Tasmanian wolf-marsupial).”

Figure 6.5 Variety of beaks of finches that Darwin found in Galapagos Island