Question

The presence of different types of beaks in finches of Galapagos islands adapted to different feeding habits provides evidence for:
(A) Intraspecific variations
(B) Adaptive radiation
(C) Intraspecific competition
(D) Interspecific competition

Answer 1

Different types of beaks in finches of Galapagos islands state that organisms are changed from ancestral species to the new one to survive in different environmental situations.

Complete answer:
Darwin's finches clearly explain the process of Adaptive radiation. There were different species of finches derived from the same ancestors. This adaptive radiation is necessary for survival.
There were 18 different species of birds. They all were different as there is diversity in their beaks. For example, ground finches have the thickest beak as they feed on seeds and have to break the seed for food. Cactus finches have longer beaks as it helps them to feed on nectar and pollen of cactus. The warbler-finches have short and sharp beaks as they feed on insects. These Darwin finches also differ in their size and type of feathers. Some are short and some are long. Similarly, some have black feathers and some have grey feathers.
Adaptive radiation leads to speciation. Speciation is an evolutionary process that leads to the formation of distinct species.
There was a need for speciation because as population increases, the source of food decreases and if evolution will not take place, the species may become extinct due to scarcity in food requirements.
Or evolution also takes place if ancestral species is transferred to some new environmental conditions.
So, the correct answer is ‘(B) Adaptive radiation’.

Note: Environmental factors are the most important reason for change seen in ancestral species. This leads to a change in species morphologically as well as physiologically.