Question

Analyse the illustration and answer the following questions.
(a) What happens to finches in A and B categories in terms of survival ?
(b) What will happen to the population of finches that survive ?
(c) How can these changes in survival lead to the formation of new species of finches ?

Hint:

Natural selection means organisms with useful adaptations survive and reproduce more, gradually leading to evolutionary change and sometimes new species.

Answer 1

Step 1: Understanding the illustration.
The diagram shows finches of Galapagos Island divided into two groups. Group A has finches with beaks suitable for the available food, while Group B has finches with beaks not suitable for the available food. This represents natural selection.
Step 2: Survival of A and B categories.
Finches in A category will survive better because their beaks are adapted to the available food source. Finches in B category will have less chance of survival because their beaks are not suitable for obtaining food efficiently.
Step 3: Effect on the surviving population.
The finches that survive will reproduce and increase in number. As a result, the population will gradually contain more individuals with favourable beak characteristics.
Step 4: Role in formation of new species.
Over many generations, these favourable traits are inherited and become more common in the population. Continuous selection, variation, and adaptation to different food habits can make the group more and more distinct from the original population.
Step 5: Conclusion.
Thus, natural selection favors finches with suitable beaks, increases their population, and over a long period can lead to the evolution and formation of new species of finches.