The Living World Question 264
Question: Assertion : Darwin?s finches show a variety of beaks suited for eating large seeds, flying insects and cactus seeds. Reason : Ancestral seed-eating stock of Darwin?s finches radiated out from South American mainland to different geographical areas of the Galapagos Islands, where they found competitor-free new habitats. [AIIMS 2005]
Options:
A) If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B) If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C) If the assertion is true but the reason is false
D) If both the assertion and reason are false
Show Answer
Answer:
Correct Answer: A
Solution:
Darwin finches are an excellent exmaple of the way in which the species gene pools have adapted in order for long term wurvival via their offspring.
Finches were formed due to divergent evolution (Adaptive radiation) to avoid interspecific competition.
The common birds of Galapagos islands, the finches were markdly different from the finches of main land.
The closely related species of finches had beak of different shapes and sizes, and adapted for feeding on completely different diets.
Darwin also found that fossils of Galpagos islands are most similar to living species of South America.
The food supply increases in arithmetic ratio but the population increases in geometric ratio.
With the study of this theory it struck to Darwin that there is struggle for existence among plants and animals.
BETA
