Evolution Assertion Reason Based Questions

The following questions consist of two statements, one labelled as Assertion (A) and the other labelled the Reason ®. Examine these two statements carefully and select the most appropriate answer codes.
A. Assertion and reason both are correct and reason is the correct explanation of Assertion.
B. Assertion and reason both are correct and reason is not the correct explanation of Assertion.
C. Assertion is correct but reason is wrong.
D. Both Assertion and Reason are false.

1. Assertion: The first formed Earth originally had reducing atmosphere.
   Reason: Hydrogen was abundant and their was no free oxygen.
2. Assertion: The first living organisms were heterotrophs.
   Reason: Hot dilute soup was formed in the ocean.
3. Assertion: Some babies are born with tail.
   Reason: Vestigial organs support the concept of organic evolution.
4. Assertion: Natural selection is the outcome of difference in survival and reproduction among individuals that show variation in one or more traits.
   Reason: Adaptive forms of a given trait tend to become more common while less adaptive ones become less common or disappear.
5. Assertion: Adaptive radiation results in Cladogenesis.
   Reason: Adaptive radiation results in convergent evolution.
6. Assertion: Black coloured Biston bitularia are abundant due to industrial pollution.
   Reason: Natural selection of darker forms occur in response to industrial pollution.
7. Assertion: Most common struggle for existence is intraspecific.
   Reason: All the members of a species have same food, shelter and mate.
8. Assertion: Interspecific struggle is not severe.
   Reason: In between the different species of animals, the fighting is severe for food and shelter only.
9. Assertion: Amphibians have evolved from fishes.
   Reason: Archaeopteryx is a fossil linking fishes and amphibians.
10. Assertion: Gene flow increase genetic variations.
    Reason: The random introduction of new alleles into recipient population and their removal from the donor population affects allele frequency.
11. Assertion: The long neck of giraffe is due to centripetal selection.
    Reason: During directional selection when the mean value of phenotype coincides with new optimum environmental conditions, centripetal selection takes over.
12. Assertion: The concept of survival of the fittest is central to natural selection.
    Reason: Individuals who possess advantageous characters to adapt to the environment have better potential for survival.
13. Assertion: Population of a species inhabiting different geographical areas are in a continuous process of adaptation to their surrounding environments and this lead to the evolution of new species.
    Reason: Geographical barriers obstruct interbreeding of populations of a species leading to reproductive isolation and evolution of new species.
14. Assertion: The thorns and tendrils of Bougainvillea and Cucurbita represents homology.
    Reason: Both these structures arise in the axillary position.
15. Assertion: Among the primates, chimpanzee is the closest relative of the present day humans.
    Reason: The banding pattern in the Autosome number 3 and 6 of man and chimpanzee is remarkably similar.

Answer Sheet

1. A
2. B
3. B
4. A
5. C
6. A
7. A
8. A
9. C
10. B
11. A
12. A
13. A
14. A
15. A