Question

Given below are four statements (A-D) each with one or two blanks.
Select the option which correctly fills up the blanks.
Statements :(A) Wings of butterfly and birds look alike and are the results of ....(i).....evolution.
(B) Miller showed that $C{H}_4,H_2,N{H}_3$ and .... (i) ..., when exposed to electric discharge in a flask resulted in formation of ...... (ii)....
(C) Vermiform appendix is a .......(i)..... organ and an ...... (ii).... evidence of evolution.
(D) According to Darwin evolution took place due to ...... (i).... and .......(ii)..... of the fittest.

• A. (C) - (i) vestigial, (ii) anatomical; (D) - (i) mutations (ii) multiplication
• B. (D) - (i) small variation, (ii) survival; (A) - (i) convergent
• C. (A) - (i) convergent; (B) - (i) oxygen, (ii) nucleosides
• D. (B) - (i) water vapour, (ii) amino acids; (C) - (i) rudimentary (ii) anatomical

Answer 1

Answer: (B)

(D) - (i) small variation, (ii) survival; (A) - (i) convergent

Natural selection is the theory given by Darwin. It states that evolutionary change comes through the production of variation in each generation and differential survival of individuals with different combinations of these variable characters. The members of a species most fitted to the environment in which they live, have the better chance of reproduction and passing on their own genes. In the course of evolution, convergent evolution is the process, whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. Thus, the correct answer is option B.