Question

Match List-I with List-II.
$\begin{array}{cccc}& \text{List-I}& & \text{List-II}\\ \text{(a)}& \text{Adaptive}& \left(i\right)& \text{Selection of resistant}\\ & \text{radiation}& & \text{varieties due to excessive use of herbicides and}\\ & & & \text{pesticides}\\ \text{(b)}& \text{Convergent}& \left(ii\right)& \text{Bones of forelimb in Man}\\ & \text{evolution}& & \text{and Whale}\\ \text{(c)}& \text{Divergent}& \left(iii\right)& \text{Wings of Butterfly and}\\ & \text{evolution}& & \text{Bird}\\ \text{(d)}& \text{Evolution by}& \left(iv\right)& \text{Darwin Finches}\\ & \text{anthropo}& & \\ & \text{genic action}& & \end{array}$

Choose the correct answer from the options given below.

• A. a - i, b - iv, c - iii, d - ii
• B. a - iv, b - iii, c - ii, d - i
• C. a - iii, b - ii, c - i, d - iv
• D. a - ii, b - i, c - iv, d - iii

Answer 1

The correct option is B a - iv, b - iii, c - ii, d - i

(a) Darwin, during his voyage, reached the Galapagos Islands. He observed small black birds with modified beaks in the islands which shows adaptive radiation. These are called Darwin's finches, assumed to have originated from a common seed eating ancestor. Adaptive radiation is the formation of new species from a common ancestor by adapting to a specialized mode of life due to different geographical habitats.

(b) Wings of butterfly and of birds are analogous structures. The structures that are not anatomically similar but perform similar function are called analogous structures. Analogous structures are a result of convergent evolution - different structures evolving for the same function and hence having similarity.

(c) When the same structure develops along different directions due to adaptations to different needs, it is called divergent evolution and these structures are called homologous structures.
The forelimbs of man and flippers (modified forelimbs) of whales are homologous organs. Both animals share similarities in the pattern of bones of forelimbs but have different functions. In man, forelimbs are used for holding, grasping and writing while it is used for swimming in whales.

(d) Anthropogenic actions refer to the activities that are caused by human beings. It has commenced the evolution of a number of new species in a short time. This hastens the method of evolution.

Example: excessive use of herbicides and pesticides has resulted in selection of resistant varieties in a much lesser time.