question_answer 60)

  Two organisms occupying a particular geographical area (say desert) show similar adaptive strategies. Taking examples, describe the phenomenon.

Answer:

                  This phenomenon indicated in the question is convergent evolution where by organisms, not closely related, evolve similar traits independently as a result of adaptation to similar environment, e.g., (i) Streamlined shape of sharks and dolphins. The former is a fish, while dolphin is amammal, but both of them depend on swift movement through the water, so a streamlined shape is essential. Thus it is the similar habitat that resulted in. selection of similar adaptive features in different groups of organisms, but toward the same function. (ii) Spines (modified leaves) and thorns (modified stems), both look similar and provide protection to the plant, but the plants to which they belong are distantly related.