Factors influencing evolution UPSC Prelims PYQ 2014

Which of the following phenomena might have influenced the evolution of organisms?

1. Continental drift
2. Glacial cycles

Select the correct answer using the code given below.

1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Explanation

Both phenomena are correct

• The movement of tectonic plates caused geographic isolation, speciation (e.g., distinct fauna in South America and Africa), and habitat changes, forcing species to adapt or migrate.
• Glacial Cycles: Ice ages caused climate fluctuations and habitat fragmentation, isolating populations for independent evolution. Glacial retreats allowed recolonisation, fostering adaptation and biodiversity.

Answer: (c) Both 1 and 2; Difficulty Level: Easy