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

  1. Continental drift
  2. Glacial cycles

Select the correct answer using the codes given below

  • 1 only
  • 2 only
  • Both 1 and 2
  • Neither 1 nor 2

Answer: (c) Both 1 and 2

Continental drift theory
  • Continental drift is the hypothesis that the Earth’s continents have moved over geologic time relative to each other, thus appearing to have “drifted” across the ocean bed.
  • Continental drift theory deals with the distribution of the oceans and the continents.
    • According to the theory, all the continents formed a single continental mass- Pangea and mega ocean- Panthalassa surrounded it.
    • Pangaea started splitting and broke down into two large continental masses as Laurasia and Gondwanaland forming the northern and southern components respectively.
    • Subsequently, Laurasia and Gondwanaland continued to break into various smaller continents that exist today.
  • The Continental drift must have moved some animals from one continent to others and few getting stuck in the same place, which must have influenced the evolution.
Continental drift theory
Glacial cycles 
  • A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances.
    • Interglacials, on the other hand, are periods of warmer climate between glacial periods.
  • Glacial cycles would affect evolution as many might not able to tolerate extreme cold and would have extincted.
    • The rise in sea level due to glacial melt also might have affected the evolution of organisms.