Previous Year Question
Which of the following phenomena might have influenced the evolution of organisms?
Continental drift
Glacial cycles
Select the correct answer using the code given below.
Correct Answer: C
Detailed Solution
Continental drift—Correct: When continents separated, populations that had previously lived together became geographically isolated. Gene flow between them declined, while natural selection under different environmental conditions produced different adaptations and new species. Conversely, continental collisions enabled organisms to disperse into new regions, changing competition and predator–prey relationships. Continental drift also altered climates, ocean currents and habitats.
Glacial cycles—Correct: Alternating glacial and interglacial periods produced major changes in temperature, precipitation, vegetation, ice cover and sea level. Expanding glaciers contracted or fragmented habitats, while falling sea levels exposed land bridges. When glaciers melted, sea levels rose and populations became isolated again.
These changes compelled organisms to migrate, adapt or become extinct. Genetic divergence among isolated populations could also produce speciation.
Thus, both continental drift and glacial cycles influenced the distribution and evolution of organisms.