Which of the following phenomena might have influenced the evolution of organisms? Select the correct answer using the code given below.

Answer: (c) Both 1 and 2

Both shaped evolution.

Statement by statement

1. ✓ YES Continental drift isolated populations (marsupials in Australia).

2. ✓ YES Glacial cycles forced migration, adaptation and extinction.

The idea

Evolution is affected when populations become isolated or their habitats change. Moving continents alter connections between lands and oceans; repeated ice advances alter climate and living space. Both can change which organisms survive, migrate and reproduce.

Land connection or climate changes → Habitats expand, shrink or split → Populations move or become isolated → Selection pressures and gene flow change → Over many generations, populations diverge

Why the others are wrong

(a) Drops glacial cycles.

(b) Drops continental drift.

Also know

Geographical isolation can lead to speciation, but it does not guarantee a new species every time. Land bridges can also reunite populations: low sea levels exposed Beringia between Asia and North America during ice-age periods. Refugia are places where organisms survive unfavourable climatic periods before spreading again.