The animals and plants of India are very different from the species in nearby Southeast Asia. Why might this be true?
a. India was once covered by oceans and Asia was not.
b. India is in the process of separating from the rest of Asia.
c. Life in India was wiped out by ancient volcanic eruptions.
d. India was a separate continent until about 45 million years ago.

Verified step by step guidance

1. Understand the context of the question: The problem is asking why the species of animals and plants in India differ significantly from those in nearby Southeast Asia. This requires knowledge of biogeography and Earth's geological history.
2. Recall the concept of plate tectonics: Earth's crust is divided into tectonic plates that move over time. These movements can cause continents to drift apart or collide, influencing the distribution of species.
3. Consider the history of India's geological position: India was once part of the supercontinent Gondwana, which included Africa, South America, Antarctica, and Australia. Around 120 million years ago, India began to drift northward as a separate landmass.
4. Recognize the significance of India's isolation: While India was a separate continent, its flora and fauna evolved independently, leading to unique species. About 45 million years ago, India collided with Asia, forming the Himalayas and allowing some species exchange, but the distinct evolutionary history remained.
5. Evaluate the options: Based on the geological history, the correct explanation is that India was a separate continent until about 45 million years ago, which explains the differences in species between India and Southeast Asia.

Key Concepts

Plate Tectonics

Plate tectonics is the scientific theory that describes the large-scale movement of Earth's lithosphere, which is divided into tectonic plates. These plates float on the semi-fluid asthenosphere beneath them and can collide, separate, or slide past each other. This movement can lead to the formation of continents, mountains, and ocean basins, significantly influencing the distribution of species and ecosystems.

Biogeography

Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. It examines how historical events, such as continental drift and climate changes, have shaped the biodiversity of regions. Understanding biogeography helps explain why certain species are found in specific areas and how geographical barriers can lead to distinct evolutionary paths.

Evolutionary Isolation

Evolutionary isolation occurs when populations of organisms are separated by geographical barriers, leading to divergent evolution. This isolation can result in the development of unique species adapted to their specific environments. In the case of India, its historical separation from other landmasses allowed for the evolution of distinct flora and fauna, contributing to the biodiversity observed today.