Question

Short answer type question

Tropical regions exhibit species richness as compared to polar regions. Justify.

Answer 1

i. Factors like overall stability of tropical regions for millions of years, lesser climatic changes throughout the year, and availability of plenty of sunlight have favoured speciation.

ii. Tropical areas have less often experienced drastic disturbances like periodic glaciations observed at poles. Such stability over millions of years might have favoured speciation.

iii. Lesser migrations in tropics might have reduced gene flow between geographically isolated regions and favoured speciation.

iv. Scientists also have considered the availability of more intense sunlight, warmer temperatures and higher annual rainfall in tropics, as factors responsible for the bountifulness of these regions.

v. Some animals enjoy food preferences under climatic conditions and abundance of resources. e.g. Fruits being available throughout the year in rain forests, a variety of frugivorous organisms is obviously more as compared to the temperate regions.

vi. In short, species richness or diversity for plants and animals decreases as we move away from the equator to the poles. It is maximum in tropical rain forests.

e.g. Amazon rain forest (40,000 plants, 1300 birds, 427 mammals, 3000 species).

Hence, tropical regions exhibit species richness as compared to polar regions.