Question

What is so special about tropics that might account for
their greater biological diversity?
a. Unlike temperate regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.
b. Temperate environments, unlike tropical ones, are
less seasonal, relatively more constant and predictable. Such constant environments promote niche specialisation and lead to a greater species diversity.
c. There is more solar energy available in the tropics, which contributes to higher productivity, this in turn might contribute indirectly to greater diversity.

• A. a and c
• B. a, b and c
• C. b and c
• D. a only

Answer 1

The correct option is A a and c

Glaciations

• The environmental conditions in the tropics have remained constant since a very long time whereas the temperate region has often experienced extreme disastrous events such as glaciations.
• This has allowed the organisms living in the tropics to evolve undisturbed over a long period of time which has led to greater species diversification.
• Thus the tropics have greater biodiversity than the temperate regions and statement ‘a’ is correct.

Seasonal changes

• The seasonal changes in the tropics are much less compared to the temperate zones.
• The climate in the tropics remains warm and humid throughout the year without any extreme changes.
• This allows organisms to specialise the niche (role played by an organism in its ecosystem) they belong to and promote better species diversification in the tropics. Thus statement ‘b’ is incorrect.

Productivity

• As the tropics receive a constantly high amount of overhead sunlight throughout the year, the photosynthetic productivity in these regions is high.
• Hence availability of food and energy for all life forms is high which can indirectly promote higher diversity in life forms in the tropics. Thus, statement ‘c’ is correct.

Final answer

(C) a and c