Give three hypotheses for explaining why tropics show greatest levels of species richness.

Question

The diversity of living organisms present on the Earth is very vast. According to an estimate by researchers, it is about seven millions.
The total number of species present in the world is calculated by ecologists by statistical comparison between a species richness of a well-studied group of insects of temperate and tropical regions. Then, these ratios are extrapolated with other groups of plants and animals to calculate the total species richness present on the Earth.

Answer 1

There are three different hypotheses proposed by scientists for explaining species richness in the tropics.

•  Tropical latitudes receive more solar energy than temperate regions, which leads to high productivity and high species diversity.
•  Tropical regions have less seasonal variations and have a more or less constant environment. This promotes the niche specialization and thus, high species richness.
•  Temperate regions were subjected to glaciations during the ice age, while tropical regions remained undisturbed which led to an increase in the species diversity in this region.