Question

1. Species richness changes with latitude. Using an example explain what the pattern looks like and how many species groups we see it in.

Answer 1

Species richness is one of the most important attribute of biodiversity. It tells about the number and distribution of the individuals belonging to a species living in an particular area. So, greater the species richness, higher will be the species variation in an area. However, species richness changes significantly with latitude. Species richness increases as we move from the poles to the equator and decreases on moving from equator to poles. This significant change in the number of species between poles and the tropical areas is known as latitudinal gradient. One of the most important reason behind this is altitude, which on 1000 m increase drops the temperature of that place by 6.5⁰C. As a result of this, species diversity decreases on moving from low altitude areas to high altitude areas.

The pattern of species richness with changing latitude is shown below-

Figure- General distribution and number of species according to the latitude

Example- Except for extremely harsh deserts, tropical areas hold maximum number of species because of their warm climate which makes it possible for the species to survive for longer period. This is because of more rainfall and adequate amount of food is available to the organisms living here. An example of this is tropical rain forests of Amazon where more than 430 mammal species are currently living and on the other hand, Antartica is home to only 23 mammalian species and all of them are marine species.