What is the main pattern observed in the distribution of species diversity worldwide?

Species diversity decreases from the equator towards the poles.

b) Species diversity decreases from the equator towards the poles is the correct option .

The main pattern observed in the distribution of species diversity worldwide is that species diversity generally decreases as we move away from the equator towards the poles. This phenomenon is known as the "latitudinal gradient in diversity."

In tropical regions, which have a latitudinal range of 23.5° N to 23.5° S, there is a higher concentration of species compared to temperate or polar areas. For example, the largely tropical Amazonian rainforest in South America is known to have the greatest biodiversity on Earth, with a vast number of plant and animal species.

As we move towards the poles , the number of species tends to decrease. The polar regions, such as Greenland at 71° N, have significantly fewer species compared to the tropical regions. For instance, Greenland has only 56 species of birds, while Colombia, located near the equator, has nearly 1,400 species of birds.

The latitudinal gradient in diversity is a well-documented ecological pattern, and several factors contribute to this phenomenon. Some proposed hypotheses include longer evolutionary time and less disturbance in tropical latitudes, which allow for more speciation and species diversification. Additionally, constant and less seasonal environments in the tropics may promote niche specialization and lead to a greater variety of species.

Overall, the latitudinal gradient in diversity is an important aspect of global biodiversity distribution and has significant implications for understanding the ecological dynamics and conservation priorities across different regions of the world.