Final answer:
The greatest biological diversity is found along the equator due to factors like the greater age and stability of tropic ecosystems, higher energy input, and more complex habitats which provide numerous ecological niches, leading to increased speciation and biodiversity.
Step-by-step explanation:
The greatest biological diversity is expected to be found along the equator. This pattern is consistent across various taxonomic groups and is one of the oldest observed patterns in ecology.
Factors contributing to this include the greater age of the ecosystems in the tropics, the higher energy input from the sun, the increased habitat complexity and the perceived stability of tropical climates. All of these factors may contribute to a higher rate of speciation and more ecological niches, thus greater diversity.
Why is biodiversity lower in temperate and polar regions?
Temperate and polar regions have less biodiversity than tropical regions due to factors like the relatively recent recolonization following the last ice age, which means less time for species development, and pronounced seasonality in climate and day length, which can be a stressor for many species. In contrast, the stability and complexity of tropical ecosystems promote biodiversity and speciation.