For most, but not all groups of organisms, biodiversity increases from the poles to the tropics

• This is called a latitudinal gradient in species diversity

• Reason for this pattern is a mystery in ecology. Four hypotheses-none is sufficient to explain it alone.

• 1) greater productivity in tropics

• 2) history

• 3) complexity of habitats

• 4) less disturbance

Previous slide

Next slide

Back to first slide

View graphic version