Generating more questions
The data we've seen help explain the LDG, but they also inspire new questions. For example, we know that higher rates of speciation may play a role in generating the LDG but what causes those higher speciation rates? Latitude alone can't explain it. After all, latitude is just a number that we humans have assigned to regions of Earth. There must be some set of environmental, biological, or evolutionary factors at work in the tropics that cause increased speciation rates there, or some other factors that cause decreased speciation elsewhere.
We can ask similar questions about the underlying cause of the speciation and migration patterns we studied. Why are tropical species protected from extinction? Is there some special characteristic of tropical species or tropical environments that allows or encourages these species to spread out of the tropics?
Scientists have come up with many hypotheses that might help answer these questions and so can you! Work with your class or other students to answer this last question.