Narrator: This is Science Today. One of the biggest questions facing ecologists today as they try to understand the natural world is, why are ecosystems so diverse and what happens when we damage or destroy that diversity? Christopher Wills, a professor of biology at the University of California , San Diego has explored that very question in a recent study of tropical forests worldwide.
Wills: We're looking at rainforests around the world in both the New and Old World tropics where the ecosystem is more or less stable and they have achieved the kind of level of diversity that we tend to think of when we think of undisturbed tropical ecosystems. And our question was what happens to these systems over time?
Narrator: The researchers found that nature encourages diversity, since older trees are more diverse than younger ones.
Wills: The diversity really is reflected at every level of organization. There are many different kinds of animals, of birds, of insects. If you go further down towards what I call the invisible world, which underlies much of this diversity, you'll find a great diversity of fungi, of insects of various kinds, of bacteria, even of viruses.
Narrator: For Science Today, I'm Larissa Branin.