Friends in nature : discover earth's amazing ecosystems

"All living things in the natural world, from the trees and the bees to the dogs and the frogs, depend on one another. There wouldn't be a coral reef without the help of all the fish that have made it their home. Rain forests are only filled with lush and colourful plants because of the birds and mammals who eat and scatter their seeds. Acacia trees have a whole army of ants to protect them, while elephants rely on egrets to keep them parasite-fr...