In order to survive and reproduce, each organism must adapt to its physical environment, as well as to the other organisms in that environment it shares relationships with. As you dive through Australia's Great Barrier Reef in this Evolution Web feature, you'll discover relationships that have evolved between the resident organisms. Some are predators and prey; others compete for space, food, or mates; and still others are dependent or codependent on each other.
© 2015 PBS & WGBH Educational Foundation. All rights reserved.