AMPHIBIANS

"The 4,000 or so species of the amphibians include salamanders, frogs, toads, and the limbless caecilians. They occupy a variety of freshwater and terrestrial habitats. Frogs are by far the largest group, and most are found in tropical rain forest. Salamanders, on the other hand, are primarily found in the temperate zones. Amphibians play key roles as predators in aquatic and terrestrial ecosystems, and the chemicals in their skins are increasingly being investigated for new pharmaceuticals. The poison arrow frogs in front of you are good examples. Unfortunately, amphibians, especially frogs, have suffered major and mysterious declines in recent years. Much of the evidence points to an increase in ultraviolet radiation that has accompanied the loss of atmospheric ozone, but other factors such as pollution have also been implicated."