Rainforests contain around 50% of all life on Earth and only take up 6% of the Earths surface area. It contains more species of plant and animals than any other ecosystem. It's climate and geography lend it to growing more plant life which sustains many small animals. The arctic is inhospitable to most species because of the extreme cold. It's food webs do not sustain themselves well as there are fewer species at the bottom the the chain. The genetic variations are greater at the equator than the arctic giving the organisms a greater chance to survive.
