We can still restore many of the world's lost ecosystems.

The American pronghorn can run so fast because it evolved to escape the American cheetah.The surviving animals live in ghost ecosystems adapted to threats from species that no longer exist.Today, it may be possible to resurrect those ghosts,to bring back lost species using genetic material.For instance, there's been research in to cloning woolly mammoths from frozen remains.But even if it's not possible,we can still restore many of the ecosystems the world has lost.