Overview:Examine the paradox of whales, penguins, iguanas and dolphins that inherited a burdensome legacy from their land-dwelling ancestors: they must breathe in open air. Visit the Galapagos Islands, where evolution still experiments with life's ebb and flow between land and sea. Off the South American coast, witnesses an orca whale family teach their young the art of beaching to hunt sea lions. On the Antarctic ice, emperor penguins care for their land-locked baby chicks.