In nature, living long enough to breed is a monumental struggle. Many animals and plants go to extremes to give themselves a chance.
Reptiles and amphibians look like hang-overs from the past. But they overcome their shortcomings through amazing innovation.
Birds owe their global success to feathers - something no other animal has. They allow birds to do extraordinary things.
There are 200 million insects for each of us. They are the most successful animal group ever. Their key is an armoured covering that takes on almost any shape.
Mammals' ability to learn new tricks is the key to survival in the knife-edge world of hunters and hunted.
Marine invertebrates are some of the most bizarre and beautiful animals on the planet, and thrive in the toughest parts of the oceans.