Oxygen – we all need it, we can't live without it. It's integral to life on this planet. And it's probable that, as you watch this film, you will be breathing in an oxygen atom that was also breathed by Genghis Khan – or by the first ever apes to stand upright on the plains of Africa. The oxygen that we breathe is made from two oxygen atoms joined together – O2. They were first joined more than 3 billion years ago by the earliest blue-green algae to evolve. The oxygen molecule first came from bacteria and was present in the fires that destroyed the dinosaurs and the chemical reactions in all human cells, and as ozone they protect the earth from radiation. Since then, both together and apart, they've had the most extraordinary adventures. Each of the two atoms in an oxygen molecule is virtually indestructible – so they have been first-hand players in some of the most dramatic events in the whole of Earth's history. It's often said that we are breathing the same oxygen that the cavemen did. The life of a single molecule of oxygen is traced on it's astonishing journey spanning millions of years, from its creation, into photosynthesis, through the age of the dinosaurs, early man, and on into today.
In nature, living long enough to breed is a monumental struggle. Many animals and plants go to extremes to give themselves a chance. Uniquely, three brother cheetahs band together to bring down a huge ostrich. Aerial photography reveals how bottle-nosed dolphins trap fish in a ring of mud, and time-lapse cameras show how the Venus flytrap ensnares insect victims. The strawberry frog carries a tadpole high into a tree and drops it in a water-filled bromeliad. The frog must climb back from the ground every day to feed it. Fledgling chinstrap penguins undertake a heroic and tragic journey through the broken ice to get out to sea. Many can barely swim and the formidable leopard seal lies in wait.
The Luangwa Valley in Zambia experiences one of the toughest dry seasons imaginable. Seven months with no rain and spiralling temperatures. And with this year’s El Nino conditions the drought is threatening to be even more intense than usual.