What triggered the incredible diversity of life on Earth, and how have complex life forms, including humans, evolved? Is there direction to evolution? And is human intelligence inevitable? This program focuses on evolution's 'great transformations' —among them the development of a standard four-limbed body plan, the journey from water to land, the return of marine mammals to the sea, and the emergence of humans. Driven by a combination of opportunism and a genetic 'toolkit', these astounding leaps forward define the arc of evolution. And they suggest that every living creature on earth today, and every species that has ever existed, is a variation on a grand genetic theme—a member of one, and only one, tree of life

Is mankind alone, or are there aliens out there, either waiting to be discovered, or on their way to find Earth? Professor Brian Cox spends this episode asking such questions, and what he discovers may raise a few eyebrows. He begins by exploring the human race's efforts to find neighbours in outer space, including the launch of two golden discs containing a greeting from Earth in the 1970s; they are still travelling and are now the most distant man-made objects from the planet. Brian also meets members of the Search for Extra-Terrestrial Intelligence, who have been monitoring radio signals for 50 years without success, before discussing the ingredients needed to make an intelligent civilisation with astrophysicist Dr Frank Drake.

Human Planet is a majestic portrait of humankind and the power of nature in extraordinary symbiosis, struggle and strife. For the first time, the camera has turned on ourselves. In doing so, we see how amazing human beings can be and how we adapt to any habitat, anywhere. Human Planet is epic in ambition, extreme in content, intimate in effect. It explores how we have devised ways of surviving in every corner of Earth – from the remotest deserts to the busiest urban metropolis. Each episode focuses on an iconic environment and reveals how we have adapted to the challenges of the landscape and the endless diversity of animals and plants we live with. Discover how our remarkable intelligence, tool use, and close-knit social lives have enabled us to cope with just about anything nature can throw at us". As an air-breathing animal, the human is not built to survive in water. But people have found ways to live an almost aquatic life so they can exploit the sea's riches. From a 'shark-whisperer' in the Pacific to Brazilian fishermen collaborating with dolphins to catch mullet, this journey into the blue reveals astonishing tales of ingenuity and bravery. Daredevil Galician barnacle-collectors defy death on the rocks for a catch worth 200 pounds per kilo. In Indonesia an epic whale-hunt, using traditional hand-made boats and harpoons, brings in a sperm whale. The Bajau 'sea gypsies' of the Sulu Sea spend so much time on water they get 'land sick' when they set foot on the land! We dive 40 metres down to the dangerous world of the Pa-aling fishermen, where dozens of young men, breathing air through a tangled web of pipes attached to a diesel engine, capture thousands of fish in a vast net. We see how surfing has its origins in the ancient beliefs of the ocean-loving Polynesians, and we join a Borneo free-diving spear-fisherman on a breath-taking journey 20 metres down in search of supper.