Dr Adam Rutherford tells the extraordinary story of the scientific quest to discover the secrets of the cell and of life itself. Every living thing is made of cells, microscopic building blocks of almost unimaginable power and complexity. The first part explores how centuries of scientific and religious dogma were overturned by the earliest discoveries of the existence of cells, and how scientists came to realize that there was, literally, more to life than meets the eye.

Fourth episode examines how plants either share environments harmoniously or compete for dominance within them. Attenborough highlights the 1987 hurricane and the devastation it caused. However, for some species, it was that opportunity for which they had lain dormant for many years. The space left by uprooted trees is soon filled by others who move relatively swiftly towards the light. The oak is one of the strongest and longest-lived, and other, lesser plants nearby must wait until the spring to flourish before the light above is extinguished by leaves. Tropical forests are green throughout the year, so brute force is needed for a successful climb to the top of the canopy: the rattan is an example that has the longest stem of any plant. As its name suggests, the strangler fig 'throttles' its host by growing around it and cutting off essential water and light. Some can take advantage of a fallen tree by setting down roots on the now horizontal trunk and getting nutriment from the surrounding moss and the fungi on the dead bark. The mountain ash (eucalyptus regnans) grows so tall, that regeneration becomes a considerable problem. It is easily flammable, so its solution is to shed its seeds during a forest fire and sacrifice itself. It therefore relies on the periodic near-destruction of its surroundings in order to survive. Attenborough observes that catastrophes such as fire and drought, while initially detrimental to wildlife, eventually allow for deserted habitats to be reborn.

This episode explores the palaeogeography of Earth over millions of years, and its impact on the development of life on the planet. Tyson starts by explaining that the lignin-rich trees evolved in the Carboniferous era about 300 million ago, then explains on the nature of plate tectonics that would shape the landmasses of the world and the asteroid impact that initiated the Cretaceous–Paleogene extinction event, leaving small mammals as the dominate species on earth. Earth's landmasses are expected to change in the future and postulates what may be the next great extinction event.

In a far cry from the steamy jungles of Rwanda or the icy waters of the Arctic, British naturalist Sir David Attenborough has donned a necktie and met with US president Barack Obama to discuss climate change and the future of the planet. The two met at the White House — a place the naturalist had never yet explored — on Sir David's 89th birthday in May to film the interview". It was the first time the respected wildlife filmmaker had met an American president and he seemed a little awed by the experience. Mr Obama, who grew up watching Sir David's programs, seemed equally thrilled. The president has the environment and climate change on his radar and is anxious to see progress made as his presidency comes to a close. He faces stiff opposition from Republicans in Congress on his plans to tackle climate change, but remains determined to make changes before leaving office. "I don't have much patience for anyone who denies that this challenge is real," he said. "We don't have time for a meeting of the Flat Earth Society." Sir David, who has been called "the godfather of natural history TV" by the BBC, brought to the meeting six decades dedicated to sharing the wonders of the natural world with television audiences. After initially being rejected for television because his teeth were deemed "too big", Sir David went on to make his Life on Earth television series, which has been watched by more than 500 million people worldwide. His name is now synonymous with nature, conservation and wildlife. During the television interview, the men discussed global warming, renewable energy and how children and young people hold the key to reversing the damage.

From the Philippines to the US, Madagascar and Mexico, Professor Brian Cox explores the globe to reveal how a few fundamental laws of science gave birth to the most complex and unique feature of the universe - life. In the first episode, Brian journeys to the volcanic landscapes of South-East Asia, seeking to understand how life first began and how that spark has endured to this day.

Grasslands feed the world. Over thousands of years, we humans have learned to grow grains on the grasslands and domesticate the creatures that live there. Our success has propelled our population to almost seven billion people. But this episode reveals that, even today, life in the 'Garden of Eden' isn't always rosy. We walk with the Dorobo people of Kenya as they bravely attempt to scare off a pride of hungry lions from their freshly caught kill. We gallop across the Steppe with extraordinary Mongolian horsemen who were 'born in the saddle'. And in a perfect partnership with nature built up over generations Maasai children must literally talk to the birds! The honeyguide leads them to find sweet treats, but they'll have to repay the favour.