In episode two, Fortey focuses on the 'KT boundary'. 65 million years ago, a 10 km diameter asteroid collided with the Earth and saw the end of the long reign of the dinosaurs.

It is estimated that 99 per cent of species have become extinct and there have been times when life's hold on Earth has been so precarious it seems it hangs on by a thread.

Series in which mathematician Marcus du Sautoy explores the stories behind some of the world's most familiar and influential scientific diagrams.

David Attenborough narrates a natural history of the oceans

Wildlife documentary looking in particular at the elusive Blue whale, and following a Grey Whale and her newborn calf as they are pursued by Killer whales

2007. A thousand metres down, in the twilight zone, animals play a constant game of hide and seek.

2007. An unfortunate shoal of sardines is first attacked by three-metre-long striped marlin with metre-long, needle-sharp javelins on their heads. The commotion attracts juvenile yellowfin tuna and then a 14-metre Sei whale scoops up the remains.

2007. In winter the temperature drops to below -50 degrees centigrade and in Antarctica most animals escape the weather. But emperor penguins stay put and huddle together, incubating their eggs and rearing their chicks in the worst weather on the planet. Weddell seals also remain, keeping their breathing holes open by scraping away the ice with their teeth.

This next instalment is about coral reefs, which are so crowded that they play host to a perpetual battle for space, even among the coral itself. It starts life as a larva that becomes a polyp. Having multiplied, it hardens into a limestone skeleton and grows to form a reef. As the community flourishes, animals develop relationships with one another and such a place can feature a huge variety of ocean life.

This programme surveys the effects of the seasons on the world's temperate seas — the most productive on Earth.

2007. A huge tidal wave, sweeps 200 miles inland up the River Amazon. It's an event that only happens on key days each month, when the moon and sun combine their gravitational pull to maximum effect. The force of the wave shatters immense rainforest trees.

2007. Each year the entire population of green turtles that live off the coast of Brazil undertakes a massive 5,000-mile migration to the tiny seven-mile-wide island of Ascension, lost in the middle of the Atlantic.

In a three-part series, 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. This episode explores how scientists delved ever deeper into the world of the cell, seeking to reveal the magic ingredient that can spark a bundle of chemicals into life.

In a three-part series, 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 final part reveals how our knowledge of cells has brought us to the brink of one of the most important moments in history.

The film is an unvarnished account of the scientists who dared to discover the secret of life - told through fascinating and revealing archive - in their own words.

A portrait of the spectacular, dynamic nature of Britain over the course of one year.

Spring arrives, marking the start of an epic race for life where timing is everything.

A portrait of the spectacular, dynamic nature of Britain over the course of one year. In the midst of winter, time-lapses show a magical country shrouded in frost and mist.

The fading sun brings a change to Britain: a time of storms and unpredictable weather.

The Great Rift Valley provides the stage for an epic battle between trees and grass - its course influenced by volcanic eruptions, landscape and rainfall. On its outcome rests the fate of Africa's great game herds.

A look at the natural history of birds, narrated by David Attenborough.

A look at the natural history of birds, narrated by David Attenborough. This programme reveals how birds have become highly sophisticated communicators, using extraordinary patterns of colour and beautiful songs to deter predators, intimidate rivals and impress potential mates.

A look at the natural history of birds, narrated by David Attenborough. This programme reveals how male birds use extraordinary displays and bizarre mating rituals to attract the attentions of females.

David Attenborough presents a natural history of birds. In this programme, he examines the variety of ways in which birds construct their nests and protect their eggs from predators. Including breathtaking scenes of aerial piracy and a remarkable 3-D animated view of the processes involved in laying an egg.

David Attenborough presents a natural history of birds. This programme provides an illustration of the fascinating diversity of feeding practices and behavioural patterns employed by birds. Sweeping through an incredible range of species, including pelicans, sea eagles, babblers and finch chicks, it offers a thorough study of the way in which birds solve the problems of parenthood.

David Attenborough presents a natural history of birds. This programme looks at how birds cope with living in some of the harshest and most bizarre places on the planet, looking at the sandgrouse in the Namibian desert, spectacled eiders in the Arctic, a 10,000-strong nesting colony of oilbirds in a Venezuelan cave, and black vultures nesting on the sixteenth floor balcony of a skyscraper in Sao Paulo.

The history, wildlife and exploration of the River Nile.

Since the dawn of history the miraculous annual floodwaters have risen to transform the desert into a fertile paradise where the great civilisation of Ancient Egypt grew, but their existence was on a knife-edge held hostage by the river and the Pharaoh maintained the balance by appeasing the gods to ensure the gifts of the river.

The annual flooding of the Nile brought the water and fertile volcanic soil that made the Ancient Egyptian civilisation possible, but impassable rapids made it impossible for them to discover the source of this bounty they attributed to the gods.