Sir David Attenborough chooses his favorite recordings from the natural world --from the song of the largest lemur to the song of the humpback whale to the song of the lyrebird-- that have revolutionized our understanding of song. The science of song had been transformed by Charles Darwin’s theory of sexual selection: singing is dangerous as it reveals the singer’s location to predators, but it also offers the male a huge reward, the chance to attract a female and pass on genes to the next generation. Today, new science in the field of birdsong is transforming those long-held ideas.
Scientists are discovering that, in fact, in the majority of all songbird species, females sing - and it is only now they are being properly heard. Through this revelation and others, we can understand that animal songs are marvellous examples of the spectacular survival strategies that species have developed.

Genetic breakthroughs have shed light on how life evolves in real-time. From filling in the missing links to creating a new species, in the last 50 years scientists have solved some of the biggest mysteries of evolution. In this episode, we look at revolutionary discoveries that shook the world and may shape our future.

The question of our human origins is one of the most controversial science has wrestled with. This is the story of how scientists came to explain the beauty and diversity of life on earth, and reveal how its evolution is connected to the long and violent history of our planet. Featuring ocean adventurers, eccentric French aristocrats, mountain climbers, a secret Victorian publisher with 12 fingers, a ridiculed German meteorologist, and only a brief hint of Charles Darwin.

Written and presented by David Attenborough, who said: 'One of the most wonderful things about filming plants is that you can reveal hidden aspects of their lives, you can capture the moment as one plant strangles another, and as they burst into flower. But whilst time-lapse photography allows you to see things that no human being has ever seen before". David begins his journey inside the magnificent Palm House, a unique global rainforest in London. Here, he explores the extraordinary plants that are so well adapted to wet and humid environments and unravels the intimate relationships between wet zone plants and the animals that depend on them. It was in the wet zones of the world that plants first moved on to land and in the Waterlily House David reveals how flowers first evolved some 140 million years ago. Watching a kaleidoscope of breath-taking time-lapses of these most primitive of flowers swelling and blooming in 3D, he is able to piece together the very first evolutionary steps that plants took to employ a wealth of insects to carry their precious pollen for the first time. David discovers clues to answer a question that even had Charles Darwin stumped: how did flowering plants evolve so fast to go on to colonise the entire planet so successfully?

Richard Dawkins deals with some of the philosophical and social ramifications of the theory of evolution. Dawkins starts out in Kenya, speaking with palaeontologist Richard Leakey. He then visits Christ is the Answer Ministries, Kenya's largest Pentecostal church, to interview Bishop Bonifes Adoyo. Adoyo has led the movement to press Kenya's national museum to sideline its collection of hominid bones pointing to man's evolution from ape to human.[5] The collection includes the Turkana Boy discovered by Kamoya Kimeu, a member of a team led by Richard Leakey in 1984. Dawkins discusses social darwinism and eugenics, explaining how these are not versions of natural selection, and that 'Darwin has been wrongly tainted'. He then meets with evolutionary psychologist Steven Pinker to discuss how morals can be compatible with natural selection. He goes on to explaining sexual selection, with peafowls as an example. To find out whether sexual selection plays a role for altruism and kindness among humans, he visits women who are looking for sperm donors, as well as a sperm bank manager. Dawkins also explains kin selection and selfish genes.

David Attenborough asks three key questions: how and why did Darwin come up with his theory of evolution? Why do we think he was right? And why is it more important now than ever before? David starts his journey in Darwin's home at Down House in Kent, where Darwin worried and puzzled over the origins of life. David goes back to his roots in Leicestershire, where he hunted for fossils as a child, and where another schoolboy unearthed a significant find in the 1950s. And he revisits Cambridge University, where both he and Darwin studied, and where many years later the DNA double helix was discovered, providing the foundations for genetics. At the end of his journey in the Natural History Museum in London, David concludes that Darwin's great insight revolutionised the way in which we see the world. We now understand why there are so many different species, and why they are distributed in the way they are. But above all, Darwin has shown us that we are not set apart from the natural world, and do not have dominion over it. We are subject to its laws and processes, as are all other animals on earth to which, indeed, we are related.