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.

Mammals from tiny shrews, giant anteaters, armoured armadillo to bats have specialised in eating insects. Some have evolved into complex and effective hunters, even pursued their prey into the skies

Narrated by Ewan McGregor, Humpback Whales is an extraordinary journey into the mysterious world of one of nature's most awe-inspiring marine mammals. Set in the spectacular waters of Alaska, Hawaii and the remote islands of Tonga, this ocean adventure offers audiences an up-close look at how these whales communicate, sing, feed, play and take care of their young. Humpbacks were nearly driven to extinction 50 years ago, but today are making a slow but remarkable recovery. Join a team of researchers as they unlock the secrets of the humpback and find out why humpbacks are the most acrobatic of all whales, why they sing their haunting songs, and why these intelligent 55-foot, 50-ton animals migrate up to 10,000 miles round-trip every year.

David Attenborough continues his search for the origins of flying animals, as he charts the rise of new, larger creatures – extinct reptiles that flew on wings of skin, dinosaurs that sprouted feathers to become the ancestors of birds, and gliding mammals that emerged from a life in the trees to dominate the night as bats. His journey spans the globe – from the rainforests of Borneo to see bizarre gliding animals, to China and its new discoveries of dinosaur fossils. Stunning CGI brings to life creatures that disappeared over 200 million years ago, and new filming techniques bring us closer than ever to the secrets of flight itself.

Moving on to the Late Eocene period 36 million years ago and mammals have prospered and are now the largest creatures on land and sea. This is an era of animals like andrewsarchus, the biggest mammal carnivore ever to walk on land, and the brontotheres, small-brained herbivores. It is in the sea, however, that the most monstrous mammals of all can be found. We follow the fate of a female basilosaurus, a huge serpent-like early whale, but nothing like the gentle filter feeding whales of the 21st century. Four times the length of the great white shark, with jaws to match, she is every inch a killer.

25 million years ago the biggest land mammals of all time, the indricotheres, stalked the Earth. Up to seven metres tall and weighing 15 tonnes, adults were too big to be eaten by any predator of the time. Only in the first few years of its life was indricotheres vulnerable. The programme follows the fate of a calf from his traumatic birth to see whether it can survive droughts, killer hogs and hyaenodon - a predator the size of a rhino with jaws that could crush a rock.