The Cambrian period is the earliest time that we can plot recognisable parts of today's continents. Most of the land lies in tropical latitudes, although the large continent of Gondwanaland, comprising Africa, South America, Antarctica, Australia and India, stretches almost to the South Pole. In the west lies the continent of Laurentia, consisting of today's North America, and in between lies Baltica - today's northern Europe. The north pole is covered by deep ocean.

The Cambrian was originally defined as the time of the earliest recognisable fossils - marine invertebrates - although we now have evidence of life on Earth as early as 3,000 million years ago.

400 million years ago (Silurian period)

Gondwanaland has moved south, across the south pole, resulting in the accumulation of the Earth's first icecap over what will become North Africa and parts of South America. The Iapetus Ocean which had separated Laurentia from Baltica has closed, giving rise to the Caledonian mountain chains of north-east North America and north-west Europe. Laurentia and Baltica are separated from Gondwanaland by the narrow Tethys Sea.

The Silurian period sees the first vertebrates - fish - widespread throughout the world's oceans, the first corals in shallow tropical seas, and the first plants on the land surface.

300 million years ago (Carboniferous period)

The western end of the Tethys Sea has closed, joining Laurentia and Baltica to Gondwanaland, forming the super-continent of Pangea. The Appalachian Mountains result from this continental collision. Present-day Siberia and Kazakhstan form a smaller continent - Angaraland - in the north. Today's Antarctica has reached the south pole and the large southern icecap extends to cover parts of Argentina, south-central Africa, India and Australia.

A warm climate encourages the growth of dense coastal swamp forests in equatorial and southern temperate regions, providing an environment in which insects and amphibians thrive. Large deposits of coal are laid down as sea levels fluctuate, burying forest material under successive layers of sediments. A mass extinction of marine species occurs at the end of the Permian period, about 250 million years ago, possibly caused by ocean current shifts after the collision of Laurentia with Gondwanaland.

200 million years ago (Early Jurassic period)

Pangea has drifted north, with Angaraland in collision with Baltica, forming the Ural Mountains. The Tethys Ocean has started to lose its identity, with parts of eastern Asia moving north away from Gondwanaland towards the northern landmass of Laurasia.

Reptiles are the dominant animal group on land, sea and even in the air, with dinosaur species reaching their maximum size and found throughout the super-continent of Pangea. The first small mammals appear around 220 million years ago, evolved from warm-blooded reptiles.

150 million years ago (Late Jurassic period)

Pangea starts to break up, with the North Atlantic opening between North America and Africa and, in the south, a rift opening between Africa, India and Antarctica. The northern landmass of Laurasia accumulates several fragments in the east which will form Asia.

The late Jurassic sees the first birds, thought to have evolved from dinosaurs. The organic remains of marine organisms in shallow equatorial seas start to form deposits of oil. The largest concentrations are formed at this time over the Arabian plate.

100 million years ago (Cretaceous period)

The South Atlantic and Southern Ocean now separate South America, Africa, India and Antarctica. A subduction zone will soon develop under the western shore of South America, giving rise to the Andes Mountains. Antarctica is back at the pole, but warm ocean currents keep it ice-free. As the continents break up, blocking migration, land animal species become isolated and develop unique local characteristics.

The first flowering plants appear and rapidly spread to dominate the landscape worldwide. The end of the Cretaceous period is marked by a mass extinction event 65 million years ago, which wiped out two-thirds of the planet's animal species, including the dinosaurs. A sudden climate change is the likely culprit, possibly resulting from a large asteroid impact or an immense eruption of flood basalts.

50 million years ago (Tertiary period)

The North Atlantic continues to open, separating North America from Europe. Western North America is uplifted, forming the Rocky Mountains. The Tethys Sea is disappearing as Africa and India approach Eurasia. India's progress northward is particularly rapid, and the resulting collision will produce the Tibetan Plateau and the Himalayas - today's highest mountain range. The breakup of Pangea is completed as Australia and South America separate from Antarctica.

The first grasses emerge and spread to cover large areas of the land surface. Mammals and birds flourish. Early horse, elephant and bears appear and the first apes emerge 35 million years ago.

Today

In the North Atlantic, the new island of Iceland is visible, the tip of the mid-Atlantic ridge, where Europe and North America continue to move apart at a rate of 2cm per year. A new ocean rift is opening in the Red Sea, between Africa and Arabia, part of the Great East African Rift Valley. The Alps, Pyrenees and Caucasus Mountains show where Africa has collided with Eurasia.

3 million years ago, South America had moved far enough away from Antarctica to allow Southern Ocean currents to isolate the south pole from equatorial heat, leading to today's southern icecap. This has lead to a dramatic cooling of the global climate, with the Arctic Ocean now covered by sea ice, and the periodic advances of continental icecaps we call ice ages. The last ice age, peaking 18,000 years ago, provided the land bridge which enabled modern humans to migrate from Africa/Eurasia to the Americas.