Scientists have revealed that 10,000 years ago people in Britain had "black" skin. The discovery partly rewrites the history of early humans - a story that stretches back millions of years.

How did they find that out? It all started with a skeleton called Cheddar Man (named after the Cheddar GorgeA limestone gorge in Somerset, England. It is home to a network of caves and underground rivers. where it was discovered). At around 10,000 years old it is the oldest complete skeleton in Britain. Most scientists assumed the living person would have had pale skin and fair hair.

But they were wrong. After groundbreaking analysis of DNADeoxyribonucleic acid is the material in an organism that carries genetic information. taken from its skull, researchers found that the man would have had "dark to black skin", blue eyes, and dark curly hair. This suggests that light skin became common in Europe later than originally thought.

So how long have humans actually been living in Britain? Archaeologists have found human tools dating back as far as 950,000 years. But people have not lived in Britain constantly since then, as several generations would have been wiped out by ice agesLong term reductions in the temperature of Earth. This results in the spread of huge glaciers across large parts of the planet. The previous ice age finished around 11,700 years ago.. Plus there was plenty of dangerous wildlife to contend with, including sabre-toothed tigers and woolly mammoths.

Cheddar Man would have lived in Britain after the most recent ice age, and the country has been inhabited by people ever since.

But we have found older human skeletons elsewhere, right? Oh yes, much older. Although the word "human" gets a little complicated. For example one of the most famous ancient skeletons ever found belongs to a human-like primate called Lucy. She was found in Ethiopia in 1974 and is 3.2 million years old. A remarkable 40% of her bones had survived through the ages.

Technically Lucy came from a different group of animals to humans known as Australopithecus afarensis. However, she had one key skill that we still rely on today: walking on two legs

Known as bipedalism, it was the ability of primates like Lucy to walk upright that separated them from other four-legged creatures. According to anthropologistSomeone who studies human beings and societies. The word "anthropology" comes from the Greek "anthropos", meaning "human". It developed as a subject in Europe in the 19th century, although some regard the Arab historian Ibn Khaldun as the first anthropologist. Chris Stringer this "freed the hands for manipulating tools" which may have been a crucial step in causing "our ancestors' brains to grow."

And what came after Lucy? To answer this, let's quickly whizz through some biology. Whilst every individual animal is part of a species, each species is also part of a wider group called a genus. For example, lions and tigers are different species, yet are in the same genus called panthera.

Humans are categorised into the Homo genus. This group slowly evolved and eventually separated from the Australopithecus genus (the group that Lucy belonged to) about three million years ago. 

Got it. So apes evolved into humans around three million years ago? Not quite. You see, just like tigers and lions, there have been lots of different species within the Homo genus. For example, the species Homo erectus evolved around two million years ago. 

And they were quite the ground-breakers. According to researchers these ancestors were the first to migrate out of Africa, and were first to develop hunter-gatherer societies. They used teamwork to hunt animals, and utilised the power of fire to cook their food.

Modern humans are classified into the similar, but distinct, species called Homo sapiens. And we arrived on the scene fairly late, around 300,000 years ago (although still a long time before Cheddar Man got to roaming around Britain). 

Fascinating. But why is this relevant to modern humans today? Knowing about the past can make us realise how ridiculous modern prejudices are. Take the example of Cheddar Man. As archaeologist Tom Booth suggests, the man's blackness demonstrates that racial categories are really "very modern constructions". Human beings have a deep shared history that moves beyond contemporary obsessions with the different colours of people's skin.