A brief history of humans 2.5 – 2 Million Years ago: Homo habilis is the first human ancestor to master stone tools using flakes to butcher and skin animals 1.9 – 0.5 Million Years ago: Homo erectus is distributed in east and southwest Africa and is the first human ancestor to control fire

A brief history of humans Loss of body hair related to bipedalism (for temperature control through sweating) favoured the emergence of skin pigmentation to protect from increase sunlight exposure With hairless skin, sweat glands, melanin rich skin, early humans could forage for food under the sun for extended periods of time, giving them an evolutionary advantage

A brief history of humans 430000 – 40000 years age: Homo neanderthalensis are an extinct species of humans Compared to modern humans, they are stalkier with shorter legs and bigger bodies Ancestor of Neanderthals migrated out of Africa where they gave rise to them in Europe Neanderthals lived in Europe and Asia from Spain and England to Siberia Often depicted as dumb brutes, they were strong hunters and creative artists The genomes of modern humans, not from Africa, share 1.5 – 2.1 % Neanderthal DNA

A brief history of humans 300000 years ago – present: Homo sapiens speciate out of Homo erectus, still in Africa and diverging from Neanderthals 80-50 thousand years ago is the beginning of a migration of modern humans from Africa to populate the rest of the world Behavioural modernity are the cultural and cognitive foundations that give rise to technological and bahavioural innovations This development in modern behaviour, paired with the last ice age, is responsible for the replacement of the Neanderthals

A brief history of humans

A brief history of humans From about 1.2 million years ago to less than 100,000 years ago, early humans were dark-skinned. As Homo sapiens populations began to migrate, dark skin decreases proportionally to the distance north a population migrated, resulting in a range of skin tones within northern populations. Northern populations experience a positive selection for lighter skin due to the increased production of vitamin D from sunlight and the genes for darker skin disappeared from these populations.

A brief history of humans Peopling of the Americas (20000 – 10000 years ago) During the ice age, much of the Earth’s water was trapped in ice and sea levels were much lower This left a land bridge between North America and Russia

A brief history of humans Humans are still evolving to this day and evolutionary pace is estimate to have sped up 100 times since the first human ancestors Lighter skin in Europeans and Asians in response to less sunlight Need less melanin to absorb more UV radiation to produce vitamin D The sickle cell anemia trait, in response to malaria (one copy of the malaria gene protects against malaria). Lactase persistence in adults, in several cultures with dairy farming. High altitude (low oxygen) tolerance in the Andes, Ethiopian highlands, and Himalayas.

A brief history of humans