An ape is a mammal, and further, a primate without a tail. Apes include gorillas, chimpanzees, orangutans, bonobos, and humans, as well as gibbons that are relatively small in size.

Sixty-six million years ago, an enormous asteroid crashed into Earth. Most animals vanished into oblivion; for example, dinosaurs were no more (except birds). Mammals, however, survived. They evolved more than 200 million years ago but had remained small and insignificant creatures, hiding in burrows and holes – that is probably why they survived the devastating hit.

When life began to recover, mammals crawled out of their nests. It was their time to take over the world. They grew bigger, spread around continents, and diversified. The first versions of dogs, cats, horses and others began to evolve. For us, they were still peculiar beings, whales walking long on the ground before diving into the oceans (40 MYA), elephants not even knee-high tall.

Some mammals began to develop long fingers in their paws and climbed into the trees. Others got long tails and became known as monkeys, while some lost their tails, grew bigger, and evolved into apes.

Many apes settled in Africa, which was then covered in thick forests, broken only by rivers and lakes. They lived in the trees, swinging from one branch to another, and sometimes, clumsily knuckle-walking in the vegetation. Around eight million years ago, however, the climate of the continent began to cool. Forests thinned out as grass took over the land, and typical food for apes – fruits, nuts, and seeds – became scarce. There was no food for everyone, and many became extinct.

Some apes, however, climbed down from the trees and began to take wobbling steps on two legs to reach another fruit tree in the distance. Over time, their steps turned into longer walks, their postures became more upright, and their heads balanced on top. Hands became free for carrying, foraging, and using tools that could be used for butchering other animals, perhaps fellow apes as well. A modicum of meat was included in the diet (3.4 MYA), and brains began to grow¹.

Larger brains enabled our ancestors to think and solve problems, envision and plan ahead – useful abilities in a world full of dangers. Relationships between individuals became more complex in growing social groups, perhaps formed to give protection against lurking predators. Moreover, larger brains enabled better motor control of nimble fingers. This made it possible to build more complex tools from stone, a skill associated with the first humans evolving around two and a half million years ago.

¹ The change from herbivore to omnivore – from less to a more nutritional-rich diet – initiated the growth of larger brains. The growth was later fostered by cooking, which enabled humans to digest better and make do with a shorter intestinal tract. This released energy for the development of larger brains (intestines and brains are major energy consumers, so it is hard to maintain both).

Bibliography

Brusatte, S. 2022. The Rise and Reign of the Mammals. London, United Kingdom: Picador. 500 p. ISBN 9781529034233. Pages XXII, 192-193, 277-278, 295-296, 368-374.

Pettitt, P. 2022. Homo Sapiens Rediscovered the Scientific Revolution Rewriting Our Origins. London, United Kingdom: Thames & Hudson. 304 p. ISBN 9780500252635. Pages 13-26.

Frankopan, P. 2023. The Earth Transformed an Untold History. London, United Kingdom: Bloomsbury Publishing. 695 p. ISBN 9781526622563. Pages 41-43.

Smil, V. 2018. Energy and Civilization a History. Cambridge, United States. MIT Press. 552 p. ISBN 9780262536165. Pages 22-24.

Panciroli, E. 2022. The Earth a Biography of Life The Story of Life On Our Planet Through 47 Incredible Organisms. London, United Kingdom: An Hachette UK company. 255 p. ISBN 9781529413984. Pages 240-242.

Rutherford, A. 2017. A Brief History of Everyone Who Ever Lived. London, United Kingdom: Weidenfeld & Nicolson. 419 p. ISBN 9781780229072. Page 23.

Rutherford, A. 2020. The Book of Humans a Brief History of Culture, Sex, and the Evolution of Us. London, United Kingdom: Weidenfeld & Nicolson. 240 p. ISBN 9781615195909. Page 29.

Smithsonian. 2018. Inventions a Visual Encyclopedia. New York, United States: DK Publishing. 304 p. ISBN 9781465458384. Page 8.

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2.5 MYA
Humans evolve

Around 2.5 million years ago, the first humans evolved from an earlier genus of apes in Africa. Some remained in their homelands, while others began to migrate to the vast areas of Asia and Europe. Since living conditions varied widely around the world, humans began to evolve in different directions, and many distinct human species came into being.

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66 MYA
Chicxulub Asteroid hits Earth, causes mass extinction

Life on Earth began almost 4 billion years ago and has since evolved into myriads of different forms and sizes. Multiple times, life has also been wiped out for all but a small proportion of living organisms, yet always paving the way for new species. Perhaps the best-known of these mass extinction events was caused by an enormous asteroid that brought to an end the era of dinosaurs.