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How did the people who are today come to be?

2022-10-19 21:15:11Histori SHKRUAR NGA DAVID BEGAN
How did the people who are today come to be?
How did the people who are today come to be?

Ecological conditions in Europe set apes on the path to becoming humans millions of years before Homo sapiens evolved, says anthropologist David Began. Without the developments that took place in Europe, humans would never have been able to evolve

By David Began*

Science fiction? No, it really happened. Between 20 and 7 million years ago, Earth was actually the planet of the apes. At least 100 species populated the world before the first humans appeared. They were remarkable in number and diversity, but even more interesting are what they can tell us about our own origins. Key human traits, including large brains, dexterous hands, upright posture, and long childhood, can be traced back to that period. And the really amazing thing is that all these traits evolved in European monkeys.

The news is full of discoveries that change our ideas about human evolution. But when we think about our ancestors, we tend to focus on the last 8 million years, where our lineage split from that of chimpanzees. But what was there earlier? Three decades of study have convinced me that this early period was absolutely decisive.

There is no doubt that apes originated in Africa, or that our most recent evolution took place there. But for a period between these two developments, monkeys were on the brink of extinction on their continent, while they were flourishing in Europe. Furthermore, the transformation of the European species during this time has made us humans who we are today.

Fossil records show that apes began to exist in Africa about 26 million years ago, and were definitively established 4 million years or so later. A close relative, who lived 18 million years ago, gives us a remarkable picture of these early apes.

Ekembo's remains have been found preserved in Pompeii – as well as in layers of volcanic ash on Rusinga Island in Kenya, Africa. What we have is an animal with arms and legs of equal length, a horizontally oriented spine, and a brain the size of a modern baboon. In other words, Ekembo looks like a slightly larger monkey, but with one essential difference – no tail.

The tail enables many monkeys to balance their posture, but Ekembo compensates by having more joints, stronger hands, and legs for grasping. This puts the apes on a different path than the Old World monkeys. A second important change occurred with a contemporary of Ekembo, named Afropithecus.

The two look very similar from the neck down, but have very different jaws and teeth. Those of Afropithecus are much more powerful, adapted to grind hard materials. Equipped with these qualities, they could extract nutrients from plants with impenetrable bark, for the thinner jaws of the Ekembos.

It may not sound very impressive, but this ability has had huge consequences for monkeys. With the capacity to eat a wide variety of foods, they could expand their range from Africa, to Europe and Asia. We know that the old monkeys in Europe belonged to the Gryphopithecus genus and date back 17.5 million years.

They inherited the powerful bite of Afropithecus, but their teeth were slightly different, more similar to those of our earliest, direct African ancestors. According to the fossil record, gryphopits lived in parts of present-day Germany and Turkey about 17 million years ago. At this time, many parts of Europe belonged to the subtropical zone. Seasonality was low and the climate suitable for animals such as monkeys, who relied on a constant supply of fruit throughout the year.

However, when the gryphopits migrated north, conditions would prove much more difficult – forcing them to eventually develop some new adaptations. After moving north, the gryphopits returned south, so until about 15 million years ago their species covered an area stretching from Europe to East Africa.

A member of the family, Nakolapiteku, then living in Kenya, had evolved limbs with larger elbows and wrists, possibly predating the development of the longer arms found in modern apes and early humans. However, gryphons seem to be dying out in Africa, although we don't know why. In fact, the fossil record shows that between 14 and 8 million years ago, monkeys there were rare, and most were from the ancient lineage related to Ekembo and forced to become extinct.

The kings of rhythm

Meanwhile in Europe, monkeys were appearing as monkeys with today's appearance. About 12.5 million years ago, the first ape appeared with a more upright posture. Pierolapithecus, sometimes called Dryopithecus, and which was discovered in Catalonia in northern Spain. The partial skeleton has a more vertical spine, a broad chest, arms longer than legs, highly mobile wrists, and long, curved, powerful fingers for grasping objects.

These characteristics made Driopithecus look more like today's great apes. They also witness a major transition from walking like an ape on 4 four legs to moving like a monkey, climbing through the branches of trees. Hispanopithecus, which lived in present-day Catalonia a few million years later, had longer arms and a straighter spine.

So did Rudapiteku, his contemporary in what is now Hungary. Most importantly, to our knowledge, Rudapitecus is the first ape to develop two other key characteristics of modern great apes – a large brain and extended childhood. In 1999, my team discovered a well-preserved Rudapithecus skull at the archaeological site of Rudabanja. The structural details – including the skeleton, jaws and base of the skull – all resemble the anatomy of modern African apes, especially gorillas.

The brain was comparable in size to that of today's chimpanzees. And evidence from teething studies shows that Rudapite had a longer childhood than its predecessors. In my new book, The Real Planet of the Apes, I argue that these and other important developments in ape evolution were driven by the harsh ecological conditions encountered in Europe.

Apes colonized the continent during the warm phase of the Miocene, but starting 14 million years ago it was cooling, forests were becoming less dense and food scarcer. To survive, monkeys were forced to develop new strategies to find food both in trees and on the ground. This led to physical and cognitive changes. Bigger brains and longer childhoods are associated with higher levels of intelligence, memory, complex learning and strategic thinking, important tools for apes living in seasonally challenging environments – and characteristic qualities of our own species.

Gradually, the conditions in Europe became too difficult for the monkeys, and about 10 million years ago they left the continent to go to Africa. There, separate lines of our relatives evolved, first into gorillas and then chimpanzees into humans. But the anatomy and behavior of the earliest humans only makes sense in light of the apes of the Miocene era. I would go so far as to say that without the developments that have taken place in Europe, humans would never have been able to evolve.

*anthropologist, university of Toronto


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