Given its huge success in describing the natural world for the past 150 years, the theory of evolution is remarkably misunderstood. Many still ask “if humans evolved from monkeys, why haven’t today’s monkeys evolved”?
So … was your great ancestor a monkey? No, your great-great-great-ancestor was not a monkey. Evolution theory indicates that we have common ancestors with monkeys and apes – among the existing species, they are our closest relatives. Humans and chimpanzees share more than 90% of their genetic sequence. But this common ancestor, which roamed the earth approximately 7 million years ago was neither a monkey nor a human, but an ape-like creature that recent research suggests had traits that favored the use of tools.
While we were migrating around the globe, inventing agriculture and visiting the moon, chimpanzees — our closest living relatives — stayed in the trees, where they ate fruit and hunted monkeys.
Modern chimps have been around for longer than modern humans have (less than 1 million years compared to 300,000 for Homo sapiens, according to the most recent estimates), but we’ve been on separate evolutionary paths for 6 million or 7 million years. If we think of chimps as our cousins, our last common ancestor is like a great, great grandmother with only two living descendants.
But why did one of her evolutionary offspring go on to accomplish so much more than the other?
The reason other primates aren’t evolving into humans is that they’re doing just fine. All primates alive today, including mountain gorillas in Uganda, howler monkeys in the Americas, and lemurs in Madagascar, have proven that they can thrive in their natural habitats.
Evolution isn’t a progression. It’s about how well organisms fit into their current environments.
In the eyes of scientists who study evolution, humans aren’t “more evolved” than other primates, and we certainly haven’t won the so-called evolutionary game. While extreme adaptability lets humans manipulate very different environments to meet our needs, that ability isn’t enough to put humans at the top of the evolutionary ladder.
Take, for instance, ants. Ants are as or more successful than we are. There are so many more ants in the world than humans, and they’re well-adapted to where they’re living.
While ants haven’t developed writing (though they did invent agriculture long before we existed), they’re enormously successful insects. They just aren’t obviously excellent at all of the things humans tend to care about, which happens to be the things humans excel at.
Scientists think ancestral humans began distinguishing themselves from ancestral chimps when they started spending more time on the ground. Perhaps our ancestors were looking for food as they explored new habitats, Isbell said.
“Our earliest ancestors that diverged from our common ancestor with chimpanzees would have been adept at both climbing in trees and walking on the ground,” Isbell, a professor of anthropology at the University of California, said. It was more recently — maybe 3 million years ago — that these ancestors’ legs began to grow longer and their big toes turned forward, allowing them to become mostly full-time walkers.