Constant climate change may have given Homo sapiens our flexibility
In the 5 million years since early hominids first emerged from east Africa’s Rift Valley, the Earth’s climate has grown increasingly erratic. Over cycles lasting hundreds of thousands of years, arid regions of central Africa were overrun by forests, forests gave way to grasslands and contiguous landscapes were fractured by deep lakes.
It was within the context of this swiftly changing landscape that humans evolved their sizable brains and capacity for adaptive behavior, said Rick Potts, director of the Human Origins Program at the Smithsonian Institution National Museum of Natural History. In such a world, the ability to think creatively, to imagine novel solutions to survival threats, proved to be a major asset, he said.
"The evolution of the brain is the most obvious example of how we evolve to adapt," he explained. "But in the modern era, we know that in the human genome there are all kinds of interactions that allow human organisms to have plasticity — the capacity to adjust is itself an evolved characteristic."
Man had two key advantages, he said: our brains and our capacity for culture.
"Our brains are essentially social brains," he added. "We share information, we create and pass on knowledge. That’s the means by which humans are able to adjust to new situations, and it’s what differentiates humans from our earlier ancestors, and our earlier ancestors from primates."
This adaptive ability not only allowed our progenitors to ride the massive seesaws of climate shifts but subsequently helped them to colonize new habitats. The earlier hominid species Homo erectus ranged across much of Africa and Asia. Meanwhile, Homo neanderthalensis — Neanderthals — occupied large parts of Europe. Our own species, Homo sapiens, dispersed to even more far-flung corners of the globe, employing boats to reach Australia more than 50,000 years ago” (read more).
(Source: Scientific American)