The journal Science published a brace of papers recently, in which researchers described the discovery of a 2.8 million year old jawbone studded with teeth in Ethiopia’s Afar regional state. This finding, according to scientists, reveals that our genus, Homo, appeared nearly half a million years earlier than previously believed. This came after branching off from the more apelike Australopithecus genus that included “Lucy,” perhaps the most famous set of skeletal remains in history. Researchers say the significance of the discovery is twofold. First, it solidly fixes the origins of Homo in East Africa. Second, “it fits the hypothesis that climate change drove key developments in a variety of mammals, including our early forebears,” stated an article in the Los Angeles Times about the papers findings.
When “Lucy” trod the Ethiopian soil roughly 3.2 million years ago, the region had lengthy rainy seasons that supported the existence of many trees and a broad array of vegetation. By the time Homo first appeared on the Horn of Africa, however, the climate had become much drier and the landscape was treeless and looked very similar to today’s Serengeti plains or Kalahari desert. A tough climate in which to survive.
But the genius of the genus that includes Homo sapiens is resourcefulness. Larger brains, the ability to fashion and use tools, and teeth suited to chewing a variety foods gave our early ancestors the ability to live in an inflexible environment, researchers claim.
“This early Homo could live in this fairly extreme habitat and apparently Lucy’s species could not,” said an Arizona State University paleontologist who worked on both studies, according to the Times’ article (titled “Human evolution likely guided by changing climate”).
The studies’ co-author is the director of Arizona State’s Institute of Human Origins. He stated, “The time period between 2 (million) and 3 million years ago is one of the least-well-understood in human origin studies.”
We do now know two things. One, we weren’t responsible for the vast changes in climate 2 or 3 million years ago. And two, we wouldn’t be who we are without them.
We didn’t make climate change, it made us!