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!
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