Posted on 11/19/2007 6:46:55 PM PST by blam
Climate swings shaped human evolution, researchers claim
Ian Sample, science correspondent
The Guardian Monday November 19 2007
The evolution of our earliest human ancestors was driven by wild swings in eastern Africa's ancient climate, scientists claim today.
The rapidly changing climate reshaped the landscape, leaving once plentiful food and water resources in scarce supply and placing enormous pressure on early humans to adapt.
The sustained upheaval drove some species to the brink of extinction, while other better-suited relatives emerged and flourished, the scientists believe.
Researchers identified several extreme shifts in climate dating back millions of years to when humans were first emerging on the continent. Three of the greatest periods of climatic change took place around 2.5m, 1.5m and 1m years ago. These roughly coincide with the appearance of Homo habilis, the first human species; Australopithecus afarensis, a sturdy primitive ape, and the later human species, Homo erectus, which became adept at stone tool use and hunting.
Researchers led by Mark Maslin, director of the Environment Institute at University College London, conducted geological surveys of ancient lakes throughout eastern Africa. They found evidence that over the past 3m years, giant lakes up to 300 metres deep formed and then vanished with the changing climate. The disappearances of the lakes were followed by periods of extreme drought.
"At one extreme, the landscape would have been a true Garden of Eden, with beautiful freshwater lakes, beautiful shorelines and forests along the rivers. There would have been open spaces allowing early humans to exist easily, with water and lots of resources," said Maslin. "But occasionally, these quickly flipped into bone dry periods, where it's 45C in the middle of the day and no natural water resources."
(Excerpt) Read more at guardian.co.uk ...
GGG Ping.
LOL. So global warming made us the people we are today!
Obviously you are part of the problem. How could you post an article that states the truth about Global warming. /S
The original article seems to have the dates wrong, unless things have changed a lot recently.http://www.freerepublic.com/focus/f-news/1927667/posts?page=7#7I was under the impression that A. afarensis is more like 3.5 million years old, with H. erectus and habilis coming in at just under about 2 mya.
A few posts later I noted:
Another environmental change -- from my grad school days I remember that expansion of the grasslands and reduction of the forests probably caused the most recent ape/man split some 6 mya.I can imagine the stronger groups holding onto the forests and the weaker groups being forced to the edges, and the grasslands. Being pushed out of the "nest" led to the changes which led to modern humans.
The critters that stayed in the forests didn't need to change -- they had it made!
They really don't know for sure, do they.
As I understand it they are saying that as climate changes, temperatures and water supplies change, and life adapts to these changes, or it doesn’t.
Naturally, that is how the world works. And the point is?
Evolution. Global warming. The liberal circle is now complete.
I suspect their point is that human special traits developed from environmental pressure. Only this doesn’t make sense because humans went where their food went. All animals experienced the same adaptation pressure. The truth is more likely that humans evolved special traits from having to compete with the world’s most deadly animal: other humans. Leftists hate the idea that we are born from war, that the whole natural purpose of walking upright was to carry a club. They will grasp at any straw to explain human evolution in more peaceful terms.
Have to disagree with you on some of this.
Environmental pressure explains a great deal in human prehistory, from nasal form to skin color, even body form.
And all animals do not experience the same adaptation pressure. Previous adaptations make a very big difference in how a population will react to environmental change. Over-specialization is usually a problem when conditions change, while generalization is usually favorable.
I doubt war was developed early; the struggle for survival, against man and animal was probably an early adaptation, but I suspect other factors, such as group cooperation, played an even greater role.
I think it is more likely that war as we know it was a very late condition in human prehistory, and I suspect little significant evolution has occurred since war developed. First, the time span has been too short, and second, the nature of war has continually changed. Adaptation to one form of war carries no benefit when the nature of war changes. (How do you adapt to aircraft-delivered bombs?)
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Most modern human traits can be traced to their advantage in war, and war is the only pressure significant enough to explain why humans developed intelligence far in excess of that needed to find food and shelter. War is a very special high speed form of evolution in that any genetic or cultural evolution advantage is selected for in a few years rather than the many thousands of years natural selection takes. This is the reason humans evolved to be the most genetically advanced animal to ever walk the face of Earth despite the late start.
The evolutionary advantage of our long life, far greater than our breeding years, is so we have old wise men around to direct a successful war. Our armpit hair, and sweat which kicks in under stress, is to provide lubrication for extended manipulation of weapons during battle. It has little to do with mobility or extended fighting with prey. Intelligence is the most general adaptation and adapts quickly to different war technologies. The "cutting edge" of technology is usually war related.
Jews have experienced an especially long history of war upon them and this is likely the reason for their unusual intelligence. I bet you could measure a small amount of this evolution in modern times by looking at World War 2. Hitler killed half the population of European Jews. What effect did this have and is it measurable in average test scores? Did the Einsteins have a greater chance of surviving than the slum dwellers? Hitler applied extreme evolutionary pressure over a short span and I bet the human evolutionary impact can be detected in very recent human history.
Human evolution works on a much longer scale.
War most likely developed with the city states and their agricultural surpluses. That is very late on the evolutionary time scale, and most likely led to very few changes in human morphology.
Sorry, I simply can't buy your argument in this.
Now, war did lead to major technological changes. That I will agree with.
The other humanoids were very viable animals. They are no longer with us because we killed them off in war many years ago. There's your evidence that war has been with us going back a very long time. There's little other explanation.
LOL. So maybe this Global Warming will make us all smarter, dumber? A new species, perhaps—Homo Gullibus Sapiens? ;-)
Hmmmmm; survival of the, er, weakest??? Curious observation, that could lead to never-ending debate I suspect.
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