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Adversity breeds strength -- and perhaps human intelligence

It's a widely held hypothesis that ecological and climatological changes had a crucial driving role in evolution throughout history.  Now Penn State University geoscience professor Katherine Freeman and her graduate student, Clayton Magill, have put forth an intriguing study, which suggests that chaos in the ecosystem of East Africa drove mankind's ancestors to radically evolve 2 million years ago.

I. Life on the Chaotic Savanna

Mr. Magill comments, "The landscape early humans were inhabiting transitioned rapidly back and forth between a closed woodland and an open grassland about five to six times during a period of 200,000 years.  These changes happened very abruptly, with each transition occurring over hundreds to just a few thousand years."

To examine the ecological transition that coincided with this crucial phase of hominid evolution the researchers traveled to the Olduvai Gorge in northern Tanzania, collecting lake sediments.  Filtering the sediments of different ages, they performed biochemical analysis looking for fossilized chemical traces of grasses and trees.

Specifically, they sifted through sediments looking for leaf waxes, hardy biochemicals that tend to resist breakdown and survive, even over millions of years.  By performing gas chromatography and mass spectrometry analyses on the various waxes, the researchers were able to pinpoint both the foliage and composition to within a couple centuries.

Tanzania Gorge
Biochemical analysis of local sediments in a Tanzania gorge have offered key clues as to the evolutionary path of mankind's hominid ancestors. [Image Source: Gail Ashley]

What they discovered was that the "Great Drying", which is widely proven to have occurred in Africa around 3 million years ago, was not as much of a one-way process as was previously thought.  Rather, the sediments showed that the local ecosystem appears to have gone through a chaotic transition period in which the climate would fluctuate between wet and dry, before eventually gravitating fully to drier savanna.

To better understand the source of such strange and chaotic cycling, the researchers used statistical and mathematical models to formulate a hypothesis on the causes.  

Explains Professor Freeman, "The orbit of the Earth around the sun slowly changes with time.  These changes were tied to the local climate at Olduvai Gorge through changes in the monsoon system in Africa. Slight changes in the amount of sunshine changed the intensity of atmospheric circulation and the supply of water. The rain patterns that drive the plant patterns follow this monsoon circulation."

"We found a correlation between changes in the environment and planetary movement.  We find complementary forcing mechanisms: one is the way Earth orbits, and the other is variation in ocean temperatures surrounding Africa."

II. Adversity Breeds Evolved Intelligence

The chaos would obviously cause great stress on hominids living in the region forcing them to adapt to different food sources, different landscape, and different predators.  Mr. Magill and Professor Freeman suggest this was a key driver of the evolution of human intelligence.

Comments Mr. Magill, "Early humans went from having trees available to having only grasses available in just 10 to 100 generations, and their diets would have had to change in response.  Changes in food availability, food type, or the way you get food can trigger evolutionary mechanisms to deal with those changes." 

"The result can be increased brain size and cognition, changes in locomotion and even social changes -- how you interact with others in a group. Our data are consistent with these hypotheses. We show that the environment changed dramatically over a short time, and this variability coincides with an important period in our human evolution when the genus Homo was first established and when there was first evidence of tool use."

human intelligence
The papers suggest chaotic climate changes triggered the rise of human intelligence.
[Image Source: Pace J. Miller]

The research was published as a pair of papers [abstracts] in the prestigious peer-reviewed journal The Proceedings of the National Academy of Sciences (PNAS).  Among the other researchers working on the team was Rutgers University earth and planetary sciences professor Gail Ashley.  The research was funded by a National Science Foundation (NSF) grant.

Sources: PNAS [1], [2]



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RE: Interesting new research paper
By BillyBatson on 1/2/2013 5:55:17 PM , Rating: 2
Whether evolution is real or not and whether we come from apes or not to some of us doesn't change the fact that some of us don't believe in a god no matter what. Humans naturally need to believe in something greater than ourselves, it also brings us great comfort to think this isn't the only life we get and that we will be with lost loved ones in the future. Basically we made up fairy tale bedtimes stories rather than face the truth of our finite mortality.
The majority of the world still likes to live in fantasy denial.


RE: Interesting new research paper
By wgbutler on 1/2/2013 6:24:44 PM , Rating: 2
quote:

Humans naturally need to believe in something greater than ourselves, it also brings us great comfort to think this isn't the only life we get and that we will be with lost loved ones in the future


Of course people believe in God for those types of reasons. And other people refuse to believe in God because it makes them extremely uncomfortable to think that they are ultimately accountable for their behavior.

I agree that emotions aren't a good basis for believing or disbelieving in God. The fact that some people may base their beliefs on emotion doesn't meant that the worldview in inherently incorrect, one way or the other.


RE: Interesting new research paper
By wgbutler on 1/2/2013 6:28:17 PM , Rating: 2
One more thing. If I were to choose my beliefs based solely on emotion I'd pick a belief system that saved me from universal scorn and derision, one that the majority of people around the world thought was "cool", and one that let me live my life however I wanted with no bad consequences of any kind.

In other words, Christianity would be the last thing I would pick. I'd probably be just like most of the people who comment on this blog.


By BillyBatson on 1/3/2013 4:04:03 PM , Rating: 2
Agreed that just because emotions are involved doesn't mean that those views are incorrect.

I also understand that Christianity would be the last religion people pick if it was created today... But when Christianity first started it was nearly nothing like the religion and church is today but people have already bought into it and every generation born into it is more likely to blindly follow that faith.


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