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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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So Check It
By wkepner on 12/30/2012 2:44:27 PM , Rating: 2
Let me clarify something about evolution that will hopefully make this debate a lot easier to discuss.

Basically there are two types of evolution- Micro and Macro.

When someone says "evolution is accepted by every scientist in the world," You're actually referring to
"Micro Evolution" which is simply a change in gene frequency within a given population. Evolution at this scale can be observed over short periods of time — for example, between one generation and the next, e.g. the frequency of a gene for pesticide resistance in a population of crop pests.

On the other hand, "Macro Evolution" is the broader, more controversial topic which many people still disagree on to this day. Macro Evolution deals with the bigger question such as "Where did the FIRST organism evolve from? Primordial soup...Divine Intervention, etc."

So when one understands the basic differences between these two classifications of evolution, it becomes easier to discuss the relative merits of each others' arguments.

So let me put something to rest- Nobody is debating the fact that homo sapiens (humans) evolved from an ape-like creature over millions of years, and that we share a common ancestor with modern day chimps.

People who do NOT believe in this portion of the "theory", are part of an insignificant minority and are mostly just mistaken or misinformed about the overwhelming evidence that debunks their views.

Even the most venerable Christian scientists all concur that micro-evolution is an undeniable fact, so just please learn to accept this as the truth people.

However, don't lose hope yet cuz there is still room for debate in regards to Macro Evolution because of its ridiculous complexity. Where did the first fukin prokaryote amoeba piece of shit cell pop into existence? Who knows? and sorry but nobody can either prove, or disprove the various theories that are floating about in the scientific community, but honestly that's not even what were talking about right now.

Anyways, I hope this bit of info provides some clarity to people who have, like myself, spent many a frustrated afternoon trying to convince the mouth-breathers of the world that "evolution" is more than just a theory.

RE: So Check It
By retrospooty on 12/30/2012 8:45:04 PM , Rating: 2
"Nobody is debating the fact that homo sapiens (humans) evolved from an ape-like creature over millions of years, and that we share a common ancestor with modern day chimps."

Yes they are. Several people on this thread are debating that we evolved from apes, and have on previous articles as well. it's absolutely phenomenal in this day in age that some people are actually ignorant enough to believe that we didn't evolve but they do. And they're very vocal about it, as hilarious as it is to hear. read some of these other post they are actually saying that the thousands and thousands of fossils found all over Africa in all different sediment layers from all different ages are all fake they're saying they're all fake. As if every scientist on earth are involved in a conspiracy to make people believe in evolution. It's absolutely ridiculous but they are saying it. they're saying the DNA evidence, archaeological evidence, geological evidence are all fake and or incorrect. Lol

RE: So Check It
By Piiman on 12/31/2012 4:11:16 PM , Rating: 2
They don't believe scientist but believe a book writen 2000 years ago and rewritten hundreds of times about a dude in the sky that controls everything and made us out of dirt. Amazing isn't it?

RE: So Check It
By retrospooty on 1/1/2013 2:37:37 PM , Rating: 2
LOL, I know right?

Seriously, just so everyone is on the same page and we all know where these nutjobs are coming from I urge you to go back and read the old testament (the first part of the bible). The god described there, isnt an all knowing all powerful being. The God in the Bible, is an insecure, immature, narrow minded, vindictive a$$hole. Seriously, go read it, It is soooo hilarious.

I am not non-religious myself. I do believe that there is "something" guiding the universe, something that created the laws of physics, something greater than ourselves, but I absolutely refuse to believe that the childish prick described in the bible is anyone's god. IF anything the God described in the bible is actually Satan becasue he's an evil lil' turd.

"So, I think the same thing of the music industry. They can't say that they're losing money, you know what I'm saying. They just probably don't have the same surplus that they had." -- Wu-Tang Clan founder RZA

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