Posted on 12/29/2004 9:14:28 AM PST by aculeus
Emergence of society may have spurred growth
The sophistication of the human brain is not simply the result of steady evolution, according to new research. Instead, humans are truly privileged animals with brains that have developed in a type of extraordinarily fast evolution that is unique to the species.
"Simply put, evolution has been working very hard to produce us humans," said Bruce Lahn, an assistant professor of human genetics at the University of Chicago and an investigator at the Howard Hughes Medical Institute.
"Our study offers the first genetic evidence that humans occupy a unique position in the tree of life."
Professor Lahn's research, published this week in the journal Cell, suggests that humans evolved their cognitive abilities not owing to a few sporadic and accidental genetic mutations - as is the usual way with traits in living things - but rather from an enormous number of mutations in a short period of time, acquired though an intense selection process favouring complex cognitive abilities.
Evolutionary biologists generally argue that humans have evolved in much the same way as all other life on Earth. Mutations in genes from one generation to the next sometimes give rise to new adaptations to a creature's environment.
Those best adapted to their environment are more likely to survive and pass on their genes to the next generation.
The evolution of a large brain in humans, then, can be seen as similar to the process that leads to longer tusks or bigger antlers. In general terms, and after scaling for body size, brains get bigger and more complex as animals get bigger.
But with humans, the relative size of the brain does not fit the trend - our brains are disproportionately big, much bigger even than the brains of other non-human primates, including our closest relatives, chimpanzees.
Prof Lahn's team examined the DNA of 214 genes involved in brain development in humans, macaques, rats and mice.
By comparing mutations that had no effect on the function of the genes with those mutations that did, they came up with a measure of the pressure of natural selection on those genes.
The scientists found that the human brain's genes had gone through an intense amount of evolution in a short amount of time - a process that far outstripped the evolution of the genes of other animals.
"We've proven that there is a big distinction," Prof Lahn said. "Human evolution is, in fact, a privileged process because it involves a large number of mutations in a large number of genes.
"To accomplish so much in so little evolutionary time - a few tens of millions of years - requires a selective process that is perhaps categorically different from the typical processes of acquiring new biological traits."
As for how all of this happened, the professor suggests that the development of human society may be the reason.
In an increasingly social environment, greater cognitive abilities probably became more of an advantage.
"As humans become more social, differences in intelligence will translate into much greater differences in fitness, because you can manipulate your social structure to your advantage," he said.
"Even devoid of the social context, as humans become more intelligent, it might create a situation where being a little smarter matters a lot.
"The making of the large human brain is not just the neurological equivalent of making a large antler. Rather, it required a level of selection that's unprecedented."
Guardian Unlimited © Guardian Newspapers Limited 2004
Ah. You were discussing a very specific set of fossils. That was not clear in the original post. Pardon.
"Evolution has been working hard to produce us as humans"
This suggests that a foolhardy theory is assigned anthromorphic qualities, such as the ability to plan for an outcome. This tripe does not deserve any type of quality of discussion. Even my worthy proevolutionist must be completely embarrassed by what this post hole digger (PhD) is pumping out. Not to be too harsh but to assignment but this guy has assigned a purpose of design to a theory of evolution as if there is an evolutioner who is thinking that is involved.
What's the bit about "society?" Apes are highly social (except for orangutans.) It's the *kind* of society that produces intense selective pressure for intelligence.
"The theory of natural evolution, understood in a sense that does not exclude divine causality, is not in principle opposed to the truth about the creation of the visible world, as presented in the Book of Genesis."
Thank you.
I guess kinda up to her.
Does she fulfil ALL the requirements of the Jewish law as found in her Holy Writings??
I think somewhere in The City of God St. Augustine also discussed the idea of "seeds" of characteristics over time turning into the differences between various animals.
Lot's of print with no evidence.
Many references to "probably".
No species transition.
Cites the Lucy fraud where the hip and knee bones are found hundreds of yards apart laterally and several yards difference in depth.
Why sure!
It's obvious that a whole lot of SOCIETYING was going on den!
Yes, but finding the meaning that makes the best sense can be humorous. Or humerus in this context.
Where cAN WE READ ABOUT THESE PROPHECIES?
Several years ago Scientific American did an overview article of whale evolution from predatory land animals. Excavations in Pakistan from 1960s-1980s basically showed the whole progression, with *lots* of intermediate forms.
Well if you read my initial post you would see that I don't attempt to explain creation.
Instead, I suggest that creationists focus on exposing the lack of science associated with explaining evolution.
post 191 tried to overwhelm with a volume of print.
When the volume is examined , it fails.
Where are the pic's of the supposed fossils of one species in transition to another?
Giving a latin name to a series, and assert one begat the other is falacious.
I guess they evolved themselves to death.
Side Note:
Are Evolutionists for or against repairing any 'birth defects' in their offspring?
You "E" folks wanna reply??
Even so, a simple shelf won't be adequate. I've read that there are about 300 complete Neanderthal skeletons that have been found. Source. And that's just Neanderthal. The older species are far more difficult to find, intact or partial, and are obviously far fewer.
Unlike the "E" folks here, who think they are riding first class.
Workin' on it. Takes time to fabricate them. The conspiracy is short-handed right now.
"leads them to ..." what? I don't know this old saying...
I have arbitrarily made a cutoff to exclude anything recent such as Neanderthals because that is current events rather than fossil records.
Which "race" would that be? The black Jews of Ethiopia who are indistinguishably African? The Russian Jews? My one friend's children whose mother converted from Scottish Anglicanism to Judaism? The original Sumerian of Abraham?
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