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
atlaw: "Funny, I don't recall being nasty to you. Perhaps you should take your own admonitions against ad hominem to heart."
Unless you are able to quote me where I made a personal attack against you as "being nasty" or any other such thing, we will just have to assume that you suffer from paranoid perceptions.
atlaw: "That said, was I somehow wrong in my assessment of your stand on the difference between "micro" and "macro" evolution? If so, perhaps you could correct me (as opposed to simply ducking and dodging)."
You do have your "perceptions", don't you? Not only did you perceive me to be accusing you of "being nasty", but now you're accusing me of "ducking and dodging".
If I post all the links to my dealiings with you on this thread, the intellectually honest reader will have to admit that if there was any "ducking and dodging" going on, you were the one engaging in it.
If you don't get it this time, please pick on someone else, OK? Here you go one last time:
The theory of biological evolution maintains that living things (plants, animals, humans, etc.) have descended with modifiction from shared common ancestors.
[1. Macroevolution (Darwinianism) refers to large-scale changes - where one species transforms into another completely different species.
For example, birds are said to have evolved from dinosaurs.
This process would require the addition of new information to the genetic code. [DNA]
[NOTE: It is IMPOSSIBLE for "new information" to be naturally added to DNA, so that should end it right there for rational people who don't have an agenda.]
[1.-a] Gradualism refers to the theory that macroevolution proceeds through the slow and basically constant accumulation of many small changes in order to effect large changes. This theory predicts that the fossil record would provide abundant evidence of intermediary life forms as one species is progressively transformed into another.]
[2.] Microevolution refers to changes in the gene expressions of a given type of organism but does not produce a completely different species. This is perfectly normal and natural and is indeed what occurs.
For example, through selective breeding, dogs ranging from Great Danes to Chihuahuas have been produced from wolves. That process doesn't require new information because the changes are a function of the genetic makeup [DNA] already present in the gene pool of the species. [Note: No "new information" in the DNA is needed].
The general public seems blithely unaware that no transitions from one species to another [known as macroevolution / Darwinianism) exist, even though it is common knowledge among paleontologists. That's why novel theories ---[ involving Archaeopteryx (false links between reptiles and birds), pro-avises (pure figment of someone's imagination;science fiction), and punctuated equilibrium (a new species appears all at once fully formed aka the theory of the "hopeful monster") ]--- are constantly "evolving".
Hahahahaha
"Natural selection" could include selection by survival of a natural event such as an asteroid colliding with earth. How do you explain the apparently missing fossils? Deistic sense of humor?
And rightly so.
"Evolutionists who assert things like this are kooks who should not be listened to: "... at no very distant date..an endless number of the lower races will have been eliminated by the higher civilized races throughout the world", and "the chief distinction in the intellectual powers of the two sexes is shown by man's attaining to a higher eminence, in whatever he takes up, than can a woman - whether requiring deep thought, reason or imagination, or merely the use of the senses and hands. ... We may also infer ...[that] the average of mental power in man must be above that of a woman". ~ Charles Darwin
"No rational man, cognizant of the facts, believes that the average Negro is the equal, still less the superior, of the white man... It is simply incredible [to think] that ... he will be able to successfully with his bigger-brained and smaller-jawed rival, in a contest which is to be carried on by thoughts and not bites." ~ Thomas Huxley Darwin's best student - and the man most responsible for advancing macroevolution (Darwinianism)"
"If the unfit survived indefinately, they would continure to infect the fit with their genes. The result is that the more fit genes would be diluted and compromised by the less fit genes and evolution could not take place. The concept of evolution demands death. Death is thus as natural to evolution as it is foreign to biblical creation. The Bible teaches that death is a foreigner, a condition superimposed upon humans and nature after creation." ~ Darwinist / macroevolutionist, Marvin Lubenow."
I agree. They should not be listened to, nor should their ideas be taught to impressionable school children.
"... every Darwinist does argue from an unproven and unprovable premise: that something can come out of nothing. That takes "Darwinianism" out of the realm of science and into the realm of blind faith religion. If you want to have a theological debate, that's one thing. But don't assert that evolution is factually correct ...and don't force the state to spread that doctrine in schools.
I agree.
"You simply don't know what the hell you are talking about. ... It's called talking out of your ass."
Whaaaat??? I was just agreeing with you. Hahahaha
Too much of creation science is about missing what is available. Let's just do the vertebrates for now.
But let's back up a bit and illustrate what a slippery, dishonest game is being played here. You posted an extraordinary claim that something reasonably to be expected from the fossil record is missing. The post alludes to a specific period right after what mainstream science calls the Cretacious/Tertiary extinction, the one in which the dinosaurs disappeared. Genuinely unfamiliar with this particular claim, I asked you what you were talking about.
And, SHAZAM! Now any gap anywhere in anything is proof of whatever in Hell you were saying.
Oh, I must have missed the evidence of a fossile record illustrate complete and clear lineage of all animals. Please provide YOUR source for that.
Sliding goalposts! If you had a specific objection up front, as you were making a brave show of pretending, why are you cowering in a different trench now? What happened?
I see the "moving goalposts" fallacy on this forum all the time. Called on something not particularly defensible, but upon which he had hoped to slide, the creationist just pretends he had the bar set higher all along.
There aren't any honest creationists, and there are no good arguments for creationism. Except for that, creationism is great science.
It continues to highly entertain me that Darwinians cover every base yet stick to their illusion of falsifiability.
From post 299
Faster reproductive rates result in faster evolution, for example, which is why bacteria and viruses evolve much faster than, say, fruit flies, and fruit flies evolve faster than horses, etc.
ok....
but HOW did the SEXUAL creatures arise??
demonstrate to whom?
However, it IS possible for new info to be added to a computer program that is stored in RAM, by random cosmic ray changes to bit polarity.
I wonder how many times we've gotten programs that still DO something functional (live) after this process occurs?
Just curious, how much do you remember from the last time we did this?
I'm pretty sure the bible hasn't been telling anyone anything for 6 or 7 thousand years.
Below, a lesser light paraphrases a more detailed treatment in a book by Schopf.
http://www.freerepublic.com/forum/a3a535d71403d.htm#111.
A point on sexual versus asexual (from the introductory year in which the online Britannica was a free site):
Since viruses survive better than human beings, why did we bother to evolve?
Why do I keep catching crap like this from people who obviously know better?
The answer to that question is the answer to all the others. Why not "teach the controversy?" Why not "teach both theories?" Why not teach the valid "alternatives" (and / or "the valid objections") to evolution?
The only controversy is outside of science, so the controversy does not belong in science class. (Unless perhaps we spend some little time teaching the kids how to tell crackpot presentations from serious science, in which case there's exactly that much room for analysis of creationist claims.) There is only one reasonably tight scientific hypothesis square with the evidence and it isn't creation or ID. There are no alternatives and no objections which are reasonable or even honest.
Or, as sometimes shows up around here: "What are you afraid of?"
Which is kinda like gays labeling the attitude of normal men as "homophobia." It ain't fear. It's revulsion.
As my mind fails, I seem to have forgot the actual text of the lawyerly dodge in mid-post. It was reproductive rates and not lateral transfer. The fallacy is the same:
A bacterium is not a eukaryote.
A eukaryote is a cell with a nucleus. (As opposed to a prokaryote, which is a cell without a nucleus.) Plants and animals are made up of eukaryotes.Single-celled eukaryotes reproduce faster than multi-cellular eukaryotes, but bacteria are in another league. Screamingly fast with streamlined, all-gene-no-junk DNA. And bacteria have lateral transfer and eukaryotes don't.A eukaryote might be 25 microns across, and a nucleus is about 5 microns across. So, one cubic inch of flesh might hold a billion eukaryotes. An adult human has about a trillion eukaryotes.
An E. coli bacteria is a prokaryote and is about one micron across. So, about 10,000 E. coli would fit inside one eukaryote. About a thousand viruses could fit inside one E. coli.
So the path to sexual eukaryote multicellulars logically goes through a slowdown of evolution rates when lateral transfer is lost and fast reproduction is lost. This probably happens in the larger archaebacteria before the first true eukaryotes even appear. The invention of sex by multicellulars will then boost evolution rates by mechanisms fully explained.
Anyone understanding all of the preceding but nevertheless waving simultaneously true and logical statements, inviting the listener to perceive a contradiction where there is none, demonstrates what is meant by the term "Twist and Shout."
Thing is, we can see what to be afraid of.
"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. "
Oh my, finally a peer review that says it all, "evolution" is a 'god'.
I love it!
So much better than the old "If we descended from apes how come apes still exist?"
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