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
Translation: "Once again, we are confronted by evidence that completely goes against the Darwinist paradigm, but we're going to avoid the obvious inferences by again describing evolution in personified terms, i.e. 'it's working hard . . .'"
What makes you think God isn't an alien? If there is a God he certainly isn't of this world.
It took only one day. The sixth.
Creationists ARE the 'Missing Link'.
You're kidding, right?
It's not working hard the Darwinettes are working hard to explain how rocks turned into sludge/slime and we "appeared" with brains.
They just make this stuff up as they go along, don't they? I mean, as the need arises.
"Our study offers the first genetic evidence that humans occupy a unique position in the tree of life."
Doesn't he know there are no unique positions in evolution. Why must he give fodder for the enemy.
HeHe...
I don't know whether you are serious. By "alien," I mean a creature from a species that originated off-Earth. "God" as traditionally understood does not fit that definition (not a creature, for starters, but the Creator).
Remember, dogs are NOT simply made of 'dog stuff', nor cows 'cow stuff' ...
All fossils are transitionary by definition -- organisms either evolve or they go extinct facing ever-changing conditions. If you're talking about documented evolution, it exists in abundance. Just one of many examples:
From the Oligocene onward, the main carnivore lineages continued to diverge. Here is the dog/bear line.
Dogs:
Cynodictis (late Eocene) -- First known arctoid (undifferentiated dog/bear).
Hesperocyon (early Oligocene) -- A later arctoid. Compared to miacids like Paroodectes, limbs have elongated, carnassials are more specialized, braincase is larger. From here, the main line of canid evolution can be traced in North America, with bears branching out into a Holarctic distribution.
Cynodesmus (Miocene) -- First true dog. The dog lineage continued through Tomarctus (Pliocene) to the modern dogs, wolves, & foxes, Canis (Pleistocene).
Bears:
Cynodictis (see above)
Hesperocyon (see above)
Ursavus elmensis (mid-Oligocene) -- A small, heavy doglike animal, intermediate between arctoids and bears. Still had slicing carnassials & all its premolars, but molars were becoming squarer. Later specimens of Ursavus became larger, with squarer, more bear-like, molars.
Protursus simpsoni (Pliocene; also "Indarctos") -- Sheepdog-sized. Carnassial teeth have no shearing action, molars are square, shorter tail, heavy limbs. Transitional to the modern genus Ursus.
Ursus minimus (Pliocene) -- First little bear, with very bearlike molars, but still had the first premolars and slender canines. Shows gradual tooth changes and increase in body size as the ice age approached. Gave rise to the modern black bears (U. americanus & U. thibetanus), which haven't changed much since the Pliocene, and also smoothly evolved to the next species, U. etruscus:
Ursus etruscus (late Pliocene) -- A larger bear, similar to our brown bear but with more primitive dentition. Molars big & square. First premolars small, and got smaller over time. Canines stouter. In Europe, gradually evolved into:
Ursus savini (late Pleistocene, 1 Ma) -- Very similar to the brown bear. Some individuals didn't have the first premolars at all, while others had little vestigial premolars. Tendency toward domed forehead. Slowly split into a European population and an Asian population.
U. spelaeus (late Pleistocene) -- The recently extinct giant cave bear, with a highly domed forehead. Clearly derived from the European population of U. savini, in a smooth transition. The species boundary is arbitrarily set at about 300,000 years ago.
U. arctos (late Pleistocene) -- The brown ("grizzly") bear, clearly derived from the Asian population of U. savini about 800,000 years ago.. Spread into the Europe, & to the New World.
U. maritimus (late Pleistocene) -- The polar bear. Very similar to a local population of brown bear, U. arctos beringianus that lived in Kamchatka about 500,000 years ago (Kurten 1964).
The transitions between each of these bear species are very well documented. For most of the transitions there are superb series of transitional specimens leading right across the species "boundaries". See Kurten (1976) for basic info on bear evolution.
Sorta like 'particle physics', computers and automotive technology; we just roll it out of Area 51 when needed ...
Gotta love the way something like this pops up, that lies LIGHT-YEARS outside the evolution model we've had pounded into us, and bingo, there's zero mention of the fact that they were wrong. Only a new twist to force-fit unexpected findings into their tortured logic. Evolutionists are so incredibly predictable and boring.
Doesn't matter who you are. If you're reading these words, YOU will take a knee before the Creator, and with your mouth you will acknowledge that Jesus Christ is Lord. You have a choice as to the future you'll have ahead of you at that point, but you'll have no choice on the kneeling and confessing.
MM
Huh? You can fit a triceratops skull (just ONE mind you) on a shelf? Are you like a giant or something?
Yes, it is called science. You start with a problem, you propose a hypothetical solution and you look for evidence to support or refute that hypothesis. So yes, scientists "just make" up hypotheses. Because that's what they're paid to do. What competing scientific method would you suggest?
Thanks, I'll pass that along to my Rabbi.
Creationists are not. They are an evolutionary dead-end.
I call this coming generation the "throw away the instructions generation". It seems appropriate.
I got the idea after seeing one youngster open a Christmas present and promprlty, knowingly and intentionally throw away the instructions.
Tell me about it. I've been fighting a nasty bug/sinus infection for a month. You think it's cured, then back it comes.
One sometimes reads that all hominid fossils could fit in a coffin, or on a table, or a billiard table. That is a misleading image, as there are now thousands of hominid fossils. They are however mostly fragmentary, often consisting of single bones or isolated teeth. Complete skulls and skeletons are rare.Source: Prominent Hominid Fossils.
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