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Author Topic:   Human Brain Evolution Was a 'Special Event'
skepticfaith
Member (Idle past 5721 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 1 of 65 (352674)
09-27-2006 4:39 PM


A recent article has confirmed that human brain evolution was special unlike anything else they have observed.
The full article can be found at:
Human Brain Evolution Was a 'Special Event' | HHMI
The key point here which gives Creationists a lot of fuel for their case is this quote:
quote:
One of the study's major surprises is the relatively large number of genes that have contributed to human brain evolution. “For a long time, people have debated about the genetic underpinning of human brain evolution,” said Lahn. “Is it a few mutations in a few genes, a lot of mutations in a few genes, or a lot of mutations in a lot of genes? The answer appears to be a lot of mutations in a lot of genes. We've done a rough calculation that the evolution of the human brain probably involves hundreds if not thousands of mutations in perhaps hundreds or thousands of genes”and even that is a conservative estimate.”
It is nothing short of spectacular that so many mutations in so many genes were acquired during the mere 20-25 million years of time in the evolutionary lineage leading to humans, according to Lahn. This means that selection has worked “extra-hard” during human evolution to create the powerful brain that exists in humans.
The whole questio is how did humans obtain so many mutations in such a small period of time? This is incredible even for evolutionists, but it is of course easier for creationists to explain.
So the question is : Is this special event a series of chance mutations that just happened to go the right way or divine intervention? [/b][/i]
Of course this goes back to the age old argument of beneficial mutations. But I am curious why do evolutionists themselves admit to a special event. It seems to me that they are somehow acknowledging a Divine Creation. Or at the very least, expressing incredulity towards the very process they claim to know about . That process of course being evolution driven by random beneficial mutations which has not been proven.

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AdminNWR
Inactive Member


Message 2 of 65 (352679)
09-27-2006 5:03 PM


Thread moved here from the Proposed New Topics forum.

  
Wepwawet
Member (Idle past 6108 days)
Posts: 85
From: Texas
Joined: 04-05-2006


Message 3 of 65 (352684)
09-27-2006 5:29 PM
Reply to: Message 1 by skepticfaith
09-27-2006 4:39 PM


This accelerated rate of evolution is consistent with the presence of selective forces in the human lineage that strongly favored larger and more complex brains. “The human lineage appears to have been subjected to very different selective regimes compared to most other lineages,” said Lahn. “Selection for greater intelligence and hence larger and more complex brains is far more intense during human evolution than during the evolution of other mammals.”
Sounds like the authors of the paper didn't consider the possibility that goddidit.
and...
To further examine the role of selection in the evolution of brain-related genes, Lahn and his colleagues divided these genes into two groups. One group contained genes involved in the development of the brain during embryonic, fetal and infancy stages. The other group consisted of genes involved in “housekeeping” functions of the brain necessary for neural cells to live and function. If intensified selection indeed drove the dramatic changes in the size and organization of the brain, the developmental genes would be expected to change faster than the housekeeping genes during human evolution. Sure enough, Lahn's group found that the developmental genes showed much higher rates of change than the housekeeping genes.
On reading this article (not the actual paper which appeared in a 2004 edition of Cell) it appears as though what really happened is that the researchers made predictions based on the Theory of Evolution and then examined the evidence to find that those predictions in fact appear. This paper is evidence that supports the ToE rather than creation. Specifically the paper shows that the changes are not a single event, but rather a series of events which occured more rapidly in the line leading to humans and macacques than it did in less related species.
Nothing to see here folks...move along.
Edited by Wepwawet, : Clarifying the point that humans and macacques share an evolutionary line...

When science and the Bible differ, science has obviously misinterpreted its data.
- Henry Morris, Head of Institute for Creation Research

This message is a reply to:
 Message 1 by skepticfaith, posted 09-27-2006 4:39 PM skepticfaith has replied

Replies to this message:
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skepticfaith
Member (Idle past 5721 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 4 of 65 (352686)
09-27-2006 5:41 PM
Reply to: Message 3 by Wepwawet
09-27-2006 5:29 PM


It still is 'Special'
of course they did not assume that God did it, but they still called it special - a special event.
Even from an evolution point of view, there is a lot to see here. How did such rapid change take place in such a short time?
quote:
It is nothing short of spectacular ...
And with the current experimentation with lab rats, its quite obvious that they have not been able to artificially create rats that are significantly more intellegent than their counterparts.
The whole process seems incredible even to the evolutionist - so there must be something groundbreaking about this story...

This message is a reply to:
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Chiroptera
Inactive Member


Message 5 of 65 (352688)
09-27-2006 5:52 PM
Reply to: Message 1 by skepticfaith
09-27-2006 4:39 PM


Let's see; thousands of mutations (at most, according to the article) in 20 million years (at the least, according to the article) -- that works out to
20 million / thousands = 20,000 years for a couple of mutations.
Is this really so unbelievable?

"The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one." -- George Bernard Shaw

This message is a reply to:
 Message 1 by skepticfaith, posted 09-27-2006 4:39 PM skepticfaith has replied

Replies to this message:
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Wepwawet
Member (Idle past 6108 days)
Posts: 85
From: Texas
Joined: 04-05-2006


Message 6 of 65 (352690)
09-27-2006 6:01 PM
Reply to: Message 4 by skepticfaith
09-27-2006 5:41 PM


Re: It still is 'Special'
of course they did not assume that God did it, but they still called it special - a special event.
A special event that ocurred over 20-25 million years and decided to take along primates for most of the ride? Despite the wording nobody in the paper contends that the changes ocurred due to a single event.
Even from an evolution point of view, there is a lot to see here. How did such rapid change take place in such a short time?
25 million years is a short time? That's 4166 and 2/3 times longer than YEC's think the earth has existed. Why some folks are saying we did all this evolutionizing and more just since Noah.
And with the current experimentation with lab rats, its quite obvious that they have not been able to artificially create rats that are significantly more intellegent than their counterparts.
Well if 25 million years is such a short time to achieve these results why would you expect to see similar results in less time? By the way, the timing is closer to 80 million years if you're going to talk about relating rats and humans. Would you mind referencing the findings of the experiments where they tried to genetically engineer hyper-intelligent rats? I'm sorry, episodes of Pinky and The Brain are not acceptable since Warner Brothers declined to present them for peer review. If you're going to claim we have failed you'd better be able to prove someone has tried.
The whole process seems incredible even to the evolutionist - so there must be something groundbreaking about this story...
You are mistaking incredible for unexplainable. Scientists see the evidence and they posit reasonable explanations...they are excited and delighted by their findings which give them greater insight. Nowhere do the authors even hint that they have shaken the foundations of the ToE or brought credible evidence to light for goddunitism. You're clutching at imaginary straws.

When science and the Bible differ, science has obviously misinterpreted its data.
- Henry Morris, Head of Institute for Creation Research

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subbie
Member (Idle past 1254 days)
Posts: 3509
Joined: 02-26-2006


Message 7 of 65 (352693)
09-27-2006 6:37 PM
Reply to: Message 1 by skepticfaith
09-27-2006 4:39 PM


This is incredible even for evolutionists, but it is of course easier for creationists to explain.
Of course it is. Creos are known throughout the scientific community for their lucid and well-reasoned explanations. And I'm sure we have all read dozens of papers by creos explaining 25 millions years of evolution.

Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin Franklin

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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 8 of 65 (352707)
09-27-2006 8:45 PM
Reply to: Message 1 by skepticfaith
09-27-2006 4:39 PM


A couple of points ...
(1) The 20 to 25 million years is based on the divergence of the human lineage from that of the macaque, and does not say when in that period the mutations occurred. Similar studies show much more brain mutation\selection in the human lineage than in the chimp lineage, cutting the time period down to 6 to 7 million years, except that we don't know the base values for macaque to chimp and how much more mutation\selection is evident in chimps vs macaques.
My feeling is that including chimps would show a higher rate and (but not all) of the mutations\selection occurred since {chimp\human} split. My reason for this feeling is both the major change in brain size in Homo sapiens (as noted in the article) and because:
(2) Sexual selection operates on every mating\generation. This means that any mechanism that employs sexual selection will consistently show a higher rate of selection than one that only employs survival. Survival is only tested in bad times, so it does not provide and selection pressure in good times (beyond basic viability).
The human brain shows signs of classical Fisherian run-away sexual selection (from the article linked in OP):
quote:
Humans have extraordinarily large and complex brains, even when compared with macaques and other non-human primates. The human brain is several times larger than that of the macaque”even after correcting for body size”and “it is far more complicated in terms of structure,” said Lahn.
So large it endangers the life of the mother at birth. So large it can't get larger (unless all births are by C-section and we 'evolve' a new technique for birth to avoid this problem).
(3) rates of mutation and "genetic clocks" are basically post hoc ergo propter hoc calculations rather than predictive in values.
I have trouble with "genetic clock" type inferences that seem to fall back into old stereotypical gradualism models of evolution that ignore (a) differential rates of selection beteen sexual and survival and (b) ignore periods of intense survival selection that can cause punk-eek type evolution rate changes.
Example again from the article:
quote:
They then obtained the rate of evolution for that gene by scaling the number of DNA changes to the amount of evolutionary time taken to make those changes.
They only consider the average rates within each period. There could easily be a range of rates that depend more on selection pressure acting on the populations than on the rates of mutation, so what you are seeing is not a change in rates of mutation, but an increased selection for change instead of for stasis.
Until some studies are done to delineate the actual maximum (minimum = 0) rates of changes possible and compare those to actual selection mechanisms and mutation rates, the whole concept of {faster\slower} is ill-defined and sloppy thinking.
In my, of course, humble (but sometimes arrogant) opinion ... (imochbsao?)
(4) the selection is for is not necessarily 'intelligence' in spite of what the article says:
quote:
“The human lineage appears to have been subjected to very different selective regimes compared to most other lineages,” said Lahn. “Selection for greater intelligence and hence larger and more complex brains is far more intense during human evolution than during the evolution of other mammals.”
I think this is more human hubris than fact. We like to think we are so much smarter than any other animal eh? Yet the range of human intelligence still overlaps the ranges in other animals.
If the selection is sexual, driven by mating preferences rather than survival, then the critical elements are the ones that benefit mating: creativity, dance, song, etc -- and brain capacity for 'intelligence' is a by-product. For anecdotal evidence that this is so, just look at who is usually listed as the 'sexiest' (= most matable) people: actors, artists, dancers, rock stars, and NOT nobel prize winners.
Enjoy.

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Rahvin
Member
Posts: 4032
Joined: 07-01-2005
Member Rating: 9.2


Message 9 of 65 (352719)
09-27-2006 9:49 PM
Reply to: Message 1 by skepticfaith
09-27-2006 4:39 PM


Oh, please. We already knew the human brain was special, becasue we are (theoretically, anyway) the most intelligent species on the planet, and (perhaps debatably) the only sentient species.
But to say that just becasue an individual adaptation is "special" doesn't give any credence to Creationism. It just means it's relatively unique. The platypus is evolutionarily weird. You could call its evolution "special." It doesn't mean it was specially Created by some deity.
You're nitpicking on the semantics of the article, latching on to the word "special" as if it means anything more than "gee, that's interesting." You'll notice the article also put the timeframe for the evolution of the human brain in the millions of years. While perhaps that is not as long as they expected to find for such a complex organ, it's still a far cry from 7-day Creationism. And the same arguments against ID still stand. The article doesn't change anything.

Every time a fundy breaks the laws of thermodynamics, Schroedinger probably kills his cat.

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skepticfaith
Member (Idle past 5721 days)
Posts: 71
From: NY, USA
Joined: 08-29-2006


Message 10 of 65 (352730)
09-27-2006 10:57 PM


The Gap
The mutations must could not have occurred long before homoerectus since we know that the Australopithecus had about the brain size of a chimpanzee.
So the mutations must have given rise to homo erectus - this cuts down the time span even before..Since while the brain size of sapiens is higher than erectus the major increase must have taken place just before and during the time of erectus...But there is no fossil evidence of any creature before erectus right and after Australopithecus.. .
That's why its incredible.
And why was suddenly brain size so important, obviously Australopithecus didn't need very large brains and they lasted for quite a while. What conditions would select for brains size in such a small space of time..

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RAZD
Member (Idle past 1405 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 11 of 65 (352731)
09-27-2006 11:12 PM
Reply to: Message 10 by skepticfaith
09-27-2006 10:57 PM


Re: The Gap
... we know that the Australopithecus had about the brain size of a chimpanzee.
But we don't know how much brain development separates Chimps and Macaques, so we can't claim it is all since we diverged from Chimps.
And why was suddenly brain size so important, ...
Is it? The real question is "what is important that results in a large brain" eh?

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Chiroptera
Inactive Member


Message 12 of 65 (352733)
09-27-2006 11:37 PM
Reply to: Message 10 by skepticfaith
09-27-2006 10:57 PM


Re: The Gap
quote:
The mutations must could not have occurred long before homoerectus since we know that the Australopithecus had about the brain size of a chimpanzee.
So? Even if it's "thousands" of mutations since Australopithecus, that's "thousands" in 5 million years, or about one mutation in 1000 years or so.
Still doesn't seem too unreasonable to me, but then, I'm not a creationist.

"The fact that a believer is happier than a skeptic is no more to the point than the fact that a drunken man is happier than a sober one." -- George Bernard Shaw

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ReverendDG
Member (Idle past 4110 days)
Posts: 1119
From: Topeka,kansas
Joined: 06-06-2005


Message 13 of 65 (352747)
09-28-2006 2:48 AM
Reply to: Message 1 by skepticfaith
09-27-2006 4:39 PM


The whole questio is how did humans obtain so many mutations in such a small period of time? This is incredible even for evolutionists, but it is of course easier for creationists to explain.
magic?
So the question is : Is this special event a series of chance mutations that just happened to go the right way or divine intervention?
not just mutation, also NS, special event is really not very telling of what happened, i think he was mean special as in important really, not a sperate thing that is more important than everything else like creationists use it
Of course this goes back to the age old argument of beneficial mutations. But I am curious why do evolutionists themselves admit to a special event. It seems to me that they are somehow acknowledging a Divine Creation. Or at the very least, expressing incredulity towards the very process they claim to know about . That process of course being evolution driven by random beneficial mutations which has not been proven.
i think you are drawing a big assuption from his use of special event, its kind of building a house on sand. sigh doesn't it get tiring repeating the same old nonsense over and over again?
its not just mutation its natural selection, he even says this in the quote
i'm thinking he's amazed by nature and its system, not that its magic

This message is a reply to:
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Equinox
Member (Idle past 5142 days)
Posts: 329
From: Michigan
Joined: 08-18-2006


Message 14 of 65 (352826)
09-28-2006 12:50 PM
Reply to: Message 10 by skepticfaith
09-27-2006 10:57 PM


Re: The Gap
sf wrote:
quote:
The mutations must could not have occurred long before homoerectus since we know that the Australopithecus had about the brain size of a chimpanzee.
So the mutations must have given rise to homo erectus - this cuts down the time span even before..Since while the brain size of sapiens is higher than erectus the major increase must have taken place just before and during the time of erectus...But there is no fossil evidence of any creature before erectus right and after Australopithecus.. .
Wha? There are tons of fossils between Aust. A and H. erectus. Here is a graph that shows the species:
Hominid Species
(look at the bottom of the page)
There are species named in there, though of course with the smooth evolution from Aust. A. to us, deciding how to slice up the progression into species is kinda arbitrary (we can't test mating capability, obviously). It's like if you took a rachet set, and if you said:
4 mm to 12 mm = species fred
13 mm to 18 mm = species jim
19 mm to 27 mm = species sam
Or you could say instead:
4 mm to 8 mm = species lucy
9 mm to 11 mm = species sue
12 mm to 15 mm = species linda
16 mm to 20 mm = species jenny
21 mm to 24 mm = species bonnie
25 to 27 mm = species heather
To see this progression, here are a few of the skulls we have:
29 Evidences for Macroevolution: Part 1
one thing that confuses things a bit is the fact that there appear to be (and certainly logically could be) side branches. So in addition to the rachet set, you have several parts from anther ratchet set in there. The proposed robustus side branch is easy to seen in the first link.
quote:
That's why its incredible.
As Dr. pointed out, it seems that the word "special" is being used in one way in the article, and another by you. "special" can mean "really neat, and rare", which is what it seems they mean. Examples of this are sundogs, gysers, supernovae, and come-from-behind football victories.
You seem to mean "special" in the other way, which means "only happening once" or "miraculous" or "outside of the realm of normal possibility". Examples are alleged events like the resurrection of Jesus, the inspiration of Mohammad, the enlightenment of buddha, or the appearance of the virgin of guatemala.
quote:
What conditions would select for brains size in such a small space of time..
As was pointed out, the space of time isn't small. Even if we jump all the way up to Aust A (though the article is about the 25 million years since our ancestors were like monkeys), then we are still talking about millions of years. Doing the math, even then we have thousands of years per mutation - quite easy. The selection pressure Dr. pointed out is easily enough to bring those out.
It's certainly true our brains are special. Convergent evolution shows that evolution is quite capable of making a lot of special things. Hell, eyes have evolved separately at least 4 different times (molluscs to a squid eye, rattlesnakes have a new set of infrared eyes in addition to their normal ones, crustacean eyes, and our eyes). Same for wings - there are over a half dozen times flight has evolved. Brains have evolved many times too, though none as good as ours. Parrots have evolved a brain much larger than our last common reptilian ancestor with time, octopi have decent brains, and our last common ancestor with them was barely multicellular, dolphins too have an impressive brain - bigger than our in proportion to our bodies - and our last common ancestor was less than a rat.
Overall, the fossils (along with molecular evidence) shows that the evolution of the human brain was a really cool event, but quite consistent with what we know is possible as for evolutionary speed.
have a fun day-

This message is a reply to:
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Taz
Member (Idle past 3291 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 15 of 65 (352846)
09-28-2006 1:41 PM
Reply to: Message 4 by skepticfaith
09-27-2006 5:41 PM


Re: It still is 'Special'
skepticfaith writes:
How did such rapid change take place in such a short time?
Define "short".
PS I just went through and read other people's posts on this point. You haven't responded yet. I'd like to give you an opportunity to define what you meant as "short".
PPS Don't try to ignore this simple request.
Edited by gasby, : No reason given.

This message is a reply to:
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