Human Brain Evolution Was a 'Special Event'

sf wrote:

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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.. .

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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 samOr 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 heatherTo see this progression, here are a few of the skulls we have:
29 Evidences for Macroevolution: Part 1one 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.

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That's why its incredible.

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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.

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What conditions would select for brains size in such a small space of time..

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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-

skepticfaith writes:

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The problem with evolution theory is that it still does not have the smoking gun - the actual mechanism of beneficial mutations charted out.

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OK, if you mean that brain beneficial mutations are somehow different than mutations in general, that's silly. We do have the actual mechanism of mutation charted out - there are many types, such as these:

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You mentioned wondering about the details of mutations. Here are some basic types of mutations and how they work:
Duplication of a stretch of DNA. This is like accidentally copying part of a book twice. Example - when making a copy of a book that has chapters 1, 2, 3,4,5,6,7,8,9,10,11, 12, you end up with a book that has chapters 1, 2, 3,4,5,6,7,3,4,5,6,7,8,9,10,11, 12

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Deletion of a base pair. AATCTGTC becomes ATCTGTC

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Addition of base pair AATCTGTC becomes ACATCTGTC

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Transposition (like a mirror) AATCTGTC becomes CTGTCTAA

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All of these can have no effect, an effect which is selected for, or an affect which is selected against.

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To add information, first, take a functional gene, and make an extra copy using the duplication mutation. That won’t hurt the organism, since the second copy is simply redundant. Then use any of the other mutation methods so as to make the second copy do something new. The organism still has the original copy doing whatever it is supposed to do, but now has the added ability of whatever the new gene does (such as digesting nylon, as in a species of bacteria).

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The process can also add entire chromosomes .

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Now, as we've discussed many times, this leads to demonstrated instances of beneficial mutations, as even Faith has agreed. Examples come up all the time, like Apo, conquistador algae, beautiful buttocks, muscles, and on and on. I think so far we have around 20 examples of beneficial mutations. Many were discussed on this thread:http://EvC Forum: Natural Limitation to Evolutionary Processes (2/14/05) -->EvC Forum: Natural Limitation to Evolutionary Processes (2/14/05)OK, so now that we have the smoking gun of the mechanism for the formation of beneficial mutations, and the demonstrated instance of this over and over, of course this could happen in the brain just as anywhere else in the body. The brain uses DNA - it's not some alien organ.Speaking of observed brain evolution in history, yes that has been shown - an article on that came out in the last year. It was about genes that help with language use.

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And I am assuming NO ONE knows what these couple of mutations are? They stimulated a part of the brain - increasing its cranial capacity ?

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*sigh*OK, we have muliple levels of misunderstanding here (or deliberate obfuscation).
First, Chiro was mentioning a rate - 20,000 years for a few mutations. Your response is like if I said my car drives at 30 miles per hour, and you say "yes, but has anyone found that missing hour?".The rate Chiro mentioned was to show that this number of mutations in the 25 million years mentioned really isn't that fast in everyday terms.As far as those "two genes" goes - yes, they do know many of them. It says so right in the article. They looked at 214 genes, and found the changes in them (thousands of them) - that's what a mutation is.

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Obviously when you think about it - these changes must have happned from Australopithecus to erectus not before because this creature has a brain the size of a chimpanzee.

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again, no. Did you read my post #14 on the last page? Also, don't forget that in nature, things often work geometrically not linearly. For instance, if AA had evolved brain structures that could do good thinking, then doubling or tripling those structures only takes a doubling type mutation - you don't have to start from scratch.Have a fun day-Edited by Equinox, : typoEdited by Equinox, : No reason given.

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-Equinox_ _ _ ___ _ _ _
You know, it's probably already answered at An Index to Creationist Claims...
(Equinox is a Naturalistic Pagan -  Naturalistic Paganism Home)