Design and the Brain

[Vene]

That weird because I see lots of chaos and randomness. Weird, eh?

Especially when you try to learn how they all fit together. It's a mess, I would think that a decent designer would have a much simpler system. And backups would be nice. And how about doing something with the left and right hemispheres, they can only communicate through the corpus callosum.

And I really think we deserve some quality trolls over here.

 

[Chalnoth]

So basically if you give a species enough time, they are bound to become superior. If I leave my car in the snow for years, I do not think it will look like a better car in the spring.

Superior? No. If you give a species enough time, it is bound to become different. This is because selective pressure changes over time. Evolution has no notion of superiority, only survival and reproduction. But since it is competing with other species that are also evolving, it may not even become better at survival or reproduction with time: it may die out if other species out-evolve it, or the environment changes too dramatically for it to evolve to the new environment.

 

[BeamMeUpScotty]

When I look at the human brain, I see workmanship and intelligent design.

If the human body was designed why were the reproductive and waste removal systems put in the same place using some of the same body parts?

 

[Vene]

If the human body was designed why were the reproductive and waste removal systems put in the same place using some of the same body parts?

I prefer to point out the eye. The sensory receptors are behind the nerves that transmit the information. And since the optic nerve enters the eye we all have a blind spot. The octopus doesn't have this blind spot. The only reasonable conclusion is that if there is a creator, s/he likes the octopus more than us.

 

[Naraoia]

The only reasonable conclusion is that if there is a creator, s/he likes the octopus more than us.

Octopi are without doubt far cuter than humans are. If I were a creator I'd certainly like them better. Ha.

 

[Vene]

Octopi are without doubt far cuter than humans are. If I were a creator I'd certainly like them better. Ha.

And they don't blow each other to pieces with explosives. Nor do they launch metal projectiles at each other with the purpose of ripping messy holes in their victim.

I would like the octopus better too.

 

[Byelotsar]

And they don't blow each other to pieces with explosives. Nor do they launch metal projectiles at each other with the purpose of ripping messy holes in their victim.

I would like the octopus better too.

All part of the atheist octopus conspiracy. Clearly you've fallen for it hook, line, and sinker.

As far as I'm concerned, proof that any Creator must hate humanity is in the knee. Honestly, it's the product of a madman.

 

[BeamMeUpScotty]

Octopi are without doubt far cuter than humans are. If I were a creator I'd certainly like them better. Ha.

No, octopi are clearly proof of the Flying Spaghetti Monster as they seem to be made more in his image than we are in God's.

 

[Blayz]

All part of the atheist octopus conspiracy. Clearly you've fallen for it hook, line, and sinker.

As far as I'm concerned, proof that any Creator must hate humanity is in the knee. Honestly, it's the product of a madman.

Nah, I vote for a quadruped arrangement of internal organs in a bipdeal organism.

And God said "let there be hernia and spontaneous pneumothorax..."

 

[Blayz]

It fasinates me that evolutionists are unconcerned about the lack of a scientific explanation or a genetic basis for this unprecedented expansion.

It fasinates me that someone would use a scientific paper as evidence of science's "disinterest"


At any rate, A mate of mine that is currently working on the opposum genome suggested that heightened intelligence shows all the hall marks of sexual selection.

A more interesting question is not why are we smarter, but why did we stop getting smarter?

 

[USincognito]

Our ancestor would have had to triple their cranial capacity awfully fast.

6-7 million years isn't all that fast, but because Mark thinks the Earth is 6,000 years old he has trouble grasping how long a time frame we're looking at.

{snip image}

Uh oh, Mark's cheating again. The image he uses to show how "different" human and chimp brains are because of cranial capacity actually comes from an article that uses similarities between human and chimp brains as evidence of hominid evolution.
Here's the whole article:
http://www.nature.com/nature/journal/v422/n6934/full/nature01495.html
Here's the caption and relevant paragraph for that image:

Figure 2: Comparative neuroanatomy of humans and chimpanzees.
Lateral views of the left hemispheres of a modern human and a chimpanzee brain. Although the overall skull sizes are roughly comparable, the human cranial capacity and brain are much larger. a, Two areas of the human brain that are associated with communication are shown: Broca's area in the frontal lobe and Wernicke's area, which overlaps the posterior temporal lobe and parts of the parietal lobe. In the left hemisphere, Broca's area is larger, as is the planum temporale, which lies below the surface in Wernicke's area. b, These asymmetries have been found in corresponding regions of chimpanzee brains15,17, suggesting that the areas in humans might be elaborations of a pre-existing communication centre in a common ancestor of apes and humans.
------------
A second area of interest is Wernicke's posterior receptive language area in the temporal lobe (Fig. 2). A site within this area, the planum temporale, is implicated in human communication (both spoken and gestural) and musical talent, and also shows a left-hemisphere dominance. In most humans, the Sylvian fissure associated with the left planum temporale extends more posteriorly. Evidence for this asymmetry has been found in fossil endocasts in H. habilis, H. erectus and H. neanderthalensis16. More importantly, an asymmetrical planum temporale pattern has recently been demonstrated in chimpanzees17, 18 (Fig. 2).

Evolutionists simply don't have a genetic basis for how this is possible. It's not just the size but the density and the radical development of genes that would have remained virtually unchanged since the Cambrian Explosion.

{snip abstract quote}

You've had a year and a half to contact the authors of the HAR1 paper and tell them you've found the magic bullet to kill hominid evolution. If your position is so tenable, why haven't you done so?

And Mark's wrong about the human brain being a whole new invention after our split from our ape LCA. From the Nature article he lifted that photo above:

Was human evolution special?

The magnitude, rate and pattern of change during hominin evolution, inferred from the fossil record, comparative neuroanatomy and embryology, provide the essential foundation for approaching the genetics of human evolution. From the studies discussed above, five key points emerge that have a bearing on attempts to reconstruct the genetic events that underlie the origin and modification of human traits.

First, trait evolution was nonlinear. The 1,000-cm3 increase in brain size over 5–7 Myr did not occur at the same relative rate in hominin phylogeny: it was static at times, faster in some intervals, and reversed slightly more recently. Second, most trait evolution can be characterized as simple quantitative changes (that is, traits are continuous). Third, evolutionary rates were not at all exceptional with respect to mammalian evolution. For example, fossil horse lineages in the late Pliocene–Pleistocene show similar rates of body-size and other character changes as do those of hominids31. Fourth, much evolutionary change preceded the origin of the Homo genus and of H. sapiens: the history of our species represents just the last 3% of the time span of hominin evolution (Fig. 1). And fifth, many characters are present not only in humans, but also in apes. This suggests that modification of existing structures and developmental pathways, rather than the invention of new features, underlies much of human evolution.

These observations indicate that morphological evolution in hominins was not special, but the product of genetic and developmental changes typical of other mammals and animals.

It fasinates me that evolutionists are unconcerned about the lack of a scientific explanation or a genetic basis for this unprecedented expansion.

Of course all one has to do is enter the right words into a search engine and one can see work is being done. Take the Google results for "genetic basis for human brain evolution".

 

[mark kennedy]

due to a diet very high in protein, as compared with our earlier ancestors, humans were able to get protien through there diets. Do you know where the body gets protein if you dont have enough of it in your diet? It gets it from your brain. thats right, your brain. your body will metabolize your brain if you dont get enough.

That's absurd, the brain can only increase in size, density and complexity when protein coding genes are altered at an amino acid sequence level.

Thats the first way our ancestors tripled their brain size.

No it's not, this is one of the things that would have had to occur and there is no known molecular mechanism to facilitate such a major overhaul of such a highly conserved gene.

HAR1 lies in a pair of novel non-coding RNA genes

The 118-bp HAR1 region showed the most dramatically accelerated change (FDR-adjusted P , 0.0005), with an estimated 18 substitutions in the human lineage since the human–chimpanzee ancestor, compared with the expected 0.27 substitutions on the basis of the slow rate of change in this region in other amniotes (Supplementary Notes S3). Only two bases (out of 118) are changed between chimpanzee and chicken, indicating that the region was present and functional in our ancestor at least 310 million years (Myr) ago. No orthologue of HAR1 was detected in the frog (Xenopus tropicalis), any of the available fish genomes (zebrafish, Takifugu and Tetraodon), or in any invertebrate lineage, indicating that it originated no more than about 400Myr ago (An RNA gene expressed during cortical development evolved rapidly in humans, Nature 443, 167-172 14 September 2006)​

the second one is that it was obviously beneficial for our ancestors to have higher brain capacity because this converges an advantage because you can hunt more effectively if you are smarter and more clever

That is assuming that such an adaptive development is possible. In fact, you are relying exclusively on an a priori assumption. Science has never been nor can it be directed by these naturalistic assumptions but evolutionists would have you believe that science and supposition are synonymous, that's absurd.

 

[necroforest]

So basically if you give a species enough time, they are bound to become superior. If I leave my car in the snow for years, I do not think it will look like a better car in the spring.

I didn't know cars could replicate themselves?

 

[mark kennedy]

6-7 million years isn't all that fast, but because Mark thinks the Earth is 6,000 years old he has trouble grasping how long a time frame we're looking at.

The unprecedented expansion of the human brain started 2 mya according to natural history.

The average brain weight would have to go from 400-450g, 2 1/2 MY ago to 1350–1450 g 0.2–0.4 MY.

"It is generally believed that the brain expansion set the stage for the emergence of human language and other high-order cognitive functions and that it was caused by adaptive selection, yet the genetic basis of the expansion remains elusive." (Evolution of the Human ASPM Gene, a Major Determinant of Brain Size, Genetics, Vol. 165, 2063-2070, December 2003

Uh oh, Mark's cheating again. The image he uses to show how "different" human and chimp brains are because of cranial capacity actually comes from an article that uses similarities between human and chimp brains as evidence of hominid evolution.
Here's the whole article:
http://www.nature.com/nature/journal/v422/n6934/full/nature01495.html
Here's the caption and relevant paragraph for that image:

No matter how many times the evidence is put in front of evolutionists they invariably resort to these disingenuous ad hominem remarks. What exactly was the point of the cut and paste quote you promoted because I'm not convinced you even read it.

You've had a year and a half to contact the authors of the HAR1 paper and tell them you've found the magic bullet to kill hominid evolution. If your position is so tenable, why haven't you done so?

The gene accumulates 2 substitutions in 350 million years and then suddenly has 18, the evidence speaks for itself.

And Mark's wrong about the human brain being a whole new invention after our split from our ape LCA. From the Nature article he lifted that photo above:

First of all it's not 5–7 Myr, it's 2 Myr. For another thing saying something is true and demonstrating it are two very different things, unless your an evolutionists of course. Then you are allowed and even expected to beg the question of proof on your hands and knees.

Of course all one has to do is enter the right words into a search engine and one can see work is being done. Take the Google results for "genetic basis for human brain evolution".

Not a single substantive argument, I guess I'm not surprised since none exist.

 

[Naraoia]

The gene accumulates 2 substitutions in 350 million years and then suddenly has 18, the evidence speaks for itself.

Did you know that not all genes have the same mutation rates? And that there are different types of selective pressure that can have a different effect on the rate at which mutations are fixed? (I don't think selection affects the rate of the appearance of mutations, though - it's only that sometimes more, sometimes less of them are weeded out before they can spread)

If selective pressures are stabilising - i.e. deviation from the current sequence in any way would decrease the organism's fitness - then mutations (more precisely, nonsynonymous mutations, those that actually change the gene product) are going to be fixed at a very slow rate. However, directional selection (i.e when deviation in a certain way is advantageous) can accelerate the process immensely.

 

[mark kennedy]

Did you know that not all genes have the same mutation rates?

As a matter of fact I did:

"Rates and patterns of molecular evolution:
We observed a total of 199 differences between the human and chimpanzee sequences: 131 transitions (66%), 52 transversions (26%), and 16 insertion-deletion variants (8%). Insertion-deletion variants were less than one-tenth as common as nucleotide substitutions and consisted of changes of 1 bp (8 mutations), 2 bp (5 mutations), 3 bp (1 mutation), and 4 bp (2 mutations). Thus, 15/16 of these insertion-deletion variants would have resulted in frameshift mutations in coding regions. Approximately one-fifth of all single nucleotide mutations were transitions at CpG dinucleotides...

Table 3. Estimates of mutation rate assuming different divergence times and different ancestral population sizes

4.5 mya, pop.= 10,000 mutation rate is 2.7 x 10^-8
4.5 mya, pop.= 100,000 mutation rate is 1.6 x 10^-8
5.0 mya, pop.= 10,000 mutation rate is 2.5 x 10^-8
5.0 mya, pop.= 10,0000 mutation rate is 1.5 x 10^-8
5.5 mya, pop.= 10,000 mutation rate is 2.3 x 10^-8
5.5 mya, pop.= 10,000 mutation rate is 1.4 x 10^-8
6.0 mya, pop.= 10,000 mutation rate is 2.1 x 10^-8
6.0 mya, pop.= 100,000 mutation rate is 1.3 x 10^-8

Table 4. Estimates of mutation rate for different sites and different classes of mutation

Transition at CpG mutation rate 1.6 x 10^-7
Transversion at CpG mutation rate 4.4 x 10^-8
Transition at non-CpG mutation rate 4.4 x 10^-8
Transversion at non-CpG mutation rate 5.5 x 10^-9
All nucleotide subs mutation rate 2.3 x 10^-8
Length mutations mutation rate 2.3 x 10^-9
All mutations mutation rate 2.5 x 10^-8

Rates calculated on the basis of a divergence time of 5 mya, ancestral population size of 10,000, generation length of 20 yr, and rates of molecular evolution given in Table 1.


Calculations are based on a generation length of 20 years and average autosomal sequence divergence of 1.33%
-----------------------------------------------------

Estimate of the Mutation Rate per Nucleotide in Humans (Michael W. Nachmana and Susan L. Crowella
Genetics, 297-304, September 2000) "​

Since this was published the known divergence has grown by 5X:

"Gene families are groups of homologous genes that are likely to have highly similar functions. Differences in family size due to lineage-specific gene duplication and gene loss may provide clues to the evolutionary forces that have shaped mammalian genomes. Here we analyze the gene families contained within the whole genomes of human, chimpanzee, mouse, rat, and dog. In total we find that more than half of the 9,990 families present in the mammalian common ancestor have either expanded or contracted along at least one lineage. Additionally, we find that a large number of families are completely lost from one or more mammalian genomes, and a similar number of gene families have arisen subsequent to the mammalian common ancestor. Along the lineage leading to modern humans we infer the gain of 689 genes and the loss of 86 genes since the split from chimpanzees, including changes likely driven by adaptive natural selection. Our results imply that humans and chimpanzees differ by at least 6% (1,418 of 22,000 genes) in their complement of genes, which stands in stark contrast to the oft-cited 1.5% difference between orthologous nucleotide sequences. This genomic “revolving door” of gene gain and loss represents a large number of genetic differences separating humans from our closest relatives."(The Evolution of Mammalian Gene Families, PLoS ONE. December 20, 2006
​

And that there are different types of selective pressure that can have a different effect on the rate at which mutations are fixed? (I don't think selection affects the rate of the appearance of mutations, though - it's only that sometimes more, sometimes less of them are weeded out before they can spread)

Considering that the vast majority of mutations are selectively neutral with the bulk of the rest being deleterious I'd say your point is moot.

If selective pressures are stabilising - i.e. deviation from the current sequence in any way would decrease the organism's fitness - then mutations (more precisely, nonsynonymous mutations, those that actually change the gene product) are going to be fixed at a very slow rate. However, directional selection (i.e when deviation in a certain way is advantageous) can accelerate the process immensely.

If and only if a mutation with a beneficial effect happens in the first place.

 

[TeddyKGB]

That's absurd, the brain can only increase in size, density and complexity when protein coding genes are altered at an amino acid sequence level.

Utterly false. A number of environmental factors, from nutrition to stimuli, can affect a developing brain. And complexity fluctuates throughout a lifetime, owing largely to the formation of new synapses.

 

[mark kennedy]

Utterly false. A number of environmental factors, from nutrition to stimuli, can affect a developing brain. And complexity fluctuates throughout a lifetime, owing largely to the formation of new synapses.

That does not account for the unprecedented expansion of the human brain from that of apes. Neural genes would have had to underwent a major overhaul from giant ASPM protein coding gene to the HAR1f regulatory gene. There are dozens of others and leading researchers are virtually unanimous on this point.

 

[mark kennedy]

By the way Pete, check out post 86 and maybe estimate what the mutation rate is when the divergence jumps from 1.33% to 6%. At any rate, have fun guys and I'll check back in on the thread later to see if anything relevant or substantive emerged.

 

[Naraoia]

As a matter of fact I did:

That's cool. It means you actually understand something about evolution.

Considering that the vast majority of mutations are selectively neutral with the bulk of the rest being deleterious I'd say your point is moot.

Perhaps the vast majority of mutations are synonymous or deleterious, but advantageous mutations aren't nonexistant. And once they appear, they are fixed much more easily than a neutral mutation, not to mention a harmful one.

I advise you to play with the free evolution simulator Populus. Quite cool; I've just done a few sims with it (single autosomal locus diallelic simulations, fyi). I gave the advantageous allele an initial frequency of 10^-5 (one copy in a population of 50 000), and tried selective advantages of 1%, 2%, 3%, 4%, 5% and 10%. For all but the 1% case the allele increased in frequency within 1000 generations, the maximum Populus can display (and from 4% upwards the allele tended to get fixed before 1000 generations). And that happened consistently in more than five runs per parameter value. With an initial frequency of 10^-6 (and I would think that implies a huge population size for an early hominid), the results were much the same, though I didn't do as many sims with that setting.

You see, it would seem that a mutation with only 2-3% of a selective advantage could conquer a population of 50 000 in a few hundred or thousand generations. And in a population of 50 000 there will be many mutations in each generation, some of which will probably be beneficial. (How long is that gene in question? It would be nice to actually calculate how many mutations are likely to arise within it per generation. Of course there will be fewer mutations in a smaller population, but they will also be quicker to get fixed if beneficial)

Besides, two million years is 80 000 human generations if we calculate with a 25-year generation time, which is probably a very conservative estimate for earlier humans. I mean, we didn't really start postponing children until Bridgetjonesian ages before the twentieth century, did we?