Evolution: more genomic evidence of pre-planning (Evolution)

by dhw, Wednesday, February 24, 2021, 12:00 (1366 days ago) @ David Turell

dhw: We are going back over exactly the same ground as before. Neither chance nor anticipation is involved! So let me give you the same example as before, purely as an illustration. Small-brained homo is hunting. He knows it’s dangerous to come too close to the animal. He has an idea: a weapon he can throw from a distance. As we know from the modern brain, new skills cause changes to the brain. In designing, making, and learning how to use the new weapon, our small-brained homo causes changes to his own brain, and since his brain is so small, new cells are required to perform these tasks. Hence expansion. Once he has accomplished his task, he has no need of further expansion (i.e. there is stasis) until a new idea/circumstance/ opportunity/discovery again requires an increase in capacity, and so we have the next expansion.

DAVID: Your old proposal is thinking of a new weapon, a spear, enlarged the brain.

Not just thinking of it, but designing it and learning how to use it.

DAVID: All we know from our brain is that it stays the same size and complexifies. Since new organs build on past capacities I think it is reasonable to complexification mechanisms were present in all older smaller brains. No need for expansion.

Of course it’s reasonable to suppose that their brains complexified. But it is equally reasonable to suppose that since their brains were smaller, there was less capacity for complexification! And so when that capacity had been reached, more cells were needed. You have yourself pointed out that even within our modern brains, certain parts expand when needed. And why on earth would your God have expanded the smaller brain if the extra capacity was not needed?

Behe

DAVID: You constantly scurry around to protect Darwin. The article mainly discusses loss of genes, but does note new genes also contribute to changes. I've said that.

dhw: It has nothing at all to do with Darwin. Please tell me why it is unreasonable to argue that new adaptations and the acquisition of new genes will make some old genes redundant. […] I will extract one sentence from the article: “Total gene loss is the most obvious case of loss of function.” This is the nub of the argument, which you refuse to deal with. I suggest, as I did before, that adaptation results from new genes and changed functions of existing genes. LOSS OF FUNCTION means that when the organism adapts, there are genes which are no longer of any use, and so they are discarded. It does not mean that their uselessness is the CAUSE of adaptation! Please tell me what is wrong with my proposal.

DAVID: Talk around it all you wish, but what you have said is in adaptation genes (information) are discarded. I've agreed new genes may be added.

I’m not talking round anything. I’m pointing out that adaptations and innovations will make certain genes unnecessary and so they will be discarded. That does not mean that the loss of genes CAUSES the adaptation/innovation

DAVID: Back to Behe:
https://salvomag.com/article/salvo49/darwinism-dissembled

Here’s a summation of the evolutionary picture that has emerged, according to Behe:
• The large majority of mutations are degradatory, meaning they’re mutations in which the gene is broken or blunted. Genetic information has been lost, not gained.
• Sometimes the degradation helps an organism survive.
• When the degradation confers a survival advantage, the mutation spreads throughout the population by natural selection.
In genetics, a loss of information generally translates into a loss of function, so it might seem counterintuitive to suppose that a degradatory mutation would confer a survival advantage. Behe gives several examples, though, of instances where damaged genes have been shown to aid survival. In the case of the sickle-cell gene, for example, a single amino acid change causes hemoglobin to behave in a way that inhibits growth of the malaria microbe. It’s a loss-of-function mutation, but it confers a survival advantage in malaria-prone regions.
Sickle cell is a prime example. Proper hemoglobin is damaged, degraded.

We were not discussing mutations! This is getting absurd. A mutation is not a loss, it is a change, and sickle cells have nothing whatsoever to do with the subject of adaptation and speciation. The sickle cell may have developed as a counter to malaria, but it is also the cause of sickness (anaemia)! (My wife had sickle cells, but fortunately only mildly). It’s good to hear you talk of the role survival plays in evolution, but you do yourself no favours by pretending that sickle cells and other examples of beneficial mutations somehow prove that the loss of genes causes adaptation and innovation.