Monday, August 16, 2010

If you're going to quote Dawkins, do it completely!


Once again, we have our irrepressible evangelical blogging pastor engaging in the dishonest ploy of giving partial quotes to back up a specious argument to the effect some supernatural "creator" trumps evolution. In his latest tack, he somehow manages to locate Richard Dawkins' excellent monograph The Blind Watchmaker, then attempts to use it to defend his supernaturalist stance. Had he quoted the entire relevant passage, one would not now have to correct his misguided perceptions - as I already had to do with Conservapedia's anti-relativity loons.

Anyway, he writes:

"Can life be attributed to a supernatural cause - a Giver of life ?" These are ...valid questions , for which we need BELIEVABLE answers , right ? This area is particularly troublesome for those who embrace enthusiasm and the evolutionary explanation for life . Even Richard Dawkins , the die-hard atheistic evolutionist admits that "the essence of life is statistical improbability on a colossal scale. Whatever is the explanation for life , therefore , it cannot be by chance . The true explanation for the existence of life must embody the very antithesis of chance" ( The Blind Watchmaker , p. 317 , emphasis mine ) .

Now, in the interest of education and completeness let's attend to the WHOLE of what Dawkins was writing, as opposed to cherry-picking only a wedged out fragment to support a nutty argument. Thus, the entire appropriate passage reads thusly:

"The theory of evolution by CUMULATIVE NATURAL SELECTION (emphasis mine) is the ONLY THEORY we KNOW OF that is capable of explaining the existence of organized complexity. Even if the evidence did NOT favor it, it would still be the BEST THEORY available. In fact the evidence DOES favor it, but that is another story.

Let us hear the conclusion of the whole matter. The essence of life is statistical improbability on a colossal scale. Whatever is the explanation for life , therefore , it cannot be by chance . The true explanation for the existence of life must embody the very antithesis of chance. The antithesis of chance is NONRANDOM SURVIVAL, properly understood.

Nonrandom survival, improperly understood, is not the antithesis of chance, but chance itself. There is a CONTINUUM CONNECTING THESE TWO EXTREMES, and it is the continuum from single step selection to cumulative selection. Single step selection is just another way of saying pure chance. This is what I mean by nonrandom survival improperly understood.

CUMULATIVE SELECTION, by slow and gradual degrees, is the explanation, the ONLY WORKABLE explanation for the existence of life's complex design"


Now, we know that given he's taken short cuts, it is too much to expect this fundie blogger to understand what that full passage means (especially as he still hasn't taken the basic, 10-question evolution test I linked for him some blogs ago - so hasn't demonstrated he knows barley beans what he's writing about). What I will do here is given an example of "single step selection" then cumulative, and use a most recent example to do it. This is in reference to the NDM-1 "superbug gene" which scientists have uncovered, e.g.

http://www.huffingtonpost.com/2010/08/11/ndm-1-new-superbug-gene-c_n_678427.html

Which can turn any bacteria into a "superbug" - totally resistant to antibiotic treatment.

At some point of time (t - to) in the past, some mutation occurred (likely in India) that converted a normal bacterial gene into the NDM-1. At that point, it could easily have been a "one off", in other words, a one time event limited to one bacterial type in one patient. Had it remained so, it would have been a totally random event. If an event only occurs statistically once, or is confined or limited by probabilities, then it is a chance event - and Dawkins in several other papers has already explained this before.

Dawkins, indeed, once stated (in his book The Selfish Gene) that “the single most unfortunate misunderstanding of Darwinism – that it’s a theory of chance" . He elaborated by observing that the misconception arises because one input for natural selection is mutation, and it is largely governed by random chance. (I.e. Up to 60% or more of mutations may be caused by external factors such as cosmic rays interacting with DNA. But who can say when or at what frequency these interactions occur?) However, natural selection itself is anything but random.

We can see this simply by doing simple experiments, as with fruit flies, and examining the emergence of specific traits over generations – governed by gene frequency. It can be seen that over time there is a genetic "favoritism", as it were, for certain traits or characteristics to be passed on or selected out of a group of competing traits in the gene pool. Thus, what natural selection does is to consolidate particular random mutations into a more stable, adaptive adjustment – governed by deterministic factors and inputs.

Thus, that while the selected trait often appears at random, its preservation in the gene structure cannot be relegated to randomness. Thus, at the point the trait displays some significant advantage to the species, say an insect’s resistance to a particular pesticide or a bacteria's resistance to all antibiotics (as in the NDM-1 gene), some directed process must be at work to retain and incorporate it, e.g. in successive generations of offspring, to enhance the odds of survival for species' genetic information.

At this stage, one might say that trait or morphologically novel feature has been ‘naturally selected for’. Mutation and natural selection often work in tandem, and certainly aren’t mutually exclusive. In other words, a mutant gene that’s been naturally selected stands a better chance of stabilizing in the genome.

In quantitative genetics we actually have indices and markers to show how strong the selection survival effects are. We refer these as preferential alleles[1] and they appear by virtue of their relative increase in gene frequency. Two quantitative measures for gauging the success of natural selection are the fitness (w) and the selective value (s).

These can be measured on either absolute or relative scales, but are related algebraically on the latter by:

w = 1 – s, or s = 1 – w

As an illustration, consider a cockroach species (Blattella germanica) with allele D, where D denotes resistance to the pesticide dieldrin, and d denotes non-resistance. In the population after some defined time, let three genotypes be exhibited in the population: DD, Dd and dd.[2] Now, on average over time let each dd and Dd individual produce one offspring, and each DD produce two. These average numbers can be used to indicate the genotype’s absolute fitness and to project the changes in gene frequency over succeeding generations. The relative fitness (w) is meanwhile given by:

w = 1 for DD

w = 0.5 for Dd

w = 0.5 for dd

The selection values, relative measures of the reduction of fitness for each genotype, are given respectively by:

s = 1 – 1 = 0 for DD

s = 1 – 0.5 = 0.5 for Dd

s = 1 – 0.5 = 0.5 for dd

As we expect, the dieldrin-resistant genotype displays zero reduction in fitness, and hence maximum survival rate. By contrast the d allele can be regarded as ‘deleterious’. Indeed, it can be shown that over successive generations of roaches, the gene frequency (of d) will decrease by:

delta( q)= -spq^2/(1 - sq^2)

Here p is the frequency of the favored allele, and q the frequency of the disadvantaged (‘deleterious’) allele.

In other words, once an allele (e.g. DD) emerges with ZERO reduction in fitness (s =0), then we have nonrandom survival - which - as Dawkins noted, is the antithesis of chance. In other words, once one attains the level an active allele in a species displays s= 0, chance no longer factors into the mix. Thus it is totally erroneous to claim that evolution by natural selection is a "random chance process". Nope - because by the time natural selection incorporates the mutation, randomness goes out the window!

In the same way, we may surmise that for the mutation of a bacterial gene to the NDM-1 form, at some stage the single selection gave way to a favored allele of the gene - call it BB, which is resistant to antibiotics and moreover can trigger switches in proximate bacteria (exposed to it) to incorporate the NDM-1 gene also. In this way, we get the cumulative selection- which Dawkins also noted- wherein the bacterial species worldwide may change by gradual degrees to all become NDM-1 dominated, or all resistant to all antibiotics.

Contrary to helping him to make his specious case for a supernatural being intervening in the world and cosmos, Dawkins quoted insight (the full quote!) allows us to shut it down permanently - since properly understood it means one can't argue the "natural selection is random chance" malarkey to try to put down Darwinian evolution. It works precisely because a single mutation (originally a random event) CAN at some point, become established as a self-replicating change in the genome - as we behold with dieldrin resistant roaches, as well as antibiotic resistant bacteria.

The moral of this little story? Once again, it's that non-scientific people (especially blowhard "pastors" - who've never taken an evolution test to demonstrate they're qualified to comment on it) ought to stick with the baloney they know best. Like inventing spurious gibberish about a Pascal's wager for which we know the premise is bollocks, e.g. http://brane-space.blogspot.com/2010/07/taking-chances-on-going-to-hell-no-more.html AND

http://brane-space.blogspot.com/2010/07/once-more-pascals-wager-and-fundie.html

That way, at least their baloney and bunkum is confined to what we already know is a zone of palpable crap - as opposed to misleading gullible and other under-educated types (like those from Conservapedia) about claimed insights into evolution, or the origin of life. (He also makes another error in claiming the theory of ontogenesis (which he still confuses with evolution) requires "spontaneous origin of life" - which it does not. It merely requires something analogous to the nonrandom selection Dawkins already described, but applied to a coacervate - water droplet that can exchange energy with its environment and become replicative. On the basis of appropriate chemical reactions, the hypothetical coacervate would consist of a combination of autocatalytic molecules that would generate peculiar properties including: simple organization, ability to increase in size, and ability to maintain itself over extended intervals. My point is, by the time the cumulative selection is solidified, the process of its emergence is no longer "spontaneous" and certainly not random or a product of random chance!





[1] By which I mean one of the more adaptive forms of a single gene, hence favored to multiply at greater rates in the gene pool.

[2] The genotype Dd might be thought of as ‘partly’ resistant, i.e. depending on the concentration of dieldrin used.

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