Monday, March 14, 2022

Banning Darwin's 'Origin Of the Species' In Some School Districts? Give Me A Break!

 Don't look now but Charles Darwin's theory of evolution is back in the dock, at least in too many U.S. high schools. More and more states, including some here in the west,  are restricting the teaching of evolution in schools. Or forcing biology teachers to teach creationism along side it.  Amazingly, 47% of Americans now believe God created life some time in the past 10,000 years, despite research that has established the universe as 13 billion years old and that humans are descended from apelike ancestors, e.g.


 The last especially ought to be elementary to process. 
But nearly all "problems" the religionists yammer about to do with evolution could be dispelled if basic genetics (Mendelian) was taught as an integral part of the course.  In particular the process of micro-evolution could be demonstrated as a kind of precursor to macro- evolution.  

By micro-evolution” we mean minute evolutionary change, involving a small proportion of DNA. For example, the emergence of an orange-eyed fruit fly (drosophilia melanogaster) after 20 generations would demonstrate microevolution. Of course, microevolution can also appear at the microscopic level, for example in changes in haemoglobins, histo-compatability antigens, and biochemical environmental adaptations (e.g. formation of blood chemicals which confer some form of restance to environmental toxins or agents).

Consider a hardy form of bedbug that emerged around mid-2010, impervious to nearly all forms of insecticide.  This change occurred somewhat suddenly, as one examines the statistics for infestation, with barely 50 cases in New York City in 2006 vs. more than 3,000 in 2010. The evidence then suggest clearly a punctuated equilibrium in terms of micro-evolution in the bedbugs species leading to a resistance to nearly all insecticides.

In terms of the concept of fitness so critical in adaptation and evolution we can use the table of gene frequencies shown below:

Let B refer to a favored allele for a bedbug with total resistance, let b refer to a deleterious allele ( one with zero resistance) Recall the measures for 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


Let’s say at a particular time a gene frequency ‘snapshot’ of the bedbug population under study yields: p(B) = 0.60, q(b) = 0.40, i.e. the favored allele B is reproducing at the ratio 3:2 relative to the disadvantaged one, b. As before, the selective value s = 0.50. A simple table showing the declining gene frequency of b relative to B is shown appended to this blog

On average over time let each bb and Bb individual produce one offspring, and each BB 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 BB

w = 0.5 for Bb

w = 0.5 for bb

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

s = 1 – 1 = 0 for BB

s = 1 – 0.5 = 0.5 for Bb

s = 1 – 0.5 = 0.5 for bb

As we expect, the pesticide-resistant bedbug genotype displays zero reduction in fitness, and hence maximum survival rate. Thus, the table provides a brief “snapshot” of how micro-evolution has been working in the bedbug population to generate billions of these pests that can’t be exterminated by ordinary pesticides – necessitating the use of varieties currently prohibited for safety and health reasons.

Macroevolution, by contrast, entails a proportionately large change in the DNA underlying it that probably reflects ongoing natural selection, over significant time. For example, the change from a cold-blooded dinosaur to a warm-blooded dinosaur that’s a precursor of modern birds would be a case of macroevolution. Similarly, the change from an ape-human ancestor to Homo sapiens (by telomeric fusion of the 2p and 2q chromosomes to the ‘2’ chromosome in humans) would be a case of macroevolution, despite the fact the evidence is available at the chromosomal level.

As another point to note in this discussion, punctuated evolutionists don’t see any sharp divergence between the micro-evolutionary foundation and macro-evolution in their formulation. Thus, they see the fossil record as long intervals of micro-evolutionary stasis or equilibrium – during which there is relatively little change, punctuated by rapid macro-evolutionary emergence. (Which again, is not to be confused with saltationism, thus in this case what is going on micro-evolutionarily in an apparent equilibrium – may simply not be visible at the macro-scale, but which ultimately incepts macro-scale features. E.g. scales suddenly converted to feathers for raptors).

What does all this show? That most of the alleged "problems of evolution" are confections or fabrications which exist only in the minds of creationists who insist on seeing problems - perhaps beause "problems" with evolution assuage some doubts that their good Book gives them the whole truth. What is somewhat puzzling, and I've never been able to process is: Why, if their good Book provides them with all the truth needed, they feel compelled to venture into scientific arenas they know nothing about? Is it to try and pretend they know some science to confer an imagined gravitas on their beliefs? (Or to use big words like "punctuated evolution" and "gradualism" - to show off for their followers?) WHY? Why not then just have "faith" that their nonsense is true and leave evolution to the evolutionists? That's a question only these zealots can answer! But we can be sure they never will, at least honestly!


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