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Friday, 27 May 2016

Universal common ancestry in the hotseat III

Toward a Consensus: An Open Letter to BioLogos on the Genetic Evidence
Cornelius Hunter

Dennis Venema, professor of biology at Trinity Western University and Fellow at BioLogos, has written a series of articles that have been noted by evolutionists for their clarity and persuasiveness. So as a collector of evidences and reasons why evolution is a fact, I was interested to see Venema's articles. What does the professor have to say to help confirm what Samuel Wilberforce rhetorically called "a somewhat startling conclusion"?


One of Venema's basic points (see  here and here ) is that the genomes of different species are what we would expect if they evolved. Allied species have similar genomes, and genetic features fall into evolution's common descent pattern:If indeed speciation events produced Species A-D from a common ancestral population, we would expect their genomes to exhibit certain features when compared to each other. First and foremost, their overall genome sequence and structure should be highly similar to each other -- they should be versions of the same book, with chapters and paragraphs of shared text in the same order. Secondly, the differences between them would be expected to fall into a pattern.
Does the evidence confirm these evolutionary expectations? Venema answers with an emphatic yes.

Here Venema is appealing to the empirical evidence. He is comparing the evidence to the theory of evolution, and finding that the evidence confirms evolution's predictions. This means the theory can be empirically evaluated. And if evolution can be genuinely evaluated empirically, then it is, at least theoretically, possible for evolution to fail. If the evidence can confirm evolution, then it also can disconfirm evolution.

This is important because focusing the attention on the evidence means the non-scientific arguments go away and science is allowed to speak. What does it say? Here I will take the opposing view, for it seems that what the science shows is that Venema's claim, that the genetic evidence confirms evolutionary predictions, is inaccurate.

This is not to say that evolutionary explanations cannot be offered. As philosophers well understand, another sub-hypothesis is always possible. Such hypotheses raise more profound questions of parsimony, likelihood, and so forth. But it seems that such philosophical questions ought to be addressed after there is a consensus on what the empirical evidence has to say. The goal here is to move toward that consensus. Venema, and evolutionists in general, make a straightforward claim about the evidence. We ought to be able to dispassionately evaluate that claim.

Of course I realize that reaching consensus is not as simple as reading an article. There will be differing interpretations by fair-minded critics. And the topic of origins is certainly not always dispassionate. If you argue against evolution you will be disparaged. My response to such attacks has and always will be to forgive.

One final preliminary is simply to point out that it is a challenge just to do justice to this story. A thorough treatment could easily require an entire volume. But a few, typical, examples will have to suffice. They can provide readers with an approximate understanding how the evidence bears on Venema's claim.

What Does the Evidence Say?

For starters, phylogenetic incongruence is rampant in evolutionary studies. Genetic sequence data do not fall into the expected evolutionary pattern. Conflicts exist at all levels of the evolutionary tree and throughout both morphological and molecular traits. This paper reports on incongruent gene trees in bats. That is one example of many.

MicroRNAs are short RNA molecules that regulate gene expression, for example, by binding to messenger RNA molecules which otherwise would code for a protein at a ribosome. Increasingly MicroRNAs are understood to be lineage-specific, appearing in a few species, or even in just a single species, and are nowhere else to be found. In fact one evolutionist, who has studied thousands of microRNA genes, explained that he has not found "a single example that would support the traditional [evolutionary] tree." It is, another evolutionist admitted, "a very serious incongruence."

Trichodesmium or "sea sawdust," a genus of oceanic bacteria described by Captain Cook in the 18th century and so prolific it can be seen from space, has a unique, lineage-specific genome. Less than two-thirds of the genome of this crucial ammonium-producing bacteria codes for proteins. No other such bacteria has such a low value, and conversely such a large percentage of the genome that is non-coding. This lineage-specific genome, as one report explains, "defies common evolutionary dogma."

It is not unusual for similar species to have significant differences in their genome. These results have surprised evolutionists and there does not seem to be any let up as new genomes are deciphered.

The mouse and rat genomes are far more different than expected. Before the rat genome was determined, evolutionists predicted it would be highly similar to the mouse genome. As one paper explained:

Before the launch of the Rat Genome Sequencing Project (RGSP), there was much debate about the overall value of the rat genome sequence and its contribution to the utility of the rat as a model organism. The debate was fuelled by the naive belief that the rat and mouse were so similar morphologically and evolutionarily that the rat sequence would be redundant.
The prediction that the mouse and rat genomes would be highly similar made sense according to evolution. But it was dramatically wrong.

One phylogenetic study attempted to compute the evolutionary tree relating a couple dozen yeast species using 1,070 genes. The tree that uses all 1,070 genes is called the concatenation tree. They then repeated the computation 1,070 times, for each gene taken individually. Not only did none of the 1,070 trees match the concatenation tree, they also failed to show even a single match between themselves. In other words, out of the 1,071 trees, there were zero matches. It was "a bit shocking" for evolutionists, as one explained: "We are trying to figure out the phylogenetic relationships of 1.8 million species and can't even sort out 20 yeast."

What is interesting is how this false prediction was accommodated. The evolutionists tried to fix the problem with all kinds of strategies. They removed parts of genes from the analysis, they removed a few genes that might have been outliers, they removed a few of the yeast species, they restricted the analysis to certain genes that agreed on parts of the evolutionary tree, they restricted the analysis to only those genes thought to be slowly evolving, and they tried restricting the gene comparisons to only certain parts of the gene.

These various strategies each have their own rationale. That rationale may be dubious, but at least there is some underlying reasoning. Yet none of these strategies worked. In fact they sometimes exacerbated the incongruence problem. What the evolutionists finally had to do, simply put, was to select the subset of the genes that gave the right evolutionary answer. They described those genes as having "strong phylogenetic signal."

And how do we know that these genes have strong phylogenetic signal. Because they gave the right answer. This raises the general problem of prefiltering of data. Prefiltering is often thought of merely as cleaning up the data. But prefiltering is more than that, for built-in to the prefiltering steps is the theory of evolution. Prefiltering massages the data to favor the theory. The data are, as philosophers explain, theory-laden.

But even prefiltering cannot always help the theory. For even cleansed data routinely lead to evolutionary trees that are incongruent (the opposite of consilience). As one study explained, the problem is so confusing that results "can lead to high confidence in incorrect hypotheses." As one paper explained, data are routinely filtered in order to satisfy stringent criteria so as to eliminate the possibility of incongruence. And although evolutionists thought that more data would solve their problems, the opposite has occurred. With the ever increasing volumes of data (particularly molecular data), incongruence between trees "has become pervasive."

What is needed now is less data. Specifically, less contradictory data. As one evolutionist explained, "if you take just the strongly supported genes, then you recover the correct tree." And what are "strongly supported" genes? Those would be genes that cooperate with the theory. So now in addition to prefiltering we have postfiltering.

Another issue are the striking similarities in otherwise distant species. This so-called convergence is rampant in biology and it takes on several forms.

Consider a paper from the Royal Society on "The mystery of extreme non-coding conservation" that has been found across many genomes. As the paper explains, there is currently "no known mechanism or function that would account for this level of conservation at the observed evolutionary distances." Here is how the paper summarizes these findings of extreme sequence conservation:

... despite 10 years of research, there has been virtually no progress towards answering the question of the origin of these patterns of extreme conservation. A number of hypotheses have been proposed, but most rely on modes of DNA : protein interactions that have never been observed and seem dubious at best. As a consequence, not only do we still lack a plausible mechanism for the conservation of CNEs -- we lack even plausible speculations.
And these repeated designs, in otherwise different species, are rampant in biology. It is not merely a rare occurrence that perhaps evolution could explain as an outlier. That the species do not fall into an evolutionary tree pattern is well established by science.

Furthermore, these repeated designs do not merely occur twice, in two distant species. They often occur repeatedly in a variety of otherwise distant species. So now the evolutionist must not only believe that there are many of these repeating design events, but that in most cases, they repeat multiple times, in disparate species.

Evolutionists have labeled this evidence as recurrent evolution. As a recent paper  explains:

The recent explosion of genome sequences from all major phylogenetic groups has unveiled an unexpected wealth of cases of recurrent evolution of strikingly similar genomic features in different lineages.
In addition, many instances of a third more puzzling phylogenetic pattern have been observed: traits whose distribution is "scattered" across the evolutionary tree, indicating repeated independent evolution of similar genomic features in different lineages.

Of course these puzzling, striking similarities cannot be explained by common evolutionary history. Instead, they are explained by common evolutionary forces:

As ancestrally shared features are the result of a common evolutionary history, shared features evolved by recurrent evolution are often the result of common evolutionary forces acting on different lineages.
If the pattern fits the evolutionary tree, then it is explained as common evolutionary history. If not, then it is explained as common evolutionary forces.

With all of this contradictory evidence, even evolutionists have realized in recent years that the traditional evolutionary tree model is failing. As one evolutionist  explained, "The tree of life is being politely buried."

There are many more fascinating examples of biological patterns that are not consistent with the expected evolutionary pattern. These are not anomalies or rare exceptions. Here we have focused on the genetic level since that was the theme of Venema's article. It seems that the species and their genomes do not fall into a consistent evolutionary pattern as evolutionists such as Venema claim. This does not mean evolutionists cannot explain any of this. They have a wide spectrum of mechanisms to draw upon, of varying levels of speculation and likelihood. These explanatory mechanisms greatly increase the theory's complexity. They raise questions of realism, and whether the theory is following the data, or the data is following the theory.

But such questions are for another day.

The point here is that evolutionist's claims that the genomic data broadly and consistently fall into the evolutionary pattern and expectations do not seem to reflect the empirical data. This is the first step in moving the discourse forward. We need to reach consensus on what the evidence reveals.

In a subsequent post I will continue with an examination of the next evidences Venema presents.

Thursday, 26 May 2016

The design debate through the looking glass


Design through the Looking Glass


You don't have to hold an amino acid up to a mirror to see its mirror image. Amino acids (except for one, glycine) come in pairs, like gloves, on the real-world side of the looking glass. So do the sugars used in DNA and RNA; they are assigned a "handedness" based on conventional rules of describing their orientation in 3-D space. In all other physical respects, chemical and thermodynamic, they are identical in their activity. This makes them difficult to separate.
The phenomenon is known as chirality. The chiral "isoforms" are called enantiomers of each other. Left-handed enantiomers are preceded byL- (from Latin levo) as in L-alanine, while right-handed enantiomers are preceded by D- (fromdextro) as in D-ribose. A mixture of both hands is said to be racemic, or heterochiral. A pure mixture of one hand is called homochiral.
With only rare exceptions, all living things use just one "hand" of these molecular gloves: left-handed amino acids in proteins, and right-handed sugars in nucleic acids. How this came about has long been a mystery, as four Chinese scientists from Tsinghua University in Beijing explain in Nature Chemistry:
Despite biology's seemingly limitless diversity and the vastness of its territories that permeate into virtually every corner of the Earth, at the fundamental level of biochemistry, all known forms of life are narrowly deļ¬ned by a single version of molecular machinery based on L-amino acids and D-ribose nucleic acids. Although rare examples of the use of D-amino acids, such as D-aspartic acid in animal brains, and L-sugars, such as L-arabinose in plants, do exist, the central dogma and most of the biological macromolecules have followed the homochirality established by life's earliest ancestorsProcesses that led biology onto this particular chiral path have remained largely elusive, even though experimental evidence for breaking the mirror symmetry has been reported and many theoretical models have been proposed.[Emphasis added.]
As it stands, no experimental or theoretical model explains the origin of life's homochirality by natural processes. Some experimenters have produced a slight enantiomeric excess of one hand or the other, but usually with non-biological chemicals, and nothing approaching the purity of life's chiral molecules. Proteins and nucleic acids cannot work with mixed handedness. A single wrong-handed building block is enough to destroy DNA, RNA, and proteins. As we saw last year, checkpoints ensure that life's building blocks remain homochiral.
This purity of handedness baffles materialists, because their causal toolkit only includes natural law and chance. The probability of getting a single-handed polymer from racemic ingredients is comparable to getting a string of coin tosses coming up all heads. The longer the sequence, the more improbable it becomes -- quickly swamping the chance hypothesis. Yet as Wang et al. state, our knowledge of natural laws isn't helping solve the problem.
Recently, an in vitro selected catalytic RNA capable of incorporating nucleotides in a cross-chiral fashion without enantiomeric cross-inhibition was reported. The fact that no known laws of physics and chemistry preclude biology's use of either of the two chiral systems, mirror-image twins of one another, has led to an intriguing question as to whether a parallel mirror-image world of biology running on a chirally inverted version of molecular machinery could be found in the universe or be created in the laboratory.
Turning from origins to application, they describe their initial attempts to create mirror-image life:
We reasoned that towards synthesizing a mirror-image biological system, an imperative step would be to reconstitute a chirally inverted version of the central dogma of molecular biology with D-amino acid enzymes and L-ribose nucleic acids--although reconstituting a mirror-image, ribosome-based translation systemthrough the total synthesis of all the ribosomal RNA (rRNA) and protein building blocks is still beyond the current technology, the totalchemical synthesis of (small enough) mirror-image polymerases might be feasible. Here we set out to synthesize such a mirror-image polymerase and to test if two steps in the central dogma, the template-directed polymerization of DNA and the transcription into RNA, can be carried out in a synthetic mirror-image molecular system (Fig. 1a).
(For present purposes, we won't dispute the central dogma, although biologist Jonathan Wells has written extensively on its problems.)
These scientists did, in fact, succeed in getting some template-driven polymerization and transcription of opposite-handed amino acids. It was very slow, but it demonstrates that, in principle, life could exist in a mirror image of itself. Alice through the looking glass would appear identical to her mirror image, but would not be able to eat opposite-handed food!
Commenting on this work for Nature, Mark Peplow explains why synthetic mirror-image biomolecules have desirable properties:
In principle, looking-glass versions of these molecules should work together in the same way as normal ones -- but they might be resistant to attack by conventional viruses or enzymes that have not evolved in a looking-glass world.
That makes mirror-image biochemistry a potentially lucrative business. One company that hopes so is Noxxon Pharma in Berlin. It uses laborious chemical synthesis to make mirror-image forms of short strands of DNA or RNA called aptamers, which bind to therapeutic targets such as proteins in the body to block their activity. The firm has several mirror-aptamer candidates in human trials for diseases including cancer; the idea is that their efficacy might be improved because theyaren't degraded by the body's enzymes. A process to replicate mirror-image DNA could offer a much easier route to making the aptamers, says Sven Klussmann, Noxxon Pharma's chief scientific officer.
Wang et al. took the smallest known polymerase enzyme, just 174 amino acids long, and laboriously constructed a right-handed counterpart. They succeeded in getting it to extend a primer from 12 nucleotides to 18 nucleotides in 4 hours. Getting it to 52 nucleotides took 36 hours -- a "glacial pace," Peplow remarks. Nevertheless, it was an important discovery. Both the normal and mirror-image enzymes worked independently, without interference, when mixed in the same test tube.
The Design Inference
The researchers admit it would be a "daunting task" to build a mirror-image version of a ribosome where translation could take the left-handed RNA and translate it into a right-handed protein. Building a "looking glass cell" is a far-off dream. At this stage, though, we can draw some conclusions about chance and design.
Peplow confirms that homochirality remains a vexing problem. He surely would have said otherwise if a likely non-random cause were known.
In their research paper, the Tsinghua researchers also present their work as an effort to investigate why life's chirality is the way it is. This remains mysterious: it may simply be down to chance, or it could have been triggered by a fundamental asymmetry in nature.
But Steven Benner, at the Foundation for Applied Molecular Evolution in Alachua, Florida, says it's unlikely that creating a mirror form of biochemical life could shed any light on this question. Almost every physical process behaves identically when viewed in a mirror. The only known exceptions -- called 'parity violations' -- lie in the realm ofsubatomic physics. Such tiny differences would never show up in these biochemical experiments, says Benner.
Benner and Peplow just conceded that natural law cannot explain homochirality. To a materialist, that leaves chance. For a short polypeptide of 100 amino acids to have formed by chance would be ½ x ½ x ½ ... 100 times: 1 chance in 2100, which is approximately 1 in 1030. There aren't enough probabilistic resources to make this likely to happen in a primordial soup of racemic amino acids. But then, even if it did, homochiral DNA or RNA would have to form independently out of its own racemic building blocks. There's just no realistic chance of success in a materialistic world. Intelligence, by contrast, can easily select one hand over the other; consider how quickly an eight-year-old could sort a pile of coins into heads and tails.
Another conclusion from this paper is that homochirality as observed in life is contingent: i.e., it could exist in the opposite mirror-image form. There is no chemical or thermodynamic reason why proteins must be left-handed as opposed to right-handed, or why nucleic acids must be right-handed as opposed to left-handed. The experiments show that chemical reactions can proceed just as well in a mirror-image world. When a choice has been made one way to the exclusion of other possibilities, and it is beyond the reach of chance, it gives indication that intelligence has embedded information into the system.
Finally, these researchers demonstrate empirically how intelligence can embed information into a system. They purposefully selected building blocks of one hand to construct their polymerase. They had a goal, and a means of reaching it. If we rightly judge their work as a product of intelligent design -- as glacially slow as it was -- how much more the products of a cell that work rapidly and accurately, using machinery at a level of sophistication beyond our ability to imitate?
It's logical. If a system on the far side of the looking glass is intelligently designed, then the system on the near side is also intelligently designed. Only a fun-house mirror could distort that conclusion.

Tuesday, 24 May 2016

Universal common ancestry in the hotseat II

The Vitellogenin Pseudogene Story: Unequally Yolked

Monday, 23 May 2016

Universal common ancestry in the hotseat.

Functional Pseuodogenes and Common Descent

Saturday, 21 May 2016

The pink slip for Mendel?

Teach students the biology of their time
An experiment in genetics education reveals how Mendel’s legacy holds back the teaching of science, says Gregory Radick.


Historians study the causes and consequences of past events, but also consider alternative scenarios. What might have happened, for example, if Britain had stayed out of the war in Europe in 1914? Science historians also ask such counterfactual questions, and the results can be surprisingly instructive.Take genetics. The past year has seen prolonged celebrations of the work of Gregor Mendel, linked to the 150th anniversary of the paper that reported his experiments with hybrid peas. Mendel’s experiments are central to biology curricula across the world. By contrast, the criticisms levelled at Mendel’s ideas by W. F. R. Weldon, Linacre professor at the University of Oxford, UK, are a footnote.

From 1902, Weldon’s views brought him into increasingly bad-tempered conflict with Mendel’s followers. In basic terms, the Mendel­i­­­­ans believed that inherited factors (later called ‘genes’) determine the visible characters of an organism, whereas Weldon saw context — developmental and environmental — as being just as important, with its influence making characters variable in ways that Mendelians ignored. The Mendelians won — helped by Weldon’s sudden death in 1906, before he published his ideas fully — and the teaching of genetics has emphasized the primacy of the gene ever since.The problem is that the Mendelian ‘genes for’ approach is increasingly seen as out of step with twenty-first-century biology. If we are to realize the potential of the genomic age, critics say, we must find new concepts and language better matched to variablebiological reality. This is important in education, where the reliance on simple examples may even promote an outmoded determinism about the power of genes.

But what if Mendelism had never come to dominate genetics in the first place? What if Weldon’s perspective had emerged as the winner in that historical battle, and his interactionism, allied to his vivid sense of how variable the real characters of real organisms are (never just yellow or green, round or wrinkled, or any other Mendelian binary), had become the core of the subject? This is where I, and colleagues, have tried to run an experiment.

In a recent two-year project, we taught university students a curriculum that was altered to reflect what genetics textbooks might be like now if biology circa 1906 had taken the Weldonian rather than the Mendelian route. These students encountered genetics as funda­mentally tied to development and environment. Genes were not presented to them as what inheritance is ‘really about’, with everything else relegated to ignorable supporting roles. For example, they were taught that although genes can affect the heart directly, they also affect blood pressure, the body’s activity levels and other influential factors, themselves often influenced by non-genetic factors (such as smoking). Where in this tangle, we ask them, is a gene for heart disease? In effect, this revised curriculum seeks to take what is peripheral in the existing teaching of genetics and make it central, and to make what is central peripheral.Our experimental group consisted of second-year humanities undergraduates. First-year biologists, who were taught the conventional approach, acted as our control. We saw a difference — those students taught the Weldon way emerged as less believing of genetic determinism, and, I suspect, better prepared to understand the subtleties of modern genetics. (The difference was statistically significant, but I hesitate to make much of that, given that numbers were small and there were differences between the groups. I am mindful, too, that it was Weldon who first drew attention to Mendel’s own problems with exaggerated statistics.)

With such experiments — bringing insights from the archive into the science classroom — the scientific past can inform and maybe even improve the scientific future. In turn, they suggest a broader vision of collaboration. To advance scientific knowledge, historians and philosophers of science should work in close proximity to scientists, not actually in the lab but right down the corridor. Then, investigations into neglected phenomena and debates that were shut down too soon might provide the spark to serve creative science.

What of Mendel? Some might complain that it is a poor anniversary gift to jettison him from his place of honour in the genetics curriculum. Let me suggest that this grumbling, although understandable, is misguided. If we want to honour Mendel, then let us read him seriously, which is to say historically, without back-projecting the doctrinaire Mendelism that came later. Study Mendel, but let him be part of his time.

Likewise, let our biology students be part of their time, by giving them a genetics curriculum fit for the twenty-first century. If we teach them about Mendel, we should do so not to fill them with slack-jawed wonder at his foundational achievement, but to help them to appreciate how even the most imaginative and rigorous science — and Mendel’s was first rate on both counts — bears the stamp of the historical circumstances of its making. To learn that lesson about past science is to bring a welcome level of self-awareness and critical self-reflection to the present.

On the evolution of a Darwinist.

The Evolving Dr. Schafersman (Again)
John G. West

Dr. Steven Schafersman, self-proclaimed "secular humanist" and head of Texan Citizens for Science, is once again insisting that "language by the anti-evolutionists about doubt or weaknesses or controversy involving evolution is just rhetoric. Doubts or weaknesses don't exist among scientists." Poor Dr. Schafersman needs to recheck some of his previous public statements, for despite what he says now, during the 2003 biology textbook adoption process in Texas he ultimately conceded that there are plenty of scientific controversies in modern evolutionary theory. As I pointed out in a podcast in January, Schafersman in 2003 did initially assert that there were no scientific controversies over evolution for textbooks to cover. But then he began to...well... evolve. By the time the adoption process was finished, Schafersman was admitting that there are in fact many scientific controversies raised by modern evolutionary theory, only he thought that students were too stupid to study them. Recounting Dr. Schafersman's evolving statements is a great way to expose the sham claim we've been hearing throughout this week that evolution has no weaknesses.

Below is a step-by-step account Dr. Schafersman's amazing evolution in 2003:

1. In his written testimony submitted to the Texas State Board of Education on July 9, 2003, Dr. Schafersman asserted categorically:

All the biology texts are factually accurate and free of errors concerning evolution; the books do not misrepresent any details of the modern scientific understanding of evolution, nor do they omit scientific information critical of evolution, because there isn't any such information, contrary to what you have led to believe. (emphasis added)
2. In his oral testimony before the Board on July 9, 2003, Dr. Schafersman made the same general point but added a slight, unexplained qualification:

There is no scientific controversy about the fact of evolution and, thus, no weakness concerning its occurrence. There are also no weaknesses about the theory of evolution at the level it is presented in these textbooks. [Transcript of Hearing on July 9, pp. 112-113] (emphasis added)
3. In the web version of Dr. Schafersman's written testimony of July 9, 2003, a more extensive qualification suddenly appeared (which was not in the version of his testimony he actually submitted to the Board). In his revised written testimony, Dr. Schafersman explicitly acknowledged that there are in fact "disagreements and controversies ('weaknesses') concerning evolutionary theory," but he implied they are only appropriate for professional researchers and graduate students to hear about:

There is no scientific controversy about the fact of evolution and thus no scientific weaknesses concerning its occurrence. There are also no weaknesses about the theory of evolution at the level it is presented in these textbooks. Disagreements and controversies ("weaknesses") concerning evolutionary theory are found at the frontiers of research and graduate education, not at the level of introductory biology textbooks. [originally posted at http://www.txscience.org/files/testimony.htm] (emphasis added)
4. Finally, in the web version of Dr. Schafersman's written testimony submitted to the Board for the Sept. 10, 2003 hearing, Dr. Schafersman acknowledged that there are in fact "many disagreements among scientists" about evolution, and he even conceded that learning about these disagreements need not be limited to just graduate students and researchers, but also some upper-division undergraduate students might be able to study them. Dr. Schafersman also provided a detailed list of what he regarded as the genuine scientific controversies over evolution. Notably, Schafersman's list included some of the key controversies previously raised by critics of evolution (such as the sufficiency of microevolution to explain macroevolution, and questions about the primacy of natural selection):

There are many disagreements among scientists about the correct nature or explanation of the evolutionary process. These should be studied in a university evolution class, usually taught in the senior year because of the great amount of prior biological knowledge needed to understand the issues. Their existence indicates that evolutionary science is a very healthy, active, and productive field. Here are some of them, including all the most contentious ones:
A. The sufficiency of microevolution to explain macroevolution v. the existence of specific macroevolutionary processes such as mass extinction, species selection, macromutation, etc.

B. Disagreements about the tempo and mode of evolution under different circumstances: slow v. fast, gradual v. punctuated, before and after a mass extinction event, background evolution v. adaptive radiation, etc.

C. Adaptation of all features in evolution via natural selection v. features resulting from non-adaptive events and processes, such as correlation of growth, body constraints, neutral theory, genetic drift, etc.

D. The role of contingency and non-progression in evolutionary history v. evolutionary progress, improvement, and repetition due to convergent evolution.

E. Disagreements about the primacy of natural selection of individuals compared to other levels of the evolutionary hierarchy, such as gene selection, group selection, and species selection.

F. Nature v. Nurture, Genes v. Environment--this is the most divisive controversy. There are at least three positions: blank slate/human potential proponents v. sociobiologists and evolutionary psychologists v. biological determinists and IQ and race investigators.

G. The extent to which evolutionary theory can explain or account for human morality, religion, behaviors, self-awareness, free will, etc.

H. The reality or not of memes in the human population; memes are similar to genes, but are actually ideas or concepts that evolve throughout the human population and are affected by similar processes that affect genes, such as natural selection, genetic drift, founder effect, etc. Memes affect cultural evolution in the same way that genes affect physical evolution.
[originally posted at http://www.txscience.org/files/icons-revealed/index.htm ] (emphasis added)

5. So Dr. Schafersman eventually conceded that there are many scientific controversies over evolutionary theory, and he was even willing to allow some undergraduate students to study them. But he continued to oppose the right of high school students to learn about them. Why? To be blunt, he seemed to think that high school students are too dumb to understand scientific controversies. So in his view, even "Real scientific problems, controversies, etc., should not be included in introductory science textbooks." It's better for high school students to simply accept existing theory and learn not to question:

Scientific theories are too massive and established to expect any high school student to critique or question. The vast majority of high school students would not be able to perform such critiques in a scientific way. Scientific theories should be accepted as reliable knowledge in K-12 classes, and not made the object of questioning until they have the educational training necessary to do so, which consists of years of graduate study at universities.
Real scientific problems, controversies, etc., should not be included in introductory science textbooks, because they are almost always too difficult to understand and their presence would only lead to student confusion and frustration.

There are certainly problems, controversies, difficulties, and knowledge gaps with the modern theory of evolution--the explanation of how the mechanism of the evolutionary process operates over time--but for the reasons stated above, these topics are just too complex to be dealt with in high school. They almost never are, and the textbooks need not and usually do not cover them.

The concept of students learning about the 'strengths and weaknesses' in scientific 'hypotheses and theories' in high school is unscientific and pedagogically useless.

[originally posted at http://www.txscience.org/files/icons-revealed/index.htm] (emphasis added)


6. So who are the ones trying to "dumb-down" how biology texts cover evolution? Those who want textbooks to cover evolutionary controversies, or Darwinists like Steve Schafersman who think allowing students to learn about the strengths and weaknesses of existing theories (as mandated by Texas law) is "unscientific and pedagogically useless"?