How Can the Nebraska Religious Coalition for Science Education Assist the
Teaching of Evolution?
(Presented to the Nebraska Association of Teachers of Science in Fremont,
Nebraska on October 25, 2003 by C. F. Austerberry, Ph.D.)
Part I: Creation and Evolution
I’m delighted to have the privilege of being with you this morning. I’m a molecular biologist, teacher, parent, Christian, Nebraskan, and co-founder of the Nebraska Religious Coalition for Science Education.
I’d like to talk first about why those of us in the Nebraska Religious Coalition for Science Education feel that evolution need not contradict religious faith. I also want to talk about some data that provides compelling support for evolution. Finally, and most importantly, I want to hear your ideas about how the Nebraska Religious Coalition for Science Education might support you.
The Nebraska Religious Coalition for Science Education
Young people can get excited about studying challenging mysteries. But first, they need to see that there is a mystery to be solved. They need to see that the mystery is potentially solvable. They don’t need unnecessary fears about religious or social implications of either the mystery or its potential solution.
Some people find evolution incompatible with the creation teachings of Christianity, Islam, and Judaism. These include religious people who oppose evolution, and atheists who oppose religion. However, survey and case studies suggest that most scientists and science teachers view evolution as compatible with religious faith, as do the governing bodies of many major religious denominations.
The Nebraska Religious Coalition for Science Education is a network of Nebraskans from diverse religious faiths with the shared conviction that academic freedom, religious freedom, and scientific integrity are compatible. It is our position: 1) that evolution is a viable scientific theory, 2) that a Creator is a viable theological proposition, and 3) that creationism or "creation science," as well as intelligent design theory, lack evidence and represent erroneous deviations from the scientific method.
We recognize the duty of Nebraska's schools to help students understand the best available science. We believe that evolution can and should be widely taught, in a scientifically sound and philosophically neutral manner. Our goal is to help defend Nebraska's teaching standards from weakness or confusion regarding the scientific theory of evolution. We also raise awareness, particularly in Nebraska's religious communities, that the scientific search for natural explanations is not anti-religious.
Treatment of Evolution in Nebraska’s Science Content Standards
Recall that in February of 1999 the Nebraska Attorney General's Office instructed Education Commissioner Doug Christensen to revise proposed Nebraska Science Content Standards. The main reason given in the letter was that "it appears they require 12th grade students to be taught that present forms of life, including humans, are the product of evolution."
The letter said nothing about the origins of individual humans, nothing about teaching how babies develop naturally from fertilized eggs. Apparently the Nebraska Attorney General's Office felt that embryology and other scientific theories do not have atheistic implications, even though all these other scientific theories also leave God out of their explanations. But there is something about the origins of species, particularly ours, that requires special handling. According to the Attorney General’s Office, evolution means that God had nothing to do with the origins of species. Therefore, they argued that teaching evolution alone would infringe upon students’ freedom of religion.
We in the Nebraska Religious Coalition for Science Education responded that religious and scientific understandings are usually complementary, not competing alternatives. Scientific explanations leave God out, but that doesn’t mean that God had nothing to do with whatever is being explained scientifically. Scientific concepts and terms don’t refer to God for the simple reason that scientific methods can’t distinguish whether or not God is involved.
Each school district establishes their own standards, but Nebraska's state standards, or L.E.A.R.N.S., do serve as benchmarks. They were slightly revised in response to the Attorney General Office’s request. We in the Nebraska Religious Coalition for Science Education think the compromise language is pretty good. The revised state science content standards say that: By the end of twelfth grade, students will develop an understanding of the theory of biological evolution.
Here are the relevant example indicators included in L.E.A.R.N.S:
Understand that the concept of biological evolution is a theory which explains the consequence of the interactions of:
(1) the potential for a species to increase its numbers;
(2) the genetic variability of offspring due to mutation and recombination of genes;
(3) a finite supply of the resources of life; and
(4) the ensuing selection by the environment of those offspring better able to survive and leave offspring.
Investigate and use the theory of biological evolution to explain diversity of life.
Investigate whether natural selection provides a scientific explanation of the fossil record and the molecular similarities among the diverse species of living organisms.
Investigate and use biological classifications based on similarities.
Why do some Nebraskans still object to these revised standards? There are two main kinds of religious objections.
1. First, evolution is incompatible with a literal interpretation of Genesis 1 & 2 as scientific descriptions of origins.
2. Second, there are other religious objections not directly tied to Biblical literalism. These include the philosophical implications of "random chance," competition and death as part of the mechanism of evolution, and the genetic continuity between humans and other species.
Our coalition responds first by affirming that it is the right of each student to freely choose religious beliefs, including Biblical literalism. Science content standards do not call for personal acceptance of evolutionary theory, just an understanding of it. We also want it known that many persons of faith find evolution compatible with their religious faith.
A literal reading of Genesis 1 & 2 as scientific narrative has long been rejected by many religious denominations, and not just for scientific reasons. Indeed, that Genesis 1 & 2 isn't to be interpreted literally was part of very ancient Hebrew tradition, as well as early Christianity (St. Augustine, for example).
As for the various other religious objections to evolution, we note the following points:
Compatibility is a Common View
1. Reaffirms that God is Creator, in accordance with the witness of Scripture and the Reformed Confessions.
2. Reaffirms that there is no contradiction between an evolutionary theory of human origins and the doctrine of God as Creator.
3. Encourages State Boards of Education across the nation to establish standards for science education in Public Schools based on the most reliable content of scientific knowledge as determined by the scientific community.
4. Calls upon Presbyterian scientists and science educators to assist congregations, presbyteries, communities, and the public to understand what constitutes reliable scientific knowledge.
Is Evolution Taught in an Anti-Religious, Atheistic Manner?
Johnson and Giberson (Perspectives on Science and Christian Faith Vol. 54, pp. 242-248, 2002) analyzed evolution teaching in Quincy, MA (pop. 88,000, 12 elementary schools, five middle schools, two high schools). No evolution is taught in those elementary schools, but there is significant coverage in middle and high schools. Textbooks and teachers were generally found to present evolution in a philosophically neutral, balanced way that respects both science and religion. Evolution is not taught dogmatically or atheistically, but it is stressed as being of central importance. One teacher said that he presents a number of possible natural mechanisms for evolution. Although he excludes creation, he is careful not to give evolution a purposeless or meaningless tone.
Intelligent Design Theory
Of course, not everyone shares this compatibility view held by most scientists and science teachers, mainline religious denominations, and our coalition. "There are only two models for the origin of humans: evolution and creation," wrote Cal Thomas in a column carried by the Omaha World-Herald and many other U.S. newspapers on August 29, 2002. Mr. Thomas wants evolution and creation to compete with each other in the science classroom. On what basis is unclear, however, because according to Mr. Thomas, "both theories are accepted on faith" (and) "neither theory can be tested scientifically."
Clearly some people reject the idea that evolution can be compatible with their religious faith, so they reject evolution. When evolution is taught, they want it presented as a speculative hypothesis, and they want as much evidence against evolution presented as evidence for evolution. If you are ever required to do that I will feel sorry for you, because the evidence is rather one-sided.
We don't want to ignore truly open questions, the real unsolved mysteries that scientists are currently investigating, which are the genuine lifeblood of any active, vital science. We are talking about an organized effort to discredit evolution as if it were a bad politician, law, or court decision. Instead of peer-reviewed scientific publications and professional scientific conferences, this struggle for the hearts and minds of voters is going on in churches, political campaigns, and school boards. The alternative to evolution that is now being promoted most actively is intelligent design theory.
Intelligent design theory has been analyzed and rejected by professional scientific research organizations and educational organizations. It is virtually absent from peer reviewed journals. Unlike creationism or “creation science,” intelligent design theory does not arise from Biblical literalism. Nonetheless, most intelligent design advocates are motivated by their belief that intelligent design theory is compatible with theism while evolutionary science is atheistic.
If intelligent design theorists simply criticized attempts to present atheism as a scientific conclusion, my colleagues and I would join them. Unfortunately, intelligent design theorists go much farther. Just as we can distinguish between arrowheads and natural stones, or between homicides and deaths from natural causes, intelligent design theorists say they can distinguish whether living organisms were designed or naturally produced. Intelligent design theorists say it doesn't matter to their theory who the designer is. Their point is that no natural explanation for the origin of living organisms will ever be possible. They claim to be able to show, scientifically, that there must have been an intelligent designer.
In the Feb. 2003 issue of Research News & Opportunities in Science and Theology (Vol. 3, #6, p. 18) intelligent design theorist William Dembski contrasted his theory with claims like “ancient technologies could not have built the pyramids, so goblins must have done it." Dembski stated the difference as follows: "We can show how, with the technological resources at hand, the ancient Egyptians could have produced the pyramids. By contrast, the material mechanisms known to date offer no such insight into biological complexity."
Dembski's assessment of known evolutionary mechanisms is too pessimistic. More troubling, however, is his logic. What if we were not yet able to show how the Egyptians built the pyramids? What if we were not yet able to even imagine how they built them? Would such ignorance by itself really increase the status of extra-natural alternative theories? Of course, archeology and forensic science are valid disciplines. They draw from both the natural sciences and the human (social) sciences. But what do arrowheads or pyramids or any other products of human design really have to do with the origin of biological complexity?
Paleontologist Keith B. Miller wrote the following apt criticism of intelligent design theory (from "God's Action in Nature", Perspectives on Science and Christian Faith Vol. 50, #1, 1998, p. 75):
"Science can identify
areas of inquiry in which no demonstrated cause-and-effect explanations presently
exist, but that is all. To establish that a given process or event has, in
principle, no possible causal explanation would require essentially complete
understanding of all relevant factors and historical contingencies. Such knowledge
has not been even remotely obtained in any field of scientific inquiry, nor
is it likely in any foreseeable future."
In a poll taken last year, 93% of Ohio science professors see no evidence
for intelligent design theory (Bishop, 2002). This is not surprising,
as the so-called "evidence" for intelligent design theory is limited to supposedly
intractable problems facing evolutionary theory. How so many wonderful species
of living organisms came to be on earth is certainly a challenging mystery.
Some parts of the mystery are currently more solvable than others. Direct evidence for genetic
continuity between species is particularly abundant, and more is rapidly
accumulating. Evidence for the adequacy of neo-Darwinian mechanisms, including
natural selection and genetic drift, is also accumulating.
Conclusion to Part I: Creation and Evolution
The evidence supports evolution not because it is somehow incompatible with creation, as if creation were an alternative scientific theory to be disproved, or as if we somehow knew that a creator would never employ a process like evolution. Is God supervising some, or perhaps all, of evolution? That is a religious question unanswerable by science, and of course is really no different from questions about God's involvement in any other kind of event or process. Each of us, including our students, must decide for ourselves the extent to which we believe God is behind the conditions and events that have shaped, and will continue to shape, the course of evolution.
Science neither proves nor disproves a creator or designer. Because silence on the issue is so often misconstrued, brief acknowledgment that there are many religious and philosophical perspectives on evolution would seem appropriate.
Part II: Genetic Evidence for Common Ancestry
Which Similarities Provide the Strongest Evidence for Common Descent?
Homologous structures provide strong evidence for common descent. Why do the bones in a seal flipper look so much like the bones in a human hand? There are countless other examples. Cetaceans (dolphins, porpoises, and whales) provide a striking example of gradual evolutionary transition from a land dwelling ancestor to aquatic species. The whale evolution fossil record is extraordinarily good; both molecular and fossil data support an evolutionary relationship between cetaceans and artiodactyls such as hippos and the other even-toed ungulates.
We don’t always have such good fossil evidence, because many species (including our hominid ancestors) lived in habitats where bodies rarely fossilize. Nevertheless, the molecular evidence by itself can be very strong. Yesterday afternoon at this conference I understand that Dr. George Veomett discussed bioinformatics databases using beta-globin sequences as examples. Students can see for themselves that bat beta-globins are more similar to other mammalian beta-globins than to bird beta-globins, and whale beta-globins are more similar to other mammalian beta-globins than to fish beta-globins.
Some critics of evolution argue that maybe mammals are molecularly similar not because of shared ancestry but because (however each mammal species originated) we group together organisms that share mammalian characteristics. It’s not surprising, so this argument goes, that the molecules responsible for those characteristics will be similar. Note that this anti-evolutionary argument rests on the assumption that all the molecular similarities between mammals are functionally important to mammalian characteristics. This assumption has been shown repeatedly to be false. Many of the genomic similarities and differences reflect no more functional necessity than do craters on the moon. And just as craters on the moon provide direct evidence for a history of meteor impacts, DNA sequences provide direct evidence for an evolutionary history of inherited mutations.
Imagine our moon somehow being able to divide repeatedly into two, then four, then eight moons, etc. Over many years, many moons could be produced. More of the moons would share old craters; fewer moons would share young craters created by recent impacts. When meteors would hit existing craters, new craters would be superimposed upon old craters.
Do we have lots of identical “meteor impacts” (mutations) in exactly the
same genomic locations in closely related species? Yes, we do. Species bear
genetic similarities beyond those required by their physical characteristics.
They do indeed bear similarities that can be reasonably explained only if
inherited through common ancestry.
Edward Max has suggested the analogy of a document being plagiarized. Two different people independently writing about the same subject would not be expected to use exactly the same words, unless there really were only one way to express something about the subject. Evidence for plagiarism is not found everywhere the same words are used, but it is found in two places:
1) where multiple common synonyms could have been used, but were not.
2) where spelling errors in the original also appear in the copy.
In closely related species do we see identical genomic “words” (codons) and “sentences” (genes) where synonymous codons and genes are used in more distantly related species? Yes, we do. Do we see identical “errors” (mutations) in closely related species, but not in less closely related species? Yes, we do. Note that these genetic changes (mutations) may be “errors” only in the sense of being different from previous DNA sequences. Some mutations have no detectable consequences for the organism, and a few are beneficial.
Synonymous Point Mutations - The Examples of Cytochrome C and FOXP2
The genetic code is redundant. 61 triplet codons code for 20 amino acids, so on average each amino acid is coded for by three synonymous codons (that’s an average - methionine and tryptophan are each specified by single codons, and some other amino acids are coded for by six codons). The important point is that each protein can be encoded by an astronomically large number of synonymous DNA sequences. For example, humans and chimpanzees have exactly the same cytochrome C amino acid sequence (104 amino acids long), and it differs from the cytochrome C proteins in other mammals by about 10 amino acids. 3104 (about 1049) different DNA sequences can code for the human/chimp cytochrome C, yet the human and chimp genes differ by only one codon, due to a silent mutation. By “silent” mutation I mean a nucleotide difference between DNA sequences that are synonymous in terms of amino acid coding, so that these DNA differences make no difference whatsoever in the protein sequence.
Other proteins besides cytochrome C are identical in chimps and humans. Of course, the differences are also of great interest. Specific mutations that made chimps and humans different from their common ancestors and from each other are also now being identified. A good example is a protein called FOXP2. It's identical in many different mammalian species, and for example the human and mouse FOXP2 proteins differ by only four amino acids. Interestingly, our FOXP2 protein was shown to be essential for the uniquely human fine neuromuscular control of the larynx and mouth. While the human and chimpanzee FOXP2 proteins are identical for 713 of each protein's 715 amino acids, there are two amino acid differences. One of these two amino acid changes might render the human protein uniquely controllable by cellular signaling pathways (experiments are underway to test this hypothesis). This may have been one of many genetic changes enabling humans to talk.
As with cytochrome C, synonymous codons mean that the DNA sequences need not be as similar as the protein sequences encoded by the DNA. As with cytochrome C, the pattern of similarities and differences among the synonymous codons provides compelling support for the mammalian phylogenetic tree. Human FOXP2 DNA is most similar to that of gorillas and chimps, with only 6 or 7 differences out of 2145 nucleotides. It is moderately similar to the monkey gene, with 18 nucleotide substitutions. Our FOXP2 gene is much less similar, with 145 differences, to the mouse gene. Recall that the mouse and human FOXP2 proteins differ by only 4 amino acids. Clearly in some cases more evidence for evolutionary relationships lies in the genes (DNA) than in the protein sequences encoded by those genes.
Fossil Genes: Pseudogenes
One striking finding of DNA sequencing is the large number of genes that have long been inactivated by mutations. Genes used only in evolutionary ancestors are often still very recognizable. They are inherited through eons, persisting as molecular fossils in descendent species.
The enzyme gulonolactone oxidase is required to make ascorbate (vitamin C). While most mammals have a functional copy of the gene for this enzyme, the gene was inactivated early in primate evolution and exists in our genome and in the genome of most other primates as a pseudogene. Among primates, only prosimians have an unmutated copy of the gene, so only they can make their own ascorbate. By the way, guinea pigs sustained a different mutation in the same gene in their evolutionary history - they too must have vitamin C in their diet.
Various genetic processes can result in duplications of genes, leading to large families and subfamilies of genes, each with many member genes. Often pseudogenes are members of such gene families. For example, besides sharing many functional globin genes, all primates (and only primates) share a particular globin pseudogene, in exactly the same location, with the same inactivating mutations. Humans and chimps also share the same eight bp deletion in the steroid 21-hydroxylase pseudogene, and share another, functional gene for steroid 21-hydroxylase. The largest mammalian gene superfamily consists of ~1,000 genes for olfactory (smell) receptors, over half of which are nonfunctional pseudogenes in humans. A greater fraction of olfactory receptor genes are still functional in other primates, and more still in mice, reflecting the relative importance of the sense of smell in these species. Dolphins, not surprisingly, have an even higher proportion of nonfunctional olfactory receptor genes than we do.
At least one gene has been inactivated recently in our evolutionary lineage, since we last shared a common ancestor with the other great apes. Only humans lack the enzyme CMP-N-acetylneruaminic acid hydroxylase. We can date the inactivating mutation (a 92-bp deletion) quite precisely. We know it occurred before Neanderthals, because their fossilized bones contain the same precursor (Neu5Ac) that modern humans have, and like us they lack Neu5Gc, which is found in the bones of other mammals and is the product of the reaction catalyzed by CMP-N-acetylneruaminic acid hydroxylase that converts Neu5Ac to Neu5Gc.
We should not think of this loss as necessarily a bad thing. Sometimes less is more. For example, Neu5Gc might have been exploited as a host receptor for pathogenic microbes, and thus individuals lacking it might have been resistant to infection.
We should also remember that mutations can add functionality. For example, the tumor suppressor protein p53 activates many genes whose products protect us from cancer. One gene strongly activated by p53 in humans and apes is not activated, or is activated only weakly, in other primates. This promoter to which p53 binds strongly in our genome gained such p53 responsiveness when a particular kind of tandemly repeated sequence called a microsatellite increased in copy number. Where there are only 5 or 6 repeats of TG(T/C)CC in monkeys, apes and humans have 14 or more repeats. We know that such microsatellite expansion can lead to negative consequences (such as Huntington’s disease) if it occurs in some genomic locations, but perhaps less often, it can be adaptive. Similar mutations may be responsible for the fact that many genes are expressed at a higher level in the human brain than in the chimp brain.
Large-Scale Mutations in Nongenic DNA
Many mutations have no measurable effect, good or bad, in large part because most of our genome is not gene-containing DNA. Until recently we were largely ignorant of the structure of nongenic DNA. Much of this nongenic DNA sequence evolves rather rapidly. The evolutionary history of single base substitutions or even small insertions and deletions in nongenic DNA can be especially hard to trace because so many such changes have occurred, and often they’ve occurred repeatedly in the same location. Using our meteor impact analogy, imagine trying to study lunar surfaces in which so many small meteorites have hit that crater boundaries overlap one another, and existing craters are constantly being altered by new impacts. In other words, the phylogenetic signal to noise ratio of the data may be low.
Large DNA inversions, insertions, or deletions, analogous to large meteor impacts that create big craters, may still be discernable even if smaller mutations continue to alter that location. One can’t always count on finding such rare large changes, but when you do, their inheritance across species provides very clear evidence for evolution. Some of the events we’ve already discussed (e.g. CMP-N-acetylneruaminic acid hydroxylase gene inactivation) were caused by such large mutations, but there are even more of them to be found in the nongenic component of the genome. They can help resolve questions left unsettled by other data.
For example, are chimps more closely related to us or to gorillas? Are we more closely related to gorillas or to chimps? In 2000 Satta et al. studied 45 genes and found that while 60% showed that humans and chimps have the closest relationship, the remaining 40% of the gene comparisons couldn't settle the question.
To be really confident, we need to find large, unambiguous mutations that occurred during the relatively brief time between when the lineage leading to us diverged from the lineage leading to gorillas, and when it diverged from that leading to chimps. We have recently identified such events.
A large (100,000) bp section of DNA was found to be in the Y chromosomes of humans and chimps that is missing from the Y chromosomes of gorillas and all other primates. This fragment apparently transposed from its original location on chromosome 1 to the Y chromosome in an ancestor common to chimps (including bonobos, or pygmy chimps) and humans.
Some smaller elements in the genome transpose frequently enough to be called transposable elements. Many transpose copies of themselves to new locations, keeping the original copy intact (copy and paste rather than cut and paste). The most abundant copy and paste elements in our genomes are retroelements, which first make RNA copies of themselves and then reverse transcribe the RNA copy to a DNA copy which is then inserted into a new genomic location. Different families of these retroelements were busy doing this during different periods in our evolutionary history.
The Alu Ye5 subfamily contains members that were retrotransposing throughout recent primate evolution, including the period critical for settling whether chimps or gorillas are our closest relatives. A cross-species study of the genomic locations where 81 such Alu elements are found in humans gave the following unambiguous results:
Conclusion
In my experience, those opposed to the teaching of evolution will not be able to understand the distinction between valid evolutionary science on the one hand and creationism or intelligent design theory on the other hand until they understand that: 1) evolution is compatible with many religious faiths, and 2) the evidence for common ancestry is overwhelming. I've emphasized molecular genetic evidence showing that evolution (common ancestry, common descent) has occurred. Other kinds of evidence for evolution may be more clear or compelling to some people. In some contexts, mechanisms of evolution (how it occurs) might be more important than whether it occurs. I would be happy to point those interested either to additional scientific evidence for evolution (including neo-Darwinian mechanisms) or to publications concerning the relationship between religious faith in a Creator and scientific explanations of origins.
Charles (Chuck) F. Austerberry, Ph.D.
Assistant Professor of Biology
Hixson-Lied Science Building Room 438
Creighton University
2500 California Plaza
Omaha, NE 68178
Voice: (402)-280-2154
FAX: (402)-280-5595
e-mail: cfauster@creighton.edu
web: http://puffin.creighton.edu/Austerberry
Nebraska Religious Coalition for Science Education