Education: What's the value of molecular evolution training?
Brendan Maher
Wednesday, 30 April 2008 17:53 UTC
Andrew Moore of EMBO, in a 1 May commentary chides the european education system for not including more instruction on molecular evolution. Are students being shortchanged by not seeing the bioinformatics-based evidence supporting Darwin’s theory?
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Replies
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I’ve blogged on this here
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… or, more accurately, here
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From the discussion at End of Pier show (Henry Gee’s blog), Brian Wetterow writes
Bob O’Hara said:
Unless the DNA work connects back to morphology, physiology, ecology, behaviour or whatever, it’s still just shuffling a 4 letter alphabet. What’s more interesting is how that can produce a beast capable of insisting that it should given a piece of sausage (and then falling asleep 5 minutes later).At the risk of unintentional sarcasm… Isn’t that the point of the DNA work in this particular context?
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“Worse still,” Moore continues, “the understanding [students] have – based on the fossil record – is easy prey to specious arguments from anti-science movements”.
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The “anti-science” people are capable of crafting specious arguments for any bit of evidence you can present them. They have developed this skill into an art. -
Posted on behalf of Ulrich Kutschera
Populations of living organisms, and not DNA-sequences, are the units of biological evolution
Knowledge in biodiversity is the key to an understanding of evolutionary biologyIn his Commentary “Science teaching must evolve”, published in the 1 May issue of Nature, Andrew Moore(1) argues that “pupils leave school without fully understanding how well supported evolutionary theory is” and that “molecular evolution [is] the best approach yet to understanding biology’s central theory”. In addition, Moore claims that fossil data are of minor importance, phylogenies that are based on form (anatomy, embryology) and function (physiology) are “fundamentally unsound” and that speculations on the origin of life are “far from sound evolutionary theory” and of “questionable relevance … for evolution”.
As chairman of the German Association of Evolutionary Biologists, which aims to promote the teaching of evolution in public schools and Universities in our country(2), I fully agree with Dr. Moore’s central theses that evolution education must be strengthened and that molecular phylogenetics should become an integral part of European science curricula. However, I disagree with Moore on several points and would like to add the following general remarks and suggestions:- 1. After more than 150 years of research, biologists and geologists distinguish between the fact of evolution (in Darwin’s words of 1859: “descent with modification”) and the mechanism(s) that bring about the documented adaptations and diversifications in populations of evolving pro- and eukaryotic micro- and macroorganisms (according to Darwin and Wallace 1858: “natural and sexual selection” in groups of animals and plants). This important distinction is largely lacking in Moore’s article.
- 2. In the natural sciences, theories explain sets of well-established facts. Hence, the first and most important task should be to teach pupils and the general public why macroevolution – the principal target of the Young-Earth- and Intelligent Design (ID)-creationists – is a fact and not “only a theory”. Here, cell biology (principle of endosymbiosis) and paleobiology (transitional forms in the fossil record) are the disciplines of central importance(3,4,5).
- 3. Evolutionary biology, which evolved from Darwin’s famous three books published between 1859 and 1872, is a system of theories that aims to explain the origin and diversification of life on Earth. This interdisciplinary branch of the biological sciences encompasses both chemical and organismic evolution(3,4). It is obvious that evolutionary biology can not be reduced to molecular phylogenetics and an associated narrow view on the genotype of extant organisms. In evolutionary research, virtually all major branches of the life sciences are of equal importance: taxonomic studies at the organismic and molecular level (comparative morphological and DNA-sequence analyses), cytological investigations (endosymbiosis and cell evolution), comparative embryological, physiological and ethological studies (evolutionary developmental and behavioural biology), insights from the Earth sciences (plate tectonics, geochronology, paleobiology, mass extinctions), microbiological investigations (experimental evolution of bacteria and ribozymes in vitro), computer simulations (evolution of digital organisms, i.e., the new in silico biology) etc. (see refs. 3 and 4 for a more complete list). In other words, both the organismic and molecular aspects of evolutionary biology should be presented and integrated. In my view, a sound knowledge of the diversity of living organisms (classical taxonomy) is the key to an understanding of evolution. The short-sighted “molecularization” of biology resulted in the almost complete elimination of biodiversity research at the universities throughout Europe and the United States: The consequence (rising illiteracy in taxonomy among many biologists and science teachers) are good news for the anti-evolution movement around the world(2).
Unfortunately, Dr. Moore’s implicit claim1 that the fossil record (i.e., “similarity of forms”) is of subordinate importance (“unsound”) and should therefore be replaced by gene sequence information reminds me of an analogous assertion of Michael Behe. This prominent advocate of ID-creationism repeatedly argued that the “truth” can be found only at the molecular level – in published statements, Behe dismissed the fossil record as “irrelevant”. Based on this reductionistic view of the organism Behe deduced his pseudo-religious dogma of the alledged “irreducible complexity” of intracellular nano-machines, such as the base of the flagellum of bacteria that are maintained in liquid culture (see ref. 6 for a solid rejection of this claim).
Hence, the phenotype as a whole (i.e., the living or extinct fossil organism in its natural environment) should be the focus of science education in evolutionary biology; the genotypes (i.e., the sum of the coding and non-coding DNA-sequences of the cells) are only the “blue prints” of the units of biological evolution (populations of reproducing organisms with variable offspring).
Nevertheless, I think that the Commentary of A. Moore(1) is a timely reminder to those organizations that are responsible for science education throughout the world. If the international community of biologists does not react to the ongoing attacks of religiously motivated anti-evolutionstis (ID-creationists etc.)(2-6), scientific illiteracy will rise further and, in the long term, threaten our future as an evolving species of intelligent macroorganisms.
U. Kutschera
Institute of Biology, University of Kassel,
Heinrich-Plett-Strasse 40,
D-34109 Kassel, Germany
E-mail: kut@uni-kassel.de (Germany) and ukut@stanford.edu (USA)1. Moore, A. Science teaching must evolve. Nature 453, 31 – 32 (2008).
2. AG Evolutionsbiologie in Germany
3. Kutschera, U. & Niklas, K. J. The modern theory of biological evolution: an expanded synthesis. Naturwissenschaften 91, 255 – 276 (2004).
4. Kutschera, U. Evolutionsbiologie. 3. Auflage (Verlag Eugen Ulmer, Stuttgart, 2008).
5. Prothero, D. R. Evolution: What the Fossils Say and Why It Matters (Columbia Univ. Press, Columbia, 2007).
6. Miller, K. R. Falling over the edge. Nature 447, 1055 – 1056 (2007). -
As the commentary’s author I wish to clarify a point or two, lest others think that I would like to banish comparison of form from the classroom. I do not think that comparative morphology and the fossil shouldn’t be included in school teaching, and I did not write that.
Instead I voiced the concern that comparison of form might continue as THE PARADIGM on which evolution teaching in secondary schools tends to rest. I do not believe that molecular phylogeny should be the only scientific method used in the study and teaching of evolution, and I didn’t write that either. I hope that teachers can increasingly take the best parts from many disciplines, understand them properly, integrate them and deliver them to students in a credible and interesting way.
Doubtless, the object of main interest is the organism (as Ulrich Kutschera points out in this blog), after all, the organism as a whole is the unit that undergoes natural selection. This addresses the MECHANISM of evolution. But what I was saying was something different – concerning the EVIDENCE for evolution: i.e. that when it comes to working out the most probable phylogenetic tree relating species, molecular phylogeny had distinct advantages over comparison of form alone . Maybe Sean B. Carroll – in his book “The Making of The Fittest” – entertains the subtitle “DNA and the ultimate forensic record of evolution” as a “throw-away” comment, but I don’t think so.
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Thanks for the clarification, Dr Moore. It, together with the comments from Dr Kutschera, has helped me to see what you are proposing much more clearly. It is a constructive exchange. (I’m generally knowledgeable about biology, but not to the extent that I understood exactly what was being proposed re fossils/molecular phylogeny). I’m glad that both are considered necessary.
I’m quite old, I suppose, but I do not forget that I was taught A level biology in the early 1970s at a “good” school, in which the DNA helix had barely made it into the curriculum – certainly not into our textbooks: we learned it as “outside reading” (Watson’s book, actually, which our teacher told us to buy and read). Shocking, the time it takes for scientific advances to filter into schools. -
I’ve enjoyed the debate so far. As a UK school teacher of biology for many years, I have often felt frustration that because of the exam specifications it is barely possible in an overcrowded syllabus, to bring students (undeniably but understandably confined by these constraints) to much of an appreciation of where modern biology is at, or going. I do not, in all honesty, believe that any school student can get very much of a feeling for evolutionary biology while the student expectations of exam boards in fields such as molecular biology and genetics are as limited as they are.
I have long lamented the almost complete lack of any developmental biology, certainly of non-human animals, in school biology. Indeed, as my colleagues are keen to complain, it is difficult at present to see how any school biology student can appreciate from their studies that there is a biosphere filled with non-humans. Extraordinary, isn’t it? And disgraceful. -
I agree that the question of teaching molecular evolution is part of a larger issues which pertains to the place of molecular biology (or ‘modern’ biology) in our eduction system.
Andrew writes: ‘the use of animal models could be an excellent entry point’. Certainly true. But maybe starting with the human case might be even better. In this context, the rise of personal genomics and genetics migth give some hope.
The recent lauch of personal genomics services (23andMe, deCODEme, Navigenics, etc..) offering personalized genome-wide genotyping may have a profound impact on the perception by the public of the importance of the fields of genetics, genomics and therefore, molecular biology. One can maybe stay agnostic on whether (or how soon) these services will provide decisive information for health care decisions. But I am convinced of one thing: the educational potential of browsing your own genome. All of the sudden, the genome is not an abstract or anonymous concept anymore but it becomes tangible, and, maybe even for those who are very familiar with genetics, there is the sudden realization that this very personal and unique string of DNA inhabits everyone of your cells. It does not take that much then to become personally interested into your ancestors, migration patterns and evolution of the human species, asking questions about gene families and gene duplications, relation between genotype and phenotype, etc etc etc…
In a little toy survey we conducted on our blog , it turned out that one fifth of the respondents replied they would use personal genomics services ‘just for fun’. Obviously, I don’t want to make too much out of this survey, but in a way I find it symbolic and hopefully indicative of some natural curiosity and fascination that might well serve as a promising starting point for convincing students (and teachers!) of the importance of learning more about the molecular basis of life and evolution.
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SCIENTIFIC TEACHING OF EVOLUTION
José A. F. Diniz-Filho & Luis Mauricio Bini
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Caixa Postal 131, 74001-970, Goiânia, GO, Brasil, E-mail: diniz@icb.ufg.br
Telephone: 55 62 3218 11 06More than 200 years after the Darwinian revolution, the continuing debate about teaching evolution (Nature 453, 31-32; 2008 and Nature 453, 719 – 719) shows that, even though evolutionary theory has certainly achieved the status of a scientific paradigm, society is far from accepting it as such. This is not totally unexpected, considering that science is a recent enterprise for humans, and that our civilizations have been dominated by mystical and magical views of the universe and human existence for so long.
Moore (Nature 453, 31-32; 2008) claimed that the teaching of evolution must evolve, and we agree. However, this would not necessarily be achieved by increasing students’ exposure to molecular analysis or data. Certainly there is a lag in the diffusion of recent scientific findings into society via textbooks for primary schools. This is obviously not the fault of biology, as we will not find many references to string theory in introductory science texts, or gravitational collapses generating black holes or dark matter in high school physics textbooks. But in physics this gap is not used as an excuse for adopting a non-scientific or anti-scientific approach as currently occurs in biology. Because of the way science advances, it is virtually impossible to eliminate the distance between what is done in research and what is taught in schools, but there must be a way to reduce it.
We agree that adding advances in molecular biology might be helpful for teaching evolution, but would this really be of unique value for convincing people of the existence of evolution? Moore claimed, for example, that the fossil record provides ambiguous notions about evolution by inserting uncertainty. We strongly disagree, and given what we know about child psychology, it is difficult to imagine that learning how a DNA molecule copies itself using models or computer simulations can be more exciting than seeing a dinosaur skeleton in a museum. The difference between them is, however, ideological or psychological only and does not change the fact that doubts about evolution do not arise because of empirical evidence from the real word. After almost 150 years since the publication of “Origin of Species”, it is unbelievable that some people still argue that the evidence of evolution can be considered ambiguous. So, the root of the problem is deeper and should be discussed in a more general context.
We believe that many of the problems pointed out in the debate can be solved by placing evolution in a more general context of teaching science. In other words, the teaching of evolution must evolve by teaching it as part of science as a whole. This means that, instead of focusing only on data and evidence, we should also focus on theory and methods (and within this context molecular analysis would indeed be useful). For example, the importance of molecular analysis in reconstructing evolutionary patterns and phylogenetic relationships among species exists mainly because of Kimura´s neutral theory of molecular evolution. This in turn triggered deep philosophical debates about the validity (or at least the generality) of Darwinian-based evolutionary theory in the 1970`s and 1980’s, but in the end the Darwinian paradigm emerged even stronger. Ironically, under Kimura`s theory molecular data provide the best approximation of genetic similarity among species and evolutionary divergence, and no one has claimed that morphological similarity is adequate to reconstruct evolution (as incorrectly argued by Moore). The German entomologist Willi Henning’s initial development of phylogenetic systematics in the early 1950’s occurred exactly to decouple convergence and ancestral relationships. On the other hand, evaluating deviations of phenotypes with respect to expected molecular patterns is the logical basis of current methods in phylogenetic comparative analysis to detect the main theme of the Darwinian synthesis, the continuous adaptation of life to changing environments by natural selection. All of these issues are logically connected, but showing evolutionary patterns only (e.g., a molecular phylogeny of mammals, or humans, for example) scarcely reveals how they are related and how a synthesis can be achieved.
A theoretical and methodological approach could be used to decrease the distance between the teaching of evolution and more general scientific teaching, with many advantageous side-effects. For example, it would be possible to show how each concept (molecular analysis, palaeobiology or the analysis of adaptation and natural selection) historically developed from pre-Darwinian to current thinking as general concepts in the philosophy of science, including the origin of each of these ideas as scientific theories or parts of a broader scientific theory. They could also be linked with current technological advances and social problems, giving the opportunity to discuss “hot topics” such as population growth, cloning, genetically modified organisms or the effects of human-induced climate changes on Earth’s ecosystem, placing each of these issues explicitly in a general scientific and evolutionary context. This provides the opportunity to discuss first principles in science, how evolutionary thought developed from them, and their consequences and implications for our day-to-day life. Finally, this leads to our final and most important point: it is critical to show people that anti-evolutionary teaching is not really a problem restricted to the biological sciences, but instead reflects a deeper battle of science against the mystical beliefs that still permeate our view of the universe.Lazcano, A. et al. Nature 453, 719 (2008).
Moore, A. Nature 453, 31-32 (2008).
Williams, D. M & Ebach, M. C. Nature 453, 719 (2008).
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