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Per Ahlberg: Evolution and Palaeontology



Per Ahlberg is Professor of Evolutionary Organismal Biology at Uppsala University in Sweden and a prominent critic of so-called alternatives to evolutionary theory. I was fortunate enough to be able to ask him about his work in paleontology and why he is so passionate about educating the public about evolution.

- Interviewed by Paul Newall (2008).

PN: How did you originally become interested in palaeontology?

PA: In the first instance from being given a little book on life in the past, illustrated with the Zallinger murals from the Peabody Museum. I think it may have been a Swedish edition of the Time/Life book The World We Live In. Anyway, I was about five at the time - this was in the late '60s - and dinosaurs weren't the common cultural currency they are today, so I was blown away by these colourful and lifelike images of a world I never knew had existed. That initial fascination has never left me.


PN: In what ways does palaeontology mesh with evolutionary biology? Is it possible to study one without the other?

PA: Palaeontology provides the only direct information we have about the past history of life (as opposed to inferences drawn from comparisons between living forms), and the evolutionary events that generated present-day biological diversity occurred in the deep past that is illuminated by fossils, so the two are deeply intertwined. Of course, you can study one without the other. Biostratigraphers study fossils as age indicators for sedimentary rocks, something you can do without much thought to evolutionary relationships, and many aspects of evolutionary biology (molecular processes, natural selection etc.) can be studied perfectly satisfactorily in living organisms without reference to fossils. However, palaeontology without evolution tends to descend to mere stamp collecting, whereas evolutionary biology without fossils is sometimes led astray by the lack of this crucial data set.


PN: Can you explain how vital evolutionary theory is to biology and just how little of the subject would make sense without it?

PA: It's been said before: nothing in biology makes sense except in the light of evolution. Literally nothing at all. Biological systems are, above all, evolving systems. Of course it is possible to study aspects of biology with no knowledge of evolution, just as it would be possible to study and even understand the structure of a car engine without knowing anything about the design and manufacturing process (or even the existence of such a process), but the understanding could never move beyond the merely descriptive.


PN: You work in evolutionary organismal biology. How does this field differ from molecular and cellular biology and why did a split between them occur in the first place?

PA: Evolutionary organismal biology represents not so much as split as a reconnection of branches of biology that became sundered long ago. The oldest branch of biology is whole-organism comparative biology, which has been around ever since the days of Aristotle. Comparative embryology and palaeontology also have lengthy pedigrees. Molecular biology, by contrast, is a young subject that only developed during the 20th century. For a long time it ploughed its own furrow, and there was a widespread perception that it had left "traditional" whole-organism biology behind. However, with the emergence of genomics (the study of how genes are activated and interact with each other to govern the construction and life processes of the organism) over the past two decades we suddenly find ourselves able to reintegrate molecular and whole-organism biology, to seek detailed molecular explanations for traits such as body form. This is what evolutionary organismal biology is about: we seek to understand particular evolutionary events (say, the origin of jawed vertebrates) on both whole-organism and molecular levels.


PN: Palaeontology perhaps differs from some sciences insofar as it provides us with extraordinarily visual examples of what is being studied and what we can learn. Do you think the obvious contrast between museum displays of giant (and not-so-giant) dinosaurs and many traditional accounts of creation is one of the reasons why fossil discoveries have been so difficult to explain for critics of evolutionary theory? Do dinosaur finds have an impact that perhaps hominid finds cannot, at least for the general public?

PA: I don't actually think there is a difficulty at all, or no more than with any other science. The problem lies entirely with the fact that some people have a strong vested interest in the scientific account of Earth history (ancient Earth, evolutionary origin of humans, and all) not being true – and are prepared to systematically mislead their followers/congregations about the evidence in order make them believe this. It’s another matter that evolution is not always presented well to the general public – popular versions tend to be subtly influenced by progressivist narrative structures that really have little or no basis in the evidence – but this is a marginal problem compared to the impact of the popular misinformation put out by the anti-evolution movement.


PN: In philosophical terms, evolutionary theory is interesting because it is said to be (along with quantum theory in physics) probably the most highly-confirmed theory we have, but evolution is also often described as a fact. One of the main misunderstandings with regard to evolutionary theory concerns this distinction between evolution as a fact and evolution as a theory. Can you explain the difference and why it is important?

PA: I don't really like the description of evolution as a "fact". A "fact" (to my mind, anyway) is an observation that can be securely verified without reference to an elaborate framework of theory and inference. It is a fact that there is a blue coffee cup on my desk; it is a fact that atmospheric carbon dioxide levels are rising year on year. From this perspective, there are numerous facts that underpin evolution: the fact that organisms share hierarchically distributed non-overlapping sets of similarities (molecular as well as morphological); the fact that the fossil record shows a succession of forms, becoming more similar to those living today as you look at successively younger strata; the fact that variation is heritable; the fact that organisms produce supernumerary offspring; and so forth. The theory of evolution accommodates and explains these facts and many others: it is extremely well confirmed, and I have no doubt that it is true (though there are still aspects of it that we do not understand well), but it is not a "fact" in the strict sense.


PN: What consequences would you envisage if support and funding were withdrawn from biology departments to help fund so-called alternatives to evolutionary biology?

PA: The consequences would be disastrous. Firstly, because important biological research would not get done (so we would not learn things we need to know about how living organisms and ecosystems work), and secondly, because the "alternatives" are mere pseudoscience and would produce no usable results at all, no matter how much money you poured into them. The latter is an important point, which may not be well understood by people who do not actually work in science. Evolutionary biology is simply what you get when you apply the scientific method – i.e. the search for natural falsifiable explanations - to the study of living systems. "Alternatives" such as "Intelligent Design" are not alternative-but-valid versions of biological science but pseudosciences specifically designed to fail to find answers. The whole idea about ID is that it purports (falsely) to demonstrate that natural explanations are insufficient for the existence of living organisms, thus supposedly opening the door (again, falsely) for a magical non-falsifiable "explanation" involving an unknown and unexplained "Designer". Such a "programme of enquiry" cannot, by definition, produce explanations for anything at all.


PN: Evolutionary theory does not claim to explain how life began (abiogenesis) but the question is still a pressing one and important to many people. Some critics say that the chances of life arising in a naturalistic context are so remote that we are justified in embracing a form of design inference for abiogenesis. What is your response and what do evolutionary biologists currently think about this difficult issue?

PA: See above. There is no possible design inference that does not create more problems than it solves. Where did the designer come from? As for how life actually originated, there is a great diversity of opinion, and summarizing it would require an article in its own right. Interested readers can try web searches using terms such as "RNA world" and "autocatalytic systems". These should yield plenty of leads.


PN: Some commentators and participants in the recent debates surrounding the status of creationism and intelligent design (ID) have argued that for biologists and the science community at large to even discuss either alongside evolutionary biology provides them with a false legitimacy, - in short, making it look as though there really is a controversy where actually the scientific consensus is very much otherwise. However, others have insisted that it is always better to engage with challenges or criticisms, even where the objections are misguided. Do you think biologists have a responsibility or even a duty to get involved in these kinds of debate? What motivated you to take part yourself?

PA: I think mainstream science has a duty and a responsibility to expose creationism and ID for the pseudoscientific frauds that they are. This is something quite different from engaging them in debate, the way you would do with adherents of an opposing but conceptually sound scientific viewpoint. Scientists must expose them simply because they are frauds, and it won't do to have large parts of the population bamboozled by the lies and misrepresentations of charlatans. Apart from anything else, it creates a serious democratic deficit. We live in a world where questions that are ultimately scientific in nature (anything from global warming to wise resource management to the emergence of antibiotic-resistant bacteria) are impacting people's lives like never before: how are they supposed to make informed political decisions about them if they haven't the first idea how to assess the validity of a scientific claim? Note that there is an important point here: creationists and ID proponents by necessity attempt to befuddle their audience, not just about the evidence for evolution, but about the nature of scientific enquiry in general. They have to, because it is their only way of concealing the threadbare nature of their own claims.

From this, it should be clear why I have chosen to take part; though you can add the fact that I enjoy talking to people and presenting my ideas to popular audiences. Money, fame and hot chicks would be welcome but have not been forthcoming so far…


PN: Why do you think the debate became and remains so acrimonious? Could it have been otherwise?

PA: No, it could not have been otherwise. It is acrimonious because one side has a prior commitment to a revealed "truth" that happens to be at variance with observable reality, and they are prepared to lie and obfuscate in order to conceal this conflicting information from their target audience.


PN: Challenges to evolutionary theory have found their way into the courtrooms over the years. What is your view of the successes or otherwise of the several trials in the United States in recent times?

PA: I was pleased with the outcome of the Dover trial. Can't really speak about the others, as I didn't follow them closely.


PN: Some philosophers of science have argued that it was a mistake to take on creationism and ID via an insistence that neither are science, since this would put the debate on philosophical grounds (specifically problems of demarcation) rather than empirical. How do you think evolutionary biologists should argue in defence or in support of evolutionary theory? Have some approaches been counterproductive?

PA: No I don't think it was a mistake. Any "explanation" that relies on positing an undefined, unexplained, unobservable, untestable, infinitely malleable supernatural designer with magical attributes is no explanation at all, and certainly isn't science. We should not be afraid to say so.


PN: Although some scientists are interested in the philosophical aspects of their disciplines, many are openly hostile or consider philosophers of science useless at best and often unhelpful. Do you think the philosophy of science – and philosophy of biology in particular – have a role to play or should science be left to the scientists? Have you been interested in or benefited from philosophical considerations of your own work?

PA: I'm generally positive. The work of Karl Popper in particular has been very valuable to the development of systematic biology, as it was a key influence on the development of rigorous methods of phylogenetic analysis (reconstruction of family trees of organisms) by the likes of Willi Hennig. Palaeontology and phylogenetics perhaps need a greater degree of philosophical sophistication than experimental branches of biology, because we often have to draw rather complex inferences from incomplete and non-reproducible data.


PN: What role do you think online media have to play in educating people about evolutionary biology? Should teachers and academics be increasingly active online? Are there any Internet resources that are currently needed or lacking, in your view?

PA: I think they're becoming increasingly important, and I certainly feel that academics should be active online. A key point is the lack of geographical and cultural barriers: this is the only medium I can think of where, for example, it is possible for a young person from a culturally homogeneous rural fundamentalist Christian environment to not only gain access to a wide range of top-quality written material by leading evolutionary biologists, but actually engage with them in discussion. The kid's hardly going to get that from the magazine rack of the local corner store! I'm not sure I can point to any particular resources that are currently lacking, but I follow the development of the medium with great interest.


PN: Notwithstanding the possible perception of a controversy regarding the status of evolution, actually there are plenty of debates going on within biology itself that are perhaps at least as interesting if not considerably more so. Can you give some examples of the unresolved issues that biologists study? Do you think more should be done to focus attention on these internal questions, hence showing that biology is richer and deeper than its critics allow?

PA: The internal debates are very interesting, but often so esoteric that they are difficult to present to a broad audience. One current problem that I find particularly interesting (not saying that it is any more important than a myriad others I could mention; it just happens to come from my particular sphere of interest) is the occasional calamitous clash between phylogenies (family trees) based on molecular data versus comparisons of whole organisms. By and large these corroborate each other remarkably well, but there are specific instances where they do not. The one that particularly interests me concerns the three main vertebrate groups: the jawed vertebrates and the jawless lampreys and hagfishes. Whole-organism data indicate unambiguously that lampreys are closer to jawed vertebrates than hagfishes. For example, unlike jawed vertebrates and lampreys, hagfish hearts are not controlled by nerve impulses, the retinas of their eyes lack bipolar cells, and their body fluids are as salty as the surrounding sea water (in jawed vertebrates and lampreys they are less salty). And yet, molecular phylogenies (based on comparisons of DNA sequences) almost invariably group lampreys and hagfishes together. Clearly, something is going wrong: either the whole-organism data are wildly misleading, or some systematic error in the analysis of the DNA sequences gives us the same error every time. Whatever the answer is (and I'm leaning towards the latter) the resolution of this will have profound implications for the reconstruction of early vertebrate evolution and relationships in general.


PN: If you had to recommend palaeontology or biology in general to a prospective student or a layman in a few lines or paragraphs, what would you tell them?

PA: Biology is the study of life, in all its myriad forms. Palaeontology is the study of the history of life, from its first beginning to the extraordinary diversity of today. Both have something to say about our place in the world. If those simple prospectuses do not tickle your desire to know more, then biology is obviously not for you; if they do, welcome aboard!


PN: What are you currently working on and how do you see your research developing in years to come?

PA: I'm currently working on the origin of land vertebrates (tetrapods) and jawed vertebrates. My own work is largely palaeontological, but increasingly I am integrating this with molecular developmental biology in order to understand the molecular basis for the morphological transitions we observe in the fossil record. This interdisciplinary research is likely to form an ever-larger component of my work in coming years.

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