The Changing Face of Evolutionary Theory? | The BioLogos Forum


(system) #1

An interesting development is taking place in the biological and anthropological sciences today that has its roots in a decades-old discussion. Whispers in the halls of scientific faculties and hushed conversations in laboratories have solidified into outright dialogue and debate in top scientific journals. Scientists from across the various evolutionary disciplines have locked horns over the accepted mechanisms of standard evolutionary theory (SET) and the significance that ought to be afforded to each mechanism. Let me be clear upfront, the core of Darwinian evolution itself is NOT being questioned. Indeed, as Dobzhansky, echoing Teilhard de Chardin, asserted decades ago, “nothing in biology makes sense except in the light of evolution.” It is uncontested that variation occurs in populations and is subsequently winnowed by natural selection, generating biological change over time. SET contends biological diversity is mostly explained by natural selection, defined as the confluence of random phenotypic variation, genetic inheritance, and differential reproductive success. However, some scientists (proponents of the “extended evolutionary synthesis,” or EES) are challenging the tenet that phenotypic variation is entirely random and that natural selection is entirely driven by genetic inheritance. The dialogue focuses on the processes within evolution, where to put causal emphases, and sometimes just what to call things. These scientists are working to hone our understanding of evolutionary theory at present—even if they disagree on the severity of this honing process. The controversy helps highlight the sheer breadth and intricacy of modern evolutionary theory, which cuts across many interdisciplinary lines.

The topic of these conversations even made their way into our recent symposium on Christian doctrine and evolutionary theory. It came up when our team was deciding what kind of evolutionary scientists it would be important to invite to the symposium. Should we invite mostly evolutionary biologists? Geneticists? Paleontologists? Even psychologists and culture experts? Evolutionary theory plays a significant role for so many scientists today. A complete picture of evolutionary theory would not be possible without referencing how it functions in each of these areas, yet scientists are divided on how to parse out the significance attributed to each of these areas.

A recent article in Nature elucidates well the growing momentum of this conversation, as seen by its provocative title: “Does Evolutionary Theory Need a Rethink?” In the article, two teams of scientists respond to this question. Kevin Laland and colleagues think evolutionary theory does need to be reassessed, while Gregory A. Wray, Hopi E. Hoekstra, and colleagues agree evolutionary theory is fine as it is.

Laland et al. argue that new scientific developments in genomics, epigenetics, developmental biology, social science, and ecology are altering the prevailing, gene-centric view of evolution. They contend that organisms are not simply genetically programmed from birth to fit into a prior environment but instead can “co-construct and co-evolve with their environments, in the process changing the structure of ecosystems.”[3] in EES.

Laland et al. explain that phenotypic plasticity is also changing the gene-centered view of evolution. Phenotypic plasticity refers to the way certain organisms can directly alter their morphology, physiology, and behavior in response to an environmental change. What is interesting about these changes is that they occur within the lifetime of the individual organism itself rather than lagging behind in evolutionary time. While plasticity is most drastic with static organisms such as plants (i.e., they cannot move away from their environment and have evolved to adapt directly to their changing environment), it is also visible with insects and animals. As an example, certain grasshoppers, such as Schistocerca gregaria, change from docile, solitary creatures to the well-known, aggressive locusts when surrounded by many others of the same species. They even change color to denote this change in behavior. Laland et al. suggest these immediate phenotypic changes can help prime the genetic pump by helping to select organisms that have the advantageous phenotypic trait—paving the way for the subsequent underlying genes. As Laland et al. says “often it is the trait that comes first; genes that cement it follow, sometimes several generations later.”epigenetic markers, but it can also include the transmission of social behavior (i.e., social learning and cultural evolution) and even ecological inheritance (e.g., a beaver passing down his dam to subsequent generations). Epigenetics is one of the most fascinating areas of extra-genetic inheritance and has received a lot of attention in recent years. Epigenetics is the field that looks at “the heritable changes in gene expression (active versus inactive genes) that does not involve changes to the underlying DNA sequence; a change in phenotype without a change in genotype.”can be transmitted to progeny up to two to three generations. This means that our actions today can directly influence the phenotype of our children and grandchildren through these epigenetic markers.

Now, those in the “No” camp (Wray, Hoekstra, and colleagues) agree each of these mechanisms play a role in evolutionary development; however, they contend SET already makes room for these mechanisms, and thus, evolution does not require redefinition. The central point of disagreement, then, is the significance these other mechanisms have to the theory of evolution. Laland et al. clearly want the genetic throne of evolutionary theory shared with other extra-genetic features. However, Wray, Hoekstra, and colleagues are hesitant to allow the genetic core to be dissolved and give equal value to extra-genetic mechanisms. They have two central concerns. First, there has not been enough experimental evidence as of yet to warrant changing SET. To do so would be too hasty. The second concerns the priority of the current genetic basis of evolutionary theory to these other extra-genetic mechanisms. At the heart of the article the naysayers pose a very important and illuminating question: Could these extra-genetic mechanisms “lead” evolution rather than merely fine-tune or hone the existing underlying genetic engine?

It seems to me this is an important question and will largely dictate whether the present theory needs significant overhauling. What would it mean to “lead” evolution? Clearly, Laland et al. would contend that evolution can be “led” by many of these extra-genetic mechanisms. For instance, phenotypic plasticity might help lead evolution by providing an immediate advantageous trait in a given environment, helping to select and funnel the underlying genetic code in a particular direction towards the advantageous trait expressed by phenotypic plasticity. This phenomenon has often been referred to as genetic assimilation, and it has a very under-represented scientific heritage.Laland K, et al. 2014. “Does Evolutionary Theory Need a Rethink?” Nature. 514, no. 7521: 162.[return to body text]


This is a companion discussion topic for the original entry at https://biologos.org/blog/the-changing-face-of-evolutionary-theory

Fine Tuning and Teleology
(Michael S. Burdett) #3

Thank you for reading my article. Even though I am not a specialist in this field, I will attempt to respond to thoughtful questions or comments about the post.


(Brad Kramer) #4

I moved 6 posts to an existing topic: The ‘car’ argument against Evolution


(David Hume (nom de plume)) #6

Thank you for an excellent summary of this topic. These are exciting times for evolutionary biology, and although I think Wray and Hoekstra and their colleagues are correct, I also think that it is a sign of a robust and healthy discipline that it can engage in debate regarding its deep structure.

The Nature article also highlights an important warning to the non-expert in evolutionary theory. We need to be very cautious when making claims, religious or otherwise, that are based upon popularizations of evolution. As we have seen, the details of evolution are often much more complex than the simple explanation offered in elementary schools.

This is a very important point that you make. The simple outlines of evolution that most people begin with are like a Bohr model of an atom. The simplified versions are incomplete, as they must be to be simplified. This need not be a vexing challenge, except that the person explaining evolution has to deal with religious propaganda, whereas the person explaining atoms merely has to explain quantum mechanics. :smile:


(Daniel Groovimus) #7

“nothing in biology makes sense except in the light of evolution.” is one of the most banal phases I read from intelligent people. Did I as a ten year old have an interest in “sense” or common sense? Yes. Did I have an interest in “evolution”? No. So therefore nothing should have made sense to me based on the quote.

In actuality if I want to get into a debate with materialists over their abandonment of common sense (as did Thomas Nagel in Mind and Cosmos) all I have to do is bait them on the question of purpose. I get back something like, “Oh it would be nice for you to find purpose in life.” And I can easily demonstrate to them their own abandonment of common sense with their position on purpose and meaning, and they are left in the corner. This has happened more than once on the blogs, and it is great fun. So much for “sense” from these guys and I would be surprised at you people in the middle if you would not see it.

Let me ask you guys a question. Was God surprised at the success of evolution? If I am correct to think most of you believe in the failed RMNS paradigm, you would certainly believe in the utter unpredictability inherent in that paradigm as a stochastic process category. As indeterminism is the key feature of any stochastic process, then your belief in RMNS would be a belief that God had absolutely no plan in mind for such indeterminism, which is in fact one possible definition of indeterminism. So therefore God should have been very surprised at the advent of human beings, if you don’t mind a little amateur theology.


(Roger A. Sawtelle) #9

Michael,

Thank you for the article and I want to thank Nature also for bringing to light what is going on behind the scenes in the world of biology. It seems that often science, particularly in this area wants to put up a united front. Also I have heard that Richard Dawkins & Co. have endeavored to squash any theories that go against his Selfish Gene view, or as it has been labeled here as SET.

Before I make my general comments I want to criticize a Straw Person argument you make against teleology. > "We intuitively favour teleological and purpose-based explanations for natural phenomena (e.g., ‘‘the sun radiates heat because warmth nurtures life”) when this is scientifically incorrect "

Yes, this is incorrect, but if one says that life developed on earth in part because our sun provides the right amount of heat and energy, this is correct scientific and teleological statement with which everyone can agree. The question then is, Did these and many other factors essential to life come together by random chance, or by design. Science cannot answer that question, but the rational answer would seem to be design.

My argument with Dawkins and SET is both philosophical and scientific. It is philosophical in that they claim that evolutionary order comes through conflict, while philosophy and theology say that order comes from laws and harmony.

It is scientific when I became aware that SET conflicts with another scientific understanding of life which is ecology. This was when I read Frank Perry’s book, Darwin’s Blind Spot and my study of ecology revealed that ecology provides a different understanding of how life changes which is much better than Darwinism from both the scientific and philosophical/theological point of view.

I am glad that science is changing. I hope that BioLogos does too.


(David Hume (nom de plume)) #12

I have heard that Richard Dawkins & Co. have endeavored to squash any theories that go against his Selfish Gene view, or as it has been labeled here as SET.

This statement is incorrect. I very much doubt that Dawkins has tried any squashing on any large scale (and I’m sure he would not succeed if he did), but the big error here is the false equation of the selfish gene view (which is about gene-level selection) and SET (here defined as “standard evolutionary theory”). Rollicking debates about the levels at which selection can act are ongoing, but no specific view is overwhelmingly favoured by SET and more obviously, none is equivalent to SET. Curious readers might want to start with this Nature paper (free to read at PMC here).


(GJDS) #13

@MichaelBurdett

The debates and questions raised regarding evolutionary theories is a welcomed aspect and questions and debates are essential for progress in any and every field of science. Since QM was again raised in these exchanges, I will point out one vast difference when people compare Darwinian thinking with the way chemists considered the changes brought about by QM treatments of atoms and molecules. Chemists did not hesitate in “dumping” the previous paradigm (often explained in text books as models of balls and sticks) when discussing molecular structures (even though X-ray crystallography provide mountains of evidence for such a pictorial representation) – I do not sense a similar “open minded” approach to Darwinian thinking, even though the same people who cling to Darwin constantly show the inadequacies of such thinking. I see this as a commitment to dogma in science (as the banal quote about making sense through such thinking shows). The Academies openly acknowledge that no-one has come up with a “better” paradigm – my question is, has anyone in biology really tried to go past Darwin? When some are willing to seriously make such an attempt, the field of biology will be free from scientism, evolutionism, or whatever nonsensical terms apply to this area.


(Roger A. Sawtelle) #17

I note that you are basing your statement on what you think is the case and I am basing mine on reported instances of attempted intimidation. For instance the friends of Richard Dawkins called a conference in Europe to repudiate Niche Construction Theory as an alternative to his understanding of the gene’s eye view of evolution.

The issue as I see it is Ecology. When de Chardin wrote ecology was practically unheard. It was only after The Silent Spring and the work of Lovelock and Margulis in the second half of the last century after de Chardin lived and wrote that ecology has emerged as the primary discipline in the area of biology, surpassing I would submit the discipline of evolutionary biology.

The scientific question about evolution is not does it exist, but how it works, just as the scientific question about gravity was, Does gravity work as attraction from a distance as per Newton, or curvature of space and time per Einstein.

SET offers only one explanation for how natural selection works, which is “survival of the fittest” selection by conflict. The problem with this is that no one has been able to scientifically demonstrate how this works. On the other hand ecology has demonstrated scientifically how species change and develop.

EES in the form of Niche Construction Theory would bring a huge difference in the way evolution is understood to work. It would also strike an important blow to Dawkins’ Selfish Gene view. It would bring ecology into the relationship with evolution as it should be.

I do not think that Niche Construction Theory is playing along the margins of evolution thought and I don’t thank that Dawkins and other think that way either.

No, it does not mean that evolution is wrong and Creationism or ID is right. We must stop thinking in these either/or, black or white terms. We must demonstrate leadership in exploring new ideas and possibilities that can bring reconciliation and renewal to both science and theology.


(Phil) #18

Good stuff. Interestingly, a friend brought this related article to my attention today: http://www.scientificamerican.com/article/descendants-of-holocaust-survivors-have-altered-stress-hormones/?WT.mc_id=SA_Facebook


(Preston Garrison) #19

3/4/15
groovimus,

You seem to have missed those two little words “in biology,” which results in your comment about the Dobzhansky quote being nonsense. For what it’s worth, the Dobzhansky statement isn’t banal but it’s only half right. Biochemistry, physiology, ecology etc. make a great deal of sense about how things work now, but they don’t account for how things got the way they are. Whenever people use that statement, I want to say that the other foundational thing in biology is Watson’s (and no doubt many others) dictum that living cells obey the laws of physics and chemistry. Fundamentalists wish that that was all there was to biology, but it isn’t.

Who’s talking about materialism here?

The RMNS paradigm may be regarded as failed by the kibitzers at UD and the DI, but not by anyone who actually does research in the area. Referring to RMNS as “failed” is just bluster, which is the usual tactic of amateurs who have no training or experience in a field. For every hint that some mutations may be loosely targeted towards adaptive ones, there also this kind of thing:

On the sequence-directed nature of human gene mutation: the role of genomic architecture and the local DNA sequence environment in mediating gene mutations underlying human inherited disease.

(I didn’t realize this editor would insist on importing the abstract.)

Unpredictable to us doesn’t mean unpredictable to God. So no, He wasn’t surprised. The Biologos writers can speak for themselves, but I think most of them would agree with me. The trouble is that you are trying to answer a theological question using a scientific argument, the same kind of thing a materialist would do.


(David Hume (nom de plume)) #20

The banality of the responses to Dr Burdett’s piece must be discouraging. Thank you for a sliver of light.

I thought the piece offered a chance for BL readers to consider some of the many topics—some new, all interesting—that are contributing to an expanded understanding of evolution. Some of the themes outlined by Dr Burdett suggest that concepts similar to teleology are not as batty as many biologists would claim. Concepts like innovability (cf. A Wagner), facilitated variation, induced mutation, phenotypic buffering (cf. S Lindquist and the Hsp90 field) are all either new additions to evolutionary thought or are ideas resurfacing in the presence of new data. Materialists like me don’t see these things as magical or even mysterious, but believers might reasonably point to them while discussing purpose, guidance, and the like.

It doesn’t seem that BL readers are up to that task.


(Brad Kramer) #21

I’m not very pleased with the tone of some of the comments here, on all sides. Please refrain from ad hominem comments and large generalizations, or I will be forced to delete comments or take further action. The comments on this thread should be focused on the content of Dr. Burdett’s article.


(David Hume (nom de plume)) #22

For instance, phenotypic plasticity might help lead evolution by
providing an immediate advantageous trait in a given environment,
helping to select and funnel the underlying genetic code in a particular
direction towards the advantageous trait expressed by phenotypic
plasticity. This phenomenon has often been referred to as genetic
assimilation, and it has a very under-represented scientific heritage.[6]
It “leads” evolution because the phylogenetic variation and selection
occurs without genetic congruence. These extra-genetic mechanisms lead
the evolutionary process and are causally prior to the change in the
genome. Might we say other extra-genetic mechanisms can also “lead
evolution”?

I agree that phenotypic plasticity is important and interesting. I think it was Kirschner and Gerhart in the mid-90’s who invented the term and put it on the map (cf. Cells, Embryos, and Evolution in 1997), and genetic assimilation is one part of that line of thinking. I would say that these ideas are now very well represented in the literature, and that canalization was well established (if neglected) a long time ago. As you correctly write, no one in the professional debate disagrees.

I think it’s a bit off to think of phenotypic plasticity and canalization as “extra-genetic.” (I don’t think you intended to say that, but the paragraph gives that impression.) My preference is to apply concepts of robustness and evolvability (and/or innovability) to attempt to understand why evolution works. These concepts are not “extra-genetic,” though they are certainly far too complex to yield to basic Mendelian description. I think the ideas of Andreas Wagner are useful here.

My chief point is that I agree that these ideas usefully expand evolutionary theory, and offer interesting opportunities for everyone (believers and otherwise) to discuss evolutionary directionality.


(Michael S. Burdett) #23

Thank you everyone for your comments.

Let me respond to Roger’s comment about teleology and his quotation from the piece. I am not making any normative argument about teleology but rather pointing out that there has been some very interesting psychological work done in this area that suggests normally functioning adults do not simply outgrow what scientist Deb Keleman has called in children ‘promiscuous teleology’, the preference for teleological explanations for natural phenomenon. Rather, it remains a default cognitive bias throughout adulthood (please read the articles I cited). What these cognitive scientists have found is that we are naturally biased towards these kinds of explanations and that these cognitive biases can obfuscate scientific understanding (it even affects trained scientists, see Keleman, Rottman, and Seston 2013). So, I was not making any normative claim about teleology but pointing out how humans are cognitively primed to see purpose-based explanations in the natural world.

The issue it seems to me is whether teleological explanations for natural phenomenon ought to be considered scientific explanations or whether they ought to be treated as metaphysical. This is indeed a fascinating question and one which has been at the heart of scientific enquiry since Francis Bacon rejected ‘final causes’ in the 16th century. I don’t have a response here to that but I think Humeandroid’s responses in this direction are very interesting. In other words, do the mechanisms that motivate the EES open up the issue of teleology in a new way? As I stated at the beginning of the essay, a lot of what goes on in these conversations revolves around what to call things and the implications derived from this naming. This is definitely true in the exchange between Laland and Gardner on ultimate vs proximate causes in the journal Biology and Philosophy. So, the issue is alive and well.


(Roger A. Sawtelle) #25

Michael,

Thank you for your response.

I think that we are talking on two levels, one is the philosophical, where science has felt the need to deny the teleology of Aristotle in order to understand nature better. To say that eyes have the purpose of seeing does not explain how the eyes see, which we still do not understand.

On the other hand we have “common sense” or scientific teleology. The purpose of eyes is to see, there is no question about that. Different creatures have different kinds of eyes but they all see in one way or another. Again the question is not what eyes do, but how they do it.

The confusion and problem comes about when some people deep in the scientific tradition have tried and largely succeeded in driving purpose our of scientific thinking for no good reason. I am talking about Monod and his book Chance and Necessity which “proves” that the universe is not rational and therefore has no purpose or meaning. On the contrary the universe is rationally structured and therefore does have purpose and design.

Scientists make their argument against teleology ad hominem by labeling it as childish. However children are learning much more about their environment every day than adults are. Children are curious and looking for answers. Simplistic teleological answers do not satisfy, but can lead to deeper reasons for why things are as they are, which science cannot offer.

Dennett (or was it Dawkins) confessed that he love the adolescent teleological song par excellence, Tell Me Why. Life does have a purpose. The role of science is not to define this purpose, but if it denies this fact, then it is false.

There is no need for science if life has no purpose. Also humans could go the way of the dinosaurs if we do not use our knowledge of ecology to stabilize the environment of our world. God has given us life in the Creation meaning and purpose and we will lose both if we are not good stewards of both.


(Roger A. Sawtelle) #26

If ecology does not guide evolution, then it is a very remarkable coincidence that fish happen to live in water, that birds fly in the air, that zebras live on the savanna, and that humans live in communities.


(Preston Garrison) #27

Darwin (and Wallace) themselves were a big break from the previous ideas which had their roots in the Biblical accounts. Darwin and Wallace made their hypothesis based on a large number of observations of a lot of species in a lot of environments - in other words a lot of new data, just as those who proposed quantum mechanics did.

You tell us over and over that evolution is “inadequate” but every biologist you encounter here concludes that it is your understanding that is inadequate. You don’t tell us what you think would be a better hypothesis, but it’s hard for me not to guess that your “better hypothesis” is special creation, which is what was rejected 150 years ago. (What other option is there for where species came from? It was either gradually or rapidly. They didn’t fall out of the sky.)

Evolution was not accepted in a blind rush. There was a lot of argument in the 19th century about it, and it was only when it was combined with the early genetics and the math developed by some brilliant mathematicians that it became the accepted theory. Hardy, famous for the Hardy-Weinberg equilibrium in population genetics, was actually a world class mathematician who did many other things. The accumulation of a huge amount of data in biology culminating in comparative genomics has confirmed that Darwin and Wallace were right, even more conclusively than biologists could have imagined. My impression is that they were amazed, when sequencing began back in the '70s, at how similar the chimp and human genomes were, and much greater understanding of the events that formed the genomes (and can be observed to happen today) has just made the story stronger. You may think that biologists are dummies compared to chemists and physicists, but with regard to our own subject, we aren’t. I worked with a good number that were brilliant by any standard. If you are holding your breath waiting for biologists to see it your way, I have to predict that is never going to happen.

For biology to go back to special creation now would be the equivalent of trying to take atomic physics back to classical continuous dynamics.


(GJDS) #28

PGarrison,

I confess that I smile on the occasions that people such as you say, “…but it’s hard for me not to guess that your “better hypothesis” is special creation, which is what was rejected 150 years ago.” I think you do not bother to read my comments let alone look at any of the papers I occasional refer to (all of which have been selected BECAUSE they are written by avowed Darwinists).

I am not any sort of “creationist” (whatever that means) – I have provided many comments that show I am an Orthodox Christian and to the best of my knowledge, the Church has never had a problem with any paradigm of the Sciences, including that of biology. So I cannot fathom the apparent hostility displayed at my comments.

The paper I referred to is a continuation of debate(s) that question natural selection as a law of science (this should be obvious to you since you claim to have the credentials needed to understand such debates). I quote,

The topics of mechanisms and natural selection have been the subject of much recent discussion in the philosophy of science. Relatively little has been written, however, about the intersection of these two topics—whether natural selection can be characterized as a mechanism that explains the phenomenon of adaptation. An important exception is Skipper and Millstein (2005), which argued that existing conceptions of mechanisms fail to “get at natural selection” (2005, 341), while leaving open the possibility that a refined conception of mechanisms could resolve the problems that they identified.”

This paper defends NS by accepting that it lacks the determinism found in laws of science, but argues for a stochastic mechanism, in the hope that by adopting a different understanding of mechanisms in nature, NS may be considered a law of science. Any reasonable person can understand that within the confines of accepted notions of scientific laws, NS does not ‘stack up’.

You and others should try to leave your conflict culture regarding evolution, and simply see it as another outlook that will eventually be replaced by a better scientific outlook. It is not a matter of creationists vs evolutionists – it is rather an outlook that most scientists understand, that all paradigms of science eventually are replaced.

I accept that my outlook to the physical sciences is underpinned by scepticism, and others may prefer a different approach. I have at times given examples where a sceptical outlook served the discipline of Chemistry and old paradigms and theories been replaced, and this has greatly benefited our discipline. It astonishes me to find out such a defensive stance regarding Darwin and this in itself make me think such a stance may be there because many of you may, at some level, understand the inadequacies of Darwin’s outlook. If such matters were not intermingled with the outlook by those of the Christian faith, I really would not give a toss for Darwin or anything biology thinks is the theory of all things.


(Preston Garrison) #29

GD, I don’t mean any hostility, just puzzlement. I haven’t been able to figure out what you think might be a better hypothesis, so I was guessing. The subject of the post was some of the refinements that are being suggested, which is always a good thing, but these ideas don’t seem to me like rejections of basic Darwinian mechanisms so much as new variations on them.

There are suggestions from some that mutation may not be fully random as far as fitness is concerned - that some mutations may be at least loosely targeted to produce adaptive mutations. If that were true, it would be a fairly basic change, but I think the jury is still out on that. On another forum someone just asked why we refer to evolution as a theory and not a Law. I guessed that the reason is that there is no simple equation that describes the evolutionary process - there is the idealized math of population genetics, but since the specific nature of selection changes with time and the environment, the process isn’t smooth and regular. A forest fire, for instance could result in a group of genetically fit individuals dying without offspring. Anyway, if you have do have an idea for improvements, I’d like to hear it.