Zack Hancock has a lengthy (~2hr) but informative video that debunks many of the claims made by Denis Noble and James Shapiro, as well as the Extended Evolutionary Synthesis and Third Way (both combined into EES for the rest of the post) in general. In my estimation, Hancock’s viewpoints are shared by the majority of evolutionary biologists, and biologists in general. If you want to get a feel for what the scientific community thinks of EES, Hancock’s video sums it up well (if not briefly).
For those who are not aware, EES is a movement within biology to extend the modern theory of evolution to include concepts EES supporters think are important in evolution but being ignored by the larger scientific community. These include concepts like niche construction, epigenetics, and “natural genetic engineering”, a term coined by James Shapiro.
My takeaways from the video (for those not willing to sit through a 2 hour video):
What Denis Noble proposes is either profound or so ordinary that it is hardly worth mentioning. Noble proposes that organisms are purposeful, and this purposefulness affects their evolution. So what does this mean in real terms? Birds purposefully fly around and forage for food, and they use their brains to purposefully follow certain foraging schemes. Is this a big shock to biologists? No, not at all. Is it already part of evolutionary models? Yes. Many evolutionary models assume foragers use an optimized strategy, and these models have been around for a long time. This is nothing new.
Do organisms purposefully change their genomes in a way that we would recognize as “engineering”? No. We would assume that engineering and purposefulness would involve making beneficial changes, but the processes put forward by Shapiro and EES supporters create deleterious mutations a lot more often than they create beneficial mutations. If it really is engineering, then organisms are really bad engineers.
Inheritance of epigenetic traits makes no difference in long standing evolutionary models, such as in Fisher’s Fundamental Theorom of Natural Selection and Price’s equation. Both genetic and epigenetic traits act the same in these evolutionary models, so it really doesn’t matter if epigenetic or genetic changes are the cause evolutionary change. At the same time, there is no evidence for heritable epigenetic changes making much of an impact on overall evolution of species. What examples we do have are limited and don’t last for many generations.
Worth mentioning, Hancock also does a great job of discussing the early history of the theory of evolution and what led to Neo-Darwinism. If you were wondering what Neo-Darwinism actually meant when it was first coined, this video is for you.
Isn’t epigenetic just the concept that the environment can affect gene expression and depending on how long that variable persists, those that better express that gene , or not, can affect how well they are at adaptation? Sort of like how some plants develop different types of foliage on land than when submerged under water. The environment affects the expression. Those that are underwater longer, that better express the submerged leaves will do better underwater than those that are not as good at it. Maybe over Xmas break I’ll try to watch the video. Also under the impression that we see epigenetic showing dietary preferences changing
It’s the mechanism of gene regulation that matters in this context. One mechanism is DNA methylation where the cytosine in CpG’s have a methyl group attached to them. If the region upstream of a gene has a lot of methylated DNA then it downregulates expression. DNA methylation can be affected by conditions in the environment, so this is an example of physical changes to DNA caused by environmental challenges. In some species these methylation patterns can be inherited, but often don’t last for many generations if the environmental pressures causing DNA methylation aren’t present.
This relates to topics such as Fisher’s theorem and the Weismann barrier, both of which are discussed in the video. In fact, it is Mendelian genetics and the Weismann barrier that led to the formulation of Neo-Darwinism. As discussed in the video, Darwinism (ca. 1860-1895) was actually very Lamarckian.
The objections to Noble in this video are neither insightful nor worth listening to. I never heard of Noble before so this is not a defense of him personally. If the point is that Noble offers little more than rhetoric then I agree. But this video simply offers rhetoric which is far more pointless. Noble at least underlines the importance of these contributions to modern evolutionary theory: epigenetic inheritance, multilevel selection, and genomic evolution. This video offers nothing but the person’s personal dislike for the terminology used like “neo-Darwinism” and “integrated synthesis.” And yes Nobel emphasizes the purposefulness in biological processes – why not? Nobel’s aims are clear – to disabuse simplistic understandings of evolution and calling it purposeless which contribute both positively and negatively to various philosophical ideologies. It is a worthy aim. I see no valuable aim in this video except an attempt at mindless character assassination.
Do organisms purposefully change their genomes in a way that we would recognize as “engineering”? Not to me. Do organisms change their genomes in a way which we would recognize as purposeful? Yes. Do purposeful changes in engineering never make changes which are harmful or not beneficial? YES THEY DO!!! I guess engineers are bad engineers because… oh guess what? They are no more omniscient than any other living organisms. Go figure!
I personally would add some other things to an integrated synthesis which I think are particularly important to understanding evolution: punctuated equilibrium and the role of both communal cooperation (including symbiotes) and even non-cooperative relationships (such as parasites – which have been known to significantly alter genomes directly).
Yes if you want some historical background on the first uses of the term “Neo-Darwinism” then maybe this will interest you. But that is just history and words. Not much biological or philosophical content there. Language is ruled by consensus and the uses of “Neo-Darwinism” I have seen many times is pretty much as Noble has used it.
Thanks @T_aquaticus for posting the video which lined up with my own perception that EES proponents get “lost in the weeds”. I liked how Zach used the Price Equation to show that epigenetics, culture, etc. etc. were not mechanisms of evolution competing with natural selection, but rather they were just different modes of inheritance. In other words, EES proponents deal with proximate details of transmission between generations (things we have known about for decades already), but nothing that requires a complete re-envisioning of the basic Neo-Darwinian framework. I do research at the macro-levels in biology (individuals and populations) and often leave the genetic mechanisms in a “black box” because they are complex, but the video took time to explain things in a way that even this ecology dolt could begin to grasp
The clown emoji is telling. I listened to Noble and Dawkins hour long conversation, it seemed even handed, and Noble was obviously dancing with a lifetime of knowledge.
I can’t imagine why the evolutionary determinists are bothered so much by his relativity
Determinists? The video talks about the non-determinism of mutations, so not sure where you are getting that one from. Another example are the 12 parallel cultures in Lenski’s long term evolution experiment where each parallel culture started with the same bacteria, but they evolved in different directions even though they were in identical environments.
The reason Noble et al. have raised the ire of some is that they claim the theory of evolution needs to be rewritten or changed. The problem is that what they propose is either wrong or already a part of the modern theory of evolution.
First, I didn’t pick up on any character assassination. Hancock seemed focused on Noble’s ideas and arguments, not on his character. However, I’m willing to be wrong on this point.
As to purposefulness, the point I thought Hancock was trying to make is that science shouldn’t even approach this question and use more neutral language. For example, mutations are described as not being biased by fitness. Mutations are also described as being spontaneous and stochastic. I would be curious to hear what you see as purposeful in the way mutations happen. The view most biologists have is a purposeful mutation would be one where the organism knows which mutation would counter an environmental challenge and uses specific mechanisms to produce that specific mutation. It’s also a bit difficult to ascribe some sort of conscious purpose on the part of the organism with respect to mutations.
Those are already a part of the modern theory. Hancock has a different video on his top 10 papers on evolution, and he includes Hamilton’s classic 1964 paper on kin selection:
Sandwalk has a writeup on the video if you are curious.
But evolution is more than just mutations (i.e. variation). It is also natural selection. And that is where the purposefulness comes into evolution even in the bare bones of it. And for organisms more complex than viruses, more selection comes into it with mechanisms to selectively limit and repair alterations to the genome. Of course it has no way to know whether a particular change is beneficial or not but it can limit variation to things which are proven to be less lethal. A balance must be struck between adaptability (long term survivability) and immediate survivability.
Yes and I would agree that what Nobel is doing is not strictly science. It is rhetoric and thus battling what he sees as misguided ways of thinking. It is very much like what many here are seeking to do – bridge the gap between science and religion, which is of course not a scientific task. But then a great deal of what Richard Dawkins has done isn’t science either.
It’s a major feature of Noble’s book. I can’t quote it offhand, but I am surprised you don’t understand the concept for Noble as you are contending against his view.
That’s probably it there… and something to do in part with how the organism is not determined by DNA, but the organism also determines how it draws information from the DNA library.
And the Weismann barrier being relative. Noble had a major comeback to Dawkins on this in their conversation
For myself, I also fail to see purposefulness within natural selection, but that may be a personal foible or a difference in approaching the question. For example, I don’t see any purposefulness in the case of the classic example of the peppered moth. The moths were either eaten by birds before they could reproduce or they weren’t. I tend to view this process as an unavoidable consequence of imperfect replicators and limited resources. It is something akin to moving air over a pipe and getting a note whose wavelength happens to fit the container, a selection of sound wavelength in a way.
I think it’s also a matter of distinguishing between what we can test and conclude as scientists and what is unscientific cultural baggage or cultural inheritance. I think this approach brings focus to the questions we want to ask.
Why don’t you inform us of what Noble means by determinists.
That would be a question of cell or organismal biology. For the theory of evolution, we are concerned about heritable traits.
There are species where somatic cells are used for reproduction and can therefore pass on epigenetic traits. However, as discussed by Hancock this really doesn’t change the basic way evolution is modeled. The Price equation works whether the trait is due to DNA sequence or epigenetic markers.
I found this quote which seems to capture the sense of it
The reductionist approach (which inspired the Modern Synthesis as a gene-centred theory of evolution) has been very productive, but it needs, and has always needed, to be complemented by an integrative approach that recognises causality at multiple levels. The reductionist interpretations of evolution are not wrong in the sense that the processes they include do not occur, they are simply incomplete.
Noble’s suggestion is already a part of the modern theory of evolution. Evolutionary models look at all levels, from the difference at one base in the genome to the overall fitness of a single organism to competition between populations of organisms.
This short-sighted characterization is why so many don’t even want to consider evolution. Too often they see people failing to see purposefulness in anything of life, and they don’t see anything good coming from it. It reminds me of when someone told me philosophy has decided there is no such thing as meaning. My response was that such philosophy had become meaningless. I think the more reasonable conclusion is simply that such things as meaning and purpose are simply not what we thought they were. Just discarding them looks very foolish to me.
Perhaps what you mean to say is that purposefulness isn’t so helpful in understanding the natural process in physics, chemistry and biochemistry.
You sure it isn’t a matter of distinguishing football from soccer, and other equally arbitrary lines we draw through the middle of life. Yes these lines are important for those devoting themselves to a particular discipline. But some effort is needed to distinguish these very particular activities from life in general.
We may talk about ‘selfish genes’ but natural selection acts at the level of individuals, holobionts or comparable units. Selfish genes may be ‘favoured’ in natural selection if they alter the phenotype of the holobiont in ways that significantly alters the fitness. Otherwise, natural selection is not focusing on particular genes, it focuses on the holistic unit (individual or perhaps more accurately, holobiont). In addition, the results of natural selection are dependent on the community and ecosystem, as the success of an individual depends on the environment it experiences.
Genotype is the most influential driver of the phenotype as well as the explanation for inheritance - there is no evolution if the features that enhance fitness are not transferred to the next generations. Therefore, the selection focusing on the holobiont is at the same time working at the level of the genotype. In this sense, it is important that the models of evolution take into account all levels.
One significant component of the debate over EES is simply a matter of definition. What constitutes a new idea? It’s a variant on the ship of Theseus problem - how much change deserves a new name. Has the “new synthesis” of Mendelian genetics and natural selection sometimes been overly reductionistic and dismissive of other factors? Yes. Are the various factors invoked by fans of EES important to consider in evolution? Yes. How much difference do they make? Depends a lot on just what particular evolutionary event you are looking at. Does incorporation of these ideas need a new name, replacing the now old “new synthesis”, or is that just the latest version of the “new synthesis”? That’s a matter of opinion. Some people in the ID camp are actually promoting EES, not rejecting evolution at all, but you wouldn’t know that from Discovery Institute claims.
No, I really mean I don’t see any intrinsic purposefulness in these processes. It happens spontaneously and it is unavoidable. Whenever you have imperfect replicators competing for limited resources you will have natural selection.
That’s not to say life has no meaning or purpose. We don’t have to see purpose in everything in order for life to have purpose. Nature itself doesn’t need intrinsic meaning or purpose in order for humans to find meaning and purpose.
Sexual reproduction changes things up a bit. Since genes are shuffled around you can get selection for specific alleles separate from the genetic background that it is found in. Experiments in yeast comparing asexual and sexual populations demonstrates how sexual reproduction changes how natural selection works:
“Together, our results show that sex increases the rate of adaptation both by combining beneficial mutations into the same background and by separating deleterious mutations from advantageous backgrounds that would otherwise drive them to fixation. In other words, sex makes natural selection more efficient at sorting beneficial from deleterious mutations. This alters the rate and molecular signatures of adaptation.”
Worth mentioning, environment can have an impact on how genotype is expressed at the organismal level. This is called phenotypic plasticity, and it is already a part of the modern theory of evolution.
Natural selection can favor a genotype without increasing the fitness of the organism carrying it, as in meiotic drive. For example, if a mutation increases the probability that a sperm carrying it will fertilize an egg but also shortens the life and lowers the reproductive output of a carrier, it may still spread because it is selectively favored.
