More calls to extend the defunct Modern Synthesis

Once again, a group of scientists want to extend and revise the Modern Synthesis version of evolutionary theory in order to bring their pet projects into the mainstream. Once again, these scientists seem to have missed the real revolution that took place 45 years ago so they are attacking a strawman. And, once again, they seem to think that the core principles of evolutionary theory can be defined by how complex animals evolve, ignoring bacteria and single-cell eukaryotes that have been at the heart of the history of life for 3.5 billion years.

But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown.
                      Carl SaganThe paper by Laland et al. (2015) was published in Proceedings of the Royal Society (UK) Series B just this month (August, 2015). The usual suspects are included in the author list including three of the Altenberg 16: Eva Jablonka, Gerd B. Müller, and John Odling-Smee. This is the same group that defended the "yes" side when Nature posed the question, "Does evolutionary theory need a rethink?" back in October, 2014 [see Rethinking evolutionary theory ].

They start with a typical motherhood statement, the kind of thing you hear from everyone who has a new idea to promote.

Conceptual frameworks are necessary in science, but they, and their associated practices, inevitably encourage some lines of research more readily than others. Hence, it is vital that the conceptual frameworks themselves evolve in response to new data, theories and methodologies. This is not always straightforward, as habits of thought and practice are often deeply entrenched. In this regard, alternative conceptual frameworks can be valuable because they draw attention to constructive new ways of thinking, additional causal influences, alternative predictions or new lines of enquiry.

The target is the Modern Synthesis of evolution. Here's how they describe it.

The Modern Synthesis (MS) emerged in the first half of the twentieth century, with the integration of Darwinian natural selection, population-level thinking and Mendelian inheritance, and has provided the dominant conceptual framework for evolutionary biology. It is rightly regarded as one of the major achievements of biology and led to the widespread adoption of several core assumptions. These include: (i) evolutionarily significant phenotypic variation arises from genetic mutations that occur at a low rate independently of the strength and direction of natural selection; (ii) most favourable mutations have small phenotypic effects, which results in gradual phenotypic change; (iii) inheritance is genetic; (iv) natural selection is the sole explanation for adaptation; and (v) macro-evolution is the result of accumulation of differences that arise through micro-evolutionary processes.

This isn't a lot different from the description that Ernst Mayr published in 1963 when he said ...

The proponents of the synthetic theory maintain that all evolution is due to the accumulation of small genetic changes, guided by natural selection, and that transspecific evolution is nothing but an extrapolation and magnification of the events that take place within populations and species...Ernst Mayr

That's the "hardened" version of the Modern Synthesis and it prompted Stephen Jay Gould to write that, "... if Mayr's characterization of the synthetic theory is accurate, then that theory, as a general proposition, is effectively dead, despite its persistence as textbook orthodoxy."

He later regretted being so categorical ("effectively dead") but maintains that what he said was true [see Is the "Modern Synthesis" effectively dead?]. If that's what you mean by the "Modern Synthesis," then it died—or should have died—several decades ago. Laland et al. are a bit cagey because they don't attribute all of evolution to natural selection, only adaptive evolution. The true hardened version of the Modern Synthesis didn't make this distinction.

They go on to say ...

Following the advent of the MS, the field of evolutionary biology has continued to evolve, allowing incorporation of new theoretical and empirical findings (e.g. neutral theory, inclusive fitness theory). As a result, today's evolutionary theory is vastly more sophisticated than the original synthesis and covers a broader range of phenomena.

That's a slight improvement over previous statements made by these opponents of the Modern Synthesis. Most of the time, they don't even acknowledge Neutral Theory or random genetic drift.

As far as I'm concerned, the old Modern Synthesis died a long time ago. It was replaced by a better understanding that includes Neutral Theory, random genetic drift, and heirarchical theory, to mention just a few. Macroevolution is more than just lots of microevolution and random genetic drift plays a major role in adaptation.

The authors include a table outlining a slightly different definition of the Modern Synthesis. I don't agree that this represents the classic Modern Synthesis and I don't agree that it represents modern 21st century evolutionary theory as described in the major textbooks. Thus, they are attacking a strawman.

Classical MS core assumptions

1. The pre-eminence of natural selection. The major directing or creative influence in evolution is natural selection, which alone explains why the properties of organisms match the properties of their environments (adaptation)
2. Genetic inheritance. Genes constitute the only general inheritance system. Acquired characters are not inherited
3. Random genetic variation. There is no relationship between the direction in which mutations occur—and hence the supply of phenotypic variants—and the direction that would lead to enhanced fitness
4. Gradualism. Evolution via mutations of large effects is unlikely because such mutations have disruptive pleiotropic effects. Phenotypic transitions typically occur through multiple small steps, leading to gradual evolutionary change
5. Gene-centred perspective. Evolution requires, and is often defined as, change in gene frequencies. Populations evolve through changes in gene frequencies brought about through natural selection, drift, mutation and gene flow
6. Macro-evolution. Macro-evolutionary patterns are explained by micro-evolutionary processes of selection, drift, mutation and gene flow

I suppose I should at least acknowledge some progress among this group. They are beginning to realize that drift is important and so is Neutral Theory. This is a big change over previous writings where those ideas never entered into the conversation. Nevertheless, I still think that most members of the EES (Extended Evolutionary Synthesis) group didn't really assimilate the lessons of the 1960s and 1970s.

What do they propose? They think that the Extended Evolutionary Synthesis should include ...

1. Evolutionary Developmental Biology
2. Developmental Plasticity
3. Inclusive Inheritence
4. Niche Construction Theory

Here are my three long-standing objections to this view [see Rethinking evolutionary theory] ...

1. None of their claims about evo-devo, facilitated variation, plasticity, epigenetics, etc. have anything to do with evolutionary theory.
2. All of their claims focus on only a small subset of the history of life—mostly animals. You can't reform evolutionary theory based on what you've learned about animal development because it doesn't apply to most organism and most of evolution.
3. Their attacks on the Modern Synthesis are based on the hardened version of fifty years ago. They've missed the real revolution.

Thanks to Denyse O'Leary at Uncommon Descent for bringing this paper to my attention [New call for an Extended Evolutionary Synthesis]. She is convinced that the controversy over extending the Modern Synthesis means that evolution is in trouble and Intelligent Design Creationism is the answer [Larry Moran misses the point about Gunther Witzany].

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Laland, K.N., Uller, T., Feldman, M.W., Sterelny, K., Müller, G.B., Moczek, A., Jablonka, E., and Odling-Smee, J. (2015) The extended evolutionary synthesis: its structure, assumptions and predictions. Proc. Roy. Soc. Lon. B published online August 5, 2015. [doi: 10.1098/rspb.2015.1019]