First barbarians at the gate:Now,an insurgency within?

Tug of War! Biologists Haggle over How New the Improved Evolutionary Theory Will Be

David Klinghoffer 

r changes ahead for evolutionary theory -- an upcoming conference by the Royal Society seeking a "revision of the standard theory of evolution," and a $8.7 million research project underwritten by the Templeton Foundation offering, according to Science Magazine, an "evolution rethink" ("Intelligent Design Aside, from Templeton Foundation to the Royal Society, Darwinism Is Under Siege").

Developments like that obviously stick in the craw of Darwin defenders. For years they have assured the public that the theory requires few or no emendations. 

Think of it in domestic terms. You might make improvements around your house -- replacing worn fixtures and appliances, say -- or even add on a room or two, but it's still the same house. Or is it? Deconstruct and rebuild enough and, lo and behold, before too long you've gone and built a completely different structure, sharing little with the old other than the piece of property it sits on.

What then do we mean when we speak of the heralded "Extended Evolutionary Synthesis"? Journalist Susan Mazur got hold of two leading articulators of the Extended Synthesis and asked them how extensive the revisions will be. It turns out there's a fundamental disagreement on that.

One, Kevin Laland, an organizer of the Royal Society meeting, has in mind something improved but not entirely new. Mazur got this comment from him:

The extended evolutionary synthesis does not replace traditional thinking [he means neo-Darwinism], but rather can be deployed alongside it to stimulate research within evolutionary biology. The new perspective retains the fundaments of evolutionary theory -- genes and natural selection remain central, for instance -- but there are differences in how causation in biology is understood. [Emphasis added.]

The other, Gerd Müller, is clear that he is building a new house, not merely refurbishing the old. He told Ms. Mazur:

The term "Extended Synthesis" was never meant to refer to an "extension of" the Modern Synthesis but to a new and different kind of synthesis that includes many more components -- hence "extended." The inclusion of the new concepts completely alters the structure and "logic" of the evolutionary model, and hence (as a theory) can only replace the Modern Synthesis, not merely improve it. This is not a change in opinion. Denis (Noble) originally also thought that our term "extension" referred to an "add on," but now we are in agreement that this is not the case.

He added, after consulting a thesaurus:

I wrote to let you know what the scientific meaning of "Extended Synthesis" is. Many terms in science have a different meaning from the public usage, because they depend on particular definitions of the phenomena to which they apply.

...

There is no dilemma. I quick check with your Word thesaurus will show you that synonyms of "extended" include "comprehensive", "extensive", "broad" etc. This is the meaning in our case. As in "Extended Family", referring to the wider family and not to an extension of the family.

Laland and Müller are co-authors of a paper in Proceedings of the Royal Society B, "The extended evolutionary synthesis: its structure, assumptions and predictions." They wrote there:

The conceptual framework of evolutionary biology emerged with the Modern Synthesis in the early twentieth century and has since expanded into a highly successful research program to explore the processes of diversification and adaptation. Nonetheless, the ability of that framework satisfactorily to accommodate the rapid advances in developmental biology, genomics and ecology has been questioned. We review some of these arguments, focusing on literatures (evo-devo, developmental plasticity, inclusive inheritance and niche construction) whose implications for evolution can be interpreted in two ways -- one that preserves the internal structure of contemporary evolutionary theory and one that points towards an alternative conceptual framework. The latter, which we label the 'extended evolutionary synthesis' (EES), retains the fundaments of evolutionary theory, but differs in its emphasis on the role of constructive processes in development and evolution, and reciprocal portrayals of causation.

Heading into the November Royal Society meeting, we predict more haggling over the nature and extent of the renovation. 

A lot rides on the question, including the reputations of some hardline Darwinists. It's not merely a question of academic, or philosophic or theological, interest. There are issues of personal prestigehere, and we know those trump all for many people, not excluding scientists. The hardliners are not going to go down without a fight.

On the limits of evolution.

A Limit to Evolution? Where Is Their Imagination?

Evolution News & Views 

fe? While there are a couple of lesser-known amino acids used (selenocysteine and pyrrolysine), those follow special pathways that don't use the genetic code. Hundreds of amino acid forms exist, yet life universally uses the same subset of twenty. Here's a contest for the explanatory power of design over evolution.

In Science Advances (the open-access publishing arm of the AAAS), evolutionists from Spain tackled this question with a new proposal: the "saturation of recognition elements blocks evolution of new tRNA identities." Evolution hit a wall. Once twenty transfer-RNA (tRNA) came into operation, there weren't any more binding pockets left for additional ones in the ribosome. 

Understanding the principles that led to the current complexity of the genetic code is a central question in evolution. Expansion of the genetic code required the selection of new transfer RNAs (tRNAs) with specific recognition signals that allowed them to be matured, modified, aminoacylated, and processed by the ribosome without compromising the fidelity or efficiency of protein synthesis. We show that saturationof recognition signals blocks the emergence of new tRNA identities and that the rate of nucleotide substitutions in tRNAs is higher in species with fewer tRNA genes. We propose that the growth of the genetic code stalled because a limit was reached in the number of identity elements that can be effectively used in the tRNA structure. [Emphasis added.]

Notice, right off the bat there is a genetic code that is faithful and efficient. The authors account for this with a reasonable-sounding explanation: evolution was going about expanding the code, but ran out of possible recognition signals. Adding more would have reduced the fidelity and efficiency of protein synthesis. But do we really want to put limits on evolution? Natural selection is the force that gave birth to almost a trillion species, according to new estimates (Science Daily).

News from IRB Barcelona attempts to justify the proposal in layman's terms: 

Nature is constantly evolving -- its limits determined only by variations that threaten the viability of species. Research into the origin and expansion of the genetic code are fundamental to explain the evolution of life. In Science Advances, a team of biologists specialised in this field explain a limitation that put the brakes on the further development of the genetic code, which is the universal set of rules that all organisms on Earth use to translate genetic sequences of nucleic acids (DNA and RNA) into the amino acid sequences that comprise the proteins that undertake cell functions. [Bold in original.]

The limit is imposed by shape, the article explains:

Saturation of the genetic code has its origin in transfer RNAs (tRNAs), the molecules responsible for recognising genetic information and carrying the corresponding amino acid to the ribosome, the place where chain of amino acids are made into proteins following the information encoded in a given gene. However, the cavity of the ribosome into which the tRNAs have to fit means that these molecules have to adopt an L-shape, and there is very little possibility of variation between them. "It would have been to the system's benefit to have made new amino acids because, in fact, we use more than the 20 amino acids we have, but the additional ones are incorporated through very complicated pathways that are not connected to the genetic code. And there came a point when Nature was unable to create new tRNAs that differed sufficiently from those already available without causing a problem with the identification of the correct amino acid. And this happened when 20 amino acids were reached," explains Ribas.

You could choose to accept this explanation and rely on evolution's ability to explain puzzling realities. But here are some questions that show how shallow these explanations really are. Try for starters:

1. Why didn't the ribosome evolve to accept more shapes?
2. Why didn't the tRNAs co-evolve with an evolving ribosome?
3. Why didn't the aminoacyl-tRNA synthetases co-evolve with the tRNAs?
4. Why don't some species substitute different amino acids for the same codon?
5. Since the genetic code is degenerate, isn't there ample space for evolutionary experiments with additional amino acids?
6. You say this limit was reached 3 billion years ago. Isn't that a long time for evolution to push the envelope?
7. Evolution seems perfectly capable of building giraffes from microbes in 500 million years. Where is your faith?
8. Why wouldn't a critic be justified by calling this explanation a post-hoc fallacy, i.e., "it is, therefore it evolved"?

There are more questions, of course. The point is, evolutionists have no problem invoking natural selection to overcome far more stringent limits than this. It seems highly contrived to impose a limit 3 billion years ago that just happens to coincide with the observation that all of life uses the same genetic code, ribosome and transfer-RNA system.

If observation still matters in science, we can infer a very different explanation. The crucial observations here are: universality, fidelity, and efficiency. The incredibly efficient system elegantly portrayed in Unlocking the Mystery of Life is a lean, mean machine. It uses enough amino acid species to allow for constructing millions of protein products, but not so many as to clutter the factory. And the same elegant system appears universally in three kingdoms of life, as different as archaea and aardvarks.

The system also includes a translation from one language into another. The genetic code, composed of DNA bases, translates into the protein code, composed of amino acids. The tight coupling of these systems argues against their independent emergence. Add to that a whole squadron of error-correction mechanisms, and the resemblance to human software is uncanny -- except that the biological system far surpasses anything humans have ever devised.

Whenever we find systems that are universal, faithful, and efficient, based on coded information, we rightly infer an intelligent cause. Whitewashing these observations with a narrative gloss tends to obscure understanding, not promote "scientific advances."