Biologists debate whether evolutionary theory needs to be revised: Does evolutionary theory need a rethink? : Nature News & Comment.
There seems to be two broad camps. Those that feel that the traditional view of evolution: random unguided mutation plus natural selection, remains sufficient, and those who feel that a fundamental rethink is in order.
Does evolutionary theory need a rethink? Yes, urgently
Without an extended evolutionary framework, the theory neglects key processes, say Kevin Laland and colleagues.
…Some of us first met to discuss these advances six years ago. In the time since, as members of an interdisciplinary team, we have worked intensively to develop a broader framework, termed the extended evolutionary synthesis1 (EES), and to flesh out its structure, assumptions and predictions. In essence, this synthesis maintains that important drivers of evolution, ones that cannot be reduced to genes, must be woven into the very fabric of evolutionary theory.
We believe that the EES will shed new light on how evolution works. We hold that organisms are constructed in development, not simply ‘programmed’ to develop by genes. Living things do not evolve to fit into pre-existing environments, but co-construct and coevolve with their environments, in the process changing the structure of ecosystems.
The EES camp cites facts such as the chemical biases toward some mutations (making them at least somewhat non-random), that, in addition to its genes, an individual organism’s development is heavily influenced by its environment, that organisms often create their own environments affecting their future evolution, and that inheritance may involve more than just genes.
Does evolutionary theory need a rethink? No, all is well
Theory accommodates evidence through relentless synthesis, say Gregory A. Wray, Hopi E. Hoekstra and colleagues.
In October 1881, just six months before he died, Charles Darwin published his final book. The Formation of Vegetable Mould, Through the Actions of Worms11 sold briskly: Darwin’s earlier publications had secured his reputation. He devoted an entire book to these humble creatures in part because they exemplify an interesting feedback process: earthworms are adapted to thrive in an environment that they modify through their own activities.
…Nonetheless there are evolutionary biologists (see ‘Yes, urgently’) who argue that theory has since ossified around genetic concepts. More specifically, they contend that four phenomena are important evolutionary processes: phenotypic plasticity, niche construction, inclusive inheritance and developmental bias. We could not agree more. We study them ourselves.
But we do not think that these processes deserve such special attention as to merit a new name such as ‘extended evolutionary synthesis’. Below we outline three reasons why we believe that these topics already receive their due in current evolutionary theory.
In other words, for this camp, the concerns of the EES camp are already being addressed within standard evolutionary theory.
My (admittedly inexpert) view on this might be somewhat affected by the fact that I’m currently reading Richard Dawkins’s ‘The Selfish Gene’. But I currently find the camp that says that evolutionary theory isn’t in any great need of revision to be more persuasive. The EES advocates are pointing to things that seem like details and side effects of the standard theory. Effects that the other camp agrees warrant study and attention, but not anything that requires a fundamental shift in how evolution is understood.
An important part of the discussion involves the role of genes, and to what degree they remain the whole or main story.
Finally, diluting what Laland and colleagues deride as a ‘gene-centric’ view would de-emphasize the most powerfully predictive, broadly applicable and empirically validated component of evolutionary theory. Changes in the hereditary material are an essential part of adaptation and speciation. The precise genetic basis for countless adaptations has been documented in detail, ranging from antibiotic resistance in bacteria to camouflage coloration in deer mice, to lactose tolerance in humans.
It’s important to note that neither of these camps is questioning evolution overall, or arguing for anything along the lines of intelligent design or any other pseudo-scientific concepts. This is a debate about the mechanisms of evolution.