In 1904, Dutch botanist Hugo De Vries nailed the problem of evolution with this statement: “Natural selection may explain the survival of the fittest, but it cannot explain the arrival of the fittest.” In other words, because natural selection only preserves what already exists, it doesn’t actually explain the origin of anything at all.
Everyone seems to know that chance mutations can’t explain life, but the misconception that selection can has seductive appeal to many.
Except that you can demonstrate how a random generating process recording successes (called evolutionary algorithms) can enable machines to design things and play strategy games better than humans can. It is the same basic process by which any of us learn things and it is exactly how evolution works as well.
BUT… you should know that only the simplest of organisms use a more accidental process of generating variations by mutations from causes such as ultraviolet radiation. More complex organisms have learned to generate variations in a much more controlled and consistent manner, both insuring a steady source of variation and limiting the random elements somewhat to those areas of the genome which which have proven to be less critical for immediate survival. E-coli uses ultraviolet radiation for variation by protecting the damage done by it from their own DNA repair mechanisms.
Andreas Wagner wrote a whole book on this subject (the arrival of the fittest). No knowledgeable scientist, though, thinks that de Vries “nailed the problem of evolution.” I sure hope De Vries didn’t think that, but it probably doesn’t matter since he spoke the words before modern genetics was even born.
My thoughts are that people who think that natural selection explains most evolutionary change are people who have taken the time to inform themselves.
Since Steve has mentioned A. Wagner’s book (which I read, along with his papers), it might be of interest to discuss his theory a bit. What Wagner found (both in theoretical and empirical studies) was that innovation from mutations can happen in most biological systems, including protein function and gene regulatory networks, based on the fact that these systems are fundamentally robust. This means that one or even several mutations are not likely to have any effect on the function of the system. This allows for large number of variants all with the same functional characteristics. But at some point, one additional mutation becomes the straw that breaks the protein back, and either the system fails completely (the most common outcome) or it takes on a whole new function as a result of all the accumulated changes. It’s a good deal more complicated than that, but I find it to be quite satisfying as an explanation for how mutations can produce innovative changes in phenotype (which are then selected for).
In my long-forgotten role as Cassandra yelling about how actual conversations about design ought to go (for Christians), I often referred to Wagner’s work. I have met very few believers who actually understand or care about design (almost universally, Christian talk about “design” is about frantic efforts to find supernatural tasks for gods), but those who do have this interest should focus on the kinds of ideas that Wagner advances.
Wagner states: “adaptations are not just driven by chance, but by a set of laws that allow nature to discover new molecules and mechanisms in a fraction of the time that random variation would take.”
Stephen is the set of laws self-organizing biological networks that guide the creation of innovation - via proteins having differing multiple functions. a duplicated genetic code is duplicated, and a single mutation offers the promise of a new protein with a new function or at least a new protein with the same function?
Does Wagner see the success of evolution as the self-organization of multiple functioning proteins without any external causal influence?
I’m sorry, I couldn’t understand what you were asking.
I don’t recall that he ever committed himself to the existence/non-existence of “external causal influence”. I don’t think it matters for his argument. He also doesn’t limit his ideas to proteins.
@Paul_Allen1 – As fairly recent ‘convert’ to accepting evolutionary science after having been an OEC for something like 36 years prior, you might look at a couple of things that I have come to accept, developed (not exhaustively nor exhaustingly ) here.
One thing I don’t think that I mentioned there was that the neutral theory of evolution can and does explain how increased complexity can be produced naturally.
I would like to hear what Wagner thinks these laws are and how they operate in biology.
If you start with the same genome then there are only a limited number of things it can do. In order to get innovations you need different sequence. For example, there is no way that a fish genome can produce a human. Changes in DNA sequence can produce new functions, change functions, or increase function. This isn’t limited to just proteins since non-coding DNA and functional RNA play a role. A mutation in a gene promoter region can change gene expression profiles which can change phenotype (e.g. lactose tolerance in Europeans).
The laws that govern biological networks are the same laws that drive all of chemistry, so there is nothing “special” about them. What a protein binds to or catalyzes is determined by its chemical properties, and the same applies to DNA and RNA. How an ice crystal organize themselves into interlinked hexagons isn’t that different from how biological networks organize themselves.
Okay there is much confusion here. The primary problem is the failure to understand that the genius of Darwin’s Theory is that it recognizes Evolution is a two phased process. The first phase is Variation where a new allele is produced by genetic changes, often by sexual mixing of genes.
But Variation does not have the final say. Natural Selection does. Variation produces a variant of the existing species, but Natural Selection determines if that variation is viable or not. If that variation is viable , then it might replace the old species, or might break off into a new species. Also Natural Selection might determine that a species is no longer viable and it may go extinct because it is selected out.
Variation produces possible new life forms. Natural Selection determines which life forms are going to survival and flourish. Why is this important? It is important because the earth is constantly changing. The climate is changing. The terrain is changing. The environment is changing.
Suring the time of the dinosaurs the climate changed and the habitat that sustained the dinosaurs disappeared and so did they. Today habitat is disappearing and so are many species. All sorts of changes in the environment force species to change or die out. It is changes in the environment that causes species to adapt and change, as hominids have adapted and changed over many years. .
Regarding evolution spikes - Wagner’s thesis is - a few new proteins offer multiple functions when required - what he calls ‘self-organizing’ biological networks.
Wagner argument is the speed of change. He states new proteins with new functions respond to external changes but falls back onto self-organizing networks. Which I believe is false.
No, that’s really only part of it. His thesis is, as @sygarte discussed above, that biological networks – proteins, RNA, metabolic systems – are robust and can carry very significant amounts of variation while maintaining function. This means that a family of proteins (for example) can support an overall function while existing across a range of forms. The implication for evolution is that new functions and forms are more “nearby” than we tend to think. His recent review article on evolvability is a great summary of these ideas, and his most recent research publication, a few months ago, is about how variation facilitates adaptation.
You misunderstood him. That sentence isn’t very coherent, but it’s wrong. And Wagner’s ideas are supported by lots of hard data. He’s not just theorizing.