Natural selection challenged?

[spuriousmonkey]

http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0050142

It's open access so you can't complain you can't read it.

MEP = maximum entropy production

But recently, some physicists have gone beyond this and argued that living things belong to a whole class of complex and orderly systems that exist not despite the second law of thermodynamics, but because of it.

Darwinian selection, these researchers point out, isn't the only thing that can create order. Throughout the universe, the interaction of energy and matter brings regular structures—be they stars, crystals, eddies in fluids, or weather systems in atmospheres—into being. Living things are the most complex and orderly systems known; could they be part of the same phenomenon? And could the process that brings them about—natural selection, driven by competition between organisms—be ultimately explicable in thermodynamic terms?

And over evolutionary time, organisms tend to get better at grabbing energy—witness our own species, which now uses about 40% of the energy in sunlight, and is busy releasing the energy trapped in fossil fuels and converting it into entropy. But can such processes be explained as part of a tendency towards maximum entropy production, rather than a Darwinian competition to leave descendents? The key question is whether living things are really free to arrive at a state of MEP, or whether natural selection is precisely the sort of force that can override such a process.

It seems odd that natural selection could be not survival of the fittest, but arrival at the likeliest, but Dewar thinks just that. Recently, for example, he and his colleagues showed that the structure and workings of the ATP synthase enzyme are predictable using MEP theory [8]—that being an efficient generator of cellular fuel and an efficient leveler of energy gradients are one and the same.

Evolution, Bejan believes, has been a process whereby structures have remodeled themselves so that energy and matter flow through them as quickly and efficiently as possible

A new philosophical barrier on the position of humans in the greater scheme of things?

“Shifting the definition of life to a thermodynamic, one removes the mystique from life, in the same way that Darwin said: ‘Hey, we're another type of animal’,” Lineweaver says.

 

[river-wind]

I've always thought that this was the case. Basic physics and biochemistry seems to lend themselves to life.

Of course this doesn't invalidate evolution or natural selection, as the individual who better handles energy transfer will more likely survive to reproduce...this just provides an explanation of the mechanism behind *why* that organism is better able to handle energy transfer.

 

[GeoffP]

Interesting theory. The ultimate test of it would be whether organisms on other planets looked similar to our own - and yet, the present state of evolutionary history is the offshoot of historical accident. So the boundaries of "similarity" might be quite broad. Is DNA the most energy-efficient putative storage base for heritable information?

 

[guthrie]

I don't recall DArwinian selection creating order. HAve they read the same biology sources as I have?

 

[one_raven]

I don't recall DArwinian selection creating order. HAve they read the same biology sources as I have?

I think they are referring to more complex structures being created from less complex structures (single cell - multi cell and onward).

 

[guthrie]

But selection does not create order. IT merely sieves out the fitter structures that already exist. It is the mutations and variations that give the changes in order that permit selection to occur.

But apart from that, the paper seems to make sense.

 

[guthrie]

But the language is shocking. For example:

"Evolution, Bejan believes, has been a process whereby structures have remodeled themselves so that energy and matter flow through them as quickly and efficiently as possible"

Which makes it sound like the structures in our bodies etc have wills of their own. What actually happens are mutations and other changes, so a selection of such structures are formed. Then the most efficient one will hopefully contribute more to the organisms survival, thus that particular structure will become more common. This sort of anthropomorphic language that gets used is a gift to Creationists, and probably confuses a lot of people.

 

[Ophiolite]

I don't recall DArwinian selection creating order. HAve they read the same biology sources as I have?

Of course it creates order, as part of the evolutionary process. This is hardly revolutionary thinking. It may not be completely mainstream, but it mathches the thinking of anyone who believes complexity theory has a central role to play in evolution and abiogenesis.

 

[guthrie]

Thats right, as a part of the process it weeds out less effective things. But it is not what builds the order in the first place. That is the thermodynammics/ molecular chemistry, the same was a hurricances build up.

 

[iceaura]

- - Lineweaver also thinks the replication question is a red herring. To think that life has to store the instructions for its reproduction internally is, he says, arbitrary. The formation of stars, he points out, depends on the preceding generation of stars releasing elements and modifying the gravity of their environment. Everything depends on its environment for energy and materials; where the information is stored doesn't matter. - -

I think where the information is stored matters, and is not arbitrary. How that affects this fascinating approach I don't know - it only seems to affect the philosophical implications, off hand.

 

[Ophiolite]

Ophi, "comlexity theory?" How 'bout "too much complexity theory?"

Semantic content of above statements = zero

 

[Kumar]

Can natural selection be assessed by type and health of children which we are getting now?

 

[Ophiolite]

Yes.

 

[Fraggle Rocker]

I don't recall Darwinian selection creating order. HAve they read the same biology sources as I have?

Biology has gone far beyond Darwin's original model, especially since better microscopes allowed us to discover DNA and better computers allowed us to analyze it. Natural selection is a powerful force in evolution, but there are other forces at work as well.

 

[guthrie]

I know all that Fraggle. I was refering specifically to the way that people keep saying that selection creates order. What it does is sieve out disorder, or in this case, structures of lesser fitness. So it doesnt exaclty create it, as in bring it into being, it just ensures that the previously created structures tend in one direction.

 

[Hercules Rockefeller]

What it does is sieve out disorder, or in this case, structures of lesser fitness.

This statement seems to me to be making the assumption that increasing “fitness” correlates with increasing “order”. I do not believe that is correct. In the field of genetics, “fitness” is a term that describes an organism’s ability to reproduce. It makes my comment on the complexity of that organism. Thus, for a given specific example, a single-celled organism could be said to have the same fitness as a human.

 

[Kumar]

Yes.

What type of "natural selection" we are getting as observed by looking at our children, now? Is it superior or inferior to previous ones?

 

[guthrie]

This statement seems to me to be making the assumption that increasing “fitness” correlates with increasing “order”. I do not believe that is correct. In the field of genetics, “fitness” is a term that describes an organism’s ability to reproduce. It makes my comment on the complexity of that organism. Thus, for a given specific example, a single-celled organism could be said to have the same fitness as a human.

Disorder was probably not the best word to use, although I was trying to follow on from the very first sentence quoted from this paper. Increasing fitness does not correlate with anything except, in this case, more efficient reactions produced by variations in the genome.

 

[Billy T]

I think "natural selection," if that means selection for those individual characteristics that tend to leave more off springs in the next generations for many many generations, (assuming the natural environment remains unchanged) was “challenged” by man at least 10,000 years ago.

For example: Look at the different types of dogs man has made from the wolf. Many have serious physical problems. (Weak hips, to name a well known one.) Some breeds that once were popular only 200 years ago (judging by the "lap dogs" often seen in old French paintings) hardly exist now.

Most of the commercial plants used for food are selected for qualities man considers important, not what makes them the most "fit" as defined above. I believe I have read that wheat has been so evolved by man that it is no longer even viable in the wild on its own. Same may be true of corn.

 

[Ophiolite]

Therefore the dogs and the wheat have adapted through natural selection to be fit for the environment in which they are emplaced. The source of this environment is irrelevant: it just happens to be man made.