I’ll let John answer for himself, just for the record.
But thank you for answering the question.
Lewontin said in 2003 Santa Fe Winter Bulletin:
Blockquote The problem is that it is not entirely clear what fitness is. Darwin took the metaphorical
sense of fitness literally. The natural properties of different types resulted in their differential
“fit” into the environment in which they lived. The better the fit to the environment the more
likely they were to survive and the greater their rate of reproduction. This differential rate
of reproduction would then result in a change of abundance of the different types.
In modern evolutionary theory, however, “fitness” is no longer a characterization of the
relation of the organism to the environment that leads to reproductive consequences, but is
meant to be a quantitative expression of the differential reproductive schedules themselves. Darwin’s sense of fit has been completely bypassed …
Andreas Wagner went further
fitness is difficult to define properly, and nearly impossible to measure rigorously [12]
Regarding figures of merit, Bialek gave abundant examples (though not by that phrase) and some were covered by Natalie Angier’s article regarding what is actually maximized, and it is NOT reproductive efficiency.
The eye is fit to see, birds are fit to fly, fish are fit to swim. All these are in effect even if the individual is no longer reproducing, hence, it seems misleading to define fitness to and adaptation to reproductive efficiency. Reproductive efficiency may or may not be affected whether an organism is actually fit to an environment. Why define fitness to an environment based on reproductive efficiency.
RH Brady points out this lead to a tautologous analytic statement which as far a science goes where we trace cause and effect, it’s rather useless. RH Brady said the form should be synthetic. He give an excellent example regarding the ability to hear.
I find it interesting that someone who is an actual researcher and author in the field of Creation Science is no better able to engage in an informed, coherent and honest discussion than an utterly unqualified layperson like @colewd.
… hence the nonreproducers go extinct. So since evolution is a transgenerational and population-level phenomenon, it leaves us with survival and reproduction being key to understanding how fitness must include these to be made sense of.
Thank you for your response! We agree on something because you said “YES”. And you’re certainly easier to ask questions of and get answer from compared to others.
Nonsense. Fitness - in the sense of evolutionary theory - has to relate to reproductive success. Otherwise it can’t be related to Natural Selection. The fitness of an individual should be the “expected” reproductive success (in the sense of probability theory) of an individual with that combination of traits.
I expect your revised viewpoint of fitness will be almost entirely absent from the consciousness of working biologists, unknown aside from the creationist speaking circuit.
Like virulence is a proxy for buffed up as created viruses, such as Sanford’s inept influenza paper, where a virus experiences no genetic entropy for six thousand years only to deteriorate in a few years? It is evident that quantifying fitness in independent terms of robustness will not work.
Fitness as reproductive efficiency is not a tautology; it is a feedback. Reproductive success is the ultimate outcome that integrates functionality in given environments. How is that statement tautological?
I don’t think you understand, because you’re using it as a club to attack evolutionary biology and to propose something that Lewontin never would have. I’m not quite sure I understand Lewontin, but my opinion is that fitness has a perfectly reasonable definition if we take a probabilistic view. In a given environment, organisms with greater fitness are expected, on average to have greater reproductive success than those with lesser fitness. With greater reproductive success comes increase in frequency.
If Lewontin is such a great authority, why do you reject evolution? And why are we relying on authority to make an argument?
Because it’s the only property that matters to natural selection. Individuals that don’t reproduce don’t contribute to the next generation, no matter how good they are at seeing, flying, or swimming.
That assumes evolutionary theory is valid to begin with. That fact that as Lewontin said, “it’s not entirely clear what fitness” is should be red flags.
Further, Lewontin cited the question of fitness as one of the 4 complications of the evolutionary process, as in, an unresolved problem. This is not exactly a good situation is for a theory claiming to be scientific versus a theory that is mostly faith-based?
Contrast the problem of measuring fitness with the issue of measuring rest mass. You’re saying fitness should be tied to reproductive success. Ok, so do agree with Wagner it’s hard to define and it can’t be practically measured? How then is this first tier science vs. just-so story telling without much empirical basis as a matter of principle?
If large swaths of evolutionary processes are loss of genes in order to increase reproductive efficiency, that does not bode well the process is actually well-characterized in terms of physics, chemistry, and statistics.
One might postulate physical processes were suspended or that we live in a privilege universe out of an infinite number of multiverses, but it’s not looking like the emergence of complexity “more perfect than we imagined” (to quote the TITLE of Bialek’s Hans Bethe Memorial Lecture) is via ordinary processes.
But if you want to relate complexity to reproductive efficiency, which class of creatures are the most reproductively efficient, bacteria or primates?
So-called “Natural Selection” is a mis-nomer, as what Darwin envisioned is neither natural nor is it selection, it is elimination of the reproductively less efficient. Unless one can show elimination of the reproductively less efficient leads to “Organs of Extreme Perfection and Complication” (Origin of Species Chapter 6), one doesn’t have anything but faith statements pretending to be science.
The FACT that elimination of reproductively less efficient more frequently involves loss of genes than creation of new gene families without homologs should be a big red flag. For common descent to work it needs mechanisms of mutation that bring about sudden leaps of complexity.
I can cite several specific major protein families, and further more, most evolutionary biologists I talk to don’t think all major protein families emerged from a single common ancestral protein/gene. How then did misnomered so-called natural selection create these major novel protein/gene multimeric protein/gene families?
So called “selection” was not able through slight successive improvements that were even only as little as 5-bases away from a solution to Lenski’s LTEE. That’s why it took Lenski like 30,000 generations over 15 years to evolve Cit+ when Scott Minnich was able to evolve Cit+ in less than 100 generations and a matter of days. So-called “natural selection” does not work as Dawkins advertised. Minnich’s work showed this, and John Roth of the National Academy of Sciences wrote an article commending Minnich’s work and criticising Lenski’s interpretation of LTEE.
That fitness isn’t independent of context isn’t a red flag, nor does that in any way indicate evolutionary theory is invalid.
But it isn’t an unresolved problem. Defining fitness contextually solves it.
Physician, heal thyself.
He says it must be understood in a specific context, and then it can be defined and measured.
Because defining fitness contextually isn’t story telling. One can understand that carriers of alleles that confer antibiotic resistance outcompete non-carriers in environments with antibiotics, are thus favored by natural selection under that circumstance, and hence have increased relative fitness. So we have made sense of fitness, and observed it in real time. That isn’t a story, it’s a way to understand fitness and also an observed fact.
Large swaths of =/= all of.
Again with your dichotomous thinking. There is no problem in principle with the idea that a lot of genetic information can be lost, complexity fluctuate up and down at different times, and that it isn’t necessarly or always tied directly to fitness.
Just as there can be circumstances that favor loss or inactivation of genes, there can be circumstances that favor their gain.
It is even logically possible to increase complexity while mostly losing gene functions. Imagine whole genome duplication (say 10000 different functional genes are duplicated) where most of the duplicated genes eventually are inactivated by loss of function mutations over many generations (9900 of the duplicates inactivate), but 1% (100 duplicates) of them diverge and gain new functions. What occurred was mostly a loss of excess genes (9900 losses) spread out over a long period of time, but comparing the time before the WGD to much later, 100 new functions were gained. The organism now has 10100 different functional genes, where before the WGD it had 10000.
And therein lies the problem with not considering fitness contextually, both genetically and environmentally. The environment changes, new niches open up, and competition there can favor traits that would have been ancestrally detrimental. Natural selection can still be part of the explanation for such a long transition from single celled ancestors to large multicellular descendants. You just need to understand that the descendant is not necessarily more fit in the ancestral environment.
Elimination of the reproductively less efficient does in fact occur in nature. I return to the example of antibiotic resistant bacteria, which have evolved in nature many times where those bacteria less capable of reproducing when exposed to antibiotics produced by other organisms in their shared environment, were outcompeted. They resistant strains would thus, in Darwin’s metaphor, be selected by nature.
Besides being an example of hypocrisy—and thus stunning irony—you understand that is an obvious non-sequitur, right?
No, for reasons already explained you can have net losses outnumber net gains, for example facilitated by WGD, and yet that result in a net gain in functional genes.
Common descent is independent of the mechanism by which complexity increases. Someone like Behe accepts common descent, yet thinks certain complex features were designed.
That said, there are examples known of how genes with new functions can be gained by normal evolutionary processes, and environmental circumstances that favor such gains.
I’d go so far as to say that would be all evolutionary biologists don’t think that. And yet that isn’t a problem for evolution, because genes can be gained in many more ways than duplication and divergence (though that does happen quite a lot.)
By processes other processes such as shuffling and duplication of internal subdomain segments(like in the Zink fingers and many others), gene-gene fusions, de novo gene gain from non-coding DNA, and so on.
That’s literally diametrically opposite to fact. It is exactly because Scott Minnich and co-authors set up their experiment so the environment much more strongly favored the Cit+ trait that it evolved faster in their experiment, than in the LTEE. So in fact environmentally-dependent selection was what made all the difference.
Nice own goal Sal.
How did Dawkins advertise it, and where?
Isn’t it ironic that Roth wrote literally the opposite of what you are saying? That in fact selection is exactly what makes the difference between the time to the Cit+ function in the LTEE vs Van Hofwegen et al.?
How can you be so wrong about so many things in a single post?
No. If we are discussing the meaning and appropriate measure within a theory we should use the definitions and measures that are required by the theory - whether it is valid or not. To do otherwise would be misrepresentation.
It is an issue but hardly that serious. It’s a practical problem more than a theoretical problem. After all it is fairly obvious that Natural Selection ought to work and there are studies that support it.
This makes no sense to me.
I wouldn’t want to get involved with such simplistic thinking.
It is Natural and it is Selection and you have said nothing that suggests otherwise. Further, characterising it merely as “elimination of the reproductively less efficient” hardly does justice to the idea.
I’d need to see some argument to convince me of that - it is not obviously true. Especially as the relationship between the organism’s complexity and the number of genes is hardly simple and straightforward.
Duplication and divergence is the obvious explanation for protein families. The origin of the first members of the family would seem likely to be rooted in abiogenesis research or in the appearance of genes de novo (which does happen).
This does not seem to make sense either. Lenski’s experiments were not attempting to produce rapid evolution.
Nobody here has related complexity to reproductive efficiency. Rum specifically disassociates evolutionary mechanisms from complexity.
Returning to fitness…
Eventually, there are more offspring than resources can support. TRUE
There is variation among offspring. TRUE
The reproductively less efficient - aka less fit, will be eliminated. Who do you think will survive to contribute to the gene pool?
He also said that The emergence of complexity “more perfect than we imagined” (to quote the TITLE of Bialek’s Hans Bethe Memorial Lecture) is via ordinary processes. - Sal Cordova
