Is Darwinism Collapsing? Fitness Is Unmeasurable
Key concepts like fitness and survival of the fittest are coming under attack, say evolutionists who suggest the theory needs “critical improvements.”
Will Brown bring Darwin’s Down House down? Look at the title of a paper in the Annual Review of Ecology, Evolution, and Systematics by Christopher J. Graves and Daniel M. Weinreich of Brown University: “Variability in Fitness Effects Can Preclude Selection of the Fittest.” The very title suggests that core concepts underlying neo-Darwinism (fitness and selection) are in trouble. Although the paper is behind a paywall, we get an idea of the trouble from the Abstract:
Evolutionary biologists often predict the outcome of natural selection on an allele by measuring its effects on lifetime survival and reproduction of individual carriers. However, alleles affecting traits like sex, evolvability, and cooperation can cause fitness effects that depend heavily on differences in the environmental, social, and genetic context of individuals carrying the allele. This variability makes it difficult to summarize the evolutionary fate of an allele solely on the basis of its effects on any one individual. Attempts to average over this variability can sometimes salvage the concept of fitness. In other cases, evolutionary outcomes can be predicted only by considering the entire genealogy of an allele, thus limiting the utility of individual fitness altogether.
What? Can “salvage the concept of fitness”? Sounds like that key word in Darwinian theory is in need of rescue.
CEH has often claimed that natural selection is indistinguishable from the Stuff Happens Law: i.e., it relies so heavily on chance (both mutation and selection) that it cannot make predictions, and therefore fails as a scientific explanation. The Abstract supports this contention by saying that “Evolutionary biologists often” predict outcomes on the basis of “fitness effects” that vary so much due to multiple factors (“the environmental, social, and genetic context of individuals”) that they can “preclude selection of the fittest” completely. Fitness becomes swamped in unpredictable variability and non-fitness-related effects, until there’s nothing left to select. Stuff happens!
It’s worse than that. Look at this diagram about the paper posted on Phys.org:
Do you see a pattern there? No; you see a “see-saw between advantage and disadvantage” as individuals (vertical axis) vary over time (horizontal axis). Look at the blue line labeled “mean fitness”. The average fitness of the population goes up, down, up, down. The orange line “Fitness variance” is a constant: i.e., there is no net fitness gain. Darwin would have a fit over “fitness” that goes nowhere!
Here are some quotes from the David Orenstein’s summary of Graves and Weinreich’s study on Phys.org. The authors clearly want to cling to some form of Darwinism, and they believe fitness might work in some cases, but it’s hard to feel enthusiastic about rescuing a theory with this many problems:
Why it’s difficult to predict evolutionary fate of a new trait. The phrase “survival of the fittest” makes the principle of evolution by natural selection easy to understand—individuals with a trait that adapts them well to their circumstances are more likely to pass that trait along. But as a new study explains, multiple factors make predicting the fate of a trait fiendishly difficult….
Fundamentally, the problem is that a trait conveyed by a gene variant, or allele, may be advantageous for one or a few generations, but provide no advantage or become a liability when circumstances change, said senior author Daniel Weinreich, a professor of ecology and evolutionary biology at Brown University. But most theoretical models of population genetics assume that fitness remains constant….
Perhaps the most obvious way that the fitness of a trait can vary is that the environment can change, not only over time but also over space….
Another dimension that can vary is the “social” life of alleles. Alleles that result in “cheating” are abundant in nature, but they are most effective when they are rare. Once everyone is cheating, it might no longer be an advantage, so the trait over time can become a victim of its own success….
Even more complications. That any of these circumstances can change over time adds yet another layer of complexity, Weinreich said, because the rate at which circumstances change matters….
Indeed, Weinreich said, many models for predicting the fate of alleles have overlooked the possibility that traits can go completely extinct.
Meanwhile, the rate of environmental change is very similar to the rate at which natural selection acts, the math becomes especially tricky.
These problems recall Jason B. Wolf’s revelation about “slippage on the treadmill” in neo-Darwinian theory (see 3/17/03). Wolf said that “indirect genetic effects” lead to push-backs on fitness. Gaining a new trait that provides some advantage, for instance, puts an individual in a competitive environment where the trait has less value. It would be like walking forward on a treadmill only to slip backward to where you were before. He thought that indirect genetic effects are “considerable” in real world environments. As a result, fitness would come to a standstill, and there would be no net evolutionary progress in fitness. “[T]he traditional paradigm, focused exclusively on direct effects of genes, is inadequate,” he concluded in 2003.
Graves and Weinreich seem to be resurrecting that ghost that haunts the legitimacy of Darwinian theory. Do they have an answer to it? Yes: it’s out there in futureware land —
Weinreich said he plans to delve deeper into the complexities of changes in fitness deriving from varying rates of change in social (e.g. cheaters), genetic (e.g. competing alleles) or environmental (e.g., weather) parameters.
“The overlap between ecological and evolutionary processes—that those two things speak to each other very intimately in a way that’s been overlooked in many models—is the way forward,” Weinreich said. “That’s what’s needed to make critical improvements to models.“
After 158 years since the Origin, who’s willing to wait to see if Darwin got something right? Maybe his theory took over the world because “the phrase ‘survival of the fittest’ makes the principle of evolution by natural selection easy to understand“, not because it actually functions as a scientific theory. After all, “Stuff Happens” is easy to understand, and it works, too. It explains everything!
They talked about cheaters. Now we know who they are: the Darwinists.
You should feel cheated. You ordered an app and only got a picture of one that is under development. Oh, it was a pretty picture. It was easy to understand as a concept. But if you had expected a functioning scientific theory, the marketing department (the Four Musketeers, 1/06/04) failed to reveal all the problems the developers were having in the back room. How long are you willing to wait for the futureware to be delivered? How long before you sue for false advertising? We want our money back: compensation for 168 million lives lost because of Darwin’s dangerous idea: “Stuff Happens.”