Comment by squeefers
7 hours ago
> Assuming a scientific testing gloss, each new genetic code variation X can be considered as a hypothesis, that "variant X is fit", and then natural selection events that act on copies of X (for or against) serve as experiments testing the hypothesis
this is the problem i have with natural selection... it has no predictive power. You can never use natural selection theory to say if an organism is "fit" before it exhibits its fitness. what good is this?
This may be more a problem with how "fit" is defined and used than with natural selection theory itself. Fitness can be hard to define beyond the trivial "these organisms which survived the selection event must be the fit ones," and natural systems are usually so noisy with inputs that its hard to figure out what was actually important in retrospect, or likely to evolve in the future.
Only in situations with a powerful selection pressure (like an asteroid strike causing a nuclear winter, or antibiotic applied to a petri dish) can one have a hope of reliably predicting which variants will be selected for or against.
However, these situations are not irrelevant, especially if we can predict the likelihood of those situations developing. Real predictions of the theory of natural selection can be applied to managing antibiotic resistance in populations of bacteria. For example, we know that antibiotic resistance mechanisms that bacteria evolve will often have an energy metabolism cost to their maintenance. This means that, absent pressure to be resistant to antibiotics, we'd expect a population to gradually lose individuals with the genes for the resistance mechanism, because they would be incurring a metabolic penalty for possessing those genes. So natural selection theory accurately predicts that if you remove the selection pressure of the antibiotic, the bacteria will evolve to lose the resistance mechanism, and become susceptible to the antibiotic again over several generations of natural selection. Using this knowledge, some rural regions will discontinue use of a given class of antibiotics in agriculture to allow for resistant strains to decline, and then resume their use when they are again effective. By intelligently rotating use of antibiotics in this way, we can enjoy their benefits without incurring too much inefficiencies and worse tragedies from antibiotic resistance.
That is real & useful predictive power.