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Guybrush · 05-31-2021, 02:43 AM

Now this may BORE you, but I just wanted to quickly mention a concept in evolutionary theory which may also help understand how populations (even anthills) work and evolve.

The concept is evolutionary stable states. I believe the example in The Selfish Gene is birds grooming eachother, so we can use that. Let's say a gene mutates in a population of birds, creating a new version of a gene that makes birds cooperate in grooming. There are places on the bird body that birds can't get to without help, so this grooming gene is very successful. If you could have a population where all birds groom eachother, that would actually increase the reproductive fitness for all, maximizing the reproductive output of the population.

From a group selection point of view, one might think that's a feasible scenario, that a gene could randomly appear and become and stay "fixed" (becoming the only variety of that gene) because it works in the population's interests. But this is not what happens.

What happens instead is that in an environment where more and more birds groom eachother, selfish birds will do increasingly well. After all, a completely selfish bird in a population of altruists would enjoy the grooming of everyone else while never having to spend resources reciprocating. As a result, this bird would have a higher fitness than the altruists and so its selfish genes would spread through the population, destroying any chance of the population reaching an optimal in terms of reproductive output.

Similarly, the cooperative version of the gene does better when the population has many selfishs in it. As a result, the most likely scenario is that the ratio of groomers and non-groomers would tend towards stabilization at a ratio where the fitness difference between the two strategies is minimized. So if cooperators become too many, selfishness will be the best strategy and natural selection pushes the ratio of unselfish individuals back down towards the stable ratio again. It might be 20% selfish individuals and 80% unselfish. Such a ratio is what is known as an evolutionary stable state.

These systems may continue to evolve measures and counter measures, such as animals perhaps trying to identify selfish individuals before grooming them and more advanced manipulation behaviours from the selfish individuals.

05-31-2021, 02:43 AM	#38 (permalink)
Guybrush Juicious Maximus III Join Date: Nov 2008 Location: Scabb Island Posts: 6,525	Now this may BORE you, but I just wanted to quickly mention a concept in evolutionary theory which may also help understand how populations (even anthills) work and evolve. The concept is evolutionary stable states. I believe the example in The Selfish Gene is birds grooming eachother, so we can use that. Let's say a gene mutates in a population of birds, creating a new version of a gene that makes birds cooperate in grooming. There are places on the bird body that birds can't get to without help, so this grooming gene is very successful. If you could have a population where all birds groom eachother, that would actually increase the reproductive fitness for all, maximizing the reproductive output of the population. From a group selection point of view, one might think that's a feasible scenario, that a gene could randomly appear and become and stay "fixed" (becoming the only variety of that gene) because it works in the population's interests. But this is not what happens. What happens instead is that in an environment where more and more birds groom eachother, selfish birds will do increasingly well. After all, a completely selfish bird in a population of altruists would enjoy the grooming of everyone else while never having to spend resources reciprocating. As a result, this bird would have a higher fitness than the altruists and so its selfish genes would spread through the population, destroying any chance of the population reaching an optimal in terms of reproductive output. Similarly, the cooperative version of the gene does better when the population has many selfishs in it. As a result, the most likely scenario is that the ratio of groomers and non-groomers would tend towards stabilization at a ratio where the fitness difference between the two strategies is minimized. So if cooperators become too many, selfishness will be the best strategy and natural selection pushes the ratio of unselfish individuals back down towards the stable ratio again. It might be 20% selfish individuals and 80% unselfish. Such a ratio is what is known as an evolutionary stable state. These systems may continue to evolve measures and counter measures, such as animals perhaps trying to identify selfish individuals before grooming them and more advanced manipulation behaviours from the selfish individuals. __________________ Something Completely Different Last edited by Guybrush; 05-31-2021 at 03:12 AM.