Does sentience remove us from natural selection/evolution?

[NichG]

There is strong evidence to suggest that the lower birth rate in developed areas is a natural, non-voluntary process which mirrors the behavior of many (but not all) animal species. Without touching on any specifics, there are many historical examples of the birthrate fluctuating wildly with development levels even in places where "have lots of children" is a cultural norm.

Voluntary in the sense that the organism decides to have fewer offspring rather than external pressures preventing the organism from succeeding at its attempts to have many offspring. I don't know if I'd say whether its a voluntary act of the genes, a voluntary act of the brain, or a voluntary act of the culture - it's probably ambiguous, but a bit of all of them.

Maybe a more precise thing to say would be that in simple cases, fitness within one generation (defined as the expected number of surviving offspring of that individual) is predictive of which individual's genetic variations will dominate the population at long times. In ecological situations where interactions between individuals and species are strong, single-generation individual fitnesses can become non-predictive of the future dominance of the population. Similarly, in situations where drift is more important than selection (high mutation rate, high gradients in drift with genetic variation, presence of horizontal transfer mechanisms such as homologous recombination, sexual reproduction, etc) then individual single-generation fitness may not be predictive of future dominance.

There's also ambiguity where the 'individual' that should properly be counted is itself participating in multiple parallel replicators - for example, if we were to speak of the fitness of a phenotype rather than a species, or the fitness of a human as opposed to the fitness of a human liver cell - there you get things like group selection, kin selection, and the like; they're selective effects, but rather than directly applying to the survival of what you'd normally think of as the individual, they apply to the survival of some association that the individual is a member of, and the association may exert some control on the replication dynamics of the individuals which comprise it that is uncorrelated with environmental selective pressures. E.g. your body can tell individual cells to commit suicide, and only a few cells have a chance of reproduction in the very long term, but due to that, the collective behavior of your cells can bring about the propagation of something that is genetically much more highly correlated to them than another random individual.

So something like the demographic transition is an indication that by adopting a lower single-generation fitness than is possible for that organism, the probability of long-time dominance (now perhaps not of specific genetic variations but of a given phenotype) can be increased. But, given all these other examples, the idea of escaping a simplistic 'survival of the fittest' type mode of evolution is by no means unique in the whole of biology.

[Bohandas]

Natural selection continues but due to civilization is is overwhelmingly eclipsed and trivialized by the evolution of technology and culture. All adaptations are gradually being offloaded into this new medium.

[Max_Killjoy]

In evolutionary terms, "survival of the fittest" roughly means "who got the most grandkids into the future". It doesn't mean "bigger, stronger, faster, better", and doesn't reward genes directly -- it favors genes that lead to whatever traits that lead to the aforementioned success. It doesn't favor particular traits if there's no differentiation of reproductive success, so if there's no reproductive advantage, there's no evolution to be had.

Sadly, "evolution" has entrenched itself in common parlance as a word that means "progressive change, usually improvement, over time"... and that really clouds the issue when it comes to actual evolution.

[halfeye]

Sadly, "evolution" has entrenched itself in common parlance as a word that means "progressive change, usually improvement, over time"... and that really clouds the issue when it comes to actual evolution.

Evolution as a word means slow change, as opposed to Revolution which means fast change. Change is neither good nor bad, it just is.

[Bohandas]

Evolution as a word means slow change, as opposed to Revolution which means fast change. Change is neither good nor bad, it just is.

I thought revolution was a change that ultimately brought you back to where you were before, like the revolution of the earth around the sun, or the revolution of the Earth around its axis, or the revolution from the song "Won't Get Fooled Again" by The Who

[Tvtyrant]

My favorite part about "survival of the fittest" is how often it is "survival of the luckiest." Gradualist processes are often trumped by extinction level effects that happened to leave only bald individuals so now the species is bald.

[sktarq]

Some more articles mostly on immune system changes since I stated they exist but did not cite examples in my last post.

Article 1
Article 2
Article 3
Article 4 when combined with articles of CCR-Delta32
Article 5
Article 6


On Dietary adaptation

Article A

Enviromental

Article Alpha

[LordEntrails]

Also the issue of chase away theory comes to mind. Sexual selection often gears itself towards absurd and impractical secondary sex characteristics which are only checked by them making individuals unfit in other ways. Oversized antlers and peacock tails are normal where predation doesn't interfere, and the issues with chase away in modern times is a major point of cultural contention right now.

Is this what happened to mullets?

[Tvtyrant]

Is this what happened to mullets?

And 80s shoulder pads :)