As far as I understand things. According to Lynch who is a top populations geneticist because drift is a random effect, it can overpower selection and therefore encourage slightly deleterious mutations and minimize beneficial ones in small populations.
This is why bottlenecks usually mean extinction. When it doesn't, it often means speciation. The Founder Effect works both ways.
However, the effects of mutation and recombination are non-random, and by magnifying the role of chance, genetic drift indirectly imposes directionality on evolution by encouraging the fixation of mildly deleterious mutations and discouraging the promotion of beneficial mutations.
If it's by chance, then it merely reduced the role of natural selection. It doesn't "encourage" fixation of mildly deleterious mutations; it reduces the likelihood that they'd be eliminated. Likewise, it doesn't "discourage" the spread of beneficial mutations, it merely reduces the likelihood that they will become fixed. The real effect of a small population is to reduce the generation time in which alleles become fixed.
Once through the bottleneck, the population may grow, but the effective population size will remain small because lost alleles will not be regained. The real danger is then extinction when the population changes and there is little genetic variation by which the population might adapt.
Multicellular species experience reduced population sizes, reduced recombination rates, and increased deleterious mutation rates, all of which diminish the efficiency of selection (13).
When metazoans have greatly reduced populations, extinction is a possibility. Interestingly, many small vertebrate populations that survive are those that commonly inbreed. Do you see why that would increase chances of survival?
As far as I understand things as mutations accumulate, they can have a negative effect through epistasis.
Or a positive effect.
Combining growth-promoting genes leads to positive epistasis in Arabidopsis thaliana | eLife
But, particularly in a well-fitted population, negative epistatsis is more likely than positive epistasis. So how do individuals with negative epistasis not come to fill the population? They might, if the deleterious effect was small enough to not matter in terms of living long enough to reproduce. Shouldn't such epistatic effects then gradually pull down a population?
It could, but it's not likely. Remember "fitness" only counts in terms of environment. And subtly harmful mutations in some environments often are beneficial in others. If they are harmful enough to be acted upon by selection, then the alleles involved may well remain in the population, but aren't frequent enough to become fixed, since that event would tend to remove such an individual before reproduction.
And often sign epistasis will actually result in a slightly harmful mutation becoming useful. Reciprocal sign epistasis will result in both becoming useful.
People suspect that human fitness has declined since we have found so many ways to compensate for harmful genes. But of course, natural selection continues, it just continues in the current environment, which includes things like glasses, modern medicine, and the like. The fact that intelligence has been rising, and human physical performance is higher now then even a few decades ago, suggests that the genetic load concerns are not an immediate problem.
If human civilization collapsed and we all went back to stone age technology, you'd see a huge die-off of humans unfit for that environment. And then the population would very likely stabilize at pre-civilization levels we had before, and natural selection would make its adjustments.
Well yes because I think the creation story is speaking for all existence and not just us and reserving certain parts for some other life somewhere else. The fall affected all existence not just earth and changed the way things operated.
Seems unlikely that if intelligent beings exist elsewhere, Adam and Eve made the decision for them as well. On the other hand, there is this:
God seems to have been particularly concerned about Adam becoming able to understand good and evil. He told Adam not to eat from the tree that would give him that understanding. And after Adam did so, God acknowledges that Adam then is like God, understanding good and evil, which caused all the trouble.
If one does not accept the reality of Adam and Eve (and I do acknowledge that reality) then this could be understood as an allegory for the evolution of a nervous system capable of knowing good and evil. If so, then your idea would certainly work.
Perhaps there's a way it could be true in the context of two original ancestors. Haven't thought about that. Maybe I should.
When the Bible speaks about after the fall things changed from perfect to imperfect, I think this was regarding all existence. It seems to have changed how we experience things and how everything is measured. Things began to decay including the universe itself. Unless there is intelligent life in another dimension like a multiverse, I cannot see how everything was not affected.
I do not see any way that human disobedience would cause God to harm other beings. To what purpose? He is just. There would be no justice, particularly in harming other intelligent beings for the disobedience of others.
You have to remember that all areas of human life being studied by scientists will be traced by to evolutionary origins. The theory of evolution has been extended to include sociology and psychology.
The most common reason given by evolutionists for religious thought was because they say ancient humans attributed the rustling of grasses from a possible predator to being unknown creatures which later evolved into supernatural thought.
It's the capacity of brains to infer things from incomplete information. It's a skill that lets us put in the missing pieces of a puzzle. There was, of course, a very high survival value in that. In small amounts, it's useful.
In large amounts it's screaming paranoia, and "the Mexicans are invading us!" Not surprisingly, political inclinations can be reliably found by the relative size of two brain structures, one of which mediates fear and threat assessment, the other involving social cognition:
Political Orientations Are Correlated with Brain Structure in Young Adults
Political Orientations Are Correlated with Brain Structure in Young Adults
And so inferences of a boogyman or a good fairy causing things outside our understanding, could come from that. But that doesn't quite explain our search for meaning outside of ourselves, a longing for something greater than we are.
It is the same for human morality which is said to have grown out of primate socializing.
Would it be disturbing or wonderful if God created a universe in which Godlike creatures emerge as a consequence of creation?
Cognitive scientists underlined that religions may be explained as a result of the brain architecture that expressed in early
Homo genus, through the
history of life. However, there is disagreement on the exact mechanisms that drove the evolution of the religious mind. The two main schools of thought hold that either religion evolved due to
natural selection and has selective advantage, or that religion is an evolutionary by-product of other mental adaptations.
Yep. And what if? If He's the Creator, why not?
That is the thing about the MS of evolution is that it will try to explain just about every human behaviour through adaptive evolutionary terms. If you believe that human thought is a product of evolution then all that goes with it, language, culture, society and religion is also a product of evolution.
Maybe so. As Pope John Paul II remarked, the mind is not merely an epiphenomenon of the brain. But perhaps that's one of the things it is. The connection between our body and our soul is a mystery and likely to remain so.
I can only suppose that He got it right.