Have we changed natural selection for the better or worse?
Quite clearly for the worse.
Natural selection has been swapped for an artificial selection grounded in family wealth and political connections. The people who are being selected are giving nature the finger. Meanwhile, men living in sub-Saharan Africa who would ordinarily exhibit the peak physical attributes of our species are dying of famine and dysentery.
You're full of shit nom. We both know it wasn't humans' physical abilities that allowed them to dominate the planet. If humans had to survive solely on physical abilities, they'd go extinct in weeks. Nevermind that Africans in Africa don't have the physical abilities and body types of Western blacks who descended from slaves hand picked for their physical abilities. The Ethiopian track team's body type is nothing like the African Americans on the U.S. track teams' body type. STFU you retarded baboon.
tl;dr: Natural selection has become less dominant overall due to the dilution of selection criteria and reduced culling. Genetic health is probably getting worse due to unrestrained mutations combined with a tendancy towards chaos. I'd say things will get worse, but we could probably fix it with some meddling in gene editing.
Yay! An apolitical question that isn't more shit-talking between the regulars here.
I imagine you're referring to health and QOL as a result of natural selection so I'll start with that. I'm not an authority on anything here, but I enjoy this topic, and as a result I'm probably going to go off-topic from OP's intentions, hehe.
While hindering death is still ultimately good, probably, there are some additional issues that stem from this.
Improvements to healthcare and compassionate treatment towards the disabled has led to people with genetic abnormalities thriving where they would otherwise be less likely to pass on their genes. Mutations are great because that's how we evolve in the first place, but in general the majority of them are bad; randomly changing a system that relies on order will result in regression more often than improving it.
I believe this reduced 'culling' rate results in a feedback loop that leads to an increased spread of 'bad' genes in the gene pool that leads to increases in inheritable disease and poor traits, eg. diabetes, poor eyesight (though other potentially more prevalent causes obviously exist). Essentially, the more a society invests in treating the symptoms of a genetic issue, the more significant that issue becomes, costing further resources to treat the issue with each passing generation. I imagine this will continue until we either adopt a rather evil policy of active genetic curation or learn to use gene editing tools to treat the cause rather than the symptom. The former will probably never happen as things stand presently, but I think this issue has the potential to reach a critical mass where this may be necessary if the latter is not seriously considered, as there are significant stigma and ethical concerns against gene editing that may get in the way for some societies.
It's not all bad though. While improving healthcare is primarily only going to benefit those that require it, general standards of living have increased and average life expactancy is at its highest, which probably means that good mutations thrive more often too. evolution is based on chance, so it is also likely that a beneficial mutation dies out too in a harsher environment. Many traits are also derived from a necessary sequence of harmful mutations before having a beneficial effect eg. evolutionary development of a new organ is initially going to be a useless lump of dead weight that draws energy. Long live the appendix haha.
So for health, probably for the worse, at least in the short term until we take command over our genetics.
Then there's the criteria for natural selection in a survival perspective. In the past the most important criteria for an organism to pass on genes was obtaining energy, typically food, followed by procreation. These days subsistence is typically a given, so there's more emphasis on attracting a mate, of which the criteria: A - changes with time rather rapidly as cultural ideas and preferences shifts in and out of fashion and B - cover a massive range of strategies. There are literally infinite ways to be attractive to someone which can be as mundane as having a topical interest or skill. For the most part I think this also leads to open season for mutations, as culling criteria change by the second in evolutionary timescales, such that natural selection is perhaps not as significant for us than it was in the past for the traditional criteria of survival, resulting in further unconstrained mutation. There will probably always be certain traits and behaviours that are bad for passing on genes though; namely infertility, disfigurement, and asocial personalities.
So for natural selection itself, I think we've greatly diminished the significance of the process from a survival perspective. Whether that's good or bad depends on the purpose of the selection though.
You can also look at the purpose of the selection. Survival isn't necessarily the only result to be selected for so long as the trait isn't mutually exclusive with survival or procreation. Western society is meritocratic, so we /should/ be breeding people for success in their respective jobs that happen to exist and be relevant at the time, provided they exist for long enough for the snail pace evolution requires for us slow-breeding humans.
A more constant trait as an example of this would be intelligence, as this is generally a consistent indicator of success. You could consider this a good thing if you believe technological and cultural advancement fall under that umbrella, but intelligence may also have links with depression, so from a QOL standpoint this could be very bad. Depends on your priorities I guess.
There are probably a few more continuous traits/behaviours that are like intelligence, maybe sedentary lifestyles or humour, but for most professions and societal interests I think it's a bit of a crapshoot where through success by any manner that society deems significant enough to pay for, literally any trait can be selected for. By this reasoning we're technically selecting for everything from agility for dancers to dick/breast/arse size for porn stars to actions per minute for Star Craft loving Koreans. Are any of these things better? Largely it will depend on context in which the trait is being tested in, but I imagine for the vast majority of people, any genetic 'improvements' like this will probably go unrealised and as such are wasted investments. Personally I think many of the things people do for a living are a waste of time too, so I can't say all these traits being selected for are unilaterally for the betterment of mankind even where they are being realised. And since this judgement will be different for different individuals, cultures, and over time for a ridiculous variety of valid criteria, it's impossible to get an absolute conclusion as to wether the results of modern natural selection are good or bad for the species.
Thanks for the well-thought answer, I mostly agree with your sentiments on this issue and you raised some things I hadn't thought about.
Essentially, the more a society invests in treating the symptoms of a genetic issue, the more significant that issue becomes, costing further resources to treat the issue with each passing generation.
This could definitely cause major problems in 100+ years time.
I imagine this will continue until we either adopt a rather evil policy of active genetic curation or learn to use gene editing tools to treat the cause rather than the symptom.
Personally, I think we should to remove some (only some) of the barriers to dying that we've erected for the long term benefit. Now, what those would be in practice I'm not entirely sure and this could be dangerous territory to tread if done without a great deal of thought.
good mutations thrive more often too. evolution is based on chance, so it is also likely that a beneficial mutation dies out too in a harsher environment.
Good point, especially savant genius types that might not survive in nature.
These days subsistence is typically a given, so there's more emphasis on attracting a mate
One thing about this is that all females can find a mate and have their children supported by the state. So this selective pressure only exists on males (who carry the same genetic information as females).
A more constant trait as an example of this would be intelligence, as this is generally a consistent indicator of success.
I agree, except that it appears that this may not be the case due to a possible inverse relationship between fertility and IQ (Source 1).
intelligence may also have links with depression, so from a QOL standpoint this could be very bad
Good point, it could counter intuitively be bad. I think that having more intelligent people should in theory cause the overall QoL to increase though due to their work to make things better. But at the same time it's usually the less intelligent people that are the life of the party.
By this reasoning we're technically selecting for everything from agility for dancers to dick/breast/arse size for porn stars to actions per minute for Star Craft loving Koreans. Are any of these things better?
I get your point but in those cases I'd say that fertility (breast and arse size are related to this) and intelligence (related to APM in Star Craft) are good traits to select for.