It seems to me that evolution as it has existed throughout human history has undergone an immense change in the first world. (I will declare at this stage a quite limited knowledge of biology, hence my bringing this up here)
I make this assertion from the fact that in the West it is no longer the most succesful who spread their genetic seed the widest. The well off are more likely to have fewer children than the lower classes. I wonder if this could potentially lead to (in relative terms) a negative evolution, as genetic material which is more likely to grant success is weeded out of the population over time.
Moreover, I wonder to what extent modern medicine is allowing the propogation of disease causing genes which would have been extinguished in ages past.
Please let me know your thoughts! I have been rhuminating on this for some time of late.
Certainly, modern medicine, as fabulous and life-saving as it is, may have contributed to weakening the gene pool. More people live past childhood now than ever before in human history, which in turn, means many more people are procreating that may have weaker genomes (hereditary information). This could definitely result in weakening the overall strength of humanity's gene pool. This question makes me think of Thomas Robert Malthus' theory (Malthusian scissors) that expanding populations are eventually checked by some type of event (lack of resources, famine, disease). What would Malthus say about the rapid growth of our planet's population today? I am inclined to believe that he might point to the weakening of the human DNA as the next potential snap of the Malthusian scissors.
I don't think the perceived "dumbing-down" of humanity is genetic or biologically-based at all. Instead, I blame the media complex and (sadly) the Internet. The media complex is entrenched in its own self-righteous moral superiority, and people tend to believe what they see on television. That means that people are less likely to do research, and less likely to become informed by their own merits. Instead, they will follow a trend or fad because they think that everyone else is doing it, whether it is true or not.
The Internet exploded into being in the mid-nineties and hasn't slowed since. Humanity went from having to research authoritative opinions in libraries to being able to Google anything and having millions of pages of information, 99% of which is pablum. Anyone can say anything about anything on the Internet, and so have an instant audience. The problem is that Humanity is starting to have trouble differentiating between Internet quackery and deliberate misinformation, and facts based on real research and experimentation. The barrier between science and pseudoscience is slowly eroding, and that leads to a misinformed public and the continuation of incorrect information and lies.
Looking at it from a broader perspective, it's almost as if there is a pendulum swinging from "enlightened" to "deliberate ignorance," as if our two-hundred years of technological evolution has pushed Humanity too far, and we are unconsciously reacting by failing to continue our intellectual progress.
I, too, see a correlation in your question regarding DNA and social class. Essentially, those born into the upper class tend to stat in the upper class based upon the passing down of wealth, not genetics. That said, one does not necessarily need good genes to succeed in life. Instead, they need money, education, and a desire to succeed. Given that none of this is based upon genetics, the world's "regression" within the gene pool (as you stated) would not impact anything in regards to being successful.
You seem to be making an assumption that wealthy people have better genes than poor people. This is not the case. It is true that most of the people who are wealthy today are wealthy because their family was wealthy, but this does not mean they have better genes. Economic mobility, studies have shown, is lagely a myth. If someone in your family had money a long time ago, you are more likely to have money. If you anscestors were poor, you are more likely to be poor.
“[People] underestimate the extent to which your destiny is linked to your background. Research shows that it’s really a myth that the U.S. is a land of exceptional social mobility,” said Fabian Pfeffer, a sociologist at the UM Institute for Social Research,
So while social standing and class are metaphorically referred to as “good blood,” this does not actually mean that rich people have better genes. It just means they have had advantages. These advantages might lead to better health and longer life, but are not inherent in wealth.
Although there is no empirical connection of DNA with social class, there are indeed often reasons within people's make-ups why they do or do not succeed or excel in certain areas that can be passed on to others. The fact that many a child possesses interests and talents that a relative outside the family a generation or two ago exhibited negates the power of environment over that of genetics. (e.g. the musically talented child of parents who have no such talent) With the reduction of people who carry such genes, there is, then, the real possibility of loss of abilities, artistic or mathematical or scientific or anything that would allow upward social mobility.
Certainly, modern medicine has had a tremendous impact upon the emergence of hitherto recessive traits. When people with these new diseases or conditions survive that would have had little chance before, unfortunately, they often reproduce and the genetic conditions are passed on.
You may well be right in your speculation about medicine preventing the extinction of negative gene traits, although two world wars also contributed to the loss of positive gene traits (though, to complicate it more, both positive and negative were lost in the non-military populations during the wars).
Certainly when the ideology of Humanism took prominence in Western thinking, religious thinking was edged out from a dominant to a specialized mode of perception and understanding. As a result, even among religious people, there is a lessening of spiritual reason to accept death and an increase in humanist reasoning that requires the prolongation of life: if life is all there is (or the greatest human thing there is), then life must be preserved, extended, and safeguarded at all cost and regardless of end results.
One point to note is that historian James R. Flynn
(Flynn. Excerpt from How We Know That Humans Are Getting Smarter, published in Scientific American)
I’ll address your point about the people who are best-off having the fewest children. This is certainly true both in the West and to a growing extent in the rest of the world. But I have to take issue with the idea that this will constitute “negative evolution.” I think that characterizing it in this way assumes that there is something that is genetically superior about the people who make the most money and have the most education. I have a very hard time believing that. It smacks of Social Darwinism and it, more importantly, leaves out the huge influence that things like one’s upbringing have on one’s chances for success.
So I am not worried about a weakening of our gene pool because I do not think that “good genes” are the major factor that cause some people to be successful in life.