http://boards.straightdope.com/sdmb/showthread.php?p=13873243#post13873243
The thing is, we are changing our environment and society (and therefore “moving the goalposts”) on very fast timescales compared to the rate of natural selection.
And within a century or two technology may move to make the whole thing moot (e.g. genetically engineering any traits we desire, nanobots helping us live indefinitely etc).
Whether or not humans are evolving is a matter of definition. Humans do not have identical DNA. At some point in the future, we would expect the distribution of genetic components would change in humans, some new ones may appear, and some old ones may go away. Or not. There are an awful lot of people, and after much mixing, we might end up with the same distribution of genetic components across the population that we do now. Seems unlikely, but there may not be any readily identifiable change via evolution in humans for a long, long time.
As for losing the appendix, it would require a genetic change that spreads through the population, supplanting the genetic structure that creates appendices. One million years from now, our descendents may have an appendix, multiple appendices, or none. But there are not enough cases where appendicitis prevents successful reproduction to give an advantage to people born without an appendix, unless that variation has additional beneficial effects.
It is impossible to predict what will happen to humankind over the next 100,000 years from natural evolution. There are nearly 7 billion humans already. There are no great inherited factors that are causing highly selective reproduction. It would be very difficult for mutations or variations to spread through the population. Technology may have the greatest change to our genetic structure in the future, or unpredictable catastrophic events could be a catalyst for genetic reorganization.
Evolution doesn’t make predictions, it is an accidental process that depends on the coincidence of environment and available genetic components in a species.
Interesting that the OP refers to humans in third person. Did somebody leave the gate open at area 51 again?
Something that is oft-forgotten when talking about human evolution is that having kids is not enough. Those kids have to survive to have descendents themselves, or the whole thing was for naught. Parents dying early from obesity-related diseases decreases the chances that the offspring will be fruitful and multiply, I suspect.
I think we’ll start to see some great genetic differences in the races as western culture really outpaces the rest of the world. The predominantly white populations of Europe and the Anglosphere will develop traits that cope well with sedentary lifestyles. Africans will eventually develop resistance to things like malaria. The rest of the world…hell, I don’t know. What do you think East asians will develop?
not only malaria but age related hearing loss as well Hearing loss rate in older adults climbs to more than 60 percent in national survey
That theory presupposes that the present state of affairs will continue for thousands of years, which is…unlikely. For all you or I know, in a few centuries Africa will be the central apex of civilization while the West has collapsed into a backwater or is a poisoned wasteland.
Unlikely. Do you have a cite to back that up?
Utter nonsense. Genetic mixing between different populations is increasing, not decreasing. If anything, there will be much more blending of populations, assuming current trends continue.
Again, nonsense.
I’ve read an opinion (sorry, no Cite 
) that human evolution has sped up since the Neolithic Revolution. Lactose tolerance is the most clearcut example of recent favorable change. (Others are so controversial I’d better not mention them. 
)
Since the “cost” of the appendix is low, it may stay around. And even if it’s useless for today’s diet, millions of years from now a species evolved from Homo may “thank” us for that appendix!
Interesting to note that a recent study (can’t find the cite, sorry) identified a rural village in Italy in which a large portion of the inhabitants had very high levels of cholesterol and “bad” fats and very low levels of “good” fats yet didn’t appear to suffer in terms of their health or longevity. Might be an early variant of the sedentary gene…
Oh, and Africans already have some level of resistance to malaria, although the cost of this resistance appears to be an increased likelihood of other diseases such as sickle cell.
I recall reading about that. They had some unusual gene that gave them very high levels for those substances while protecting them from the effects.
This is pretty interesting in light of The complete failure of the niacin-Zocor trial. There may be some interesting changes in the whole lipid hypothesis in a few years. I was going to ask about this to get some input from actual MDs, but I was waiting for one more strike against the current cardiovascular biomarkers.
My mother has had shockingly high cholesterol levels since her doctor first tested her decades ago. Diet and medication did nothing. She’s pushing 90 now and has never suffered any apparent ill-effects.
my grandma is near her 90’s … she outlived my mother. her father lived over 100 years.
she claim watercress 
And neither of the last two anecdotes have anything to do with evolution. The focus is all about living long enough to procreate, and to create offspring who are also likely to do the same. Longevity has little to do with it, aside from the societal benefits of community care and responsibility for the young.
This was the thesis propounded by Drs. Zager and Evans, IIRC?
The problem is that modern medicine interferes with normal genetic selection.
If X% of the population were susceptible for fatal appendix inflamation, they would not have had children. Today, we operate, use drugs, etc. - those people live. Similarly for people with tendency to have any other live-until-reproduction-threatening tendencies that are genetic. (realy really bad eyesight, poor immune systems, allergies and asthma? Reduced fertility needing drugs? Type I diabetes?) Of course, some of these occur from time to time as random mutations from healthy parents, so the cull effect simply kept the incidence limited.
If you cure the people with problems so they can reproduce, the problem does not “slowly disappear”.
I remember someone raising the issue in a science fiction class at university in the 1970’s that technology was “polluting” the gene pool. (Cyril Kornbluth’s “Marching Morons” alluded to this). In fact, as mentioned above, the third world and poor people at home account for a dispoportionate amount of the world population growth. I have minimal concern with the third world; we have to assume the genetic distribution there is pretty random and the medical conditions tend to assist in providing healthy genetics - let’s not confuse their “poor from lack of opportunity” with our “poor from failure to succeed” (which may or may not be manifestation of genetic issues. However, our local poor (a) take advantange of modern medicine through medicare and (b) have disproportionate reproduction in our society. So is their failure generally genetic or environmental?
The fact that moderately well off people tend to have less than 2 children per couple is a side effect of our current economic arrangement; what that says about genetic selection I don’t know, but it used to be 1 income could afford a middle class lifestyle, now it takes 2 to be comfortable, and interrupting that for several children (and then supporting them) is costly. But that’s a separate debate.
I recall an article that said the current social situation actually was the most stratified in history; people socialize and eventually reproduce with people from their own socio-economic level even more than before, thanks to things like massive suburb developments with their own high schools, where houses all cost about the same and so attract the same class of families.
So how much does success correlate with genetics?
Moreso than the discovery of fire? Or basic plumbing? Those things also drastically improved the number of people who survived who probably would not otherwise have lived.
There’s a strange set of opinions out there about what constitutes “normal”. Also, it seems like this assumes some sort of genetic “ideal”, like there’s a certain ‘normal’ level of human genetic diversity.
Increased genetic diversity, even if it produces some undesired effects, is not a completely undesirable effect.
I’d like to see that article. Doesn’t make a lot of sense to me. Nobility usually married within the nobility. Tradesmen offered married the children of other tradesmen.
It’s been the rule, rather than the exception, that people socialize and reproduce within their own socio-economic level, often more restrictively than 21st century America. It’s difficult to think of any civilized society where this is not true. Heck, Jane Austen and Bronte sister novels seem to be a perfect example of this principle. Caste systems from India to Japan offer even more restrictive examples.
At least in America, social mobility is fairly high. It’s not unusual to hear a story about some poor schlub who became a millionaire and/or married the daughter of a whale oil tycoon. Those types of stories are considerably rarer before the Industrial Revolution. Outside of romance novels, pre-18th century tales of a European nobleman taking a commoner wife are not exactly common.
Of course, social mobility might be at a low point for most of the rest of the world, but I’m not sure even that’s true.
I don’t have hard numbers, but there does seem to be a genetic component to the factors that would contribute to success (risk factors for health, intelligence, appearance).
Re stratification of societies. Surely it is who one reproduces (most) with that will lead to any divergent geneetic traits being successfully carried on to future generations?
Nobles and the middle-classes may have married their own social strata but for the males at least, they may have had as many children with their servants, slaves, whores or whatever as with their wives and probably more - at least until modern social mores became dominant (if indeed they have).