Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Diet changes have increased average population heights around the world through better nutrition, but those changes in diet also affect the ability for larger people to survive and spread their genes. Changes in conditions that affect propagation rates is one of the primary engines of evolution. Though this has happened over a short time frame, it's difficult to argue that this isn't evolution, even if slight. It's important to remember that humans are always evolving, since we are always subjected to selection pressures.
I can believe your general premise is possible, but do we have actual evidence that the changes in the diet have spread genes in this case?
I'm not saying you're wrong, but can you cite evidence that that is evolution? I've always read that a change in diet on the part of Japanese resulted in them becoming taller, not evolution, and that getting fatter is, again, a diet concern, not evolution.
The diet has gotten better in Japan, but there is also sexual selection going on. In the past, short legs were useful to be a good rice farmer and survive cold winters, now not so much. Athetically, people much prefer longer legs, so it's harder for short people find a mate and have kids, and that body type is being culled from the population. This is evolution at work over just the past 150 years.
The diet has gotten better in Japan, but there is also sexual selection going on. In the past, short legs were useful to be a good rice farmer and survive cold winters, now not so much. Athetically, people much prefer longer legs, so it's harder for short people find a mate and have kids, and that body type is being culled from the population. This is evolution at work over just the past 150 years.
Sounds logical evolution-wise, but again, where are you getting that from.
I can believe your general premise is possible, but do we have actual evidence that the changes in the diet have spread genes in this case?
No. While there have been many studies attempting to identify genes associated with height, I don't know of any studies that have examined whether the prevalence of those genes has increased within a population. It's a reasonable assumption that the frequency of those genes has increased, but there is no hard evidence to support this.
No. While there have been many studies attempting to identify genes associated with height, I don't know of any studies that have examined whether the prevalence of those genes has increased within a population. It's a reasonable assumption that the frequency of those genes has increased, but there is no hard evidence to support this.
I want to thank for doing something that few people on City-Data do -- answer honestly when they are questioned about a post!
I agree with you that theoretically what you had suggested makes sense in terms of natural selection and evolution.
A somewhat related, and I think interesting topic is whether man's relative conquering of "disabilities" (in the broad sense) is changing the way evolution works in humans.
The multiregional theory is not an "alternate" theory. How many times do I have to say that all human variations are a result of natural selection, not interbreeding?
Quote:
Originally Posted by phetaroi
Since you are so demanding, I guess I need to ask for your sources or qualifications.
Again, I'm not saying you're wrong, but why should we just believe anything you post?
You might not say that he is wrong, but I will. Since we know for a fact that humans have mixed with divergent archaic species, then his statement that ALL human variation is due to natural selection and not interbreeding is blatantly false. It's been proven that certain human populations possess genes that are due to introgression, so, of course, some of the variation seen in humans is because of mixing with other species.
60,000 years isn't that long? If I make up a group of people in my head. And assume they have kids at 30 years old. That is a new generation every 30 years. 60,000/30=2,000. So we are to think not much in the form of evolution can happen in 2,000 generations? Seams to me a lot could happen. Or is my math all wrong here?
You might not say that he is wrong, but I will. Since we know for a fact that humans have mixed with divergent archaic species, then his statement that ALL human variation is due to natural selection and not interbreeding is blatantly false. It's been proven that certain human populations possess genes that are due to introgression, so, of course, some of the variation seen in humans is because of mixing with other species.
What are the species? South Asians and Europeans only have a negible amount of Denisovan and Neanderthal DNA. The vast majority of SNPs that define non Africans are through natural selection.
The oldest "human" we know of came from Africa. How are we sure that the ancestors of that oldest human we know did not come from Europe or Asia and immigrated to Africa? And, how are we sure that these ancestors did not leave some siblings behind in Asia or Europe and their offspring stayed in Asia and Europe?
The oldest "human" we know of came from Africa. How are we sure that the ancestors of that oldest human we know did not come from Europe or Asia and immigrated to Africa? And, how are we sure that these ancestors did not leave some siblings behind in Asia or Europe and their offspring stayed in Asia and Europe?
Because Africans are the most diverse. The older the population, the more diverse. Say you have a jar of gumballs of assorted colors, and you take out one blue and one green. You leave red, purple, black, brown, and pink behind. Non Africans are descendants of blue and green.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
