How does evolution work within humans?
Lets say theoretically someone created a country where only people 6’5 and above could enter. After centuries of people 6’5 and above having offspring would the offspring gain height over generations and become 7’0 to 8’0 gaint like race. Or would their people simply just Stay 6’5 to 7’0 like tallest humans around today.
- PaulLv 74 weeks ago
Human evolution was more obvious and more essential in our ancient ancestors than it is now, for two main reasons. First, we freely interbreed between races that had originally evolved separately. And second, we have medical means of keeping people alive with genetic disorders that would have removed them from the population only a few generations ago.
- The_Doc_ManLv 71 month ago
I'll give you a real-world, recent example. This article talks about how the Sherpa guides near Mt. Everest have adapted to work in thinner atmosphere over a period of several generations. "Adaptation to local conditions" is one of the mechanisms (not the only one) that is part of evolution.
- Anonymous1 month ago
Height is one human feature that is an adaptation to the environment. The taller a person, the more surface area one has, and since humans generate our own body heat to stay warm, and since heat gain or loss to the environment is directly proportional to surface area, that means a tall person can lose heat to the environment much more quickly and he has to eat more per lb. of body weight to stay warm. His heart has to work harder as well to keep up with the increased heat production, if that person lives in a cold climate. However, a tall person would have an advantage in a hot climate, since he is less likely to suffer a heat stroke, because he can lose excess body heat more quickly than a short and stocky person. Studies have also shown that tall people tend to live shorter lives than shorter ones, all else being equal, probably because their hearts have to work harder to replenish the lost heat. A tall Japanese has a shorter average life span than a short Japanese, and a tall Norwegian lives a shorter life on average than a short Norwegian, for example.
So, even though you start your society with tall people only, whether they will grow taller or shorter depends on the climate. Evolution is adaptation to a changing climate. How the body will evolve will depend on the environment that it will face in the future. Humans evolved in Africa, and 60,000 years ago, some humans migrated out of Africa to populate the rest of the world. Since many of them ended up in cold climates, they have evolved features like a taller and narrower nose bridge, more facial and body hair, shorter arms and legs, thinner lips, a more rounded torso, straight hair and a lighter skin tone. These are adaptations to cold climates in Europe and north Asia. People who migrated to places like Australia and SE Asia have not changed much and many still look just like Africans.
- CRRLv 71 month ago
The founder effect would mean that the population would tend to be above average height so long as the restriction on new arrivals continues. However they will be limited by the gene pool of the founders so they won't continue to increase in size. Due to recombination of genes some in the population will probably be below 6'5".
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- CowboyLv 61 month ago
Assuming the population was large enough and they had proper nutrition and their latitude wasn't too close to one of the poles, they would gradually shift toward the mean of the mother population - probably around 5'11" or so.
- thomas fLv 71 month ago
Human evolution is no different from evolution of any other living species. Evolution occurs through changes in a given specie's gene pool. These changes are brought about via gene mutation, followed by death or failure of reproduction of the less fit members of the gene pool. If taller humans escape death better, or reproduce better, then the gene pool will reflect that, over time.
- DWLv 61 month ago
If there's a continuing advantage, beyond the initial selection, to being tall you would eventually breed a taller population. You could, for example, expel the shorter 50% of 16-year-olds every year.
You may run into limits of the human body. A population of 7'0 people likely has a higher rate of of some health issues. You may eventually have trouble maintaining a high enough birth rate to maintain the population (while expelling half of the population).
- 1 month ago
Height isn't purely genetic. Childhood nutrition plays a major role. You can breed tall people with other tall people all you want, but if the offspring is malnourished, they'll never grow to their full potential.
- KDB KathLv 61 month ago
It's all fake, I will receive many dislikes with my answer, but Smart people do not think evolution is real, God creates all living things on Earth, no need revolution to be added.
- RaymondLv 71 month ago
Would there be a long-term benefit for humans to measure 7 feet?
Sure, tall people tend to have tall offsprings (at least, children that will grow up to be tall). But that is not automatic. Over a large population, there will still be some that are smaller, some that are taller. Over a large number of generations, IF (a big if) there is some distinct advantage to being tall, then the number of taller offsprings will prevail.