Not to judge or be a raceist but why are Asians eyes so closed verses an American's eyes. How did that evolve

Answer 1

First of all, there are no such thing as sub-species of humans. We are all the same species. Humans actually have incredibly little genetic variation compared to other organisms. We are genetically almost identical. The differences we have in appearance result from a teeny teeny tiny proportion of our genes. There are also no true races from a biological standpoint. Of all the genetic variation we have as a species, only 6% of that variation can be associated with categories of race, and none of that variation is specific to any one race. Race is a concept that humans have used to describe our society, not our biology.
The reason why humans have different physical appearances in different parts of the world is because of evolution. According to the Out-of-Africa hypothesis that most biologists prefer, Homo sapiens originated in Africa and migrated out of the African continent in waves to inhabit the rest of the Earth, which looked very different back then. Groups of humans became separated and isolated from one another, which stopped "gene flow" between the groups. Gene flow happens when individuals from different populations reproduce, which introduces new genes into the populations. When that doesn't happen, a group only has the genes that it began with and doesn't receive new genes. From there several things can happen that would make the groups become different from one another.
For instance, a random mutation can occur which might cause a change in the physical appearance of an individual. As that individual reproduces, it is possible that they can pass that mutation on to their offspring, introducing it into the population. Over time, more and more people from that isolated group will have that mutation, but no other groups will, unless the same mutation randomly occurs, which would be very unlikely. Say this mutation caused eyes to be blue instead of brown. Then people from population A might have brown eyes, but people from population B might have the new blue eyes.
Another thing that could cause the isolated groups to become different would be natural selection. This happens because of the environment a population lives in. If there are genes that make an individual more likely to survive and reproduce in an environment, those genes will be the most likely to be passed on to the next generation. On the flip side, genes that make an individual less likely to survive and reproduce will be the least likely to be passed on, because it might cause an individual to die before it can reproduce. In this way good gene A can become very common, while bad gene B can become very rare. It all depends on which traits are best for the environment the population lives in. Since human populations lived in different environments, different genes and traits would become common and rare between those groups.
For example, if there was a benefit for early humans living in Asia to have uniquely shaped eyelids, then the genes for those eyelids would become more common through natural selection. But if there was no benefit to have those unique eyelids for early humans living in Eurasia, then those eyelids wouldn't be common. The eyelids best for that environment would become common.
I have no idea what benefits or drawbacks there would be for eyelids of any shape in an environment, but it's so hard to guess. The environment was very different on the Earth that many millions of years ago.

Answer 2

By closed I assume that you mean how come the eyes of Mongoloids (Chinese, Japanese) are narrower compared to Europeans or Americans (Caucasoids).

The answer is that they evolved from two different sub species. The Africans evolved from the Negroids (That's the actual Scientific term, no racism)

Answer 3

i don't think of you're being racist...this is purely no longer understanding and of interest. yet this is besides the case - Asian's would have developed those good factors by using adaption of their ecosystem jointly with the chilly, warmth, skin replace etc. some genuine, contemporary examples are that the eyes are slightly extra slanted no longer in straight forward words by using chilly climate notwithstanding the "Yellow airborne dirt and dirt" that is a sandstorm with gusts blowing sand from so a options as Africa (allegedly) each of how over and it may genuinely kill you at severe counts. it may enter the longs or damage your eyes - it pretty a lot feels like Pollen...this is why they sometimes placed on mask outdoors seasonally. in addition they each from time to time have eyelid surgical procedure (as consumer-friendly as eliminating your tonsils contained in the U. S.) in the experience that they have difficulty seeing or for stylish purposes (double eyelid). that is purely sliced by the corners and raised slightly to provide the introduction of a larger eye. also I heard they variety of nutrition they eat impacts their the teeth. as an party, they often eat fish and typically smooth/gel like chocolates and treats in Japan - meat is amazingly severe priced! So their the teeth and gums would change into extra comfortable and adjusted by way of their eating habit. this would clarify structure...yet i'm no longer totally certain. it really is the desirable i might want to respond to and that is from doing analyze myself in this stuff and genuinely asking Asian human beings and gathering diverse opinion or responses. they actually have incredibly good inventive and prescient on a thanks to work out fantastic!

Answer 4

first of all u are useing they term "american" to apply to all caucasian groups. Secondly i believe it was simply beacause asia has a hoter climate and less open eyes shields them from the sun.