Has physical Human Evolution ceased?

Question

Has physical Human Evolution ceased, due to our modern lifestyle? I mean, since people are now marrying and having children from different continents, rather than the next village over, doesn't that hinder evolution? I mean, we really have no small isolated pockets of people for mutations to occur due to changing needs, which are then passed on to future generations.

I'm sorry I put this so badly, but I don't know much about science. I was reading the book OUR KIND, Who we are, where we came from, and where we are going; The evolution of human life and culutre, by Marvin Harris and this just came to mind.

Any opinions?

Answer 1

Er, just some guy.

No.

We were not "evolved" to be driving cars and sitting around desks. So im guessing no.

Answer 2

Hello. To "Hinder" evolution by having a more widely varied gene stock is not strictly speaking correct. If you mean to write that distinct regional differences like skin folds to keep dust from the eyes or short stature in mountainous areas that serve to assit in survival...then back the focus out so to speak...to get the big picture the globalization & international travel may well lead to the next big leap!

Answer 3

I agree that Human evolution has slowed but it hasn't ceased.  Evolution has to be thought of at the molecular scale and in terms of the pressures we have to face as a population.  Usually evolution means a mutation occurs and then the situation comes along that makes the mutation beneficial.  Most mutations are harmful and kill the cell.  Usually it happens in the long chains of nucleotides that make up DNA.  They come in sets of three's and if one is added or deleted then it changes the entire strand from that point on.  This can be billions of nucleotides long.  This happens everyday in your cells.  What has really changed is the amount of pressures that we find threatening.  Most of them now a days are medical, like the next big pandemic disease or what ever.  You won't know you're immune until it comes and everyone but you is dying.

Answer 4

This is not correct. The governing principle behind the efficiency with which selection operates is the "effective" population size. If inbreeding is high (that is, if people tend to marry and have children with people with similar genetics) then the effective population size is lower. In smaller populations, selection is less efficient - there is a much higher probability that a beneficial mutation will be lost. There is also a much higher probability that deleterious mutations will fix.

There is a thing called "outbreeding depression" as well, where if you mate with someone who is TOO genetically distant, then you have problems. But humans are all pretty close genetically (much closer than most other species), so this is almost certainly never going to be an issue. Therefore, the more "outbreeding" we have (i.e., marrying and having kids with people from the other side of the planet) the more efficient selection becomes in our species as a whole.