Human evolution

[James]

Could it be possible that humans may have stopped evolving? As with most other organisms, ‘survival of the fittest’ leads to evolution, however in modern human times. We appear to be bypassing any factors that could cause evolution. For example, we now do not hunt, for we can just visit shops. There are no longer any physical factors to prevent any of us from passing our genes on, which leads to a diverse gene pool that is not heading for any particular direction in general. One could say that those seen as ‘better looking’ have this; however, there are not many people who could not find anyone to produce offspring with. Evolution through mutation seems unlikely as there would still be equal chance of surviving no matter how beneficial the mutation, as there a so little threats to humans nowadays. Extensive medical care further reduces the chances of humans evolving. Could it be possible that we have created a world that poses so little problems of anyone passing their genes on, that our evolution has halted? If not, how and why could we be evolving?

[mith]

quote James:

One could say that those seen as ‘better looking’ have this; however, there are not many people who could not find anyone to produce offspring with

Roflmao, that just made my day. Yes, it’s easy to have children since you can get the state to take care of them if you’re poor. Also there is a trend toward smaller family sizes so being rich and successful may not mean better chances of your genes surviving. In contrast the “masses” seem to be reproducing more(Jerry Springer et. al).

[thank.darwin]

I have often wondered that myself… and if you think about it we have sheltered ourselves from natural selection (but not completely). If a disease comes along we try to come up with a cure for it – so it would seem as our medicine is evolving but not us. The problem is when a lethal virus comes along we will be wiped out…?

[biostudent84]

Human evolution, like all evolution is a slow, but ever continuous process. Proof that evolution has not stopped in humans is simply described by average height. Within the past 200 years, the average male height has gone fro 5’4” to 5’10”. Also, today, some humans are being born without wisdom teeth. Since we usually remove them surgically, and do not use them if we don’t, it is logical for us to evolve to not grow them. Growing an unused part of the body is a waste of energy.

Kyle

[mith]

Don’t forget the most important human trait is cultural evolution.

[thank.darwin]

quote biostudent84:

it is logical for us to evolve to not grow them.

Be careful there Kyle… we can’t logically evolve. We have useless parts of the body that stick around because they don’t affect how well we reproduce or how we gather food and so on…

[biostudent84]

quote thank.darwin:

Be careful there Kyle… we can’t logically evolve. We have useless parts of the body that stick around because they don’t affect how well we reproduce or how we gather food and so on…

I am being careful. But as long as we all understand that evolution is not controlled, we can say these thigns. It still stands…if it is a waste of energy to grow a body part, we will evolve to get rid of it.

Kyle

[James]

Evolution is the idea that a group in a species has something that enables them to more successfully mate and pass their genes on compared to the others in their species. Despite being useless, wisdom teeth and such useless organs such as the appendix would give neither an advantage nor a disadvantage in having offspring.
Why are we getting taller? Does this mean that those who are taller have a better chance of having children? Could it be the case that it is the very short people, nowadays are rarely having children? It could be that our human society is not only stopping evolution in some directions, but also aiding it in others, i.e. very short people are now seen as ‘abnormal’, and therefore have fewer children. Is this an example of cultural evolution?

[biostudent84]

Becoming taller is part of becoming bigger. Over time all species when left alone will grow larger. It is called the “Red Queen” hypothesis. It comes from a poem in Alice’s Adventures in Wonderland where the Red Queen was forced to run as fast as she could just to remain in place.

[Fayt]

I think we are evolving we just don’t know it such as people in colder places like the Alps or Tibet are becomings hairer while people in warmer places are becoming less hairy. Something like that more or less.

[RobJim]

Evolution occurs when any of these five factors happen:

*Mutation
*Gene Flow
*Genetic Drift
*Nonrandom Mating
*Natural Selection

Humans are exposed to mutagens, so we mutate. Humans do often travel to other parts of the world and breed with people from these other places, so gene flow takes place. Genetic drift doesn’t generally take place, except for small populations like the Amish where they don’t breed outside the population. People definitely do not choose who they mate with randomly. Lastly, natural selection does take place; people with genetic diseases may die or be unable to find a mate, people resistant to infectious diseases are more likely to reproduce, people from certain cultural groups and places may be more likely to die in war (such as Israelis, Arabs, Africans, etc)…

When these five rules fail to occur, the population is in a state called Hardy Weinberg equilibrium. This means no evolution takes place. Humans are not in HW equilibrium for the reasons I mentioned above, so we’re evolving.

If you’re interested, this website talks about it:

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/Hardy_Weinberg.html

The top part is a mathematical proof; go ahead and ignore that unless you’re into that kind of thing. Read from about two screens down onward; from where it says

So long as certain conditions are met (to be discussed next), gene frequencies and genotype ratios in a randomly-breeding population remain constant from generation to generation.

General biology texts should talk about it too.

[biostudent84]

Might want to note that Hardy-Weinberg is theoretical. No species in nature is ever in equilibrium this way 😉

[canalon]

Just a few words to react to some what I have read here:

quote :

Proof that evolution has not stopped in humans is simply described by average height.

I would not take this as a proof. Average height depend on many things, and genetic is probably not the most important in this case. A better and richer diet, well balanced during childhood is probably the best explanation for this.

quote :

Becoming taller is part of becoming bigger. Over time all species when left alone will grow larger. It is called the “Red Queen” hypothesis.

You should read SJ Gould (I think the book was called “the full house” in English) about the trend toward bigger organisms. In short its just not true.
As for the Red Queen Hypothesis (found in “beyond the looking glass”, the sequel to “Alice in wonderland” by the way) it is not about organism becoming bigger, it is more about co evolution between organisms, and mostly about the role of sex in evolution.

HTH

Patrick

[biostudent84]

I cite my source for these ideas from Noel T. Boaz, Ph.D. in the book Eco Homo

[canalon]

quote :

I cite my source for these ideas from Noel T. Boaz, Ph.D. in the book Eco Homo

Do not believe everything in the books. Gould give a few examples, the most striking is coming from the horses evolutionnary tree. The main idea being that we are lead to believe that ther is a trend increase complexity is because it is impossible to revert below a certain level (statistician call this a skewed distribution 8) ), and that usually the kind of studies that lead to this conclusion were not scientifically sound…. Read the book!

As for the red Queen hypothesis, I read the original book and papers….

Patrick, Ph.D. in bacterial evolution…. 😈

[mith]

Pulling rank a little soon aren’t you Patrick? 😀

[canalon]

quote mithrilhack:

Pulling rank a little soon aren’t you Patrick? 😀

Well, maybe 🙄

And I don’t know if Kyle/biostudent84 sources are rather wrong, or if he misunderstand it, but I had to correct his posts.
Proofs that human being still evolve exist, and I don’t think that using something as difficult to interpret as average height (depends heavily on non-genetic factors) is just not helping any demonstration.
Just a reminder to be carefull even with Ph.D: they also make mistakes (even if I’m trying not to 8))

Patrick

[Wilmer]

quote :

I think we are evolving we just don’t know it such as people in colder places like the Alps or Tibet are becomings hairer while people in warmer places are becoming less hairy. Something like that more or less.

Haha, that is silly. People from Spain are more hairy than people from Sweden.

We have stopped evolving.
Isolation is required for evolution, to make a human evolve isolate her for several generations in a different environment.

And people from Tibet doesn’t get more offspring is they are hairier. They don’t survive better if they are hairier. They have clothes.

But our planet is an isolated area, why don’t we evolve? Well, bad genes doesn’t hinder us from getting offspring. And um…people from Isreal isn’t a specific genetical group, they are a cultural group. Humans always travel and mix. Just look at your own country were most people originally are from other places (Europe, Africa, Asia).

Our evolution in the next millenias will consist of heavy mixing. As we get global isolated gene-pools will mix. I bet in ten thousand years pale skin and blue eyes will be rare when those properties just are a lack of genes.

[mith]

Isolation causes speciation, evolution happens irregarless of isolation.

According to Hardy-Weinberg, pale skin and blue eyes should remain if they confer no specific disadvantage.

[Wilmer]

Sure they will remain, but they will be rare.

Let’s say you take a group of a hundred people with eyecolorgenes representing those of the worlds population and let them breed with each other. After a couple of generations the population have grown larger. The proportion of the eyecolorgenes would be the same.

So my point wasn’t really that blue eyes would disappear. I meant that most poeple in the world have dark eyes and when the world population get more mixed the blue eyed folks would be more spread out. Like when you mix blue sand with a larger amount of brown sand.

Dark iris shuts out more light than a bright therefor dark eyes have sharper sight in strong sunlight. On the other hand bright eyes see better in dimmed light. That’s why blue eyed africans are rare.

-edit-

quote :

Isolation causes speciation, evolution happens irregarless of isolation.

What does evolution do if it doesn’t make new species?

[Anonymous]

Since we’re living in a global world and today everyone travels from one place to another, human’s greatest evolution is to learn to survive everywhere. As it’s a recent possibility for the mass, nobody still knows what are the “best adapted” like. We’ll have to wait.

[biostudent84]

quote 2small:

Since we’re living in a global world and today everyone travels from one place to another, human’s greatest evolution is to learn to survive everywhere. As it’s a recent possibility for the mass, nobody still knows what are the “best adapted” like. We’ll have to wait.

I’m not sure the statement that “everyone travels from one place to another” is completely correct. I read a statistic once that said most people never move more than 50 miles away from the place they were born. Whether or not this is accurate, it is true. And those that move away are very selective in their choice of mates. In another post, I mentioned that I attend Virginia Commonewealth University. This is a school particularly noted for its ethnic diversity…and while I cannot say that I have met everyone on campus, I can say that almost all (but not all all) first and second generation Americans I know here have confided to me that they would never consider marrying outside their ethnicity.

No, I’m not making a blanket statement…but I am saying that this is the general rule among the different ethnicities I have been exposed to. (Indian, Pakastani, Chinese, and Korean are the primary ethnicities I have been exposed to if anyone was wondering 😉 )

Part Two! (phew! this guy loves making long posts, lol)

As for “best adapted” I would have to say that anything living today is “best adapted” to its niche. The future will only bring “better adapted” organisms for niches.

Kyle

[Anonymous]

Ok Kyle, sorry for my imprecision. Let’s just say that today is easier than never to move away. And it’s probable to find different climatological conditions there. That was the point I wanted to remark, not the marriage or sexual relations between people from different cultures. Sorry, I have to go now. I’ll continue later.

[geddiknight]

evolution never stops. The only difference with humans is that the “fittest” is no longer the strongest or the fastest. We dont need to hunt animals, but open up t the idea that we now “hunt” money. Many will deny it, but money attracts the “best” ie prettiest mates. Look at any seriously rich person. They have a good looking spouce dont they? For males the “fittest” still means “most able to provide”, for the female, it is now nothing to do with being well fed (plump) but to do with being healthiest (slim). This is no coinsidence.

I hate this idea, because i am not rich, but it is true. That does not mean that poor people cant have beautiful spouses, it just means that the richer you are, the more likely you are to have a beautiful wife – or if you are female and attractive, you are more likely to attract rich males.

Just like any form of evolution, there is always a large spread as some seriously poor chap may be really good-looking, popular, famous, whatever and get the top eschelon of partner.

ta

[mith]

Very true, I find it funny that even some websites echo your words :D, and they used it to encourage ppl to diet–fat ppl might be “rich” but now the rich is “slim.”
KungPaocoupons.com

[deadfish]

quote thank.darwin:

quote biostudent84:

it is logical for us to evolve to not grow them.

Be careful there Kyle… we can’t logically evolve. We have useless parts of the body that stick around because they don’t affect how well we reproduce or how we gather food and so on…

please name the useless parts of the body……

[mith]

they’re called vestigial organs….we have another thread on it but male nipples and appendixes are two.

[DJ]

There’s lots of them. Plus there’s parts of our bodies that we actually use but aren’t fully adapted to optimal efficiency or wear, like your knees and back. Many people have knee and lower back problems as they get older because they were originally intended for quadrupeds.

And the post about the average human height increasing due to evolution made my day 😆

[MrMistery]

Why? don’t you believe it? Just visit any medieval castle and you will see that the doors are built as if they were used by dwarfs.

[DJ]

Yeah, but that has nothing to do with evolution, haha. That’s from a higher standard of nutrition and better medical practices and sanitation improvements. It’s the same reason why we don’t hear about “scurvy” or “rickets” these days.

And the thing about the wisdom teeth, I have never heard about that before. Will definitely have to check that out. I just don’t see how the trait of being born without wisdom teeth would be spread or lead to better fitness when a person with wisdom teeth problems can now just go to the dentist and problem solved.

And the whole thing about being a waste of energy to keep producing parts we don’t need, that reeks of Lamarckism, which we left behind almost 200 years ago. The body doesn’t make conscious decisions like that to not grow certain parts, even if it is a waste of energy. That’s what DNA is for. There isn’t any type of logic to it.

[MrMistery]

quote DJ:

Yeah, but that has nothing to do with evolution, haha. That’s from a higher standard of nutrition and better medical practices and sanitation improvements. It’s the same reason why we don’t hear about “scurvy” or “rickets” these days.

Really? You think the king wasn’t well fed? And how exactly is being sick more often cause you to be shorter? better medical practices means that not so many people dye of desease, not that we can treat people of shortness…

[canalon]

quote MrMistery:

Really? You think the king wasn’t well fed? And how exactly is being sick more often cause you to be shorter? better medical practices means that not so many people dye of desease, not that we can treat people of shortness…

No, probably not. If you ever get interested in middle age cooking you will see how bad the diet was (too rich in fat and meats for the nobility, and very poor in meat for the peasantry).
And diseases when you are a kid do indeed inhibit growth. If you had problem with vitamins shortage, parasitism that take in the energy that you could otherwise have put into growing etc…

In fact I remember a graph with the average size of people through time, it showed that at the beginning of the roman empire people were taller, then became smaller during the middle age, and slowly started to grow, and it is only recently (20th century) that people are slowly starting to be as tall as they were one or two millenia ago…

[DJ]

quote Canalon:

No, probably not. If you ever get interested in middle age cooking you will see how bad the diet was (too rich in fat and meats for the nobility, and very poor in meat for the peasantry)

That sounds like your average American’s diet today 😀

[mith]

And yet americans are still taller than the average middle age person.

[MrMistery]

@Patrick
What you are saying seems very logical endeed. I will complain to the ministery of education because i found that info in a genetics book..

[paupackard]

When contemplating whether or not evolution occurs in a species, you have to define a time interval. When somebody says evolution has stopped for humans is accurate in the sense that in any one generation there is no evolution. Even in 200 generations there will probably not be any clear morfological diference if there isn’t some kind of radical natural selection. Any cause that can be an obstacle in reaching reproductive age causes evolution. Including modern day sicknesses and a possible genetic predisposition to have large families when able to choose to do so or not.

[Joe44]

I recently went to the dentist to have my teeth cleaned, and an x-ray I had showed that I have no Wisdom Teeth.

[MrMistery]

How old are you?

[jesstickle]

I have all four wisdom teeth does that mean I am soon to become obsolete. Will I be over taken by all these superior non teeth individuals? Also it seems to me that evolution is still going about its business it just might act a little slower in humans. If you look at cancer which kills 1 in 4 people in the uk it can still be used as a tool for evolution. yes we can treat it and cure it but it remains that some people are just naturally more immune and they are more likely to breed. I’m sure this can be applied to lots of diseases. I guess it just means humans really only have to evolve disease resistance as all other things we can fix ourselves. just because evolution is invisible doesn’t mean it isn’t there

[sssallylane]

I think that age plays a factor in the growth of wisdom teeth. You can have them as early as 17 or as late as 25. Some don’t get them at all, while others have them, but they become impacted. Normally, they are removed because they can get rotten if food particles somehow find their way between the teeth and the gums, and also because they can affect the alignment of the other teeth.

[jakesully]

quote James:

Evolution is the idea that a group in a species has something that enables them to more successfully mate and pass their genes on compared to the others in their species. Despite being useless, wisdom teeth and such useless organs such as the appendix would give neither an advantage nor a disadvantage in having offspring.
Why are we getting taller? Does this mean that those who are taller have a better chance of having children? Could it be the case that it is the very short people, nowadays are rarely having children? It could be that our human society is not only stopping evolution in some directions, but also aiding it in others, i.e. very short people are now seen as ‘abnormal’, and therefore have fewer children. Is this an example of cultural evolution?

We’re getting taller because we’re eating WAY more of everything. A high-protein, high-carb diet leads to rapid and early growth.

[jakesully]

quote biostudent84:

Over time all species when left alone will grow larger.

Not true.

[jakesully]

quote biostudent84:

Human evolution, like all evolution is a slow, but ever continuous process. Proof that evolution has not stopped in humans is simply described by average height. Within the past 200 years, the average male height has gone fro 5’4” to 5’10”. Also, today, some humans are being born without wisdom teeth. Since we usually remove them surgically, and do not use them if we don’t, it is logical for us to evolve to not grow them. Growing an unused part of the body is a waste of energy.

Kyle

If evolution were the reason, 200 years would be far insufficient for natural selection to work it’s magic. Plus, how exactly does increased height improve one’s genetic fitness?

You know what has really changed (quite dramatically) in the last couple-hundred years? Our diet.

[jakesully]

quote canalon:

Just a few words to react to some what I have read here:

quote :

Proof that evolution has not stopped in humans is simply described by average height.

I would not take this as a proof. Average height depend on many things, and genetic is probably not the most important in this case. A better and richer diet, well balanced during childhood is probably the best explanation for this.

quote :

Becoming taller is part of becoming bigger. Over time all species when left alone will grow larger. It is called the “Red Queen” hypothesis.

You should read SJ Gould (I think the book was called “the full house” in English) about the trend toward bigger organisms. In short its just not true.
As for the Red Queen Hypothesis (found in “beyond the looking glass”, the sequel to “Alice in wonderland” by the way) it is not about organism becoming bigger, it is more about co evolution between organisms, and mostly about the role of sex in evolution.

HTH

Patrick

Oh, oops. I guess, in the future, I should read the entire thread, before posting a comment. Upon further reading, it seems you had already made my point, but in a much better way.

[jakesully]

quote Wilmer:

quote :

Isolation causes speciation, evolution happens irregarless of isolation.

What does evolution do if it doesn’t make new species?

"Speciation" is when a single species breaks off into two seperate species. Speciation is not required for evolution to take place. A single species can evolve into a new species, and that is not speciation.

[jakesully]

quote geddiknight:

evolution never stops. The only difference with humans is that the “fittest” is no longer the strongest or the fastest. We dont need to hunt animals, but open up t the idea that we now “hunt” money. Many will deny it, but money attracts the “best” ie prettiest mates. Look at any seriously rich person. They have a good looking spouce dont they? For males the “fittest” still means “most able to provide”, for the female, it is now nothing to do with being well fed (plump) but to do with being healthiest (slim). This is no coinsidence.

I hate this idea, because i am not rich, but it is true. That does not mean that poor people cant have beautiful spouses, it just means that the richer you are, the more likely you are to have a beautiful wife – or if you are female and attractive, you are more likely to attract rich males.

Just like any form of evolution, there is always a large spread as some seriously poor chap may be really good-looking, popular, famous, whatever and get the top eschelon of partner.

ta

Dude, ugly, poor people make way more babies than pretty, rich people. I’m afraid your theory is awash.

[master94]

Its not about rich or poor its not about fastest or stronger and its not about isolation either i can prove that everyone here is wrong

[germanager]

Problem is that people are constantly looking for the way to STOP evolution. Imagine we will extend our lives to million years with the help of the medicine. Pretty much no evolving would happen.

All these funny theories that next thousand years of breeding would led to domination of brownish people with dark hair and eyes are total FALSE. In a hundred years genetic engineering would allow you to change appearance as much as you like, would it be blue eyes and blonde hair in fashion than half of the humanity would take special pill or injection and get to that state.

We will start forcing evolution in next few decades, getting rid of illnesses on genetic level and programming the appearance of kids. You want your child to be shark-like creature to breath with CO and produce O2 – you get it! 🙂

Future is unknown…

[Hobble]

I believe that because evolution takes such a long time to produce any visibly significant changes, I believe that the greatest step in our evolution will be the step where technology is merged with biology, and electronics are finally integrated into the human form.

Bionic legs, arms, eyes, ears, etc., will all improve the human form, creating a stronger, faster and more alert entity.

Although, this step may take quite a long time to overcome, as ethical, religious and cultural barriers impede the developments…

[Author]

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