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Author Topic: Has There Been Any Significant Evolution in Humanity?  (Read 11106 times)

Offline Gordian Knot

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"I am surprised how little improvement there has been in human evolution. Oh, there has been technical advancement, but, how little man himself has changed." Khan Noonien Singh from the Star Trek original series episode Space Seed.

It is a question I wonder about. Just how much, if at all, has humanity evolved in the time span of recorded history. Say starting around 5,000 BCE till the present. If so, how so.


 

Offline CliffordK

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Has There Been Any Significant Evolution in Humanity?
« Reply #1 on: 12/12/2011 22:27:49 »
In the past, gene pools would separate, and remain isolated for tens of thousands of years.

Over the last thousand years or so, there has been a tremendous re-mixing of long separated gene pools.  I believe that to some extent, the "Hispanic" race has evolved as a mix between Native Americans and Spanish Europeans.

I've heard some people wonder if things like crooked teeth are related to the mixing of races and isolated gene pools.

Some people have thought that in Western countries, girls are going through puberty at younger ages, although the reason for this is not entirely clear, whether it is genetic, environmental, nutritional, or perhaps even hormone exposure.
 

Offline Nizzle

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Has There Been Any Significant Evolution in Humanity?
« Reply #2 on: 13/12/2011 06:59:10 »
There are some isolated examples of recent human evolution.
The Tibetans have evolved over the course of the last 3000 years or so to live better in low oxygen conditions compared to Chinese that live close to them, but on lower altitudes. Source: New York Times

Also, there was a study I heard of from a friend (can't be bothered to verify on internet today ☺) about a correlation of the discovery of how to turn rice into fermented alcoholic beverages in Southern China with the spread of a mutated Alcohol Dehydrogenase coding gene that was better capable of breaking down alcohol compared to the unmutated ADH gene.

Probably, there are more examples...
 

Offline CliffordK

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Has There Been Any Significant Evolution in Humanity?
« Reply #3 on: 13/12/2011 07:25:46 »
with the spread of a mutated Alcohol Dehydrogenase coding gene that was better capable of breaking down alcohol compared to the unmutated ADH gene.

So, getting drunk aids with reproduction?
 

Offline Nizzle

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Has There Been Any Significant Evolution in Humanity?
« Reply #4 on: 13/12/2011 08:28:02 »
So, getting drunk aids with reproduction?

Not getting drunk helps with reproduction you mean :) Cause the mutated gene metabolized alcohol better/faster
 

Offline Don_1

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Has There Been Any Significant Evolution in Humanity?
« Reply #5 on: 13/12/2011 11:54:49 »
I have long maintained that due to our criteria for choosing a 'mate' having changed from nature's selection of the fittest, best adapted etc etc to character, wealth, status etc etc, the human race is not advancing in evolutionary terms as nature intended.

This is going to sound cruel and harsh, but if we continued to apply natural criteria to the selection of mating partners, those with physical and psychological abnormalities would not be selected. Those with beneficial attributes would be selected and humans would continue to evolve to the next stage, whatever that may be.
 

Offline Nizzle

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Has There Been Any Significant Evolution in Humanity?
« Reply #6 on: 13/12/2011 13:49:59 »
In a way, being wealthy or having a high status can still be considered as being "fit, or best adapted" to our current (capitalist) society. It's our environment that has changed. The current threats we face are no longer sabretooth tigers lurking behind a tree, but poverty and unemployment.

Whatever the next stage of evolution for mankind will look like, will depend greatly on how our global society and the world itself will evolve.
 

Offline RD

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Has There Been Any Significant Evolution in Humanity?
« Reply #7 on: 13/12/2011 17:12:05 »
with the spread of a mutated Alcohol Dehydrogenase coding gene that was better capable of breaking down alcohol compared to the unmutated ADH gene.

So, getting drunk aids with reproduction?


Historically taking alcoholic drink instead of plain unclean water increased your chance of survival ...

Quote
In those times of lower public sanitation, water-transmitted diseases were a significant cause of death. Because alcohol is toxic to most water-borne pathogens, and because the process of brewing any beer from malt involves boiling the water, which also kills germs, drinking small beer instead of water was one way to escape infection. Small beer was also produced in households for consumption by children and servants
https://en.wikipedia.org/wiki/Low-alcohol_beer#Small_beer

So there would be natural selection for those who had genes to consume alcohol without being (too) intoxicated.

https://en.wikipedia.org/wiki/Alcohol_tolerance#Alcohol_tolerance_in_different_ethnic_groups
« Last Edit: 13/12/2011 17:19:45 by RD »
 

Offline Gordian Knot

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Has There Been Any Significant Evolution in Humanity?
« Reply #8 on: 14/12/2011 17:06:59 »
Easier travel possibilities have made mixing of racial traits more common. While that is probably a good thing for the race as a whole, I don't see that as anything to do with the evolution of the species.

I believe you are right that girls are going through puberty at earlier ages in some parts of the world.  I think that is through easier availability of resources like food. Though it is a change in the human animal, I do not perceive it as an advancement in evolution of the species.

It is like the study that showed that modern Japanese girls are maturing with larger breasts and wider hips. That has nothing to do with evolving. It has everything to do with eating less rice and fish, and eating more western types of foods.

The Tibetans have indeed learned to thrive with a much lower oxygen level. That is a form of evolution I suppose, though more due to environmental exposure than any advancement in the species.

The basic tenants of what makes a human a human. I've heard nothing so far to indicate there has been any significant change. Take  a man who worked on building the pyramids 3,000 years ago. If one could bring that person forward in time to today, give him a modern education, would he be in any significant way different from a 21st century man? I think he would fit in just fine.

That is what I am trying to get at by evolution of the species.
 

Offline Geezer

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Has There Been Any Significant Evolution in Humanity?
« Reply #9 on: 14/12/2011 18:17:08 »
Take  a man who worked on building the pyramids 3,000 years ago. If one could bring that person forward in time to today, give him a modern education, would he be in any significant way different from a 21st century man? I think he would fit in just fine.


He'd likely be a bit smaller, not just because of nutrition, but also because of selection. However, 3,000 years isn't very long. It's only about 150 generations

Humans have created environments that eliminate the need for rapid evolution. If the environment(s) changed radically, certain traits would be favoured while others would die off leading to an acceleration in evolution.
 

Offline CliffordK

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Has There Been Any Significant Evolution in Humanity?
« Reply #10 on: 14/12/2011 19:27:32 »
Take  a man who worked on building the pyramids 3,000 years ago. If one could bring that person forward in time to today, give him a modern education, would he be in any significant way different from a 21st century man? I think he would fit in just fine.
He'd likely be a bit smaller, not just because of nutrition, but also because of selection. However, 3,000 years isn't very long. It's only about 150 generations

A life of heavy manual labor, the worker might be quite strong.  However, I suppose nutrition, and whether the workers were abused would also play a role.

There are some conditions such as autistic spectrum disorders that are slowly increasing in prevalence.
 

Offline Bored chemist

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Has There Been Any Significant Evolution in Humanity?
« Reply #11 on: 14/12/2011 19:28:05 »
I think the high incidence of lactose tolerance in North West Europe is a relatively new adaptation that accompanies our enthusiasm for dairy farming.
On a simplistic level, survivors of major recurrent plagues may have been selected for by evolution. There is some evidence for this among descendants of the survivors of the plague at Eyam. By an odd coincidence they have a relatively high immunity to HIV.
 

Offline Nizzle

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Has There Been Any Significant Evolution in Humanity?
« Reply #12 on: 15/12/2011 06:14:11 »
The Tibetans have indeed learned to thrive with a much lower oxygen level. That is a form of evolution I suppose, though more due to environmental exposure than any advancement in the species.

Uhm, isn't that how evolution works? Random mutations always occur, and if the environment changes, the best adapted individuals have a higher chance of reproducing..

Take  a man who worked on building the pyramids 3,000 years ago. If one could bring that person forward in time to today, give him a modern education, would he be in any significant way different from a 21st century man? I think he would fit in just fine.

He would most likely not be a very bright student, since the average IQ has risen steadily the last centuries. Of course, the cause of this rise is debatable, and may very well have nothing to do with a change in our genetic makeup but rather our improved education.

However, and this is beautiful: Since Intelligence as we know it (as opposed to instincts) is one of the traits that separates man from animal, it is likely that there IS in fact a genetic basis for our rising IQ. The human gene pool has invested in this "path of growing intelligence" and we may very well not be at the end of that path. And maybe we are only able to improve our educational system because our brains are able to keep up ;)

NOTE: This is a hypothesis of mine, it should not be considered as fact.
« Last Edit: 15/12/2011 06:15:43 by Nizzle »
 

Offline CliffordK

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Has There Been Any Significant Evolution in Humanity?
« Reply #13 on: 15/12/2011 07:55:55 »

However, and this is beautiful: Since Intelligence as we know it (as opposed to instincts) is one of the traits that separates man from animal, it is likely that there IS in fact a genetic basis for our rising IQ. The human gene pool has invested in this "path of growing intelligence" and we may very well not be at the end of that path. And maybe we are only able to improve our educational system because our brains are able to keep up ;)

What if, as a society, we actively select against people with very low IQ's...   Say having a societal threshold of 60 or so.

Would that be sufficient to push the genetics towards higher IQ's? 

I suppose the question is whether this is actually selecting against certain genes, or if the very low IQ's are related to other processes that wouldn't necessarily be reflected in the overall genetic makeup.
 

Offline Nizzle

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Has There Been Any Significant Evolution in Humanity?
« Reply #14 on: 15/12/2011 14:53:31 »
Possibly. There surely is some social awkwardness and eyebrow raising when two people with Down syndrome (or other cause of mental challenges) reproduce nowadays, but how that awkardness compares to the past, I have no clue.

In fact, this whole discussion now makes me wonder how the "geniuses throughout history" would score on a standardized IQ test. How would Einstein, Edison, Newton, DaVinci, Galileo, Plato and Ptolemy match up to one another..
« Last Edit: 15/12/2011 14:56:32 by Nizzle »
 

Offline yor_on

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Has There Been Any Significant Evolution in Humanity?
« Reply #15 on: 15/12/2011 19:07:43 »
We have around three billion base pairs in human DNA. Each base pair can be one of four combinations. So three billion to the fourth power. The odds of two siblings getting the same chromosomes from the same set of parents is roughly 1 in 70,000,000,000,000. Add to that gene mutations that introduce new lines.

"The DNA between an egg and a sperm, in a human, has an estimated 91% chance of "getting it right", as it were, once fertilization occurs at arranging correctly to form another human. If you take into account genetic variation from sexual recombination, the number of possible combinations of DNA for the resulting offspring is astronomical. Our entire genome has upwards of 3.3 billion base pairs. If we consider that we have no way of knowing which base pairs will separate and which single strands will connect to which genes, the actual possible combinations is innumerable. If under the conditions in a zygote, the nucleotides bond around 91% of the time in a combination that is correct for a functioning human."

From DNA, Probability And Fallacy.

I sincerely doubt we need 'gene modifications', and we can't know what long term result such will have in my opinion. We're not apple trees, and our genome is not understood, even though nature knows what it does. We do a lot of 'copy and paste' to see what happens and some may want you to believe that they 'know' but looking at the figures I think they are overreaching. But it's the normal way we proceed with most new things as we want to make a profit, imitating nature telling the next guy "Not to worry, We know what we're doing"  The more complex the situation, the less true that statement becomes.

And starting to create genetically 'perfect humans' :)

Nah, I've seen people, and countries, try that before and the only thing it lead to was atrocities, and in hindsight humanity might had been better off without those planning it.  
« Last Edit: 15/12/2011 19:10:40 by yor_on »
 

Offline CPT ArkAngel

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Has There Been Any Significant Evolution in Humanity?
« Reply #16 on: 15/12/2011 19:26:02 »
Some people have no "dens sapientiae" (wisdom teeth) or only 2 of them... :D
« Last Edit: 15/12/2011 21:26:46 by CPT ArkAngel »
 

Offline CliffordK

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Has There Been Any Significant Evolution in Humanity?
« Reply #17 on: 15/12/2011 21:55:51 »
We have around three billion base pairs in human DNA. Each base pair can be one of four combinations. So three billion to the fourth power. The odds of two siblings getting the same chromosomes from the same set of parents is roughly 1 in 70,000,000,000,000. Add to that gene mutations that introduce new lines.

Obviously Identical twins are possible, but for non-twin siblings, I believe you are over-estimating the numbers somewhat.

There are 23 pairs of chromosomes.  Without crossovers, you would get 234 combinations.

With 2 to 3 crossovers per chromosome, it increases that number significantly.  It is unclear the variability in the crossover loci, somewhere the information should be available.  Anyway, it means that the probability of any two consecutive basepairs being from the same chromosome would be high.  And, the total number of actual combinations would be far less than calculated above.

Well, maybe.
(3 Billion)4, and you should have a couple more zeros than above.

--------

As far as Eugenics, it is a very complicated issue.
Some of it can be done with just selective breeding.

For example, some people are choosing to select against Sickle Cell or Huntington's disease.  I would predict that at least the prevalence of Huntington's Disease (an autosomal dominant disease) will drop significantly over the next century.

The question is whether it would be better to just select the specific desired genes, or to say just choose a different sperm donor.

If one ignored the strong desire to pass one one's own genetics to one's children, one could chose to select sperm (or eggs) from very smart donors, or from very long-lived families.  But, with 7 Billion people on the planet, it would be difficult to do this on a society basis.
« Last Edit: 15/12/2011 23:02:03 by CliffordK »
 

Offline yor_on

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #18 on: 18/12/2011 13:26:08 »
It might give some short term effects but considering the possible combinations for each pairing of genes, as in conceiving a child, it seems very improbable to me that we can single out all effective combinations. But maybe short time?

"We know that DNA copies itself within an organism, and we know that small mutations occur in each copy, which, in part, attributes to the variance among one species of organisms and the continual differences that increase exponentially from generation to generation. This is why a new organism doesn't form in utero, within our cells or any other DNA duplication process. It would seem that organisms either evolved over a substantial period of time from other organisms and/or molecules came together under certain conditions to begin the life of a new organism."

Eugenics? Then again, I don't like killing at all, especially not when done by those keeping on living :)
It's all too easy to decide for someone else, much harder to apply the same logic on your self.
« Last Edit: 18/12/2011 13:28:38 by yor_on »
 

Offline Gordian Knot

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #19 on: 18/12/2011 18:14:13 »
Nizzle wrote: "He would most likely not be a very bright student, since the average IQ has risen steadily the last centuries. Of course, the cause of this rise is debatable, and may very well have nothing to do with a change in our genetic makeup but rather our improved education".

Interesting. I have not heard this before. You mention this is your theory. Do you have any facts to support it? I am not aware of any rise in IQ over the last few centuries.

In my experience there has been quite the opposite, a dramatic lowering of IQ the past few centuries. I believe this for two reasons.

1: Advances in medicine have allowed many to live who would not have lived in the past. This is a weakening of the gene pool in my opinion.

2. We have a dramatic drop in births amongst the more developed countries and a surge in births amongst undeveloped countries. It is my understanding this holds true for lower class individuals versus middle to upper classes. Lower classes tend to be less educated, and many tend to be easily swayed by religious organizations which have their own agenda. An agenda, I believe, that is best suited by keeping people ignorant.

Please note, I am not making any moral statements about the right or wrong of my statements. I am just stating facts as I perceive them.

The essential reason for, lack of reasoning skills was best summed up by Carl Sagan,

"....the lack is not in intelligence, which is in plentiful supply; rather the scarce commodity is systematic training in critical thinking".
Carl Sagan, Broca's Brain

That has nothing to do with evolution or lack thereof of the human animal.
 

Offline CliffordK

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #20 on: 18/12/2011 19:49:50 »
Eugenics? Then again, I don't like killing at all, especially not when done by those keeping on living :)
It's all too easy to decide for someone else, much harder to apply the same logic on your self.
I think you've confused Eugenics and Euthanasia.

While you could use the two practices in conjunction, that don't need to be the case.

Eugenics is simply planned improvements of the Human gene pool (breeding, gene therapy, etc).
Euthanasia is the elimination of those individuals that are no longer needed...  for a variety of potential reasons.

Certainly 3rd world poverty doesn't necessarily equate to lower intelligence.  However, there is a global risk of a racial shift as some cultures have families of 5+ children, and others have far smaller family sizes.  Then, those with large families attempt to move elsewhere.
 

Offline yor_on

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #21 on: 18/12/2011 20:39:33 »
Nope, no mistake as far as I see it.
Hitler practiced Eugenics. It's also called Ethnic Cleansing depending on taste, and what people sees as the nicest rewrites, but to me it all falls back on some human presumption of some genetic or 'racial superiority'. As for the intelligence rising I think Nizzle is correct. Intelligence is a very tricky word, but if we assume it to consist of what is commonly seen as useful to the society where it exist then we have a lot of better educated people today. And with education comes more choices.

But then we have beliefs, they exist everywhere and we all have some, unspoken or not.
 

Offline CliffordK

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #22 on: 19/12/2011 00:06:48 »
One level of Eugenics would be to minimize the number of births with certain genetic diseases.  Abortion is a tool that could be utilized, but it doesn't have to involve killing individuals as other approaches to gene selection could be used.

Huntington's disease is an autosomal dominant neuro-degenerative disease that usually presents between age 35 and 45.  So, it is usually noted in the grandparents, but the parents would be asymptomatic during the child bearing years.

A "carrier" would have a 100% chance of developing the disease if they aren't taken by some other event earlier, and would have a 50% chance of passing on the genes.

The disease could be virtually wiped out in a generation or two, with future cases only occurring due to a low rate of spontaneous mutations.

Cystic Fibrosis and Sickle Cell are a bit more complicated as they are a recessive gene, and the heterozygous state may actually confer a minor benefit to the individual.  However, it would be possible to avoid the birth of homozygous Sickle Cell and Cystic Fibrosis children. 

These diseases could be 100% prevented with detecting the risk factors, then:
  • Sperm or Egg Donation
  • Ex-Vivo fertilization and detection in the early blastocyst stage
  • Amniocentesis and Abortion

Down's syndrome can also be diagnosed prenatally.  While genetic in origin, it has a different inheritance pattern, but can still be diagnosed prenatally. 

Over the next half century or so, we will discover the genetic basis for a number of diseases including better defining cancer risk factors. 

As a society, one way to extend the lifespan of humans would be to attempt to amplify the number of genes from centenarian individuals and long-lived families.  Or, systematically eliminating things like cancer genes.

One could also amplify the genes of the super-intelligent individuals, although I personally believe that there may be a connection between intelligence and Asperger's syndrome.  So, doing so might carry a hidden societal risk.
 

Offline yor_on

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #23 on: 19/12/2011 06:41:31 »
Life's a lottery Clifford. You do not know the outcome until dead, and by then it is far too late to do anything about it :)
Nevertheless I agree on that we should try to give children that have a bad prognosis a chance for a better life. That is what I hope can be done in the gestation period, manipulating whatever deficiency's we see developing.

As for the idea of selectively manipulate and change genes (the human gene pool)  I don't feel as comfortable. We have an enormous potential, all of us. Your son may become our next Einstein, we can't define it better than that. There is no proof existing that genius must come from education, or a special class of humans. Also it depends on what society need, and acclaim as 'valuable' at the period. A lot of the really ingenious math I've read about only come to be practical long after it's defined for example. And it's all kind of things, not only science, that can make it a better place to live.

Beliefs has a lot to do with it.
« Last Edit: 19/12/2011 06:46:53 by yor_on »
 

Offline CliffordK

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #24 on: 19/12/2011 08:56:08 »
I agree that at this point, it might be unwise to start splicing the human genome.

However,  we already have the technology to diagnose severe genetic disabilities before birth, and in extreme cases, even terminate the pregnancy.  How far this can, or should be taken, I don't know.

At this point, most of the human genes and gene variants are now being identified. 

Will we be able to tell hair color, eye color, height, and other factors from an amniocentesis?  How about getting a computer generated photo of your future teenager before choosing a name?

In a few decades, people will have to choose whether to "repair" children's genes.  Certainly one will have to carefully consider whether things like cancer susceptibility genes should be repaired at conception.

Would there be the temptation to create a Barbie&Ken generation?  xx(
 

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Re: Has There Been Any Significant Evolution in Humanity?
« Reply #24 on: 19/12/2011 08:56:08 »

 

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