Are human beings still physically evolving?

Kermit.de.frog · 07-09-2017 6:39am #1

Hi, quick question from random thought.

Are we as a species still evolving physically?

And Is it possible in 2,000 years human beings might be a lot different physically then we are now?

Might they look back at us and see us as freaks?

I ask because if we are still evolving and might end up with three eyes or an extra arm or whatever do you think everyday tech might advance pace of this process?

What is technology if not to make everyday tasks easier, if not eventually redundant?

I like to think of penguins. Use to have wings but then nature noted there were no predators to them in antartica and so abandoned the wings to fly in short order.

Thanks!

14-09-2017 12:40pm

Kermit.de.frog wrote: »

Hi, quick question from random thought.

Are we as a species still evolving physically?

And Is it possible in 2,000 years human beings might be a lot different physically then we are now?

Might they look back at us and see us as freaks?

I ask because if we are still evolving and might end up with three eyes or an extra arm or whatever do you think everyday tech might advance pace of this process?

What is technology if not to make everyday tasks easier, if not eventually redundant?

I like to think of penguins. Use to have wings but then nature noted there were no predators to them in antartica and so abandoned the wings to fly in short order.

Thanks!

Humans still have huge selection pressure in the developing world so no reason to think that naturally driven evolution would not continue there, regardless how western lifestyles do

Wheety · 14-09-2017 12:58pm

We'll probably be a bit taller in 2000 years.

Capt'n Midnight · 14-09-2017 11:28pm

Yes we are still evolving.

For many nasty viral diseases we have two main options, use vaccines now or wait until evolution kicks in over many generations.

Genetic drift means change even without selective pressure.

We have 23 chromosome pairs. So 8,388,608 different ways to split them. And square that to get the number of different possible chromosome pairings for children of two non-related people.

And then there's random mutations and crossing over to add more diversity. And retroviruses.

In Ireland Cystic Fibrosis is a genetic disease which is still a killer.
https://www.irishtimes.com/news/health/irish-people-with-cystic-fibrosis-expected-to-live-longer-1.2144490

People with cystic fibrosis have previously had low life expectancy, but improvements in treatments in the last three decades have led to an increase in survival with almost all children now living to about 40 years.

Carries may get some protection from cholera. After the 2010 Haiti earthquake 9,200 people died of it.

Capt'n Midnight · 14-09-2017 11:37pm

Kermit.de.frog wrote: »

I like to think of penguins. Use to have wings but then nature noted there were no predators to them in Antarctica and so abandoned the wings to fly in short order.

The Great Awk was the northern hemisphere equivalent.

But we have it's DNA.

macraignil · 01-10-2017 10:41pm

Wheety wrote: »

We'll probably be a bit taller in 2000 years.

The world population was estimated to have reached 7.5 billion in April 2017. The United Nations estimates it will further increase to 11.2 billion by the year 2100

In 2000 years there might not be space on the planet for taller people and if space exploration and living takes off maybe there might be more of an advantage of not being too tall in case you'd hit the roof on the space ship.

It's probably a bit controversial to talk about racial differences in physiology but I have heard of populations on the planet having characteristics that help performance in particular sports. Western europeans for example tend to have longer arms as a proportion of the rest of their body and so have an advantage at weight lifting. Some people from mountainous areas have physiology helping them deal with lower air pressure and available oxygen. Over 2000 years who knows what traits might be selected for in the future?

02-10-2017 7:09am

2000years is nothing

Victor · 02-10-2017 8:03am

Realise that the differences between individuals that are currently alive are greater than the differences between people currently alive and those alive 2000 years ago.

In another 2000 years, the likely differences will be in typical height, mass and ability to deal with specific diseases.

NIMAN · 02-10-2017 8:05am

But is modern medicine not messing with evolution?

Surely intervening when people have medical conditions is meddling?

macraignil · 02-10-2017 6:46pm

NIMAN wrote: »

But is modern medicine not messing with evolution?

Surely intervening when people have medical conditions is meddling?

Sure it is meddling with evolution but only a complete psychopath would consider the option of doing nothing for people in medical need of help, in the name of promoting evolution.

Consider the example of haemochromatosis a disorder that is relatively common in Ireland, and easily remedied by measured venesection (taking blood) when required. The sufferers of this condition have developed the ability to absorb more iron than normal and thus have too much iron in their blood unless they get medical attention. There may be a time when such an adaptation would be useful but if we allowed all the people with haemochromatosis die younger because we wanted to let evolution work without our meddling the human race might not survive if it turned out in future that this ability to absorb more iron from our diet was necessary.

Even ignoring promoting genetic diversity keeping more people alive and healthy through medicine benefits all of the community from the continued productivity of the person receiving treatment. Helping others in the community is not just what some people do but can be seen in communities of "wild" animals as well.

Kermit.de.frog · 20-10-2017 4:08am

So in 2,000 years we might be looked back on as physiological freaks?

Peregrinus · 20-10-2017 4:12am

No, the differences resulting from evolution over so short a period of 2,000 years will be tiny.

Other factors will result in greater differences. For example, our greater height today than compared to our ancestors of 2,000 years ago is not due to evolution, but to improved nutrition. That's a trend that could continue. Or, of course it could be reversed if climate change, civilisation collapse or similar means that future generations become less well-nourished. Either way, evolution has nothing to do with it.

macraignil · 20-10-2017 4:29pm

Peregrinus wrote: »

No, the differences resulting from evolution over so short a period of 2,000 years will be tiny.

Other factors will result in greater differences. For example, our greater height today than compared to our ancestors of 2,000 years ago is not due to evolution, but to improved nutrition. That's a trend that could continue. Or, of course it could be reversed if climate change, civilisation collapse or similar means that future generations become less well-nourished. Either way, evolution has nothing to do with it.

I agree height is effected by nutrition but it is also effected by genetic inheritance and not just nutrition. There is probably on average a greater height today among people worldwide due to improved nutrition but there are some people that are still not tall no mater how good their nutrition is.

There are pygmy peoples found in various parts of the world and their height is determined by genetic factors with the vast majority of these tribal groups being of lower stature. The Aka, Efe and Mbuti tribes in central Africa are most associated with the term. There are also tribes in Africa associated with being tall such as the Maasai.

I do not agree with your statement that height has nothing to do with evolution and over the next 2000 years who knows what selection pressures might emerge to favor one group over another. 2000 years might not be such a short period for evolution if a strong selective pressure was in place for one group over the other.

Peregrinus · 23-10-2017 2:24am

macraignil wrote: »

I agree height is effected by nutrition but it is also effected by genetic inheritance and not just nutrition. There is probably on average a greater height today among people worldwide due to improved nutrition but there are some people that are still not tall no mater how good their nutrition is . . .

Sure, there's a genetic link to stature, but that in itself does not mean that we will evolve to be taller, or indeed shorter. For that to happen, being tall (or being short) would have to confer a reproductive advantage, such that tall (or short) people reproduce more, and the genes which make for shortness (or tallness) are "bred out" of the human population.

The other point I had in mind is that, in evolutionary terms, 2,000 years is a fraction of the blink of an eye, particularly for species as numerous and as wide-ranging as ours. You're not going to get significant evolutionary change in that timescale. Dinosaurs, for example, were around for about 140 million years before scales began to evolve into feathers. 2,000 years is nothing.

macraignil · 23-10-2017 7:11pm

Peregrinus wrote: »

Sure, there's a genetic link to stature, but that in itself does not mean that we will evolve to be taller, or indeed shorter. For that to happen, being tall (or being short) would have to confer a reproductive advantage, such that tall (or short) people reproduce more, and the genes which make for shortness (or tallness) are "bred out" of the human population.

If you read my post I did mention that a selective pressure is required for evolution to take place. "who knows what selection pressures might emerge to favor one group over another."

The other point I had in mind is that, in evolutionary terms, 2,000 years is a fraction of the blink of an eye, particularly for species as numerous and as wide-ranging as ours. You're not going to get significant evolutionary change in that timescale. Dinosaurs, for example, were around for about 140 million years before scales began to evolve into feathers. 2,000 years is nothing.

Again this is down to the question of selective pressure being applied and what you said is true if things stay pretty much the same for the human race over the next 2000 years. I don't think we can be sure of that and as has happened in the past some areas have seen selective pressures emerge to lead to populations of consistently tall and consistently small people e.g. the pygmy people of some tropical jungle regions and the extra tall tribal groups herding animals over large areas of sub Saharan Africa. There are a number of possible situations where the human race might not be as numerous or as wide ranging as it is now and I do not share your confidence that evolution is finished for the human race.

I also question weather you can accurately compare something as variable as height to the development of new complex structures like feathers. I'm also not sure we can be accurate about the first development of feathers with the fossil record that is available as most fossils would not have structures as small and delicate as feathers preserved.

As to 2000 years being too short for evolution, take a look at the doubling in size of the mice on a remote islands since they were released there in the 19th century. Gough island example

Peregrinus · 24-10-2017 2:59am

I've never said evolution was finished for the human race; it certainly is not. I said I see no reason to expect environmental pressures which will lead to our species evolving to be taller in the next two thousand years.

As for the mice on Gough Island, the article you link to explicitly says that the growth in size is linked to "low temperature, extended longevity, reduced predation, and carnivorous eating habits". For environmental reasons, the mice live longer (and therefore have more time to grow) and are better-nourished. This is not evolution at work. They have no more evolved to grow bigger than we have evolved to live longer as a result of improved hygiene and medical technology.

macraignil · 24-10-2017 7:02am

macraignil wrote: »

The world population was estimated to have reached 7.5 billion in April 2017. The United Nations estimates it will further increase to 11.2 billion by the year 2100

Over 2000 years who knows what traits might be selected for in the future?

The mice at Gough island have had the selective pressures listed. The population of mice there is now bigger than average mice. Why are you saying this is not evolution?

Peregrinus · 24-10-2017 7:09am

macraignil wrote: »

The mice at Gough island have had the selective pressures listed. The population of mice there is now bigger than average mice. Why are you saying this is not evolution?

Why are you saying that it is? Any population of animals which is provided with better nutrition will grow bigger (on average), but that's not evolution at work. To ascribe this to an evolutionary change you need to show that the population is losing its "smallness" genes due to sexual selection - i.e. the mice who are genetically smaller are less successful at reproducing, with the result that the population becomes permanently larger for genetic reasons. Simply being well-nourished does nothing, in itself, to alter your genes; your children will not be born with "bigness" genes as a result of you having been well-nourished and growing large.

24-10-2017 8:37am

macraignil wrote: »

The mice at Gough island have had the selective pressures listed. The population of mice there is now bigger than average mice. Why are you saying this is not evolution?

Basically take a sample of those mice, have them carry a litter while not over fed, do not over feed the litter and see what size they reach.

Chances are they will only reach the size of regular mice.
For it to be evolutionary, the mice should struggle as their genetic makeup forces them to become larger even with the diminished food supply

Peregrinus · 24-10-2017 8:51am

Basically, what we have here is Lamarckian versus Darwinian evolution.

Lamarck argued that, e.g. giraffes which repeatedly stretched up to reach the higher-up leaves not only developed longer necks, but also gave birth to offspring with longer necks, who in turn stretched up a little bit further and got slightly longer necks, and so on from generation to generation until giraffes all looked like they do today.

Darwin said no, the giraffes born with naturally longer necks, due to genetic chance or mutation, were more successful feeders, and so lived longer and were healthier, and so had more offspring, passing on their genetic trait of long-neckedness to a larger and larger proportion of the giraffe population. But they had the long-necked gene from birth (indeed, from conception); they didn't acquire it by stretching their necks. Genetic variation and mutation was the driver of evolution.

Putting the mice in an environment with an abundance of food and other environmental characteristics may make the mice grow bigger, live longer and have more offspring, but (unless you're a Lamarckian) it won't give them "bigness" and "long life" genes that they can pass on to their offspring.

macraignil · 24-10-2017 6:32pm

The example, that I provided, of the Gough island mice evolving is a well studied genetic phenomenon and if you are interested in learning more about it here are some links to articles in peer reviewed journals and other publications on the subject:

National Center For Biotechnology Information. US National Library of Medicine 1

National Center for Biotechnology Information. US National Library of Medicine 2

Genetics Society of America

Genetic Society of America 2

Financial Times

Wiley Online Library

Your comments are in complete contrast to the experimental work described and I am unsure how you know so much more about mouse genetics than the scientists and journalists involved in covering the story.

24-10-2017 7:44pm

macraignil wrote: »

The example, that I provided, of the Gough island mice evolving is a well studied genetic phenomenon and if you are interested in learning more about it here are some links to articles in peer reviewed journals and other publications on the subject:

National Center For Biotechnology Information. US National Library of Medicine 1

National Center for Biotechnology Information. US National Library of Medicine 2

Genetics Society of America

Genetic Society of America 2

Financial Times

Wiley Online Library

Your comments are in complete contrast to the experimental work described and I am unsure how you know so much more about mouse genetics than the scientists and journalists involved in covering the story.

Well first only now do you provide evidence for your statement (which people may read)

Second, journalists have a habit of sensationalist writing so not a great resource for scientific purposes

If you make a statement people are free to challenge it, until you provide proof

macraignil · 24-10-2017 8:08pm

Deleted User wrote: »

Well first only now do you provide evidence for your statement (which people may read)

Second, journalists have a habit of sensationalist writing so not a great resource for scientific purposes

If you make a statement people are free to challenge it, until you provide proof

If you look at page one of this thread, to where I originally mentioned the example of the Gough island mouse there is a link in my post to a website dedicated to the story.

As to 2000 years being too short for evolution, take a look at the doubling in size of the mice on a remote islands since they were released there in the 19th century. Gough island example

24-10-2017 9:34pm

macraignil wrote: »

If you look at page one of this thread, to where I originally mentioned the example of the Gough island mouse there is a link in my post to a website dedicated to the story.

As to 2000 years being too short for evolution, take a look at the doubling in size of the mice on a remote islands since they were released there in the 19th century. Gough island example

Apologies missed that

macraignil · 24-10-2017 9:42pm

No worries. The experiment you described to check if it was a genetic feature of the mice population would make sense and it is always worth challenging what people claim. Otherwise it wouldn't be science.

Are human beings still physically evolving?

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