Where do you think humans are going in terms of evolution?

  • #1
What do you think we are going to evolve into or adapt to in the far future or mutations arise that will cause some kind of change in our features and maybe even intelligence, strength, physical attributes. Also do you think it will be the entire human race that will evolve in the same way or do you think some will evolve and others will not or evolve in a different way in the far future.
 

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  • #3
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adapt ... or mutations ... cause some kind of change
Why is the 'or' there? Those mutations (if they can persist on long run) are what would make us adapt...

What I think is that the speed of our 'natural' evolution will be crushed by our impatience at the end and - starting from small modifications to correct ill-behaving gene variations - we will take it in our own hand.

Ps.: just checked - Hawking said more or less the same. Well, I'm less afraid - as a species it was never in our genes to keep them for ourselves, so any modification will sure to spread like a wildfireo0)
 
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  • #4
Ryan_m_b
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Evolution is driven by selective pressure. Putting aside genetic modification of the genome for a moment (as it tangentially relates to evolution) to answer the question you have to consider what presence or absence of pressures there may be. Obviously it's impossible to predict with any certainty what the future will bring, all we can do is look to current trends and extrapolate sensibly. There are several modern trends that come to mind that will likely have some level of impact on future human evolution:

- Interbreeding. The weakening of social stigmas against interracial relationships as well as increased mobility mean that more offspring are born of parents of disparate genetic and geographic backgrounds than before.

- Decreases in child mortality. Many genetic diseases that historically have resulted in individuals not surviving to reproductive age are now manageable, to varying extents, enabling these individuals to have relationships and children.

- Genetic screening and abortion. Most developed nations allow the latter and genetic screening is becoming cheaper and more common. With IVF and IUI procedures also becoming more routine being aware of potential genetic disorders and being able to protect against them is becoming more possible.

- Greater generation gaps. In developed nations number of children per couple is decreasing whilst average age of first child is increasing. As one ages conceiving a child becomes more difficult, it is possible that this will create a selective pressure for later life fertility although medical intervention may mitigate the effect.

And in more general terms our technology and social institutions cause previously deleterious and advantageous mutations to be merely neutral. It's likely there are neutral mutations that are now deleterious or advantageous in this new context, though the rapid change of technology and society may keep this in flux.
 
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  • #5
jim mcnamara
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'Where do you think...' implies speculation. This belongs down in General Discussion.

AND. Evolution does NOT have a direction, an intent, or anything that we can always discern going on.

http://dalmatianbreed.com/common-health-problems/ see a list of "oops" traits.

You are talking about 'directed selection of traits' when you mention a direction - like what plants breeders do to make new varieties of flowers. The results are not always robust. We bred for dog breeds, and now ~30% of Dalmatians (breed of dog) carry genes for deafness. Deaf predator/scavengers would be at a huge disadvantage in the wild. But if they are both deaf and conformationally perfect and win dog shows, they are worth huge amounts of money.
In order to get what it seems the OP is implying would require for humans is called Eugenics. Which has really serious negative issues.

Eugenics is usually categorized as "fringe medicine": https://en.wikipedia.org/wiki/Eugenics
 
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  • #6
jim mcnamara
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As an example of the result of humans "dinking" with selecting offspring consider the sex ratio M/F ratio (Child Sex Ratio for newborns).
Consider:
One example city in India is 128:100. This means that when a cohort with this ratio reaches maturity there will be many males (1 male in 5) who cannot find a mate. Which will cause social disruption. The cause is selective abortions - abort females. As a side effect it lowers the fecundity of a population.

https://en.wikipedia.org/wiki/Child_sex_ratio
 
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  • #8
russ_watters
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- Greater generation gaps. In developed nations number of children per couple is decreasing whilst average age of first child is increasing.
Tangential to that, the birth rate disparity between developed an undeveloped countries and populations within countries is potentially concerning. It is difficult to separate the social consequences from the genetic/evolution consequences though.
 
  • #9
Ryan_m_b
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Tangential to that, the birth rate disparity between developed an undeveloped countries and populations within countries is potentially concerning. It is difficult to separate the social consequences from the genetic/evolution consequences though.
Concerning in a wider sense of resource strain I agree, not sure what other concerns there are to be had. Economic development and equality for women tend to drive the growth rates of nations way down so developing nations are likely to stabilize the same way as developed eventually. I can't think of any particularly relevant drive this would have for modern human evolution other in the basic sense that the allele frequency of the human species will shift in the same manner as it did when western nations exploded in population numbers a century or so ago.
 
  • #10
russ_watters
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Concerning in a wider sense of resource strain I agree, not sure what other concerns there are to be had. Economic development and equality for women tend to drive the growth rates of nations way down so developing nations are likely to stabilize the same way as developed eventually. I can't think of any particularly relevant drive this would have for modern human evolution other in the basic sense that the allele frequency of the human species will shift in the same manner as it did when western nations exploded in population numbers a century or so ago.
The assumption built-in there is that all countries are capable of and will achieve the same level of development and(or because) humans are genetically and socially homogenous and equal. Interbreeding increases homogenaity, but fertility rates themselves may work to separate it.

Let's set aside the different countries and just look at one diverse country: the USA. The birth rate varies substantially with income in the USA. Barring other factors, this will push average incomes down over the long term because the populations of lower income people are growing faster than the populations of higher income people. With that, any traits that affect or are affected by income and birth age/rate will feel pressure in opposite directions.

See: https://www.economist.com/feast-and-famine/2012/08/02/demography-and-inequality

Edit: It strikes me that this social/societal evolution works on the scale of decades whereas biological evolution would generally take millennia. So my example above may be out of the scope of the thread.
 
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  • #11
BillTre
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Since the OP refers to the "far future" and speculation is OK, I would consider the follow as possibilities:

Human genetic modifications will happen (as @Rive stated) and will based based upon a much greater understanding of how genetics generates human structure and function. Both of these (human modifications of human genetics and greater understanding of how things work) seem to me to be reasonable extensions of current research trends.
This could be used for fixing things or making "improvements" of various kinds.
This would also speed up any evolution by providing lots of new genetic novelties for selection to act upon.

Depending upon the rate at which new (human made) genetic changes are introduced into a population compared to the strength of selective processes, the genetic changes may overwhelm the selective forces (for a while) and drive population changes (that might not be adaptive).

In the future, reproduction may not be limited to requiring male involvement.

As a side effect it lowers the fecundity of a population.
This may not be a bad thing, depending upon the population and environmental situation. Governments might even want to promote it in some cases.

New environments could provide new selective pressures to better adapt to them (space travel/living on Mars or other places). For example, there might be selection for:
  • Larger lungs or different hemoglobin for lower oxygen levels or for reduced oxygen use in some of these different environments.
  • Different body structures for higher or lower gravity situations, or changes in metabolism for low gravity (to prevent bone loss and other astronaut issues.
Adaptive conditions on Earth could change. After one of the great extinctions (I forget if it was after the end Permian or the KT extinction event induced environmental destructions), for a while no animals existed that were larger than your forearm. Other than natural disasters, there could be really bad climate change or a nuclear war. Size reductions are adaptive in food limited situations.

Why not become extinct?
Not out of the question, but I expect that the very rich and/or powerful might be able to survive many situations in little hideaways. They might also be able to afford genetic modifications that attenuate the effects of environmental challenges.
Alternatively, people in special isolated areas like the Svalbard Global Seed Vault (which would also have a bunch of seed to restart agriculture) might survive.

Colonizing space (or extreme social situations) might lead to situations of genetic isolation, which could lead to speciation or at least populations drifting apart genetically.

Large scale cloning of people might happen. On one level this could probably be bad due to a loss of genetic diversity.
On the other hand, this could result in a caste system like bees and ants have.
Mole rats (same link) approach this situation by being inbred (thus having a shared evolutionary interest in the offspring of others) and having strong pheromonal controls of breeding status. They also live in "harsh environments" according to the wiki article.
 
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  • #12
Ryan_m_b
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The assumption built-in there is that all countries are capable of and will achieve the same level of development and(or because) humans are genetically and socially homogenous and equal. Interbreeding increases homogenaity, but fertility rates themselves may work to separate it.
Speaking in terms of human biology there's no reason why different nations don't all have the capacity to industrialise and reach developed status. Obviously there are geographic and political reasons but that's beyond evolution.

Let's set aside the different countries and just look at one diverse country: the USA. The birth rate varies substantially with income in the USA. Barring other factors, this will push average incomes down over the long term because the populations of lower income people are growing faster than the populations of higher income people. With that, any traits that affect or are affected by income and birth age/rate will feel pressure in opposite directions.

See: https://www.economist.com/feast-and-famine/2012/08/02/demography-and-inequality
Assuming low social mobility and ignoring any other factors that could be brought into play then yes. If you have high social mobility then this would be less of a problem because even if you had lower income families having more children it would be likely that those children would grow up to no longer be lower income. Regardless this isn't really anything to do with evolutionary biology.

Edit: It strikes me that this social/societal evolution works on the scale of decades whereas biological evolution would generally take millennia. So my example above may be out of the scope of the thread.
Quite. I'm not quite sure why this thread was moved into GD, there's a lot of ways you can tackle the question academically and talk about real processes of selection and adaptation. Though I get that speculating about GATACA societies/transhumanism over evolutionary biology is more fun and accessible.
 
  • #13
Ygggdrasil
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Copying my response from a previous thread on the topic: https://www.physicsforums.com/threads/modern-evolution-in-humans.711394/#post-4511126

Biological evolution at its core deals with how the frequencies of different alleles (gene variants) in a population change over time. The rate at which new alleles to become fixed in a population (i.e. for these alleles to outcompete all other versions of the gene), depends on the size of the population. Even alleles that provide strong fitness advantages will be fixed at slow rates in very large populations. Therefore, the large size of the human population (and the ease of mixing, so that no subpopulations can get isolated from the larger population) will make any significant changes to the human genome occur at an extremely slow rate.

Under what conditions might we expect human evolution to occur more quickly (relatively speaking since evolution occurs on geological time scales)? One situation would be a relatively strong selection pressure that strongly favors reproduction of individuals harboring specific traits. For example, worldwide pandemics could contribute such selection pressures.

Human evolution could also occur through genetic drift if some event drastically reduced the effective size of the human population. For example, if the population of earth were to dramatically shrink (due for example to nuclear war, disease, asteroid strike), the allele frequencies of the population would change simply due to the bottleneck effect. Such a change would also make evolution through selection occur more readily as humanity repopulates.

Alternatively, a small effective population size could be achieved if a small group would become isolated from the larger population (i.e. the founder effect). A plausible example here might be a group that colonizes a different planet. Given enough time isolated from the population on Earth, such a group would eventually diverge enough from the earthbound humans to be recognized as a separate species.

Finally, I will note that technology could potentially affect human population genetics in the near term. While natural evolution occurs over long time scales, artificial selection can occur much more quickly. Technologies are already being developed that allow for preimplantation genetic screening of embryos, allowing parents to choose particular traits for their children. Technologies to enable the engineering of specific traits into embryos could also be available soon. The widespread adoption of such technologies could significantly change the composition of alleles in the human genome over a relatively short timescale (however, I will add the caveat that it would likely be difficult to significantly enhance many of the traits we care about like intelligence).
 
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