I thought that massive changes among organisms are over long periods of time. This is caused by, to my knowledge:

  • Evolutionary pressure
  • Natural/artificial selection
  • Mutations
  • Genetic drift

Will mutations be the only factor in human change? Will humans change at all over a long time?


3 Answers 3


Issue in your introduction

I thought that massive changes among organisms are over long periods of time.

Actually, some evolutionary events can happen on a very short time scale. A single mutation can have a massive impact on the phenotype of an individual (see for example Doebley 2004). If this new phenotype has much higher fitness, then the mutation might spread over the whole population in a matter of weeks (typically if the population is not too large, without barriers to gene flow and more importantly if the generation time is short).

This is caused by, to my knowledge:

  • Evolutionary pressure

  • Natural/artificial selection

  • Non-detrimental mutations

The term evolutionary pressure typically encompass natural and artificial selection, mutations (regardless of their mutational effect, that is regardless of whether they are beneficial or detrimental) and other processes that you don't mention (such as genetic drift for example; you have now edited your post to include drift).

Answer to your questions

Will mutations be the only factor in human change?

By "human change", I will assume you mean "human evolution". The answer is: no, mutations are not the only process that leads to human evolution. All standard evolutionary processes are at play in humans as they are in other species. You might want to have a look at the posts Human Evolution in Modern Times and How is evolution possible in contemporary humans?.

Will humans change at all over a long time?

Yes, humans are currently (and will continue to do so in the future) evolving. Again, you might want to have a look at the linked posts.

Want to know more?

Your questions are quite introductory and show a number of misunderstanding you have about evolution. I would recommend having a quick look at Understanding Evolution by UC Berkeley which is a very introductory course to evolutionary biology that is fast and easy to follow.

  • $\begingroup$ Great references and thanks for the correction $\endgroup$
    – nelomad
    Nov 15, 2016 at 22:24
  • 1
    $\begingroup$ @Adamawesome4 My pleasure! I added a small comment on the very first sentence too. $\endgroup$
    – Remi.b
    Nov 15, 2016 at 22:58
  • $\begingroup$ I disagree that humans will continue to change over time - evolve, yes, of course! But as the population grows and travel increases, there is no Galapagos-style isolation; the human genome is "averaging out" and similar traits may eventually dominate the species. Additionally "survival of the fittest" has been heavily reduced due to modern medicine - how can traits be filtered out? $\endgroup$
    – Zxyrra
    Nov 29, 2016 at 23:01
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    $\begingroup$ @Zxyrra You can't say humans won't change over time but they will evolve as evolution is defined as being a change over time. Potential absence of complete reproductive barrier does not change anything to the fact that all standard evolutionary pressures exist. Medicine does reduce selection pressure for sure but selection pressures still exist. Plenty of examples exist, just have a look at the linked posts. You should have a look at an intro course to evolutionary biology and to the posts I link in my answer. $\endgroup$
    – Remi.b
    Nov 29, 2016 at 23:55

In sexed organisms, evolution is largely due to errors during chromosome duplication, cutting/copying/pasting/swapping/shortening/duplicating full genes sections. It is a way more efficient and fast way to evolve, since mixing sentences have more chances to make sense than mixing letters.

Many fast local evolutions can be seen: for instance, Sickle-cell_disease is favored a lot in some part of Africa because it happens to protect against malaria. At the scale of a few centuries, human height is growing, women pelvis is shrinking, etc. At the scale of a few millenniums, some human can digest milk while the others can't. The population at altitude got different adaptation to multiply the amount of red blood cells. etc.

  • $\begingroup$ You first paragraph is very misleading (or even wrong). You should come up with a citation to support that rate of evolution (are you referring to phenotypic evolution I would assume but that was left unclear in your answer) is mainly caused by recombination. In any way, linkage disequilibrium gets away pretty quickly and therefore this first paragraph makes little sense. For your second paragraph, you could just link to other posts (see my answer) which offer much more thorough explanations of the examples you mention. $\endgroup$
    – Remi.b
    Nov 29, 2016 at 23:50
  • $\begingroup$ This answer is flat-out wrong. Chromosome duplication usually causes severe health problems. Random mutation edits to human cells usually either breaks the cells, causes malfunctions, or produces oncogenes that either cause cancer or predispose the cell's lineage to become cancerous in the future. There's a ton of research out there and many lists of indels, point mutations, genetic fusions, translocations, and duplications (copy number mutations) associated with cancer. $\endgroup$ Mar 31, 2019 at 3:46

The genes associated with people who have more surviving and reproducing children will be more prevalent in the future. If you live in a multicultural society where different ethnic groups have different amounts of children you can get a perception of how the humans in your country will evolve over time. Also if you live in a country where there is a huge influx of people who are genetically different from the people who already live there, that will have a serious impact on the short-term change. But basically, if you want to get a hunch of where humans are evolving where you live, you can have a look at the people producing offspring and try to find out if they are different somehow in their genetic composition compared to the population at large. If stupid people are having more children, people will be dumber, if taller people are having more children, people will be taller etc.


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