Will the human species, Homo sapiens, continue to evolve in the next millions of years? If so, how? What can we learn from what we know about Homo sapiens development until now?
By professor , First version 29-May-2006, last revision 16-Aug-2017.
The human species (Homo sapiens sapiens) started its existence between 150 000 and 100 000 years ago. Its development diverged from the apes about 5 million years ago.
The earth has been capable of supporting life for about 3 billion years (billion = milliard = thousand million), and is expected to continue being able to support life for between 200 million and 5 billion years in the future.
Using the higher estimates, if we view the period of being able to support life as 24 hours, then we are now about 9 o'clock in the morning, humans diverged from the apes about a minute ago and the human species started to exist 1-2 seconds ago.
The average life span of a species on earth is a few million years. Every year, thousands of species cease to exist and thousands of new species are created. Will thus the human species cease to exist in a few million years, like most other animals? If so, why, and what will replace it? Or are humans so unique and different from other species, that experience from other species cannot be applied, and humans may continue to exist for a much longer time?
Note: This paper discusses many ethically and politically sensitive issues, and some readers will probably be offended by this. But the goal is not to give any views on what is right and wrong, what should be permitted or forbidden. The goal is only to discuss what will probably happen in the future of human evolution.
Humans differ so much from other species, that human future development may not be governed by the same principles as other animals. [Miller 2004] says that humans and human society should be seen as a fourth system of structured energy, Tetrology, different from the previous atomic, chemical and biological systems.
Miller says that humans differ in the use of advanced technology, use of controlled energy, use of clothes, use of sense-enhancements like glasses, telescopes or microscopes, advanced social organization, advanced language.
Also many religious organizations and other belief systems regard humans, or sometimes a subset of humans, as the chosen people, made by God to mimic himself.
On the other hand, it is apparent that many typical animal behaviors also occur in humans, as has been pointed out by [Morris 1967-1997] and [Diamond 1993]. Humans have a mating behavior and an aggressive behavior which is obviously inherited from our animal ancestors.
This is important when discussing the future of the human species, because humans may be so different that experience from animals cannot tell us anything about the future of Homo sapiens.
To discuss this issue, one must first discuss which processes causes a species to cease to exist. Some such processes are:
A new species, to replace Homo sapiens, might be created in different ways:
Modern Homo sapiens originated between 150 000 and 100 000 years ago. But until 50 000 years ago, it existed only in Africa. Then, in just a few thousand years, the art suddenly expanded into the whole of Europe and Asia, and eradicated all the rests of previous humanoids like Homo Neanderthalus and Homo Erectus [Klein 2004]. Many anthropologist believe that this must have been caused by a genetic mutation, for example a mutation which increased the language capabilities. Other's claim that the human brain has not changed for 150 000 years [Mayr 2001, p. 252]. But they base this claim on fossils, and fossils may not show changes in the organisation within the brain.
Humans in the Northern part of Europe evolved a lighter skin color, probably about 7000 years ago. Regions of Nepal, high in the Himalaya mountains, at 4500 meters above sea level, have an athomsphere with only 60 % of the oxygen at sea level. Normal humans have difficulty getting enough oxygen when they breathe at this height. But the Sherpa people living at this height, have evolved an ability to use the oxygen in the air more effectively, by having a tighter amount of veins than other humans. This shows how evolution has occurred within the human species, in this case to adapt to living at higher heights with less oxygen in the atmosphere.
After first occuring, Homo sapiens continued to live as a hunter-gatherer until about 10 000 years ago, when agriculture suddenly began and rapidly changed the prosperity of Homo sapiens. Why did this suddenly happen 10 000 years ago? Many anthropologists believe that again, the cause was a mutation, perhaps in the area of linguistic skills.
Genetic research shows that certain genes related to the brain size did change between 5 800 and 37 000 years ago. Exactly this gene cannot explain changes in humans, since not all intelligent humans have this particular gene. But the fact that genes related to brain size have changed in this time span indicates that humans are still evolving [Warner 2005].
One of the researchers behild this result is qouted as saying "Our studies indicate that the trend that is the defining characteristic of human evolution -- the growth of brain size and complexity -- is likely still going on If our species survives for another million years or so, I would imagine that the brain by then would show significant structural differences from the human brain of today."
Thus, it seems as if Homo sapiens has evolved, and as if the major evolutionary events occurred quite suddenly. If this continues, we might expect that a sudden good mutation perhaps 10 000 years into the future can again change Homo sapiens by natural selection. Of course we do not know exactly when this mutation will evolve.
Homo sapiens can evolve through natural selection or through breeding or genetic manipulation. Breeding and genetic manipulation is most probable for a few people in technically evolved countries.
Natural selection is most effective when many animals die before reproduction. Thus, natural selection is more effective in developing countries. In industrial countries, medical development allows most of those who would die to live and reproduce.
The size of the brain of humanoids has increased three times in the last two million years [Hofman 2002]. This increase has meant more connections, less nerve cells. This means that with the current design, the brain cannot become more than three times larger than it is today. Other studies [Pearson 1997] indicate similar results.
A Swedish study of 50000 Swedish Citizens looked at the number of children a person had and the income of this person [Weilenmann 2003]. It found that those who had more children also on average had higher income. So human evolution in Sweden might cause properties of people which gave them higher income, would increase. Among them is capabillties like intelligence, so this study indicates that human evolution might cause intelligence to increase. Note: The study only included people born in Sweden, not immigrants. But those who have the geist to immigrate are probably more intelligent and capable, this might cause people in an evolved country like Sweden to have higher capabilities, and the capabilities of those who do not immigrate might deteriorate with time.
It has been argued that the size of the brain is limited by the birth process. Children born with higher brain size might not have room to come out during vaginal birth. Children with a mutation giving higher brain size may be damaged, or might damage the body of their mother, during vaginal birth. This might have been true in earlier times, but in evolved countries, higher medicine competence might allow children with higher brain size to evolve, including the option of ceaaseran birth. Also, changed shape of the head might allow a greater brain, and brain size might grow after birth, and it would then not be limited by the birth canal size.
Note also that a species need not evolve. Some species remain identical for hundreds of thousands or millions of years [Meyr 2001, p. 193, 195]. And the evolution of humans has had long periods of little change, such as the Homo Erectus which did not change very much for 1.5 million years.
Some people say that the lack of effective natural selection for humans in industrial countries will cause the human species to deteriorate, since natural selection is necessary to keep a species healthy. As a simple example, the existence of spectacles would cause more people to be born near sighted.
However, this is counteracted by immigration of people from less developed countries. This immigration is today so large, that it might counter the risk of deterioration of the species as a whole.
Also, future use of genetic manipulation and intentional breeding can be expected to counteract degradation.
Genetic manipulation and artificial breeding is today disliked, because it was used in earlier years by governments in questionable ways. Most known is the Nazi ideas of killing or sterilizing "inferior people" like Jews and people with mental illnesses. Also in non-Nazi countries, enforced sterilization was common earlier, but is not done so much today.
The reason for this is that such government control is today not regarded as ethical, and also that the efficiency of such schemes is debatable. All schemes which reduce the genetic variation within the human species can cause more harm than value.
In spite of this, it is my belief that genetic manipulation and artificial breeding will be important in the future, but not done by the governments but by parents. Already, today, more and more pregnant women voluntarily screen for disabilities and genetic diseases of the faetus and choose abortion rather than giving birth to a child with a genetic illness [Tännsjö 1999].
This will probably become much more common in the future, with better medical and technical options of influencing the genes of future children [Pearson 1997]. There will certainly be a lot of discussions about the ethics of this, but my belief is that positive genetic manipulations will eventually become accepted ethically. And this might create a race of superhumans, which might even become a new species threatening its creator.
One can note that a Darwinian type of evolution today does not exist only for Homo sapiens itself, but for various cultural organisations of humans. In particular, the economic competition on the world market has many Darwinian features, with survival of the fittest as one central function.
If you do not agree, or have more ideas on the future of Homo sapiens, you are welcome to comment on this paper. Your comments may influence future versions of it. A forum for discussion is available.
The original of this paper can be found at http://ducnguyen.info/en/aux/homo-sapiens-future.html.
There is not very much written about the future of Homo sapiens. There are a large number of books about evolution and human evolution and about how humans were formed by evolution, and this is important for understanding what will happen in the future. Here are presentations of some such books:
By Jared Diamond.
HarperCollins publishers 1992.
By Jared Diamond.
HarperCollins publishers 1997.
A collection of essays, many of them give essential insight into how and why humans are as they are.
By Michael A. Hofman
Discusses the growth of the humanoid brain size and its limitations.
By Tobias Svanelid and Richard Klein
An interview with Richard Klein, professor of anthropology.
11:16 minutes, mostly in Swedish, MP3 format
By Richard E. Leakey and Roger Lewin.
E. P. Dutton publishers 1977.
A detailed and interesting overview of all the stages of evolution of Homo sapiens since the separation from the monkeys 5-7 million years ago.
By Ernst Mayr, Basic Books, 2001.
Lots of information about how Darwinian evolution works.
By Joel Miller.
BenTarZ Productions, 2003.
A collection of essays, many of them give interesting ideas on human development and human languages development. Are humans distinguished from the monkeys by the use of tools? But monkeys also sometimes use tools. Are human distinguished by building houses? But beavers and birds also build nests.
Miller claims that modern human society is a distinct new stage which he calls "civil society". I wonder if historians five hundred years from now will agree with this?
On the future, the author says that implanting of electronics inside the human body will be an important feature of how people live in the future. I agree with him, this is quite probable an area where major changes in our lifestyle will come in the future.
by Peter J. Bryant
An overview of how life started and developed on earth. Life started 3 billion years ago, multi-cellular organisms 2 milliard years ago, complex organisms 600 million years ago, mammals outcompeted the dinosaurs 65 million years ago.
By Joel Miller
A presentation of the view that the human system of organizing knowledge is so different from the previous atomic, chemical and biological systems, that is should be seen as a forth, Tetrastic system.
By Ian Pearson
Darwinian Evolution will have limited impact on the future of Homo sapiens, since other kinds of evolution, such as breeding, genetic engineering and electronics will take over as dominant factors.
By Ian Pearson
Darwinian Evolution in competition between companies.
By Torbjörn Tännsjö (London and New York: Routledge, 1999)
by Leni Weilenmann, Dagens Nyheter, 22 May 2003. Also published same result from another study in Dagens Nyheter, 24 March 2014.
By Jennifer Warner, The Human Genome Project, citing: Evans, P. Mekel-Bobrov, N. Science, Sept. 9, 2005; vol 309: pp 1717-1720; 1720-1722. News release, Howard Hughes Medical Institute. News release, University of Chicago Medical Center, Science Daily.
By Desmond Morris
ISBN: 0-385-33430-3, 1-56836-163-7, 0-09-1878675, 0-563-38358-5.
These books which give many interesting insights into how human behavior is governed by our animal past.
by Yuval Noah Harari
About humankind evolution during the last 70 000 years.
By Tobias Svanelid and Richard Klein
An interview with Richard Klein, professor of anthropology (in Swedish, MP3 format).