Evolution through natural selection works by allowing the better adapted/more successful examples of the species to live longer and produce more offspring, thus the traits that lead to success are passed on in greater volume, etc, etc.
It is no longer the case that successful, long-lived, and healthy humans produce more surviving offspring than less successful, short-lived, and less healthy humans. It also appears to be the case that human success in today’s world relies much more on non-biological issues (culture, education, access to technology, government, wealth, etc.). So the obvious question is: have we humans reached an (biological) evolutionary plateau?
I suppose that a major ecological catastrophe may occur in the future and that only a particularly adapted set of humans will survive. Or maybe at some point we will begin to integrate technology with our biological existence and so we will eventually have to develop a cybernetic evolutionary theory for humans. Our forays into genetic manipulation will start to change our biological evolution as well, I suppose. What do other people (who are more informed and educated on these issues) think about all of this. I’m very interested to find out.
p.s. Please don’t let this get hijacked by a debate on racism or creationism – this is not a sadly veiled attempt to open a discussion on one of those issues. Also, mods, if this is a mpsims then please move it.
Probably. But this is fairly common. Whenever a species becomes well adapted to a large geographical area and has a large, interbreeding population, it’s probably going to enter a “plateau” period. Large evolutionary changes are more common to smaller, isolated populations. But keep in mind that we are still a very, very young species-- probably only about 200k years old.
Much of humanity doesn’t live in the environment you describe. I suspect that many of who do live there wouldn’t fare well if set down in the environment of, say, Bangladesh and had to get along on the resources the greater proportion of its population has.
At some point in the future the easily available sources of stored energy from the past, such as coal and oil, will become scarce indeed and then those who are living will be forced principally to get along on the immediate energy input from the sun. They will find out whether or not human evolution has reached a plateau.
BTW, CS, if you become a paying member, you’ll be able to search this MB and read the many, many threads that have been openned to discuss this exact subject. Some of those threads were quite recent.
Personally, I do see a speciation event occuring, if we ever engage in sublight, ‘colony ship’ space travel. It’d create strongly seperated breeding populations.
There are huge problems with the idea that evolution has somehow ceased for humanity.
First off as David Simmons says most of humanity is still prey to the vagaries of disease, starvation and homicide just as they have been for the past 100, 000 years. For them evolution continues exactly as it always has. Of course those populations aren’t isolated from our own gene pool, so for tha reason alone we can say conclusively t the answer is negative.
Even if we restrict the discussion to the westernised gene pool the answer must still be negative. Evolution occurs whenever there is a non-random survival of genes in large populations. IOW whenever the gene frequencies change there is evolution. It’s almost impossible to tell whether gene reproduction is random or not in any population, so the standard surrogate is to look at rates of survival. If some individuals are producing more offspring then it’s a very safe bet that evolution is continuing, and the greater the reproductive differential between individuals the more rapid the rate of evolutionary change. In westernised societies ATM the differential reproductive rate is higher than it ever as been in human history, and it is probably higher than for any other medium mammal species ever. The most fecund western individuals are currently producing 10 or more surviving children. The least fecund are producing no children at all, often by choice. That is a huge reproductive differential. Even in the most extreme periods of human history it was a rarity for any individual to have no surviving children, and even rarer for any individual to have 10 children reach adulthood. Since the rate of reproductive differential is currently so high we have to conclude that evolution is occurring at least as fast as it ever has.
The thing you have to realise CS is that evolution doesn’t have some ultimate goal in mind. Successful can only ever be defined by the number of copies of your genes produced. It is completely invalid to say that “It is no longer the case that successful, long-lived, and healthy humans produce more surviving offspring than less successful, short-lived, and less healthy humans”. The succesful humans are still the ones having more surviving offspring, just as has been the case since we crawled out of the primordial soup. That is inherent in the very definition of success. That success is no longer dependant on longevity or physical strength or keen eyesight is totally irrelevant to the subject if the debate. Evolution isn’t aiming to produce some super-strong Methuselah with 20/20 vision. Evolution isn’t aiming at anything, it’s just shit that happens.
Whether success depends more on non-biological factors today than in the past is very much open to debate also. Culture is very strongly tied to genetic factors obviously, and so therfore as long as ciulture is a determinant of genetic success there will be evolution.
The other factors such as access to technology, government and wealth are also to a greater or lesser extent correltated to genetics. But perhaps more importantly we need to realise that people have always only really competed with their neghbours. Humans in the Namib had far fewer resources than humans in Fiji even 10, 000 years ago, and consequnetly their reproductivity was tied closely to their geogrpahic location. But that shouldn’t lead you to conclude that evoution had cesased in either group because Tongans were never in competition with Namibians. In the same way people living in a geographic location with a stable democracy or with a ruthless despotic dictatorship will certainly find their reproductivity tied closely to their geogrpahic location, but just as with climate or any other geographic variable that can’t be used to conclude that evolution has slowed. That’s because a mechanic in New Zealand isn’t competing with a mechanic Zimbabwe in any menaingful way so the relative rates of reproduction aren’t all that relevant.
They will only be forced ‘to principally to get along on the immediate energy input from the sun’ if they are so stupid that they refuse to use the several thousand years supply of nuclear fission fuels on the planet. After that time frame all bets are off as to what energy sources will be avialble. Stating that at some point in the future people wil be forced to live on solar energy in GD is completely inappropriate and inaccurate.
I think you are probably right. Certainly my statement was overstated at least. However, it seems to me that the use of nuclear fuel to supply most of our energy leads to rather enormous problems about nuclear waste. The difficulty is that the nuclear stuff is concentrated. There is no more worldwide total radiation than there was before the use of nuclear energy but that radiation is now concentrated in selected sites and when the fuel is exhaused as a source of energy for a reactor it is still radioactive and must be managed somehow.
That might not require physiological evolution but I think it will certainly call for quite rapid social and legal evolution.