Or at least not by natural selection. A few weeks ago Alan Baxter told me about an article (EDIT: found it here) that speculated that humans would evolve to cope with a high-nutrition western diet and not develop the associated diseases. I’m all for speculation but I think this is way off. There are some pieces in mainstream media about the future of human evolution, but a lot of them seem to promote common misunderstandings of natural selection.
Natural selection is a very punishing force. It works best (operating quickly and creating the most efficient adaptations) when:
- Pressure from the environment is high (ie. most organisms die before they reproduce; from starvation, disease or being torn to shreds). If there’s enough food and safety to go around, organisms with adaptive mutations have no advantage since everyone will reproduce.
- Organisms are very actively working to have as many descendants as possible. For evolution by natural selection, an adaptation must usually cause (or at least be linked to) those who have it creating more descendants. Without this, an adaptation will not spread through the population over time.
I think these 2 things are virtually absent in the human world today. Even our biggest killers like cancer and heart disease usually strike after the age most people have children. Hence some mythical cancer immunity is of great benefit to a person but it will not cause them to have more children. And of course these days reproduction is not the only game in town. Culture, social/economic circumstances and personal decisions shape how people reproduce, not genes. So even if an adaptation gives some people the chance to have more children, if they choose not to for other reasons then the population can’t evolve.
Here are links, some agreeing, some disagreeing. I’ve thought of potential objections:
- Aah, but what about the third world? — The truth is the concept of the third world is largely meaningless nowadays. See this great site for more details (complete with animations!). The gap is closing fast, and we have every reason to believe that in 100 years there will be the same lack of environmental pressure throughout the world. If however the situation in many countries worsens significantly and stays much worse than today for say 30,000 years, there is the possibility of evolution.
- What about pandemics and outbreaks? — True, a pandemic might select for traits like immunity. It is thought the Black Death selected for many immunities in Europeans (that those in the Americas didn’t have, hence massive deaths when the Europeans came). However even then, it’s a one-off case, resulting in one evolutionary step. We need many thousands to evolve truly significant changes.
- What about religious fundamentalism? They tend to have more children, their genes will spread. — An interesting idea. The most probable way homo sapiens can diverge is if there are social groups that don’t interbreed. However such divisions must again last for tens of thousands of years — it would be a very pessimistic view of society where we have a class system for so long (plus it must be MUCH more stratified than in the least egalitarian places today).
- What about evolution by a method other than natural selection? — This is true, we can still evolve by genetic drift, sexual selection, and even selection by memes. Again, these need to persist for a VERY long time though, current experience is that they don’t. But these are our best “hope” for biological evolution.
Of course I say hope with sarcasm. Note the objections above — the only situations where evolution by natural selection can occur are truly horrible scenarios. I think this is the strongest evidence that it’s a very good thing that natural selection is a thing of the past. Many frauds and liars claim there’s a link between accepting evolution and great horrors, since people will seek to “emulate” natural selection. If anything it’s the opposite — those who know how horrible natural selection truly is will active in making the human world conquer this immense cruelty. And if we haven’t succeeded already, we’re pretty close.
EDIT: There may be a point that will murder my argument here, if you can think of it let me know and I’ll post it!
9 comments ↓
Interesting. I’d never really thought about evolution being such a bad thing before!
You know, I still can’t find that article. And I’m sure I didn’t dream it.
Then my job here is done **cracks open beer**
Actually it’s only natural selection that has all these features, so doesn’t really work for any other causes.
I guess the nature-is-good ideology is everywhere, hard to resist.
We do have natural selection – the most successful reproductive strategies appear to be either fat, stupid and white, or poor and black. Or Chinese.
To a certain extent these subsets of the species have certain genes in a greater concentration than the rest of the population and so we can expect to see those genes, in the shape of the offspring, crowding out the rest of the genes.
Look at the incursion of grey squirrels in the UK and what happened to the red squirrels for an example. Although there seems to be some mutant black squirrels appearing on the scene now.
so the chinese who are allowed 1 child per family (2 in rural areas) are reproducing successfully??
There’s a billion of them, they certainly aren’t reproducing UNsuccessfully
And Indians aren’t doing too bad either.
It is only rich, well educated people (of any race) that tend to concentrate more on their work and leave children until later in life that are not being successful. And gay people.
a casual reader of this thread is likely to see some racism in your comments — what exactly did you mean?
are you suggesting that say the chinese have some specific genetic predisposition for having more babies? because that’s what’s needed for the situation as you described it (granting your assumptions) to be a case of natural selection. anything else is more likely a matter of culture influencing how many children someone has — which is not natural selection and is much more variable over the course of even a single century.
Wow, mention anything about a country or race and people will jump straight to racism. Not you michael, but I can see how you want to defend your blog from accusations that you allow such comments.
To clarify: birth rates drop as societies become more advanced. This is shown both across countries now and also over time within any of the western democracies.
One driver for this is improved healthcare, as infant mortality rates drop people need to have less children to ensure an heir. A side effect of the west exporting basic western healthcare is that societies that traditionally had lots of kids due to high infant mortality are still having lots of kids (takes generations for that to slow down) most of which are surviving, hence China’s 1 child policy.
Another driver for population growth are a lack of careers for women, societies where women are mothers and home-makers will tend to have more children than one where women go out to work. Third world and Muslim countries tend to have non-working women (not that looking after a house and children isn’t incredibly hard work, but they do not reduce the number of children women have.) Likewise with poor, uneducated women in the west, they tend to have many more children than educated professional women.
So natural selection doesn’t play a part in this, but this is unnatural selection. So looking even at just a western country (the others will fall into line with this when their economy gets more advanced…) the most effective reproductive strategy is for poor, under-educated people. While much of this is not genetic, a little part may be and it is that part that will thrive as anyone who escapes poverty will resort to the slower breeding strategy of the more wealthy, leaving the faster reproductive members in poverty and that gene pool more concentrated with the active genes.
What you have to remember about this is we are democracies. If the majority of the population are under-educated and poor they may not have much of an economic say but they have a massive political voice.
(As for the Chinese, no they don’t have a genetic predisposition for having more children, but most of them are rural and there isn’t much else to do in the evening… much like an non-industrialised country – China is industrialised, but still has a sizable rural population.)
The reason I thought people might associate your comments with racism is because they looked like a perpetuation of stereotypes (”those chinks sure like to breed like rabbits”?) — even if you meant something more behind them.
I agree with almost everything you said in terms of women’s rights, healthcare and education being crucial in dropping birth rates. The only thing I have to add is that in many countries like China the population has soared because of an increase in life expectancy and quality of life.
But the way you phrased it made it sound a bit like “help, the poor are coming with their superior breeding skills”.
We need to work as hard as we can to lift the standards of living across the world (including our own developed countries) to the point where people don’t feel the need to have so many children — but without imparting some sort of value judgement on how many children various people are having. From your comments I think you’d agree.
“help, the poor are coming with their superior breeding skills”
There is a film called Idiocracy. It isn’t very good but it does run with the idea that, in America, the dumb white trash outbreed the educated and in the future there will be only white trash. (Was originally titled The United States of Dumb.) I personally think it more likely that, unchecked, it would lead to a two tier society much like the film Metropolis.
Leave a Comment