I agree that we ought to be specific when speaking of human evolution, since it is not, as you aptly noted, a homogeneous process.

The sheer size of the human population, coupled with the widespread intermingling of all peoples (with wome notable exceptions such as the Yanomano in the Amazon and isolated groups in New Guinea) and the reach and effectiveness of technology -- particularly medical technology -- act to retard physical evolution of our species. I agree with Sean's notion that we would have to experience a severe selection event such as a pandemic or major climate change or perhaps an asteriod impact for the current genome to undergo major change. Your use of the thrill of speed selecting against that trait because the love of speed kills many young people could be countered by observing that there are many ways to enjoy speed and that most young people who enjoy it do not die but live to pass on their genes. What may be selected for is any disposition to enjoy speed without the consumption of alcoholic beverages and other reckless behaviour.

Now here in the US, there is apparently evidence that not all evolution results in more complex or sophisticated phenotypes: We have a semi-literate child of privilege in the White House, and Californians may elect The Terminator as their governor. And this has come about without the benefit of incest.

rielmajr

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We have a semi-literate child of privilege in the White House, and Californians may elect The Terminator as their governor. And this has come about without the benefit of incest

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Wonderful! This had my wife and I falling about laughing

I have to disagree with you about selection though. I think selection is everywhere, but I do think that there is probably little or no selective pressure for morphological change - behavioural change is quite another matter.
In the case of morphological change I think any selective effect is probably as a result of sexual selection and is probably of the stabilising variety.

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most young people who enjoy it do not die but live to pass on their genes.

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Those young people who don't enjoy it live to pass on their genes too!

As I understand it, the tiniest selective effect will tend to perpetuate itself given enough time. Remember that any gene frequency change due to persistent selection will be accumulate over geneological time.

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the consumption of alcoholic beverages

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Where excessive drinking is influenced by a predisposition for addictive behaviour I agree that there might well be a selective effect, especially given the prevalence of illegal drugs in the West.

Where recklessness is concerned I think that there is a clear counterbalancing effect, in that people pedisposed to recklessness might be much less likely to take care with contraception (who neeeds condoms - lets take a risk). So I think this one is definitely in the wilderness of mirrors.

Edited by: PeterDF at: 8/25/03 1:40 pm

Jeremy

Great! I'd love you to read the draft. I'm just finishing the reworking of one chapter and I'll send it to you.

Peter

It appears there is an opposite selection process. Once again, birth control and intelligence, family planning will have interesting undesireable effects.

Selective pressure will favore drug and alcohol and other less than responsible type behavior because they result in not only unintended pregnancy, but also earlier (shorter generations) births as well.

In the past, the irresponsible parents had children with lower survival rates. Now that we have a society that at least minimally ensures the survival of every child, that selective pressure is now gone. Also, the more responsible and intelligent people now have birth control to reduce their percentage of the genetic mix. I call this extreme selective pressure which has a shorter time span for change than other factors that may take a much longer time.

I am not advocating the end to birth control. On the contrary! Our population is at a crisis level and any humane way to slow that growth must be used. I am just posting a warning to what may happen in the next 200 to 500 years if we succeed in 100% available voluntary birth control over a 200 to 500 year timeframe. And that to reverse this effect we may have to consider society adapting a licensing program for chidren with upper limits for all, and strict age, minimal income standards, and education standards before licence for reproduction is granted, along with genetic screening for known genetic diseases.

Also, and probably more importantly, cultural evolution along this matter is probably more significant. Those culture that advocate higher population growth through religion or what ever means will displace the rest of the cultures. But these cultures are very hostile to generic education and the mixing of cultures, as this tends to dilute the pronatalist stand.

Of course, this is a moot subject; humanity is facing a severe bottleneck this century, and it is highly unpredictable what the mix of humans and culture will be on the other side (the survivors) of the energy crunch and eco-disasters.

Monty Vonn

All of this, while making many interesting points, involves trying to make specific predictions about certain aspects of a hugely complex system with millions of variables and unknowns involved. Oh, and Peter, I'm near Cockermouth.

Sean

Surprisingly I've never been to that part of Cumbria. I'll be in Carlisle in October though, one of my daughter's is graduating as a nurse.

You are doing well - your posts have been useful and insightful - keep it up!

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trying to make specific predictions about certain aspects of a hugely complex system with millions of variables and unknowns involved.

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This is what I meant about the wilderness of mirrors.

I still think I'm right about the effect of car accidents though. Even if the the shift in gene frequencies was only 0.5% in each generation this would still give a shift of around 20% - 25% per millennium.

Edited by: PeterDF at: 8/26/03 10:51 am