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Author Topic:   Humans are losing.
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 41 of 58 (309420)
05-05-2006 2:44 PM
Reply to: Message 36 by EZscience
05-05-2006 10:22 AM


Re: A VERY Interesting Conceptualization
This came to me in the course of this discussion with Crash where he seemed so concerned about the rate at which non-western, UD countries were gaining genetic representation in the human race, as he sees it ”at the expense of our alleles’. Numerically, I guess that’s true, but my gut reaction is, so what?
I'm not concerned about it, per se - I don't think the West has the monopoly on really excellent genes, although I do enjoy the capacity to consume dairy products as an adult - it's just important to recognize that it is happening, because the alternative smacks arrogant species-centrism. "Oh, humans are so great, we've conquered natural selection."
I realize that I'm putting forth an argument that typically is a prelude to racism - "oh, we have to save the West from being outbreeded by the darkies" - but I absolutely do not mean it in that context, of course.
So the next question becomes, which will be more important to our human destiny as a species - our genetic information or our cultural information ? I would argue the latter.
I think you're exactly right. Shared cultural knowledge fills a similar role as DNA - a way to pass on adaptations past the death of any one individual. It's why, in my view, the last step of the scientific method - sharing your results - is by far the most important.

This message is a reply to:
 Message 36 by EZscience, posted 05-05-2006 10:22 AM EZscience has replied

Replies to this message:
 Message 43 by EZscience, posted 05-05-2006 3:25 PM crashfrog has not replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 44 of 58 (309479)
05-05-2006 5:53 PM
Reply to: Message 42 by EZscience
05-05-2006 3:21 PM


Re: New story, in that case
I have pointed out that both reduced fecundity and delayed reproduction can and have evolved naturally in various lineages. Might you explain how this is possible if reduced reproduction alone is to be considered sufficient evidence of selection acting against a sub-group?
Because that isn't reduced reproduction. You're conflating two entirely seperate things - strategies such as smaller brood size or strategic delays in mating to increase offspring survival, and overall change in population size.
The strategies you mention wouldn't be successful if they didn't result in population growth for the offspring of those individuals. Halving your brood size, for instance, isn't evolutionarily advantageous unless your offspring have a substantially higher chance of survival to adulthood as a result. Reducing fecundity is only a successful strategy if it increases your population growth. In the case at hand, it demonstratably does not.

This message is a reply to:
 Message 42 by EZscience, posted 05-05-2006 3:21 PM EZscience has replied

Replies to this message:
 Message 45 by EZscience, posted 05-06-2006 2:28 PM crashfrog has replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 46 of 58 (309811)
05-06-2006 7:09 PM
Reply to: Message 45 by EZscience
05-06-2006 2:28 PM


Re: Evolution of reduced fecundity happens
Reduced fecundity is not reduced reproduction?
Fecundity is the total number of offspring produced in an organism's life.
How can you possibly evolve reduced fecundity without reduced reproduction?
If, by virtue of having less offspring, considerably more of them survive to adulthood and mating, then you've reduced your fecundity but increased your reproduction.
I mean, how else do you think that trait gets selected for?
1. evolution of reduced fecundity (fewer offspring in the lifetime).
2. evolution of delayed onset of reproduction (later birth of first offspring).
No, I get what we're talking about. There's no confusion here.
I refered to these life history traits because they are analogous to the current trends that you identified as reducing human fitness in western countries relative to UD countries.
Yes. From the fact that our populations are not growing, we know that these strategies do not increase fitness at this time. They don't result in increased reproduction, which they would, if they were fitness-positive strategies.
Right?
Now I am pointing out that many lineages, over evolutionary time, have actually evolved reduced fecundity and delayed onset of reproduction.
Right. Because, in many environments and situations, those strategies increase reproduction, and increase the population growth rate of populations with those traits compared to populations that don't have those traits.
It CANNOT, by definition, possibly increase population growth.
Nonsense. Of course it can. Here's a simple example:
You have a population of spiders. One subpopulation has an average brood size of 1 million live individuals, but less than 10% survive to adulthood. The other population has half the brood size, but because of the reduced competition, more than 50% of of those individuals survive to adulthood and mating.
The first subpopulation grows by 100,000 individuals in that generation. The second grows by 250,000 individuals. By reducing brood size, the second population grows faster than the first, and those traits come to dominate the population.
They end up *leaving* more offspring because they are *producing fewer*, but perhaps these fewer are larger, more competitive, etc. etc. (More good analogies to western humans here).
Right. No, I get it. You're right on, here, except you keep overlooking the fact that if this were what was happening, our population would be growing faster because, even though we had fewer children, more of them would survive to adulthood and mating.
But that's not what's happening. We have less children, but no more of them survive to adulthood than in the developing world. (In fact, here in America, our rates of infant mortality are about the same as in the developing world.) In the developing world, more individuals are born, and just as many of them survive to adulthood and mating. So their population grows faster than ours, and we can prove that reduced fecundity is not a fitness-positive trait in the environment in which we find it.
In human societies, group selection could easily favor populations with lower reproductive rates and selection could already be acting against those UD countries with high population growth rates.
No, again, I get that. Yes, those populations could be favored.
But the change in allele frequencies that we observe proves that they aren't being favored. That's the reality of the situation, right now.

This message is a reply to:
 Message 45 by EZscience, posted 05-06-2006 2:28 PM EZscience has replied

Replies to this message:
 Message 47 by EZscience, posted 05-07-2006 5:02 PM crashfrog has replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 48 of 58 (310073)
05-07-2006 6:33 PM
Reply to: Message 47 by EZscience
05-07-2006 5:02 PM


Re: Evolution of reduced fecundity happens
Crash, you can’t reduce your reproduction *without* reducing your fecundity.
Are we having confusion in terms, here? I guess so. You've been kind enough to define terms so I'll try to switch to those.
The way your using terms here doesn't make any sense. Could you make an effort to be clearer?
But what about your earlier claim that differences in relative rates of population growth are evidence of selection? You must admit this is a flawed inference so that we can move on to something more interesting.
If we're defining "fitness" as the number of your offspring that survive to adulthood and mating, then my inference becomes even more obvious. If one population has greater fitness than another, than the first population is being selected for and the second against, by definition.
But I actually think we're heading down the wrong path. "Fitness" as described in biology is a genetic trait, and it refers to the propensity of an individual's genes to duplicate themselves into the next generation of the population. Using it to refer strictly to reproduction might mislead us. And I think trying to construct some model of "group fitness" smacks of group selection, a concept largely dismissed by biologists.
They have higher average darwinian fitness, comparing *populations* - yes, so what? - are your kids going to compete with kids in Zimbabwe for resources and mates? Your individual fitness is determined locally, not globally (hence the resistance to immigration).
The difference between global and local is a mattter of degree. Technological advancements within the decade may very well mean that my children compete with those in Africa or Asia for any number of resources, including mates. Already today we hear of American workers having to compete with Indian and Asian workers, so the idea that conspecific competition for resources could be global doesn't seem farfetched to me.
It also doesn't mean that reduced fecundity isn't currently selectively advantageous within our population.
Within our population? That's a possibility. Just speculating, I'd say that larger families are correllated with lower incomes, and low income is correlated with a number of factors like genetic susceptibility to chemical addiction (detrimental genes) and incarceration (negative selective pressures.) I'd say you're probably not wrong.
Why is reproductive behavior in western developed countries changing away from the more primitive ”have all the kids you can’ approach?
People don't like kids all that much? I know I don't.

This message is a reply to:
 Message 47 by EZscience, posted 05-07-2006 5:02 PM EZscience has replied

Replies to this message:
 Message 49 by EZscience, posted 05-07-2006 8:48 PM crashfrog has replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 50 of 58 (310135)
05-07-2006 9:26 PM
Reply to: Message 49 by EZscience
05-07-2006 8:48 PM


Re: Units of selection
But I have already killed this argument, unless you wish to take issue with my definition of selection, which I see you haven’t.
I'm sorry, but you haven't killed anything. It's not even clear that you've actually addressed my argument.
It would be better for you to do that, in fact, than make proclamations about your supposed debate victory. It's still not clear to me why you refuse to approach this as an honest debate between interested individuals instead of an excercise where you try to slap me around with your dick.
The problem is that you are, to use your own terminology, ”conflating’ population fitness with individual fitness. To say that the “first population is being selected for" is to invoke group selection, by its very definition.
No, it's not. Group selection, to the extent that it happens, is the phenomenon where individuals experience selection not based on their own traits but on the traits of others that they're connected to; kind of a "I'm with him" effect.
You, on the other hand, are conflating individual selection on a group of individuals with selection of the group itself. It's not clear that group selection ever actuallly occurs. It's certainly not group selection that I'm proposing in this case - merely the action of individual selection operating, in parallel, on a group of individuals.
Group selection has not been discredited by any means.
I don't know any biologists, personally or by reputation, who take the concept seriously.
In addition, without the extension of kin selection to the level of group selection, you have no explanation for the evolution of altruism among unrelated individuals.
Oh, there's a very simple explanation - nonkin altruism is maladaptive.
No. It’s a matter of scale.
Is this how the debate is going to be? You're going to correct me for using the wrong synonym? Yes. Scale. Degree. That's the difference.
Not liking kids maybe simply one symptom of the trend, but why is it we should feel that way?
It's my guess that most people feel that way, and always have. People have kids not because they like kids (at least, not beforehand) but because they like sex.

This message is a reply to:
 Message 49 by EZscience, posted 05-07-2006 8:48 PM EZscience has replied

Replies to this message:
 Message 51 by EZscience, posted 05-08-2006 9:50 AM crashfrog has replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 52 of 58 (310329)
05-08-2006 2:39 PM
Reply to: Message 51 by EZscience
05-08-2006 9:50 AM


Re: Group Selection in Human Evolution
It’s not yet clear that you have one. Would you care to restate it?
If you missed it the first time, go back and re-read. My posts haven't disappeared. I've restated my argument every time that you've misrepresented it; I hardly feel the need to do it again.
I'm not really interested in discussing concepts of "group selection" in this thread. If that's something you want to have a substantive discussion on, open a new thread. And I recall that you conceeded my point several posts ago so I don't see much merit in continuing the discussion.
I keep trying to appeal to the depths of your insight, but your careless replies continue to do nothing more than reveal the limits of your education.
Ah. Since I don't value your speculations and conjecture over measureable reality, I'm the ignoramus:
Where is your justification for accusing me of dishonesty?
Where, indeed.

This message is a reply to:
 Message 51 by EZscience, posted 05-08-2006 9:50 AM EZscience has replied

Replies to this message:
 Message 53 by EZscience, posted 05-08-2006 2:51 PM crashfrog has not replied

  
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