[jdmichal]

> Things that allow you to keep reproducing longer will be less strongly selected for.

No. This is the fallacy.

> I guarantee that if there were a gene that let men and woman keep popping out babies for a century, it would be very likely to be preserved.

It would be preserved, yes. The fallacy is that it will not be perserved in preference of lack of the gene, because there is nothing selecting against not having that gene. In other words, both lines will continue to live on, because there is nothing selecting against either of them.

As long as individuals can reproduce, then their traits are not being selected against. If there are multiple variations of the traits, those will become part of the population's natural variation. Which is a good thing to have in terms of the population, because natural variation helps prevent genetic bottlenecks.

[knodi123]

> No. This is the fallacy.

I simply don't believe you.

As the one making the preposterously counterintuitive claim, it's up to you to support this with facts, beyond just saying "nope, you're wrong, it's a fallacy."

[knodi123]

To elaborate, if Sensible Sally's female descendants all produce one child, and Fertile Myrtle's descendants all produce 10 children each, then Myrtle's genes will multiply faster, and be less vulnerable to being wiped out by the odd plague or war.

[jdmichal]

You are repeating exactly what I said in the second and third paragraphs. I do not understand what you expect me to respond with. Your very own hypothetical scenario demonstrates that both lines will live on as long as the traits are not selected against.

[knodi123]

The fact that death is random and sometimes widespread is selection pressure. Did you read to the end of my comment, where I said "less vulnerable to being wiped out by the odd plague or war"? Ever heard the phrase "don't put all your eggs in one basket"?

Put 9 Smiths and a Johnson on a boat. Now kill half of them. What are the odds that Johnsons are extinct? Now repeat the experiment until my point sinks in.

[jdmichal]

You are talking about introducing a genetic bottleneck, which I already addressed. Having diversity is good because it helps prevent such bottlenecks from entirely eliminating a population.

Also, you are no longer discussing the fallacy. The fallacy is believing that something that allows an individual to survive better than another individual will be selected for, when in fact individuals can only selected against by preventing reproduction, thereby restricting the expression of those traits in the future population. The mere existence of a Johnson in the first place indicates that Johnsons were not previously selected against. An event killing the Johnson would then be the selection against.

The end result looks like Smiths were selected for, but the actuality is that not-Smiths were selected against.

[knodi123]

Okay, now imagine that Johnsons have a weird flap on their genitalia, and 9 times out of 10 it gets in the way during sex, and prevents conception.

Would THAT weird flap trait be selected against? After all, it "prevents reproduction, thereby restricting the expression of those traits in the future population."

And how is that scenario in any way different than the Smiths which merely reproduce 10 times as often, by virtue of the aforementioned century of fertility?