I have already have a very strong idea about how it works
Yes, you obviously do. And that, just as obviously, is the problem. This is far from the first time you have authoritatively argued your opinions on a matter about which you actually know rather little; your clear ignorance of such basic factors as dominant/recessive traits, predator/prey ratios, and resource consumption is ample confirmation of this. Cathar has already shown himself to have a much firmer grasp on biology and evolution than you, and so for as long as he is willing to humor you, I will save my own time and simply assume that he's right.
That audiobook goes on for 7 hours!
Part 1 of that audiobook is over 7 hours. Listen to it anyway. It might not have the strongest relevance to what we're discussing (I, personally, feel that DF evolution would best be handled at the
macroscopic scale, if indeed it should be modeled at all), but you will at least have learned something, which is never bad.
This was all about how it was a problem with only a few of dwarves reproducing but having lots of babies originally.
It started as that, yeah, before someone changed the channel. DuckTales
was a pretty good show, but I never watched it for its keen attention to scientific detail.
I think it's best to define all sex-related behaviors in terms of four distinct desires: Reproduction, Sex, Marriage/Monogamy, and Love. . . . Friendship is its own separate desire, arguably distinct from the others . . .
Those ideas seem rather complicated.
Only marginally. I feel that in
most individuals, the Reproduction/Sex/Love triad of desires will all be roughly the same (and thus represent an overall "sex drive" in general), but I think there's value in keeping them distinct because it allows for modeling different behaviors. For example, suppose a dwarf has high Love_Propensity, but relatively low Lust_Propensity and urge for Reproduction. She falls in love and gets married, willingly engages in sex as an expression of her love, and pops out a couple of kids. Her urge to Reproduce is now satisfied, she now has three people to fulfill her desire to love, and her wish to express her love physically can now take the form of parenting, rather than sex. So she's happy. But say her husband, meanwhile, has the opposite arrangement, and married primarily out of lust and the desire for children. His wife and kids satisfy his wish for love, but if his stronger desires aren't also met, he might just check his Exclusivity trait and try his hand at philandering. Depending on the wife's Exclusivity trait, she might just have some strong opinions about that. And depending on how their civilization feels about monogamy, a non-nuclear family relationship might develop--perhaps progressing towards polygamy, perhaps towards divorce.
Yeah, DF can model traditional families, again and again and again and again. Or, it can model traditional families with customizable
tendencies for telling more interesting stories.
Besides, as I said earlier, breaking the system up into separate traits allows the races, and the various civs of each race, to behave in different ways.
The idea of having the desire to have children increase as the population is reduced makes sense, but it will only really result in a larger number of beings having fewer children each rather than the reverse. Those who still happen to want to have children will just end up having an awful lot of children and breeding for everyone else.
If it truly does result in more breeding couples but fewer average children per couple as the
only change, then I will still count that as a significant improvement. You have a point about the "NEED!" to reproduce also affecting dwarves that were
already reproducing, but as all traits have a maximum, and breeding dwarves presumably started closer to the cap than non-breeders, I'm confident that it will still result in a net
decrease in disparity.