Isn't the subtle difference only hanging on the 'survival' word? The best suited genes for the situation get expressed. The fact that other genes are lurking around waiting for their opportunity, doesn't deny the point of the dialog.
Well, that too, but the most important thing is the cost to carry a particular adaptation/mutation. If it's low enough, then it won't get thrown out by the pressure of natural selection. If it's beneficial, then it'll get selected for (so it'll spread in the population). That's one way how seemingly uninteresting adaptations have spread, they got lucky and coincided with a useful mutation.
So evolution is an optimization process. On a constantly changing landscape.
Also that the fitness function applies to the system as a whole. So a trait that's just amazing at something, but carries a large cost, may not be able to survive. I guess that's kinda what you said, just phrased differently.
And this is getting away from the central point, but there's also much debate (at least at the level I'm reading; maybe it's solved by now for those in the field) about how traits can support a community at the expense of the individual - like with old humans losing the ability to procreate.
Ok I've always wondered if maybe our old-age feebleness was adaptive! It means the old folks sit around the fire with the young folks, and teach. Once social groups began, that could really boost a community at the cost of a declining agility in old age.
Feebleness in old age is simply run down machinery, otherwise there would be no old age, we'd feel the same all our lives long until we died of some kind of accident or ritual murder of those that outlived their welcome.
True. Yet other mammals have different clocks; other creatures seem to have no clock at all. So our clock is set by genetics. Why at this rate? That's the idea I was getting at.
No. When you say "the best suited" or "the strongest", that implies that the most optimal state has been reached by evolution, and that isn't the case at all.
The only thing evolution does is favor one adaptation over another. At that point in time, a particular mutation/adaptation may work out better (though frequently due to pure chance), so it survives and gains inertia. Inertia is a very powerful thing; it's why we have a lot of big companies that don't seem to do that well, laws that don't make much sense, etc. Once something is in place, it's hard to change it. The same thing is true of evolution. It does not always result in the most optimal configuration, or even frequently.
There's plenty of examples of things in the human anatomy which are actually terrible "design" choices, but when viewed through the lens of evolution, make sense. A famous example is some nerve (I forget the name now) that takes a ridiculous and non-sensical route, but when you look at the history of how we evolved, it makes sense that it got stuck there because of what came before. It's like that with a lot of human technology too; train tracks, for instance, weren't spaced at their current spacing (gauge) because it was the optimal design choice (esp. not now with modern trains and cargo sizes), they did it because technologies and tooling and infrastructure that came before made it easier to use that gauge than to switch to something different. If we could change things, it'd make more sense to increase the standard gauge on most railways, but there's too much inertia and it'd cost too much.
