[kgwgk]

Nature doesn’t chase anything. Things happen.

Arguably surviving may happen less often for the shock-proof egg than for the egg that is better in some alternative aspect (including quantity).

(Maybe the hard egg has other advantages though. Could also be used to produce a better skeleton.)

[Forgeties79]

That’s exactly what I said. “Selects out” is the terminology used when discussing evolution. It’s not an active “decision,” it’s a thing that happens. “Natural selection.”

[kgwgk]

Ok. But what does that mean in the context of the comment that you replied to? (Which doesn’t talk about decisions or nature chasing things, at least as it stands now.)

Is a harder shell which has higher costs than benefits selected out? Maybe we’re all repeating the same thing.

[Forgeties79]

Ah I get what you’re saying. My point is that yes, some other type of shell probably selected out and this one wasn’t. Maybe it was dumb luck, maybe it was a slight advantage in a very specific condition that allowed it to persist, but ultimately we can only theorize.

[the_af]

I would understand the selective advantage if it made the egg shell more resistant to accidental breaking within the nest. But for birds that nest in tree branches or perches, what advantage is there for an egg resisting a fall without breaking? That egg is lost anyway; for most bird and egg shapes, there's no way to bring it back to the nest.

[Forgeties79]

> what advantage is there

So this is a pretty common mistake people make when discussing evolution. It’s not about what is advantageous, it’s about what survives the selection process. A combination of odds that play out.

Our eyes are not advantageous or chosen by evolution, our eyes were just acceptable enough for us to survive while other variations were not. There was no decision or work/progress towards an end goal. A creature developed along a certain line by chance, the situation in nature was such that they survived and passed on that trait, while others did not. Natural selection in action.

[the_af]

No, I understand how natural selection works. I'm a fan of Stephen Jay Gould.

Please keep in mind the original comment I was responding to:

> Eggs are evolutionarily designed to survive falling out of nests and perches.

My response is "no, they are not". First, like you said, they are not "designed" in any way. But that's the pedantic response. Second, there's no selective pressure for eggs resistant to dropping from a nest, since they are lost anyway and won't pass any genes. It's likely that something else is being selected for -- or at least, that the more resistant shell is not harmful to reproduction of the species -- but there's no selection for nest-drop-resistant eggs because that confers no advantage. Maybe it's just harmless, which can make the trait survive. See the difference?

> There was no decision or work/progress towards an end goal.

It helps to assume everyone understands this, otherwise we cannot get to the meat of the discussion without nitpicking every single sentence.

[Forgeties79]

That makes sense, thank you for clarifying.

[robocat]

https://www.theatlantic.com/science/archive/2017/06/why-are-...

Off topic, but indirectly supports your point.