Psst: "evolve" doesn't mean "improve". That's not how evolution works. Pass it on.

@GeePawHill

I woudl argue that evolution **does** mean improve for the first of a species which evolves when that new species turns out to be viable. but it does not mean the species as a whole is improved (as it may be at a disadvantage from competition within its own species in the long run)... but if the initial mutations werent improvements then they wouldnt have evolved.

@freemo We can argue that Mitochondrial Eve and her immediate descendants represent a line that did not make things worse. But 1) Not making it worse is not the same as making it better, and 2) Mitochondrial Eve is only possible to identify in retrospect.

A mutation is a *change*. Some mutations get passed on, some don't, for a wide variety of reasons that aren't "improvement".

@GeePawHill

Mitochondrial eve is a specific case of evolution, but a rather exceptional case too, im not sure it is valuable to focus on that case exclusively, even though it does represent an improvement.

Ok so you are talking about evolution as "all changes". evem ones that dont get passed on and the new offspring die... but that is exactly how improvements are found.. when an evolutionary change represents an improvement then it will pass on, when it does not represent an improvement it wont. We may not always be aware of why something is an improvement as humans, and it may not even be an improvement at all (just be of equal value) until much later on in the process where it provides the ability for later evolutionary changes.

Take even something as simple as color being lost in a birds feathers... if that winds up being preserved in the species that means its "selected for" and as such represents some sort of improvement. It may be better camaflauge or it may just save energy not producing pigments... but its still an advantage.

@freemo So, that's a stance we call pan-adaptationist: "If it's in a germ line today, it must confer advantage." It would be more correct to say, "if it's in a germ line today, it must not have conferred sufficient disadvantage to prevent reproduction, and it may or may not a) have conferred advantage then or b) confer advantage now".

@GeePawHill Right, but to me that is still saying evolution results in improvement... If every change that lasts is one that either causes a break-even state, or an advantage, and advantages are favored over break-even, then in the end it is always driving towards improvement in ones local-environment.

I would argue that the genes that dont themselves confer direct advantages are still a long term advantage because they allow for more genetic variation and therefore more genes that can further mututate offering a larger search area for mutations to find advantageous mutations. In other words there may be a string of 20 or 30 mutations that are "break-even" that ultimately lead to one being an advantage. Since you couldnt leap direct to the advantage (since it would have randomly been improbably for 20-30 mutations to happen at once) it was those break-even mutations that lead to it being possible... So even break-even mutations are effectively advantageous in the long run.

@freemo At some point, one twists the meaning of "improve" so far beyond its naive usage as to prove my point. :)

@GeePawHill I'm not sure thats where we are though... the overall process is designed, built, and fundamentally about improvement. The act of improving doesnt mean every individual step towards improvement needs to be an improvement so long as those steps are fundamental int he overall process of improvement.