The ability to synthesize compounds is often lost when those compounds abound in the organism's environment because synthesis consumes energy and an organism's energy budget is limited.
Examples from the animal kingdom include frugivorous humans lacking the ability to synthesize vitamin C, and cats lacking the ability to synthesize taurine.
As I said in a sibling, this reason is more complex than it has to be.
If you can suffer a mutation and not die, because you can obtain the nutrient from food, then you can have offspring who have the same non-fatal problem.
There's no budgeting involved and whether the conditions that make this a reduction in fitness occur or not is a fluke. Vitamin C synthesis turned out to be a big deal for humans once we started going to sea.
I'm going to take a wild guess and say that this is due to low CO2 levels. Plants evolved and are use to 1200ppm CO2 level. The current levels 300-400ppm 1/4 to 1/3 of their normal level, they are starving. Its amazing they are actually surviving. Probably going to get downvoted to hell but science is science.
> Plants evolved and are use to 1200ppm CO2 level [...] they are starving [...] science is science.
Well, that's certainly a novel kind of pseudoscience pro-emission bullshit, I'll give you that.
Unfortunately -- by your logic -- both of us are simply fancy Coelacanths which "evolved and are used-to" briny sea water as our "normal" environment, which is why it's so difficult to type this with my flippers while suffocating on dry land.
No, wait, that's not true, because evolution is a constant process and doesn't just happen once and stop. I can take a literal breath of relief.
So let me get this straight. You reject the relevance of higher CO2 Levels in the past because it's too long ago. Then you point out that evolution is an ongoing process, but apparently it's too slow to accommodate a rapid rise in CO2 Levels. Is that correct? If so, it's not wrong, but it seems a little like mental gymnastics to fit a particular idea.
> You reject the relevance of higher CO2 Levels in the past because it's too long ago.
I reject his weird concern-trolling, regarding a category of "starving plants" which are necessarily extinct and have been for many millions of years. Since they do not live anymore, it makes any "more CO2 makes them happier" appeal ridiculous.
> apparently [evolution is] too slow to accommodate a rapid rise in CO2 Levels
Evolution "accommodates" rapid changes that harm a species via DEATH AND DISRUPTION. As we are both members of the supposedly-dominant species right now, surely you'd agree that generally has more risk than reward, and that we'd rather not have population die-backs from famine or economic losses from cities built in the wrong place.
Examples from the animal kingdom include frugivorous humans lacking the ability to synthesize vitamin C, and cats lacking the ability to synthesize taurine.