Problem:
I know how it gets converted because PR is more stable and when there is neither red or far red light PFR naturally converts to PR. But what is the point of it?
If PFR is the biologically active one why didn't evolution just make one pigment, PFR. At night neither is active so PR again has no point, in the morning PR gets converted to PFR.
Question: So why do we need a PR? Describe it.