What's weird is that this is based on melanin, and how fast it happened. Doeswould seem at least likely that this is life digging up an old recipe rather than coming up with something new. Melanin can usefully absorb high-energy gamma rays ... that means there must have been a period, long enough, in earth's history where high energy gamma rays were easy to come by.
That could only have been on land, or in the very top layer of the ocean (because they don't pass through water).
So where in earth's history do we have a period where a large landmass had sufficient wattage in high energy gamma rays? Or at the very least a lot of UV rays, enough to damage/kill normal life. Such a place would otherwise have been very unhealthy for almost all life, as it destroys DNA.
That could only have been on land, or in the very top layer of the ocean (because they don't pass through water).
So where in earth's history do we have a period where a large landmass had sufficient wattage in high energy gamma rays? Or at the very least a lot of UV rays, enough to damage/kill normal life. Such a place would otherwise have been very unhealthy for almost all life, as it destroys DNA.