I love the writing, it's very direct.

He may have just killed life on other planets. Or at least a fair proportion of it, if you have to have a star that outputs mainly in the water-transparent, ideal-for-photosynthesis spectrum.

Of course these evolutionary things seem to somehow fix themselves. Some other chemical might be a more suited to light from a different star, or something in the water may change its spectrum. Or simply a brighter/dimmer star might jiggle things.