Key quote:
But simple eyes should not be seen as just stepping-stones along a path toward greater complexity. Those that exist today are tailored to the needs of their users. A sea star’s eyes—one on the tip of each arm—can’t see color, fine detail, or fast-moving objects; they would send an eagle crashing into a tree. Then again, a sea star isn’t trying to spot and snag a running rabbit. It merely needs to spot coral reefs—huge, immobile chunks of landscape—so it can slowly amble home. Its eyes can do that; it has no need to evolve anything better. To stick an eagle’s eye on a sea star would be an exercise in ludicrous excess.
“Eyes didn’t evolve from poor to perfect,” Nilsson says. “They evolved from performing a few simple tasks perfectly to performing many complex tasks excellently.”
