In medical school, we all learned that the back of the eye, the retina that gathers and converts light from photons into electric signals in neurons, were cluttered with cell bodies and mitochondria that seemed to BLOCK light to the photo-receptors. We all sat around and puzzled “huh, why is that” and, in 1986, had no answer from the textbook.
Well, science progresses, and NOW there is an incredible answer, from the retinas of squirrels. Thanks to our brilliant basic science colleagues.
In a grand case of convergent evolution, birds circling high overhead, mosquitoes buzzing around their delicious human victims, and you reading this article have all independently evolved related optical functions—adaptations that bring a sharp and vibrant world to the eye of the beholder.Yasemin Sapakoglu (wired.com)