Why are the eyes located inside at the orbits? What does such a location enable them with? What difference would it make if they were just located flatly on the face? (Besides the answers ' God made it that way' or 'we'd look ugly' or something. :P)

Question

anonymous · Answer

If they were flat, we wouldn't see that much due to the focal point being nearer to the lense. (I assume, only light which hit the eye in a straight angle can be absorped instead of light from different angles.) Additionally, we couldn't move the eye. Therefore, we would only look in one direction.

But that's at best an educated guess...

anonymous · Answer

Though it may be a guess, it's a pretty good one. (At least I dont find anything wrong with it :P ) Thanks. :)

anonymous · Answer

Human eyes evolved in the "predator mammal" style - that is, unlike most prey animals that have eyes on the sides, we have eyes like those on some early carnivorous animals. These are arguably more suited to tracking things down and helping kill them than looking all around to avoid *being* killed. This, in turn, means that mammalian eyes sometimes function a bit differently than others. We've evolved to have narrow, but well-focused eyes that see in a certain range of visible light at a particular range of distances (and the binocular placement of our eyes helps us judge distance in three dimensions). Somewhere in this evolution of our unique sight abilities, it could have been that selective pressures on brain growth caused a shift in the development in certain parts of the face (including the orbits), as this dissertation claims: http://www.paleoanthro.org/dissertations/Michael%20Masters.pdf With evolution taking place over so many years, it's often hard to say precisely what "causes" something, or "why" we have certain features. A lot of our biology is also affected by our neurological evolution, so it can be helpful to see what brain developments were happening at the time that our ancestors started getting "predator vision".

anonymous · Answer

I'm going to add a guess here, that it's also related to depth perception, which allows us, as predators, to very accurately judge distance a la stereopsis and retinal convergence.

anonymous · Answer

Very interesting. :) Thank you all :D