1
vote
3answers
159 views

Why do our eyes close when we sleep?

Why do our eyes close when we sleep? Is it to relax our eye muscles? How can it be explained from an evolutionary point of view?
3
votes
2answers
265 views

How can fruit flies and mice share the same gene that says to build an eye if they evolved separately?

I saw a documentary where they inserted the gene of a mouse that basically is the starting "build an eye" command into a fruit fly, and a fruit fly eye grew. My question is, if eyes of different types ...
7
votes
3answers
766 views

What is the difference between a circular and a cat's-eye pupil?

I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on ...
11
votes
2answers
473 views

When did vision evolve for the first time?

Today I wondered what the first organism to evolve vision would have been. I assume that it would have been kind of primitive and basic, but of course extremely innovative and eventually useful to a ...