Subject: How or why did the human eye evolve?

    I am a student in High School and I am struggling with the idea of why
the human eye evolved.  I know that this may not be your exact field of study, 
but I would greatly  appreciate it if you could give me some insight on how the 
human eye evolved.  I learned that an organisms evolve becuase of some pressure 
by the environment, could you please explain to me what pressure from the
environment would cause this evolution? What did the eye look like in other 
animals before humans and why did it get to the shape and function it has now? 
If you cannot answer this, could you
please direct me to someone who can if possible?  Thank you so much for your
help.

Re: How or why did the human eye evolve?