2007-01-24 21:19:31 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Zoology
ahhh...while the best answers on evolution can perhaps only be provided by the creator.. the following can perhaps palliate yuer momentary curiosity.. in order for yuerself to delve into an even more curious question.
flies do not have a simple eye like us humans ... our eyes comprise of a single lens network n one retine.. they(them flies) have what we call as a compound eye.. a section of a fly's eye contains surface pigments which processes a small field on the horizon.. in effect a fly sees a million images at a time.. n can only focus on a few of them.. the brain kind of fuses some of these images to tell the fly an average interpretation of it's surroundings.hence if the fly had an eye lid. it'd be devoid of sight for a while.. which i guess would be disastrous to it's aspirations of survival. then again, nature has gifted it with it's 2 penny worth of a rudimentary eye lid.. tis a membrane called as a nictitating membrane... it is entirely rudimentary however.. n not fully functional!.. hence the flies cornea get's some fluid from the inner layers vide osmosis .. to keep itself lubricated!
2007-01-24 21:35:48 · answer #1 · answered by dlordoftherings 2 · 0⤊ 1⤋
Because their eye is a combination of several eyes called compound eye.
2007-01-25 13:26:47 · answer #2 · answered by moosa 5 · 0⤊ 0⤋
because if they did it would give us a chance to swat them when they were blinking, so it's a bit of a fly evolution thing.
2007-01-27 06:21:21 · answer #3 · answered by justynmooker 1 · 0⤊ 0⤋
survival of the fittest who knows? you tell us.
2007-01-28 05:17:43 · answer #4 · answered by alan j 2 · 0⤊ 0⤋
because their eyes are too big...
2007-01-24 21:43:23 · answer #5 · answered by Cookie Monster 3 · 0⤊ 0⤋
I dont know...but if it did not have wings would we call it a "walk"
2007-01-24 21:23:57 · answer #6 · answered by man with the golden gun 4 · 0⤊ 1⤋