The length of day on different earth like planets.

I understand that the distance away from the sun is important when it comes to an earth like planet, but what about the rotation of the planet? Sure we wake up and feel refreshed that its a new day but what if another planet with life had already had 2 days during our one day. or what if a 'day' on another planet was only a quarter complete... do you think the rotation has to be specific to sustain intelligent life? i know if its closer to the sun and the rotation is slow of course one side will be extremely hot... but what if that planet that was close was rotating so fast enough that each side duing its 'day' wouldnt be exposed to the extreme heat and cold for a damaging length of time? How would a longer or shorter day + the distance from the planet effect the life forms on the planet?

I think with completely artificial living habitats (I seriously doubt we would live in a cave or other natural structure) human life is possible.

But if you are referring to natural life.....Just compare life at the equator vs life at the poles.

There are huge differences in day and night and yet life still finds a way to adapt.

I don't think it's going to have too much of an impact. Human sleep patterns are part of conditioning, they can be changed and altered to fit around whatever time plan you need. I've read about a different method of sleeping whereby you take 30 minute naps every few hours. It's hard to do but really works.

I believe whatever the planet's rotation is or day lengths are, life will likely fit around it. It has a way of doing that.