The other guy answered the color sight, so I will answer this.
No it is not safer and easier. What drove the first land creatures was the escape from the predators that were in water, at first that just meant the need to be able to survive short bursts. As predators adapted they had to go further and further out, until it was necessary to be able to breath air fully, making the ability to breath water unneeded.
But in reality we still have the dna in us that allows other animals to form gils and be able to breath under water, it is just that we over the hundreds of millions of years have not needed it and those genes have been pushed aside and dormant.
This is where ID fails, it assumes that this is some kind of chance, it is not. The intellegence is in the creatures decisions on how and when to mate.
If an animal is born with something that puts then at a disadvantage they may get eaten before they can mate. Like say a bird with a gimp wing. But say that the bird was born with a mutation of better eyesight it may be a better hunter or evade predators better so survives and thrives so it is able to mate passing those mutations down through the lines.
What I don't get is when people say that God is the intelligent designer, and we are all gods creatures and he loves us all the same, why would he chose to make most the mutations negatively affect us and end up dying shortly after birth? Wouldn't that mean that the designer is willing to warp 9999 out of 10000 of the things to design a better creature? Does he need that practice to get it right?
If it was really god wouldn't it just be done right the first time?
During one of the ID trials they used this argument about a bacteria, showing that the complexity of the design would not work without any of the pieces the same. And made referance to the mousetrap. If you take any one piece of the trap away, like the trigger, or the spring it would not ever catch a mouse.
So the scientists all took out the trigger and used them as tie clips.
The reason for this is to show that the way evolution works is not in one direction. We all (animals) have the same basic structure, we just use vastly different parts to make ourselves up.
Structures like the eye can form from things they were never meant to be.
http://www.scienceagogo.com/news/20050822230316data_trunc_sys.shtml
To help you think of evolution think of it as all sciences working in concert. If one branch of science has a workable theory, you have to take it into consideration. So if you think about underwater creatures. They are able to hear vast distances to know predators are around. But think about sight underwater, things are distorted or foggy almost. So sight is very unreliable.
But on land you do not have the same scenerios. The sound waves are not as pronounced, so sight is much more valuable. So what happens the mutations that benefit it will make those animals more apt for survival.