God Is Real

[Aegrus]

Im curious to know how do you guys think life began?

Well, when a man and a woman love each other very much. . .

But in all seriousness, you seem to be making a fairly common error. Evolution isn't filled with instances of grass becoming dogs, for example, because grass is incredibly different from a dog. Way back, millions of years a go, my understanding is that there were a bunch of amino acids floating around. This is very possible, as scientists have since created amino acids in a lab. These amino acids eventually, after billions of random occurences and interactions which naturally result from chemical bonds and such, eventually became a primitive type of cell, sort of how protons and neutrons and atoms form molecules. (Though a bit unlike the cells in our bodies.) This basic cell continued to evolve, and perhaps split into a few species through divergent evolution. (Note, when I say species, I don't mean dog or cat. I mean different types of minute organism- and it's important to note that there is no correct end result in evolution, rather than a ladder with rungs, it's more of a ramp.)
Back when creatures were still very primitive (a few cells) the largest changes happened. Some cells were in places where it was beneficial for mutations which made them into what we now call grass, and some needed more mobility. The largest changes happened very early, making the first few major branches on the evolutionary tree.
Afterwards, species continued to split and evolve. Some structures, such as the eye, began perhaps as primitve cells which were sensitive enough to interact with photons. Random, primitive, simple, but useful. Thus, creatures might have a feeling of light and dark. Over billions of years, more and more complex versions might evolve, kind of like a centuries-long arms race between species.

Hope that helped.