According to Darwin, what is the signifigance of variation in the natural world?

Question

This question refers to the variation of species in the natural world? Did he suggest this to better explain his theory natural selection?

Answer 1

Variation is required so that when a particular characteristic is adaptive, a creature will evovle with favorable characteristics to allow it to better cope.  Multiply this by a million and you can understand how animals evolve over time.

Answer 2

Without every organism of a population being a variant, whether a superior or inferior phenotype, natural selection would have no selection to do. Hence, no evolutionary processes would be possible.

Answer 3

Darwin saw that there were patterns in life form.  You have seen patterns in bird flight, or even easier, in yourself.  There are variations in patterns.  Some are good and some are not profitable for existence.  

Just because Darwin saw patterns, does not make his conclusions correct.    According to Darwin, variations would absolutely involve natural selection.