Yes, SELECTION is a Scrabble word!

Letter values in Scrabble US: S 1, E 1, L 1, E 1, C 3, T 1, I 1, O 1, N 1.

Is it a valid word?

SELECTION is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the act of choosing or selecting
an assortment of things from which a choice can be made
the person or thing chosen or selected
a natural process resulting in the evolution of organisms best adapted to the environment
a passage selected from a larger work

Also: survival of the fittest, natural selection.