Fiction lives on tension and risk. It’s no surprise that fiction will implement that risk with scary bug eyed monsters.
That says nothing about humans. There is currently a controversy over how the first cell came about in the first place. Once the cell survives and reproduces, evolution is inevitable and mighty.
The difficulty is getting that first cell to fall into place. Which is why having (guessing) around 10**20 earthlike planets each with a million cubic miles of warm ocean over a span of several hundred million years may be part of the Grand Scheme that produced – – ta daaaa – – us.
Imagination is a wondrous thing; the SETI project grasps at wisps of straw, since our ability to find that kind of signal at the present only works across a fraction of a sliver of our one galaxy, out of a trillion or so.
But thank goodness the Star Wars series didn’t stand on logic.
Oh, and Another Thing 