I know, but if you believe evolution was the origin of life, you would believe the Big Bang theory too.
The theory of evolution is not involved with the origin of life, but rather with the proliferation of species, after life has begun.
As for the Big Bang, it's a theory that is only about 50 or 60 years old, and there were loads of biologists who accepted the theory of evolution before the Big Bang theory was ever dreamed of. They're quite unrelated.
It's true, however, that a science-minded person, who is impressed by evidence and rational thought, is likely to be favorably impressed by both theories; but that doesn't mean that they're related topics.