No, evolutionists ASSUME it happens based on the fossil record. It's a matter of interpretation.
Nobody ever observed macro-evolution, even with all the deliberate attempts to make it happen.
How can scientists (with a straight face) expect us to believe something happened by accident that they can't even make happen on purpose. For all the years of attempts by man to manipulate genetics, from selective breeding to the more intricate work with genetics these days, they still haven't caused the kind of species changes they say occurred that would be needed to populate this planet with the variety we see today.
No, the assumption, or theory, concerns how evolution happens, not whether it happens. We know it happens, we're just trying to figure out how.
How can scientists (with a straight face) expect us to believe something happened by accident that they can't even make happen on purpose.
As has been explained several times here, there's nothing accidental about evolution. Post 161 has a good example.