Yes, we can say with confidence. The mechanism is well understood.So we cannot comment with any evidentiary confidence (which is what the objective of science is) if it was in fact the environment itself that caused rapid change.
Confidence without evidence. This is true, no?
The environment is a category of things. Is there anything that doesn't fall into that category that has been known to cause changes? Do us a favor and give us your hypothesis. I'd love to see alternatives to the dominant paradigm. Provide an alternative hypothesis that is as well evidenced as the one we currently have.
What you actually mean is, how do we know with certainty. We don't, so stop expecting it, even in inference.How many errors?
Do we know?
If we don't know, how do we know "it is very close"?
We know we're close because we've done many reconstructions of existing creatures from fossils.
I don't think you care about "how" we know. You're merely questioning it to appear skeptical, which is pseudo-skepticism. Why not read a book on the topic of phenotypic restoration from fossil remains?
It depends on your criteria for demarcation. Is it a visceral thing, where we draw the line where we say "that doesn't look like a human?" Or is it a percentage of DNA shared? Or the ability to reproduce? Your question doesn't mean anything to me ant, because it assumes we cut nature at the knees. The lines we draw in categorizing things are artificial lines. The truth of the matter is more of a gradient. Draw your line on that gradient where you will, but wherever we draw it is an abstract point.Which of the faces is a Human Being, Interbane?