The theory of Evolution is ideology, exploiting a number of really scientific disciplines such as biology, genetics, geology, chemistry, etc. But the theory itself, which tells about the origin of all existing species on Earth and humans through mutations and selection - this is pure ideology.
Thus, under the guise of scientific disciplines, the Theory of evolution got into the field of philosophy and religion, and boldly took their place, trying to push out a philosophy and religion. She cynically said that this religion reaches into questions of science, when trying to speak on account of the origin of man.
This theory is no scientific criterion, and when she is asked to present evidence, it must present the results of other scientific disciplines, whether it be genetics or Geology, but scientific evidence for its truth it does not. Strictly speaking, what the theory calls its evidence is essentially just an interpretation of facts for the sake of the dominant paradigm
https://steemit.com/science/@discernente/brief-summary-of-the-evidences-for-the-theory-of-evolution
This does not prove the origin of all living kinds from a simpler ancestor, it is the interpretation of scientific data, in accordance with the dominant paradigm. This theory is contrary to the criterion of Popper's falsifiability, it also has no possibility of repeating in the laboratory or monitoring this process. Strictly speaking, this theory is accepted only because there are simply no other options for science.
Theory of Evolution is not supposed to explain the origin of life, only how it evolved. And it is falsifiable because it makes predicitons, or better yet, retrodictions, since anthropology is an historic science (like cosmology, forensics) and not an operational science (like physics, chemistry).
Why should evolution create barriers for crossing different species, because it could (in terms of theory) give positive results?