Biology textbooks reflect the belief that "The world is purely physical/material in nature" by not even entertaining the possibility that there could be a super natural cause for anything. Any natural activity is assumed to have a physical/material cause. This is philosophy, so it may not be physically written out that way in the biology textbooks, but everything in the textbooks points to this major world assumption.

Same with the issue of free will. Any act by a species is seen in a way that needs to be explained in chemical/biological/mechanical manner. There is no room for this mysterious/other-worldly notion called free will.

Same with the idea that there is no real purpose or meaning to the universe.

As for this statement:

If for example a person does not accept that all of existence is physical in nature, then he is more likely to question the 'evidence' of evolution.

It is not necessarily true because of specific theological beliefs only. Lets say a person has absolutely no theological beliefs from any religion, but he does not automatically assume that all of existences is physical/mechanical. That person, because of this world view by itself, now all of a sudden has a higher chance of rejecting evolution than someone who only believes in a physical/mechanical world view.

The real debate is on the level of philosophy, not science. That is because ones science is driven by his philosophical interpretations....whether he realizes it or not.