why is evolutionary theory constantly changing?

Be fair now. The Theory of Evolution has not been changing in any fundamental way for years. It still states that simple organisms evolve into more complex ones.The reason that they changed from apes to chimps is that new evidence suggests that this is the case. If more solid evidence appears to support another idea, then obviously it will change again. Science is never tied to one particular thing, like religion - in the face of new evidence, it discards outdated notions, like for instance, the idea that the world is flat.Religion, for example Christianity, has a hard time adapting, as we can plainly see from the debates in this forum.The Rock Hound------------------
"Science constantly poses questions, where religion can only shout about answers."

Bad choice of words... good point though - often the simplest adaptations are the most successful.The Rock Hound