THIS is what science is about
Beaver or Otter, It Lived in Dinosaurs' TimeIf something comes along that really contradicts what they thought before, and for which there is legitimate evidence, good scientists will abandon the previous views - maybe not without a backward look, especially if it was something they had an investment in, but they will abandon it. Look at "continental drift." When it was first proposed it was pooh-poohed because the theory for the mechanism wasn't convincing. Continents don't float on top of the ocean. When plate tectonics made its appearance, it was eventually accepted.
...Thomas Martin, an authority on early mammals at Senckenberg Research Institute in Frankfurt, said the find pushed back "the mammalian conquest of the waters by more than 100 million years" and "impressively contradicts" the conventional view.
"This exciting fossil," he wrote in a commentary accompanying the report, "is a further jigsaw puzzle piece in a series of recent discoveries, demonstrating that the diversity and early evolutionary history of mammals were much more complex than perceived less than a decade ago."...
Creationism, on the other hand, never changes or evolves. (You should forgive the expression!) It undergoes cosmetic revision, name changes, etc., but essentially is still the same as it was 20, 50, or a hundred years ago.
Update: I'm reading a very interesting book called Finding Darwin's God which goes over the basic anti-evolution arguments. I will have to concede that, to continue the analogy, creationism does mutate somewhat in response to outside threats, to the extent that there are now three different varieties. It's still the same species, though.
Here are a few excellent evolution-related websites: Talk.Origins, Understanding Evolution, The Panda's Thumb, the National Center for Science Education, Pharyngula.