Evolution within a species has been observed to happen, and can be observed to happen by anybody if you have a rapidly reproducing organism and apply to right stimulus.

Given time, you might even see this species involve into another species.

However, no one has observed evolution between phyla (e.g. between reptiles and birds) -- for one, it would take way too long. So we have to rely on indirect proof, and there are legitmate disagreements about that. Just to give one example for the pro side, if Darwinian evolutionary theory is so perfect, why did Stephen Jay Gould come up with punctuated evolutionary theory?

Evolutionary theory as responsible for the creation of all species is still very much a theory and should be taught as such, giving the various evolutionary theories, their evidence, and their problems. There are many legitimate questions about whether evolution is responsible for the creation of all the species and if so, exactly how.

Tony
Who doesn't like evolutionary fundamentalists any more than the other variety