Question

Can one species evolve into another?

Answer 1

One species does not "turn into" another or several other species -- not in an instant, anyway. The evolutionary process of speciation is how one population of a species changes over time to the point where that population is distinct and can no longer interbreed with the "parent" population. In order for one population to diverge enough from another to become a new species, there needs to be something to keep the populations from mixing. Often a physical boundary divides the species into two (or more) populations and keeps them from interbreeding. If separated for long enough and presented with sufficiently varied environmental conditions, each population takes its own distinct evolutionary path.