One of the criticisms on evolutionary theory is that evolution cannot account for the arrival of new species. Yes, species can change over time (this has been observed), but one species cannot turn into a new species. Unfortunately for the creationists, new species do arise. This process, speciation, is being studied and new insights are published on almost a daily basis.
The most important factor in the origin of species is the establishment of reproductive barriers. These barriers come in all kinds of shapes and flavors. For example, two populatios of the Madeiran Storm-petrel breed on the same islands, but at different times. So, they are isolated from each other in time. If they continue to show this particular behavior, they will diverge and in time (no pun intended) become different species. You can find the original study here.
Another form of reproductive isolation is mechanical, the key does not fit the lock. This phenomenon is common in beetles. On the picture below, you can see a beetle penis (not John Lennon, another kind of beetle...) decorated with beautiful spikes and other frills. It only fits into female beetles of its own species. Isn't that romantic!
|A Beetle Penis|
It is also possible that certain individuals display a behavior that is only attractive to males or females from a particular group. For instance, some birds have to sing a specific song to attract mates. But let's get hypothetical now (I almost wrote physical). What if a certain belief system determines whether you can find a partner. Let's say you have to believe that everything was created and did not come about by purely natural processes. If your partner thinks otherwise, he or she will be dumped. So, this behavior will create a cultural reproductive barrier and over time these populations may evolve into different species. An isolated creationist community can in theory develop into another human species, Homo ignoramus, and by doing so, providing evidence for the evolutionary process they so viciously fight. Wouldn't that be wonderfully ironic...?!
|The Evolution is Homo ignoramus (featuring Ken Ham)|