I believe Darwin had part of the answer, but not all of it. He did not dwell on mutation but it definitely plays a part.
I believe that where a creature can exist it will exist.
Recent research in chromosome / DNA indicates any given creature can be / become, evolve into, or mutate into, (no one seems to be sure which) any of a family of creatures merely by switching on or off certain sequences.
For example an ostrich contains the prototype to be a lizard or perhaps dinosaur.
So what, if anything, causes the switch?
Is it possible a creature that never existed before could turn up in Central park tomorrow?
What if humans learn to throw these switches on and off?
