Speaking as a biologist to be (by the end of the next semester) I can provide a professional (almost) point of view.
The simplest way to define evolution is as: heritage with change (meaning is that the offspring is slightly different from the parents), if the change persists in time (is present in the next generation) evolution has occurred!
Evolution is a mindless process, the changes (mutations) happen by chance, but remain on purpose.
The evolution does not always lead to the survival of the fittest, sometimes it actually does the opposite thing.
