Mitosis provides asexual reproduction in most unicellular eukaryotes.....

Mitosis provides asexual reproduction in most unicellular eukaryotes.  Since mitosis produces identical cells, variety is introduced by DNA mutations.  We tend to think of mutations as "bad" or malfuctional - but mutations may be beneficial & provide better adaptation to the environment.  One example of a favorable mutation is the development of lactose tolerance in humans - the continued expression of the DNA segment coding for the LACTASE enzyme into adulthood.  The "ancestral" gene ceased to be expressed after weaning.  Combining favorable mutations with reproductive success results in the "descent with modification" pattern of evolution.

Find other favorable (or unfavorable) mutations that have guided evolution of "your favorite species".  Discuss this interaction between genes & environment that results in the change we call evolution.