&gt; Why if they all disappeared yet all other plant and animal species variations lived are there still apes and monkeys today?<p>Because we didn&#x27;t descend from apes and monkeys (at least in the modern sense); we descended from some common ancestor that we happen to share with apes and monkeys.<p>&gt; why did not all amoeba evolve as well?<p>Because not all amoeba were subjected to the same conditions or experienced the same mutations.  Evolution by natural selection is very much a random process; there&#x27;s no guarantee of any particular outcome.