Evolution made simple

Evolution rests on two principles that are best described in the terms "Vreet" and "Spyker".
Vreet is more than eat. It means violently devoured. Spyker is more than having sex or making love. It is non-stop sexual activity to bring forth young.
Let's use the example of a mouse. It has to vreet to live and it has to spyker to ensure the survival of the species. As it is relatively low in the feeding chain, the chances are that it will be vreeted by other creatures. This is where spyker comes in. The more it spykers, the more mice will be around to compensate for those that will be vreeted.
Now the members of the species that can vreet the most are the strongest and have the best chance of not being vreeted. They are the ones that will also have the best chance of spykering, thereby passing on their strong genes to the next generation, that will also be strong vreeters and spykerers. The weaker specimens will most likely be vreeted and their genes will not be passed on. 
If there is for some reason a problem with either of these two principles, the species will become extinct. The creatures will starve or be vreeted into extinction, or they will not produce enough young.
So, evolution basically means survival of the fittest.  Vreet or be vreeted. Spyker or die.