When the God of evolution chooses to develop a species in a certain direction, He creates enemies for that species that kill off the members of that species that don't meet His requirements. God wants caribou to be strong and fast so He made wolves who catch and eat the weaker slower caribou. Slow weak wolves who lack cunning don't survive either. Down through the ages the two species shape each other.
Short giraffes starve to death.
Clumsy squirrels fall to their deaths. Trees that do not grow taller than surrounding trees die from lack of light. Mice and rabbits who are not alert get caught and eaten by owls, hawks and eagles. God wants Human beings to develop their forebrains, and their ability to think ahead towards the future. This trait is vital not only for the human race, but for all other life upon Earth.