Principle #1 Genetic Variation: The Genetic Variation within rabbits are those with short ears and then the black-tailed jackrabbit with longer ears.
Principle #2 Overproduction & The Struggle For Existence: Overproduction: Both rabbits reproduce all year long after 31 days of kindling some don't always make it. Struggle To Survive: The short eared rabbit are easier for their prey to attack them.
Principle #3 Differential Survival & Reproduction: The long eared rabbit (black-tailed jackrabbit) has a higher fitness and will survive and reproduce.
Principle #4 Changes In Gene Pool: The more advantageous trait, long eared (black-tailed jackrabbit) because they are most common and will reproduce since they have higher chance of surviving. Over time the population of the long eared (black-tailed jackrabbit) will expand