Principle 2: Overproduction & the Struggle to Survive
Principle 3: Differential Survival and Reproduction (Survival of the Fittest)
There are three different types of birds with different traits in the picture above. One bird is white, another is brown, and the last one is black. Food is scarce to find since the climate has changed.
Principle 4: Change in the Gene Pool
The white birds are spotted easier than the black and brown birds. Animals such as coyotes or hawks can spot them easier.