III. Theories of the Process of Evolution:
a. Natural Selection:
1. Variations in all directions, and adaptation.
2. Adaptation a struggle for life.
α. For place.
β. For food.
γ. For protection, through imitative color or form.
3. The value of artificial selection as partly showing us the processes of natural selection.
4. What natural selection fails to explain.
b. The theory of Sexual Selection, and its shortcomings.