Evolution is driven externally by environmental experiences.
Evolution is directed internally by Consciousness.
Graduation occurs upon completion of that goal.
A planet's evolution occurs in several stages
In the early stages, evolution occurs primarily as a process of environmentally driven mutation, survival-based selection of traits, and epigenetic adaptations.
At a certain point in a planet's evolutionary, Sapient Life evolves. When sapient lifeforms evolve, these typically take control of the environment. At that point, it becomes possible to create environments and direct evolution. As a species gains expertise and control, Natural Evolution gives way to Social Evolution. Over time, the significance of natural evolution declines while social evolution becomes the primary evolutionary driver.