I’ve recently defined Darwinian Evolution in this way:

Evolution is an unguided, Natural process which increases the genetic information in an organism; Creating new Genes which did not previously exist.These new genes then cause an increase in physical complexity and associated behavior, Both of which increase the organism’s ability to survive and pass on these traits to offspring.

But why isn’t it good enough to just increase their chances of survival OR ability to reproduce? Why must it do BOTH?

In this video, your Bryan explains this feature of the definition for evolution, and explains how it is vital to the growth of the Darwinian Tree of life.

Read Defining Evolution Ch 8: The Offspring