Five conceptual innovations from On The Origin of Species

Chapter 8 endnote 10, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:

No features are necessary, sufficient, or even typical of every individual in the population. This observation, known as population thinking, is central to Darwin’s theory of evolution. [...] Origin actually contained five conceptual innovations.

According to the evolutionary biologist Ernst Mayr, On the Origin of Species contained five conceptual innovations, several of which were the first nails in essentialism’s coffin.

1. Population thinking, the idea that a species is a conceptual category populated with individuals who vary from one another, and whose variation is meaningfully tied to the environment.
2. Natural selection is the main mechanism of evolutionary change.
3. The idea that evolutionary transformation was continuous and gradual (rather than drastic and periodic).
4. An emphasis on constructive, holistic analysis to study the interactions that produce a whole organism (i.e., the need to study the parts of a system in the context of the whole that influences it).
5. Common descent, the idea that all animals descend from a common ancestral species, which was not original to Darwin.