Introduction

Observations and experiments from the science of evolutionary biology have provided us with a solid base of knowledge about how life on Earth came to be. This is not to say that all the mysteries of the evolution of life are solved - far from it. However, the core of what we have learned about Earthly life from the study of evolutionary biology may provide important insights into the question of whether life exists elsewhere, and if it does, what form(s) it might take.

Diversity and adaptation are the defining features of life on Earth. The Theory of Evolution by Natural Selection provides an explanation for observations of diversity and adaptation in the living world. After presenting some basics about the evolutionary process, I will consider a range of issues including: 1) What determines the outcome of the evolutionary process? 2) What is the role of evolutionary innovation on the course of evolution? 3) How do periodic extinctions alter the history of life? 4) Was the evolution of intelligent life inevitable?

Consideration of the course of the evolution of life on Earth puts the search for intelligent life in other universes into a context in which contingency is of paramount importance. This raises issues about the possibility of intelligent extraterrestrial life that might otherwise be missed.

Contributed by: Dr. Sara Via