Despite knowing approximately when life first appeared on Earth, scientists are still far from answering how it appeared. The universe started from a point of singularity and expanded to infinite dimensions, and life is no exception. Today's Earth is home to a vast and varied population of living things, yet all life on this planet Earth traces back to some time more than 3 billion years ago. The histories of Earth and its life are inseparable.
Where does life's diversity come from? Where do new species come from? Why do some species go extinct? How did things go from non–living to living? From something that could not reproduce to something that could? These are just a few of the questions that can be answered by understanding life, evolution, genetics, and biodiversity. These disciplines explain the mechanisms that shape how organisms interact with their environment and in turn, how the environment shapes organisms over many generations.
Evolution is fascinating because it attempts to answer one of the most basic human questions: Where did life, and human beings, come from? The theory of evolution proposes that life and humans arose through a natural process.