The science of evolution

At the heart of evolutionary theory are the basic ideas that life has changed over time and that different species share common ancestors.

Overwhelming evidence supports these facts. Scientists continue to argue about details of evolution, but the question of whether or not different species are related through a long, shared history was answered in the affirmative at least two centuries ago.

The history of living things is documented through multiple lines of evidence that converge to tell the story of life through time. In this section, we will explore the lines of evidence that are used to reconstruct this story.

These lines of evidence include:

• Fossil evidence and transitional features
• Distribution in time and space
• Homologies
• Developmental biology
• Nested hierarchies
• Observations of evolution in the wild
• Experiments
• Artificial selection