Process
Natural selection
Individuals better suited to their surroundings leave more offspring, so their inherited traits become more common. Darwin's finches and peppered moths are well-studied examples.
Evolution
The process by which living things change over generations through changes in their genomes.Source: NHGRISource: OpenStax, 2018
Process
How Evolution connects
Evolution includes
Process
Genetic drift
Random changes in how common alleles are from one generation to the next, strongest in small populations.
Idea or model
Common ancestry
All known cellular life is thought to descend from a last universal common ancestor. Researchers infer its features from genes shared across life, and the details are still debated.
Idea or model
Endosymbiosis
Mitochondria and chloroplasts descend from bacteria that came to live inside other cells long ago.
Evolution is made possible by
Process
Mutation
A change in a DNA sequence. Mutations arise from copying errors or damage, and their effects range from none at all to disease.
Evolution includes the example
Idea or model
Transitional fossils
Fossils with in-between features, such as a Late Devonian fish from Arctic Canada that is intermediate between finned fish and four-limbed animals.
Process
Experimental evolution
Watching evolution in the lab: in a long-running E. coli experiment, one population evolved the ability to use citrate after about 31,500 generations.
Evolution is related to
Process
Mutation
A change in a DNA sequence. Mutations arise from copying errors or damage, and their effects range from none at all to disease.
Level of life
Population
All the members of one species living in the same area at the same time.
Studied in
Your progress
Sources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Evolution (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalBiology 2e (opens the original in a new tab)
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)