Process
Evolution
The process by which living things change over generations through changes in their genomes.
Evolution
How life changes over generations.
Evolution is how living things change over many generations. It explains why there are so many kinds of life and how they are related.
Evolutionary biologists study natural selection, genetic drift and common ancestry, using fossils, genomes and experiments.
The field combines population genetics (Hardy-Weinberg, drift and selection), comparative genomics, fossils, experimental evolution and the search for the last universal common ancestor.
Big questions
- How do new traits arise and spread?
- How are all living things related?
- Can we watch evolution happen?
Key ideas
Open any idea in the knowledge graph to see what it connects to, here and in other fields.
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.
Process
Genetic drift
Random changes in how common alleles are from one generation to the next, strongest in small populations.
Idea or model
Hardy-Weinberg equilibrium
Without selection, mutation, migration or drift, allele and genotype frequencies stay the same from generation to generation.
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.
Process
Human adaptation
Examples include lactase persistence, which evolved separately in Africa and Europe, and the sickle cell trait, which protects against malaria.
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.
Idea or model
Endosymbiosis
Mitochondria and chloroplasts descend from bacteria that came to live inside other cells long ago.
Process
Antimicrobial resistance
Microbes evolving to survive drugs meant to kill them. Bacterial resistance was associated with an estimated 4.95 million deaths in 2019.
Explore it in the labs
Simulation
Watch natural selection and genetic drift change how common a gene version is, in small and large populations side by side.
- Evolution
- Genetics
- Ecology
Interactive explorer
Compare bacteria, archaea, fungi, protists and viruses side by side, and model how a bacterial culture grows.
- Microbiology
- Evolution
- Immunology
Simulation
Pair bases, follow a real human gene from DNA to protein, make mutations, and predict inheritance with Punnett squares.
- Genetics
- Molecular Biology
- Biochemistry
Current research
Search published papers and preprints in Evolution, with clear labels for reviews, primary research, clinical trials and preprints.
Search papers in EvolutionSources & 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.
Biology 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)
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 sourceEducationalEvolution of character displacement in Darwin's finches (opens the original in a new tab)
Grant PR, Grant BR (2006). Science 313:224-226.
Peer-reviewedPrimary researchSelective bird predation on the peppered moth: the last experiment of Michael Majerus (opens the original in a new tab)
Cook LM, Grant BS, Saccheri IJ, et al. (2012). Biology Letters 8:609-612.
Peer-reviewedPrimary researchEvolution in Mendelian populations (opens the original in a new tab)
Wright S (1931). Genetics 16:97-159.
Historical paperTheory or modelOn the probability of fixation of mutant genes in a population (opens the original in a new tab)
Kimura M (1962). Genetics 47:713-719.
Historical paperTheory or modelMendelian proportions in a mixed population (opens the original in a new tab)
Hardy GH (1908). Science 28:49-50.
Historical paperTheory or modelThe physiology and habitat of the last universal common ancestor (opens the original in a new tab)
Weiss MC, Sousa FL, Mrnjavac N, et al. (2016). Nature Microbiology 1:16116.
Peer-reviewedPrimary researchThe nature of the last universal common ancestor and its impact on the early Earth system (opens the original in a new tab)
Moody ERR, Álvarez-Carretero S, Mahendrarajah TA, et al. (2024). Nature Ecology & Evolution 8:1654-1666.
Peer-reviewedPrimary researchConvergent adaptation of human lactase persistence in Africa and Europe (opens the original in a new tab)
Tishkoff SA, Reed FA, Ranciaro A, et al. (2007). Nature Genetics 39:31-40.
Peer-reviewedPrimary researchProtection afforded by sickle-cell trait against subtertian malarial infection (opens the original in a new tab)
Allison AC (1954). British Medical Journal 1:290-294.
Early evidence that carrying one sickle cell allele protects against severe malaria.
Historical paperPrimary researchA Devonian tetrapod-like fish and the evolution of the tetrapod body plan (opens the original in a new tab)
Daeschler EB, Shubin NH, Jenkins FA Jr (2006). Nature 440:757-763.
Description of Tiktaalik roseae.
Peer-reviewedPrimary research
Show 6 more sourcesHide 6 sources
Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli (opens the original in a new tab)
Blount ZD, Borland CZ, Lenski RE (2008). Proceedings of the National Academy of Sciences 105:7899-7906.
Peer-reviewedPrimary researchOn the origin of mitosing cells (opens the original in a new tab)
Sagan L (1967). Journal of Theoretical Biology 14.
Lynn Margulis (then Sagan) argued that mitochondria and plastids descend from engulfed bacteria.
Historical paperTheory or modelEndosymbiosis and eukaryotic cell evolution (opens the original in a new tab)
Archibald JM (2015). Current Biology 25:R911-R921.
Peer-reviewedReviewAntimicrobial resistance (fact sheet) (opens the original in a new tab)
World Health Organization. who.int. World Health Organization.
Fact sheetIntergovernmental sourceGlobal burden of bacterial antimicrobial resistance in 2019: a systematic analysis (opens the original in a new tab)
Antimicrobial Resistance Collaborators (2022). The Lancet 399:629-655.
Modelled estimate: 1.27 million deaths directly attributable to bacterial AMR in 2019.
Peer-reviewedSystematic analysisAbout Antimicrobial Resistance (opens the original in a new tab)
Centers for Disease Control and Prevention (2025). cdc.gov. U.S. Centers for Disease Control and Prevention. Published 2025-01-31.
Fact sheetGovernment source