Landmark Study Finds Natural Selection Operates at Multiple Levels

Review of 50 years of research shows evolution is shaped by selection on genes, individuals, and groups.

Mar. 14, 2026 at 2:50am

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A sweeping new review of five decades of scientific literature finds robust evidence that natural selection operates simultaneously across multiple levels of life, from genes to groups to entire communities, and not just on individual organisms. The study, co-authored by a professor emeritus at Indiana University Bloomington, gathered scholarly evidence to refute the long-held view that natural selection acts almost exclusively on individual organisms competing for survival and reproduction.

Why it matters

The findings carry implications well beyond academic debate, touching fields as varied as cancer research and agriculture, and may shape society's fundamental understanding of how life on Earth evolves. The research has already influenced approaches in cancer biology and animal breeding, where multilevel selection is now recognized as a key driver of outcomes.

The details

The landmark study, led by researchers from Chile, the Netherlands and the U.S., systematically reviewed nearly 3,000 scientific articles published between 1900 and 2024, ultimately identifying 280 peer-reviewed studies that documented "multilevel selection" - the phenomenon in which natural selection operates simultaneously at two or more levels of biological organization. The studies spanned a wide range of organisms, from viruses and bacteria to social insects, wild animals, and humans.

  • The review traced its intellectual roots to laboratory experiments with flour beetles conducted by the study's co-author in the 1970s.
  • Of the 280 qualifying studies, 199 were published between 2012 and 2024, suggesting the multilevel selection framework is gaining traction across disciplines.

The players

Michael Wade

Distinguished Professor Emeritus of Biology in the College of Arts and Sciences at Indiana University Bloomington and co-author of the landmark study.

César Marín

Lead author of the study and researcher at Universidad Santo Tomás in Valdivia, Chile.

William Muir

Professor of animal sciences at Purdue University who conducted studies in the 1990s showing dramatic improvements in egg production and reduced mortality in hens selected at the group level rather than the individual level.

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What they’re saying

“The paper is significant because it surveys field and experimental research around the world on multilevel selection, based on experimental work that I've done, as well as the ensuing research of my students, and those influenced by this research.”

— Michael Wade, Distinguished Professor Emeritus, Biology (Mirage News)

“On the applied side, for several decades now, cancer biologists have described the origin and spread of malignant tumors as a multilevel selection process acting among cells in the human body. Moreover, animal breeders have turned to multilevel selection to increase things like egg yield and diminish feather pecking, a revolution in the way domestic animals and plants are reared.”

— Michael Wade, Distinguished Professor Emeritus, Biology (Mirage News)

What’s next

With new molecular tools, genomic methods, and long-term field datasets now available, the authors suggest that many more ground-breaking discoveries on multilevel selection are likely in the coming decades.

The takeaway

This landmark study upends the long-held view that natural selection acts solely on individual organisms, showing instead that evolution is shaped by selection operating simultaneously at multiple levels of biological organization, from genes to groups to entire communities. These findings have already influenced fields like cancer research and animal breeding, and may fundamentally reshape our understanding of how life on Earth evolves.