Multicellularity and sex helped shape the Tree of Life

Lian Chen, John J. Wiens

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Across the Tree of Life, there are dramatic differences in species numbers among groups. However, the factors that explain the differences among the deepest branches have remained unknown. We tested whether multicellularity and sexual reproduction might explain these patterns, since the most species-rich groups share these traits. We found that groups with multicellularity and sexual reproduction have accelerated rates of species proliferation (diversification), and that multicellularity has a stronger effect than sexual reproduction. Patterns of species richness among clades are then strongly related to these differences in diversification rates. Taken together, these results help explain patterns of biodiversity among groups of organisms at the very broadest scales. They may also help explain the mysterious preponderance of sexual reproduction among species (the 'paradox of sex') by showing that organisms with sexual reproduction proliferate more rapidly.

Original languageEnglish (US)
Article number20211265
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1955
StatePublished - Jul 28 2021


  • bacteria
  • diversification
  • multicellularity
  • phylogeny
  • sex
  • species richness

ASJC Scopus subject areas

  • General Immunology and Microbiology
  • General Biochemistry, Genetics and Molecular Biology
  • General Environmental Science
  • General Agricultural and Biological Sciences


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