Inordinate fondness multiplied and redistributed: The number of species on earth and the new pie of life

Brendan B. Larsen, Elizabeth C. Miller, Matthew K. Rhodes, John J. Wiens

Research output: Contribution to journalArticlepeer-review

185 Scopus citations


The number of species on Earth is one of the most fundamental numbers in science, but one that remains highly uncertain. Clearly, more species exist than the present number of formally described species (approximately 1.5 million), but projected species numbers differ dramatically among studies. Recent estimates range from about 2 million species to approximately 1 trillion, but most project around 11 million species or fewer. Numerous studies have focused on insects as a major component of overall richness, and many have excluded other groups, especially non-eukaryotes. Here, we re-estimate global biodiversity. We also estimate the relative richness of the major clades of living organisms, summarized as a “Pie of Life.” Unlike many previous estimates, we incorporate morphologically cryptic arthropod species from molecular-based species delimitation. We also include numerous groups of organisms that have not been simultaneously included in previous estimates, especially those often associated with particular insect host species (including mites, nematodes, apicomplexan protists, microsporidian fungi, and bacteria). Our estimates suggest that there are likely to be at least 1 to 6 billion species on Earth. Furthermore, in contrast to previous estimates, the new Pie of Life is dominated by bacteria (approximately 70-90% of species) and insects are only one of many hyperdiverse groups.

Original languageEnglish (US)
Pages (from-to)229-265
Number of pages37
JournalQuarterly Review of Biology
Issue number3
StatePublished - Sep 2017


  • Arthropods
  • Bacteria
  • Biodiversity
  • Cryptic species
  • Parasites
  • Species richness

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences


Dive into the research topics of 'Inordinate fondness multiplied and redistributed: The number of species on earth and the new pie of life'. Together they form a unique fingerprint.

Cite this