Biology & Philosophy

, Volume 31, Issue 2, pp 191–212 | Cite as

Levels of selection in biofilms: multispecies biofilms are not evolutionary individuals

  • Ellen ClarkeEmail author


Microbes are generally thought of as unicellular organisms, but we know that many microbes live as parts of biofilms—complex, surface-attached microbial communities numbering millions of cells. Some authors have recently argued in favour of reconceiving biofilms as biological entities in their own right. In particular, some have claimed that multispecies biofilms are evolutionary individuals (Doolittle in Biol Philos 28:351–378, 2013; Ereshefsky and Pedroso in PNAS USA 112(33): 10126–10132 2015). Against this view, I defend the conservative consensus that selection acts primarily upon microbial cells.


Multicellularity Bacteria Biofilm Individuality Organism Microbiology 



Very many thanks to Marc Ereshefsky and Maureen O’Malley who gave me invaluable feedback on earlier drafts of this paper, in addition to two referees, the young folk at All Souls College, and the audience at Philosophy of Biology in the UK 2014. I also received invaluable feedback and experience from Kevin Foster, Sara Mitri, Isabel Frost and Sarah Hammarlund as well as patient guidance from Kim Sterelny.


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© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.All Souls CollegeOxfordUK

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