Species Concepts are Dynamic . . . and Crap

Because I haven’t riled up Wilkins in a while.

I was chatting with a friend who has published a fairly high profile article on speciation about species concepts. We came to the conclusion that species concepts are useless unless they guide future research. Okay, we were just echoing Coyne ‘n Orr.

As crappy as the biological species concept is, the BSC is really good for guiding research on the evolution of pre-zygotic, intrinsic reproductive isolation. I realize this is entirely circular (the BSC states that speciation has occurred when reproductive isolation is achieved). All of the research I follow on speciation falls into this category; I don’t read about speciation in non-sexually reproducing organisms.

How do people study speciation in asexually reproducing organisms? Better yet, is it even worthwhile to study speciation in asexually reproducing organisms? Just because speciation in sexually reproducing organisms (and, by speciation, I mean intrinsic prezygotic isolation) is really cool — and it is, not just because I have friends doing it — doesn’t mean that people need to study “speciation” in other taxa.

So, species concepts are useless unless you can define speciation in those taxa. If it’s just divergence, it don’t count. Wilkins, the ball’s in your court. Tell me why I’m wrong — include lots of links to articles I should read before I engage in uninformed punditry.


  1. #1 John Wilkins
    January 23, 2007

    I’m a tad busy right now with grants and stuff. But as it happens I have 80% of a Basic Concepts post done on species. When I put it up, I’ll have a go at this.

    But you might go and look at these papers:

    Lymbery, A. J. 1992. Interbreeding, monophyly and the genetic yardstick: Species concepts in parasites. Parasitol Today 8 (6):208-11.
    Sterelny, Kim. 1994. The nature of species. Philosophical Books 35 (1):9-20.
    Istock, C. A., J. A. Bell, N. Ferguson, and N. L. Istock. 1996. Bacterial species and evolution: Theoretical and practical perspectives. Journal of Industrial Microbiology and Biotechnology 17 (3 – 4):137-150.
    Moreno, E. 1997. In search of a bacterial species definition. Revista de Biologia Tropical 45 (2):753-71.
    Snow, N. 1997. Application of the phylogenetic species concept: a botanical monographic perspective. Austrobaileya 5 (1):1-8.
    Dykhuizen, D. E. 1998. Santa Rosalia revisited: Why are there so many species of bacteria? Antonie Van Leeuwenhoek 73 (1):25-33.
    Schloegel, Judy Johns. 1999. From Anomaly to Unification: Tracy Sonneborn and the Species Problem in Protozoa, 1954-1957. Journal of the History of Biology 32 (1):93-132.
    Taylor, J. W., D. J. Jacobson, and M. C. Fisher. 1999. The evolution of asexual fungi: reproduction, speciation and classification. Annual Review of Phytopathology 37:197-246.
    Cohan, Frederick M. 2001. Bacterial species and speciation. Systematic Biology 50 (4):513-524.
    Lan, R., and P. R. Reeves. 2001. When does a clone deserve a name? A perspective on bacterial species based on population genetics. Trends Microbiol 9 (9):419-424.
    Lawrence, Jeffrey G. 2001. Catalyzing Bacterial Speciation: Correlating Lateral Transfer with Genetic Headroom. Sys t. Biol. 50 (4):479-496.
    Cohan, F. M. 2002. What are bacterial species? Annu Rev Microbiol 56:457-87.
    Paster, B. J., W. A. Falkler, Jr., C. O. Enwonwu, E. O. Idigbe, K. O. Savage, V. A. Levanos, M. A. Tamer, R. L. Ericson, C. N. Lau, and F. E. Dewhirst. 2002. Prevalent Bacterial Species and Novel Phylotypes in Advanced Noma Lesions. J. Clin. Microbiol. 40 (6):2187-2191.
    Germond, Jacques-Edouard, Luciane Lapierre, Michele Delley, Beat Mollet, Giovanna E. Felis, and Franco Dellaglio. 2003. Evolution of the Bacterial Species Lactobacillus delbrueckii: A Partial Genomic Study with Reflections on Prokaryotic Species Concept. Mol Biol Evol 20 (1):93-104.
    Wertz, J. E., C. Goldstone, D. M. Gordon, and M. A. Riley. 2003. A molecular phylogeny of enteric bacteria and implications for a bacterial species concept. J Evol Biol 16 (6):1236-48.
    Finlay, B. J. 2004. Protist taxonomy: an ecological perspective. Philos Trans R Soc Lond B Biol Sci 359 (1444):599-610.
    Spratt, B. G. 2004. Exploring the concept of clonality in bacteria. Methods Mol Biol 266:323-52.
    Ochman, Howard, Emmanuelle Lerat, and Vincent Daubin. 2005. Examining bacterial species under the specter of gene transfer and exchange. PNAS 102 (Suppl 1): 6595-9.
    Hanage, W., C. Fraser, and B. Spratt. 2006. Sequences, sequence clusters and bacterial species. Philosophical Transactions of the Royal Society B: Biological Sciences 361 (1475):1917-1927.
    Konstantinidis, K., A. Ramette, and J. Tiedje. 2006. The bacterial species definition in the genomic era. Philosophical Transactions of the Royal Society B: Biological Sciences 361 (1475):1929-1940.
    Staley, J. 2006. The bacterial species dilemma and the genomic-phylogenetic species concept. Philosophical Transactions of the Royal Society B: Biological Sciences 361 (1475):1899-1909.

  2. #2 John Wilkins
    January 23, 2007

    Oh, and by BJC did you intend BSC?

  3. #3 RPM
    January 23, 2007

    yeah, BSC. the typo was made in haste. it’s fixed.

    Damn buildings on campus have similar acronyms to biological terms.

  4. #4 Matt
    January 23, 2007

    If you think animal species concepts are problematic- try bacteria. It’s a nightmare I try and tackle (unsuccessfully) here and here.

  5. #5 Matt
    January 23, 2007

    I think that in both sexually and non-sexually reproducing species, that something like the phylogenetic species concept is pretty useful- aside from the main problem of deciding what distance represents a “species”

    I agree with you though, the species concepts are in general not all that useful- and are a product of human imagination. The world is much more continuous that the rigid application of species definitions allows it to be..

  6. #6 Josh
    January 23, 2007

    I have for a long while been trying to coin the term “Pornographic Species Concept” after the great Potter Stewart… “I know it when I see it.” Which is not to say that there are not species divisions about which we can disagree, but each researcher’s definition of species is likely specific (no pun intended, though it should have been)to the questions he is interested in. And that is just fine.

  7. #7 Matt
    January 23, 2007

    Pornographic species concept= A is different species than B if A won’t mate with B??? So Josh- how many primate species do you list? 1, 2??

    OK- just having fun here…

  8. #8 Bob
    January 23, 2007

    Wow, that’s quite a reading list from John who’s, “a tad busy.” Wonder what he’d have assigned if he’d had the time to do it properly!


  9. #9 John Wilkins
    January 23, 2007

    My Species post is up here:


    I have made a few pre-emptive strikes against you there.

    I also give a reason to think species are phenomenal objects, not theoretical, and so the Potter Test would do fine here.

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