Ernst Mayr,Karl Jordan,and the History of Systematics

Mayr's Ernst essay appeared as “Karl Jordan's contributions to current concepts in systematics and evolution”, Transactions of the Royal Entomological Society of London, cvii (1955), 45–66, and was reprinted in Mayr , Evolution and the diversity of life: Selected essays (Cambridge, MA, 1976) and, along with two of Jordan's papers, in Sterling Keir B. (ed.), Contributions to American systematics (New York, 1974). For biographical information on Jordan see Rothschild Miriam , “Karl Jordan: A biography”, Transactions of the Royal Entomological Society of London, cvii (1955), 1–14; idem, Dear Lord Rothschild (Glenside, PN, 1983); Riley N. D. , “Heinrich Ernst Karl Jordan”, Biographical memoirs of Fellows of the Royal Society, 1960, 107–33; and Jordan H. E. K. , in Williams E. T. Palmer H. M. (eds), Dictionary of national biography 1951–1960 (Oxford, 1971), 560–2. The “Jordan” volume is the 1955 issue of the Transactions of the Royal Entomological Society of London.

Mayr repeats the claim that Jordan and Poulton deserve credit for the clear definition of the biological species concept in Mayr Ernst , “The contribution of birds to evolutionary theory”, Acta XIX: Congressus Internationalis Ornithologici, ii (1988), 2718–23, p. 2720, and The growth of biological thought: Diversity, evolution and inheritance (Cambridge, MA, 1982), 272.

The word ‘synthesis’ to describe the developments in evolutionary theory in the 1930s and '40s, namely a reaffirmation of the role of natural selection operating upon small variations in producing evolutionary change, was first used by Huxley Julian in 1942 in his book Evolution: The modern synthesis (London, 1942). Recent historical analyses of the synthesis period include: Cain Joseph Allen , “Common problems and cooperative solutions: Organizational activity in evolutionary studies, 1936–1947”, Isis, lxxxiv (1993), 1–25; idem, “Ernst Mayr as community architect: Launching the Society for the Study of Evolution and the journal Evolution”, Biology and philosophy, ix (1994), 387–427; Harwood Jonathan , “Geneticists and the evolutionary synthesis in inter-war Germany”, Annals of science, xlii (1985), 279–301; idem, “Metaphysical foundations of the evolutionary synthesis: A historiographical note”, Journal of the history of biology, xxvii (1994), 1–20; Smocovitis Vassiliki Betty , “Unifying biology: The evolutionary synthesis and evolutionary biology”, Journal of the history of biology, xxv (1992), 1–65; idem, “Organizing evolution: Founding the Society for the Study of Evolution (1939–1950)”, Journal of the history of biology, xxvii (1994), 241–309; and idem, Unifying biology: The evolutionary synthesis and evolutionary biology (Princeton, 1995).

Winsor Mary P. , “Cain on Linnaeus: The scientist-historian as unanalysed entity”, Studies in history and philosophy of biological and biomedical sciences, xxxii (2001), 239–54; and Vernon Keith , “Desperately seeking status: Evolutionary systematics and the taxonomists' search for respectability, 1940–1960”, The British journal for the history of science, xxvi (1993), 207–27.

See Abir-Am Pnina G. , “Essay review: How scientists view their heroes. Some remarks on the mechanism of myth construction”, Journal of the history of biology, xv (1982), 281–315; Abir-Am Pnina G. Elliott Clark A. (eds), Commemorative practices in science: Historical perspectives on the politics of collective memory (Osiris, xiv (1999)); and Bensaude-Vincent Bernadette , “Between history and memory: Centennial and bicentennial images of Lavoisier”, Isis, lxxxvii (1996), 481–99.

For exceptional studies that examine the history of systematics on its own terms see Hagen Joel , “Experimentalists and naturalists in twentieth-century botany: Experimental taxonomy, 1920–1950”, Journal of the history of biology, xvii (1984), 249–70; idem, “Ecologists and taxonomists: Divergent traditions in twentieth-century plant geography”, Journal of the history of biology, xix (1986), 197–214; and idem, “Naturalists, molecular biologists, and the challenges of molecular evolution”, Journal of the history of biology, xxxii (1999), 321–41.

See Mayr Ernst , “Where are we?”, Cold Spring Harbor symposia on quantitative biology, xxiv (1959), 1–14. Also see his “The recent historiography of genetics”, Journal of the history of biology, vi (1973), 125–54; The growth of biological thought: Diversity, evolution and inheritance (Cambridge, MA, 1982); and his contributions to Mayr Ernst Provine William , The evolutionary synthesis: Perspectives on the unification of biology (Cambridge, MA, 1980), and the preface to the 1998 edition.

The museum's public gallery is now known as the Walter Rothschild Zoological Museum, and the grounds now house the Natural History Museum (NHM), London's ornithological collection. The museum was variously known as “Rothschild's Museum” and the “Tring Museum”. Records are currently held as the Tring Museum Correspondence at the NHM Archives.

Jordan Karl , “The President's Address”, Proceedings of the Royal Entomological Society of London, iv (1930), 128–42, p. 140.

On Hartert and the work of ornithologists studying subspecies more generally, including Mayr, see Stresemann Erwin , Ornithology: From Aristotle to the present (Cambridge, MA, 1975); Haffer J. H. , “Die Seebohm-Hartert-‘Schule’ der europäischen Ornithologie”, Journal für Ornithologie, cxxxv (1994), 37–54; and idem, “The history of species concepts and species limits in ornithology”, Bulletin of the British Ornithologists' Club centenary supplement, cxii (1992), 107–58. On trinomials in ornithology in the United States, see Barrow Mark , A passion for birds (Princeton, NJ, 1998).

See, for example, Burkhardt Frederick , “England and Scotland: The learned societies”, in Glick T. F. (ed.), The comparative reception of Darwinism (Austin, 1974), 32–74.

Jordan Karl , “Notes in and Introduction to: W. Rothschild, ‘A Revision of the Papilios of the eastern hemisphere, exclusive of Africa’”, Novitates zoologicae, ii (1895), 167–463, pp. 180–1.

Rothschild Walter Jordan Karl , “Lepidoptera collected by Oscar Neumann”, Novitates zoologicae, x (1903), 491–542, p. 496.

Jordan Karl , “An examination of the classificatory and some other results of Eimer's researches on eastern Papilios”, Novitates zoologicae, v (1898), 435–55, p. 454.

Rothschild Jordan , “Lepidoptera collected by Oscar Neumann” (ref. 13), 499.

Rothschild Walter Jordan Karl , “A Revision of the Lepidopterous family Sphingidae”, Novitates zoologicae, ix (1903), Supplement, p. xlii, their italics.

Jordan Karl , “On mechanical selection and other problems”, Novitates zoologicae, iii (1896), 426–525, pp. 446 and 449.

On Romanes see Lesch John E. , “The role of isolation in evolution: George J. Romanes and John T. Gulick”, Isis, lxvi (1975), 483–503.

Jordan , “On mechanical selection” (ref. 17), 427, 428 and 441.

Ibid., 442 and 436.

Ibid., 450–1.

Ibid., 442.

On these debates see Bowler Peter , The eclipse of Darwinism: Anti-Darwinian evolution theories in the decades around 1900 (Baltimore, 1983).

Rothschild Jordan , “A revision of the Sphingidae” (ref. 16), pp. i, xxix, and xxix.

Ibid., p. xxx.

Jordan , “On mechanical selection” (ref. 17), 451.

Jordan Karl , “The species problem as seen by a systematist”, Proceedings of the Linnean Society of London, cl (1938), 241–7, p. 241.

From a letter dated 28 March 1923 quoted in Allen Garland E. , Thomas Hunt Morgan: The man and his science (Princeton, 1978), 313.

Hampson G. F. to Rothschild W. , 8 October 1894, Tring Museum Correspondence (TM) 1/7/13, Natural History Museum (NHM) Archives.

Ball E. D. to Van Duzee E. , 1 September 1927, Ball E. D. , Papers Box 4, SIA 7121, Smithsonian Institution, Washington, D.C.

Butler A. G. to Dixey F. A. , 26 May 1917, Dixey Correspondence, Hope Library Archives, Oxford University Museum of Natural History. Butler was seventy-three at the time.

Jordan , “An examination” (ref. 14), 445.

Van Duzee Edward to Ball E. D. , 17 August 1935, Ball E. D. Papers, Box 3, SIA 7121.

Schaus William to Janse A. J. T. , 1928, William Schaus Papers, Box 6, SIA RU007100.

Mayr Ernst , pers. com., November 2003.

Mayr Ernst to Jordan Karl , 11 March 1942, TM, Karl Jordan Correspondence (KJC) #5, NHM Archives.

Jordan Karl to Mayr Ernst , 29 April 1942, KJC #3, NHM Archives.

Jordan Karl to Mayr Ernst , 4 April 1942, KJC #3, NHM Archives.

Mayr Ernst to Jordan Karl , 25 March 1942, KJC #3, NHM Archives.

Jordan Karl to Steinicke Franz , 27 January 1947, KJC #5, NHM Archives (translation).

Jordan Karl to Radford Charles D. , 17 December 1947, KJC #5, NHM Archives.

Riley N. D. to Schaus William , 4 June 1933, Schaus Papers, Box 10, SIA RU007100.

Salmon Michael A. , The Aurelian legacy: British butterflies and their collectors (Berkeley, 2000), 219.

Jordan Karl to Moss Miles , 13 February 1938, MSS MILES C 7:7, NHM Entomology Library.

Jordan Karl to Mayr Ernst , 29 April 1942, KJC #3, NHM Archives.

Jordan Karl to Moss Miles , 4 May 1942, MSS MILES C 7:7, NHM Entomology Library.

Winsor Mary P. , Reading the shape of nature: Comparative zoology at the Agassiz Museum (Chicago, 1991), p. xiii.

Cain , “Ernst Mayr as community architect” (ref. 3), 416 and 417.

Mayr Ernst to Schmitt Waldo , 17 February 1948 and 9 March 1948, quoted in Cain, “Ernst Mayr as community architect” (ref. 3), 418.

Cain , “Ernst Mayr as community architect” (ref. 3), 419.

Clench Harry to Mayr Ernst , 21 December 1953, HUG(FP) 74.7, Box 2, Folder 531, Harvard University (HU) Archives.

Mayr Ernst to Clench Harry , 4 January 1954, HUG(FP) 74.7, Box 2, Folder 531, HU Archives.

Mayr Ernst to Clench Harry , 11 March 1954, HUG(FP) 74.7, Box 3, Folder 572, HU Archives. Title from Ernst Mayr to Eugene Munroe, 22 April 1954, HUG(FP) 74.7, Box 2, Folder 563, HU Archives.

Mayr Ernst to Clench Harry , 11 March 1954, HUG(FP) 74.7, Box 3, Folder 572, HU Archives.

Burma B. , “The species concept: A semantic review”, Evolution, iii (1949), 369–70, p. 370.

Mayr Ernst , “The species concept: Semantics versus semantics”, Evolution, iii (1949), 371–2.

Meinertzhagen Richard to Mayr Ernst , 16 February 1954, HUG(FP) 74.7, Box 2, Folder 540, HU Archives.

Mayr Ernst to Meinertzhagen Richard , 23 February 1954, HUG(FP) 74.7, Box 2, Folder 540, HU Archives.

Wilson E. O. Brown W. L. Jr , “The subspecies concept and its taxonomic application”, Systematic zoology, ii (1953), 97–111, pp. 106 and 108.

Mayr Ernst , “Notes on nomenclature and classification”, Systematic zoology, iii (1954), 86–89.

Mayr Ernst to Lack David , 24 November 1954, HUG(FP) 74.7, Box 3, Folder 577, HU Archives.

Mayr Ernst to Goldschmidt Richard , 19 October 1954, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

Mayr , “Karl Jordan's contributions” (ref. 1), 46.

Ibid., 50–53.

Ibid., 45.

For his previous historical work see Mayr Ernst , “Bernard Altum and the territory theory”, Proceedings of the Linnaean Society of New York, xlv/xlvi (1935), 24–38, and “The naturalist in Leidy's time and today”, Proceedings of the Academy of Natural Sciences of Philadelphia, xcviii (1946), 271–6.

Mayr , “Karl Jordan's contributions” (ref. 1), 57.

Chung has described how Mayr's use of a distinction between population and typological thinking was first formulated in his 1955 essay on Jordan. See Chung Carl , “On the origin of the typological/population distinction in Ernst Mayr's changing views of species, 1942–1959”, Studies in history and philosophy of biological and biomedical sciences, xxxiv (2003), 277–96.

Mayr Ernst , pers. com., November 2003.

Mayr , “Karl Jordan's contributions” (ref. 1), 59 and 62.

Zimmerman Elwood to Mayr Ernst , 6 February 1955, HUG(FP) 74.7, Box 3, Folder 600, HU Archives.

Mayr Ernst to Rothschild Miriam , 21 March 1955, HUG(FP) 74.7, Box 3, Folder 596, HU Archives.

Mayr Ernst to Jordan Karl , 23 March 1955, HUG(FP) 74.7, Box 3, Folder 591, HU Archives.

Mayr Ernst to Just Theodore , 10 February 1955, HUG(FP) 74.7, Box 3, Folder 591, HU Archives.

Mayr Ernst to Bronk Detlev , NAS, 25 February 1956, HUG(FP) 74.7, Box 4, Folder 625, HU Archives.

Mayr Ernst to Mather Kirtley F. , 4 March 1958, HUG(FP) 74.7, Box 2, Folder 688, HU Archives.

Mayr Ernst to Mather Kirtley F. , 4 March 1958, HUG(FP) 74.7, Box 2, Folder 688, HU Archives.

Hopkins Harry to Mayr Ernst , 13 January, 1959, HU(FP) 74.7, Box 6, Folder 715, HU Archives.

Mayr Ernst , “Difficulties and importance of the biological species concept”, in Mayr Ernst (ed.), The species problem (New York, 1974), 371–87, p. 371.

Mayr Ernst , “Species concepts and definitions”, American Association for the Advancement of Science, Publication no. 50 (1957), 1–22, p. 5.

Mayr , “Recent historiography of genetics” (ref. 7), 149. William Provine has pointed out that Mayr has often not given enough attention to naturalists' non-adaptionist theories. See his “The development of Wright's theory of evolution: Systematics, adaptation, and drift”, in Greene Marjorie (ed.), Dimensions of Darwinism (Cambridge and New York, 1983), 43–70.

Mayr , “Where are we?” (ref. 7), 3.

Mayr Ernst , “Isolation as an evolutionary factor”, Proceedings of the American Philosophical Society, ciii (1959), 221–30, p. 221.

Goldschmidt Richard to Mayr Ernst , undated, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

For example, Mayr Ernst to Lack David , 26 August 1941, HUG(FP) 74.7, Box 2, Folder 81, HU Archives.

Mayr Ernst to Moore John (Department of Zoology, University of Sydney), 15 February 1953, HUG(FP) 74.7, Box 1, Folder 499, HU Archives.

Mayr Ernst to Goldschmidt Richard (Department of Zoology, University of California, Berkeley), 14 September 1954, HUG(FP) 74.7, Box 2, Folder 558, HU Archives.

Goldschmidt Richard to Mayr Ernst , undated, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

Goldschmidt Richard , “Letter to Dr. Jordan”, Transactions of the Royal Entomological Society of London, 1955, 13–14, p. 13.

Mayr , “Karl Jordan's contribution” (ref. 1),45.

Poulton E. B. , “What is a species?”, Proceedings of the Entomological Society of London, 1904, pp. lxxvii–cxvi, p. ci.

Mayr Ernst to Goldschmidt Richard , 19 October 1954, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

Mayr , “Recent historiography of genetics” (ref. 7), 128.

Wilson Brown , “The subspecies concept” (ref. 59), 99. Mallet notes that this paper “was enormously influential on systematics in the USA, and generations of systematists trained at Harvard and Cornell, where Wilson and Brown worked, and their own many intellectual descendants, and their students' students in turn, have eschewed the practice of naming subspecies”. Mallet James , “Subspecies, semispecies, superspecies”, in Levin S. (eds), Encyclopedia of biodiversity (New York, 2001), v, 523–6. Bock, by contrast, insists Wilson and Brown's paper had little influence on systematists (Walter Bock, pers. com. 10 October 2004).

Wilson Brown , “The subspecies concept” (ref. 59), 101.

Gosline William A. , “Further thoughts on subspecies and trinomials”, Systematic zoology, iii (1954), 92–94.

Sabrosky Curtis W. , “Postscript to a survey of infraspecific categories”, Systematic zoology, iv (1955), 141–2, p. 142. See “Entomological usage of subspecific names”, Entomological news, li (1940), 159–64 for his original survey.

Hubbell Theodore H. , “Entomology: The naming of geographically variant populations, or what is all the shooting about?”, Systematic zoology, iii (1954), 113–21, p. 114.

Mayr Ernst to Hubbell Theodore H. , 9 February 1954, HUG(FP) 74.7, Box 2, Folder 536, HU Archives.

Hubbell Theodore H. to Mayr Ernst , 17 February 1954, HUG(FP) 74.7, Box 2, Folder 531, HU Archives.

The discussion regarding subspecies, the use of trinomials, and infraspecific variation in general, continued into the following volumes of Systematic zoology, including defences by Starrett Andrew , Smith Herbert M. White Fred N. Durrant S. , Arguments for trinomials and subspecies, with the recognition that such terms had come to mean different things depending on the class of organisms under consideration, were offered by Tilden J. W. , “Certain comments on the subspecies problem”, Systematic zoology, x (1961), 17–23, and others. Earlier commentaries can be found in Rosendahl Carl Otto , “The problem of subspecific categories”, American journal of botany, xxxvi (1949), 24–27.

For a more recent discussion among ornithologists regarding the usefulness or otherwise of subspecies, see the discussion “Forum: Avian subspecies in the 1980s”, in the 1982 issue of The auk.

Honey Martin R. Scoble Malcolm J. , “Linnaeus's butterflies (Lepidoptera: Papilionoidea and Hesperioidea)”, Zoological journal of the Linnean Society, cxxxii (2001), 277–399.

See Farber Paul Lawrence , “Theories for the birds: An inquiry into the significance of the theory of evolution for the history of systematics”, in Osler Margaret and Farber Paul Lawrence (eds), Religion, science, and worldview: Essays in honor of Richard S. Westfall (Cambridge, 1985), 321–39.

I should emphasize that whether entomologists' arguments against naming subspecies were valid or not is irrelevant to my argument that their concerns illustrate how non-conceptual factors have influenced what work was done. For an argument that the consideration of systematics practice should have no bearing on the value of the biological species concept, and that the latter can be assessed only through a consideration of its role within evolutionary theory, see Bock Walter , “Species: The concept, category and taxon”, Journal of zoological systematics and evolutionary research, xlii (2004), 178–90.

Jordan Karl to Riley N. D. , 12 December 1954, DF306/9, NHM Archives.

Rothschild Miriam to Mayr Ernst , 2 March 1955, HUG(FP) 74.7, Box 3, Folder 596, HU Archives.

See Greene John C. , “From Aristotle to Darwin: Reflections on Ernst Mayr's interpretation in The Growth of Biological Thought”, Journal of the history of biology, xxv (1992), 257–84; and Junker Thomas , “Factors shaping Ernst Mayr's concepts in the history of biology”, Journal of the history of biology, xxix (1996), 29–77. Various perspectives are also given in the numerous reviews of The growth of biological thought, discussed in Ruse Michael , “Admayration”, Quarterly review of biology, lx (1985), 183–92. For critiques of Mayr's description of pre-Darwinian systematics as typological, see Farber Paul Lawrence , “A historical perspective on the impact of the type concept on insect systematics”, Annual review of entomology, xxiii (1978), 91–99; idem, “The type concept in zoology during the first half of the nineteenth century”, Journal of the history of biology, ix (1976), 93–119; Stevens Peter F. , “Why do we name organisms? Some reminders from the past”, Taxon, li (2002), 11–26; and Winsor Mary P. , “Non-essentialist methods in pre-Darwinian taxonomy”, Biology and philosophy, viii (2003), 387–400.

Sloan Phillip R. , “Essay review: Ernst Mayr on the history of biology”, Journal of the history of biology, xviii (1985), 145–53, pp. 146–7. Also see Burkhardt Richard W. Jr , “Ernst Mayr: Biologist-historian”, Biology and philosophy, ix (1994), 359–71 on Mayr's use of history “to illuminate and advance a contemporary biological issue” (p. 362). Burkhardt also takes Mayr to task, in the case of his analysis of Lamarck, for not reflecting more on the role of Lamarck's practice as a cabinet naturalist in influencing his theoretical judgements (p. 365). Also see Beatty John , “The proximate/ultimate distinction in the multiple careers of Ernst Mayr”, Biology and philosophy, ix (1994), 333–56.

Mayr Ernst , “When is historiography Whiggish?”, Journal of the history of ideas, li (1990), 301–9, p. 305.

Mayr , “The recent historiography of genetics” (ref. 7), 128.

Greene , “From Aristotle to Darwin” (ref. 109).

Essays in Mayr Provine (eds), The evolutionary synthesis (ref. 7); Provine William B. , The origins of theoretical population genetics (Chicago, 1971); “Francis B. Sumner and the evolutionary synthesis”, Journal of the history of biology, iii (1979), 211–40; and idem, “The role of mathematical population geneticists in the evolutionary synthesis of the 1930s and 1940s”, Studies in the history of biology, ii (1978), 167–92. Mayr restates his synthesis story in “What was the evolutionary synthesis?”, Trends in ecology and evolution, viii (1992), 31–34, and, most recently, in “80 years of watching the evolutionary scenery”, Science, cccv (2004), 46–47.

Allen Garland E. , Life science in the twentieth century (New York, 1975), and “Naturalists and experimentalists: The genotype and the phenotype”, Studies in the history of biology, iii (1979), 179–209. See also Magnus David , “Theory, practice, and epistemology in the development of species concepts”, Studies in history and philosophy of science, xxvii (1996), 521–45. Since the early eighties, historians have usefully qualified this experimentalist-naturalist dichotomy in various ways. Most recently see Largent Mark A. , “Bionomics: Vernon Lyman Kellogg and the defense of Darwinism”, Journal of the history of biology, xxxii (1999), 465–88; and Kraft Alison Alberti Samuel J. M. M. , “‘Equal though different’: Laboratories, museums, and the institutional development of biology in late-Victorian northern England”, Studies in history and philosophy of biological and biomedical sciences, xxxiv (2003), 203–36.

Chung , “On the origin of the typological/population distinction” (ref. 68), 292. Chung examines how Mayr's 1955 paper accomplished this by establishing a new major contrast between the typological species concept on the one hand and the two biological concepts (the non-dimensional species concept of the old naturalists, and the multidimensional one of the new) on the other, and so unified what had been in fact disparate concepts of species.

Mayr Ernst , “Systematics: The role of systematics in the evolutionary synthesis”, in Mayr Provine , The evolutionary synthesis (ref. 7), 123–36, p. 123.

For additional important studies on the history of systematics, see the works by Haffer (ref. 10), Hagen (ref. 6), and Farber (refs 105 and 109) cited above, and: Winsor Mary P. , Starfish, jellyfish and the order of life (New Haven, 1976); idem, “Louis Agassiz and the species question”, Studies in history of biology, iii (1979), 89–117; idem, “The impact of Darwinism upon the Linnaean enterprise, with special reference to the work of T. H. Huxley”, in Weinstock John (ed.), Contemporary perspectives on Linneaus (New York, 1985), 55–84; idem, Reading the shape of nature (ref. 47); and Henson Pamela M. , “Evolution and taxonomy: John Henry Comstock's research school in evolutionary entomology at Cornell University, 1874–1930”, Ph.D. dissertation, University of Maryland, 1990.

Ruse Michael “Booknotes”, Biology and philosophy, ix (1994), 429–35, p. 430.

By contrast, Cain points out that Mayr's firsthand knowledge about intraspecific and geographic variation also arose from his research in the “excellent collections at the American Museum” ( Cain , “Common problems and cooperative solutions” (ref. 3), 19). Walter Bock also provides a detailed analysis of how Mayr's 1942 book and his subsequent theoretical work cannot be understood without taking into account the empirical foundation of this work, namely, to curate and study the huge collections at the American Museum of Natural History. See Bock Walter J. , “Ernst Mayr, naturalist: His contributions to systematics and evolution”, Biology and philosophy, ix (1994), 267–327.

Ruse , “Booknotes” (ref. 119), 433.

Mayr Ernst , Systematics and the origin of species from the viewpoint of a zoologist (New York, 1942), p. xii.

Ibid., 4.

Mayr Ernst to Schmitt Waldo , 9 March 1948, quoted in Cain, “Ernst Mayr as community architect” (ref. 3),418.

For example, see Mayr , “Difficulties and importance of the biological species concept” (ref. 79).

Mayr Ernst , “Fifty years of progress in research on species and speciation”, Proceedings of the California Academy of Sciences, xlviii (1993), 131–40, pp. 133–4.

See Mayr Ernst Ashlock P. D. , Principles of systematic zoology, 2nd edn (New York, 1991), 100–5.

Mayr Ernst , “Of what use are subspecies?”, The auk, xcix (1982), 593–5, p. 594.

Mayr Ernst , “A defense of the biological species concept”, in Wheeler Quentin D. Meier Rudolf (eds), Species concepts and phylogenetic theory: A debate (New York, 2000), 161–6, p. 161. Stevens notes that this tension between the extrapolation from the biological species concept to taxonomic species pervades Mayr's work, and that subspecies nomenclature was justified on evolutionary, rather than pragmatic, grounds. Stevens Peter F. , “Species: Historical perspectives”, in Keller Evelyn Fox Lloyd Elisabeth A. (eds), Keywords in evolutionary biology (Cambridge, MA, 1992), 302–11, p. 306.

Mayr Ernst to Hopkins Harry , 28 January 1959, HUG(FP) 74.7, Box 6, Folder 715, HU Archives.

See Ehrlich Paul , “Has the biological species concept outlived its usefulness?”, Systematic zoology, x (1961), 167–76. Mayr notes, however, that Ehrlich later became a strong supporter of the biological species concept (Ernst Mayr, pers. com., 8 August 2004). On the debates over systematics see Part I of Hull David , Science as process: An evolutionary account of the social and conceptual development of science (Chicago, 1988) and the works by Hagen (ref. 6) and Vernon (ref. 4). The latter notes that one of the problems inspiring numerical taxonomists was that data on breeding structure and geographic distribution necessary for evidence of evolutionary relationships were usually unknown, and that the primary evidence was therefore still morphological resemblance. See Vernon Keith , “The founding of numerical taxonomy”, The British journal for the history of science, xxi (1988), 143–59, p. 146.

Coyne claims that much of the anti-biological species concept literature “leaves the solid ground of biology for the marshy hinterlands of philosophy”. See Coyne Jerry A. , “Ernst Mayr and the origin of species”, Evolution, xlviii (1994), 19–30, p. 22.

Farber Paul Lawrence , Discovering birds: The emergence of ornithology as a scientific discipline: 1760–1850 (Baltimore, 1997; originally published London, 1982), p. x, and Farber , “Theories for the birds” (ref. 105). Also see Winsor , “The impact of Darwinism” (ref. 118), 84.

For a manifesto to including variation as an analytical category in the historiography of the life sciences on several levels, both organismal and cultural, see Geison Gerald L. Laubichler Manfred D. , “The varied lives of organisms: Variation in the historiography of the biological sciences”, Studies in history and philosophy of biological and biomedical sciences, xxxii (2001), 1–29.