The Accidental Species: Misunderstandings of Human Evolution

by Henry Gee

  26 R. J. Aldridge et al., “The anatomy of conodonts,” Philosophical Transactions of the Royal Society of London B 340 (1993): 405–421; R. J. Aldridge et al., “The affinities of conodonts: New evidence from the Carboniferous of Edinburgh, Scotland,” Lethaia 19 (1986): 279–291.

  27 A. Blieck et al., “Fossils, histology, and phylogeny: Why conodonts are not vertebrates,” Episodes 33 (2010): 234–241; A. Kemp, “Hyaline tissue of thermally unaltered conodont elements and the enamel of vertebrates,” Alcheringa 2 (2008): 23–36.

  28 J. J. Sepkoski, “A compendium of fossil marine animal genera,” Bulletins of American Paleontology 363 (2002): 1–560. It lives on as the Paleobiology Database, http://paleodb.org/cgi-bin/bridge.pl.

  29 See for example J. Alroy et al., “Phanerozoic trends in the global diversity of marine invertebrates,” Science 321 (1998): 97–100; J. Alroy, “The shifting balance of diversity among major marine animal groups,” Science 329 (2010): 1191–1194; C. R. Marshall, “Marine biodiversity dynamics over deep time,” Science 329 (2010): 1156–1157.

  30 Paleontologists express this uncertainty as the “Signor-Lipps effect,” after the two paleontologists who discussed the issues. See P. W. Signor III and J. H. Lipps, “Sampling bias, gradual extinction patterns, and catastrophes in the fossil record,” in L. T. Silver and P. H. Schultz, eds., Geological implications of impacts of large asteroids and comets on the earth, Geological Society of America Special Publication 190 (Boulder, CO: Geological Society of America, 1982), 291–296.

  31 See for example S. E. Peters, “Environmental determinants of extinction selectivity in the fossil record,” Nature 454 (2008): 626–629; S. E. Peters and M. Foote, “Determinants of extinction in the fossil record,” Nature 416 (2002): 420–424; A. B. Smith, “Large-scale heterogeneity of the fossil record: Implications for Phanerozoic biodiversity studies,” Philosophical Transactions of the Royal Society of London B 356 (2001): 351–367; P. M. Barrett et al., “Dinosaur diversity and the rock record,” Proceedings of the Royal Society of London B 276 (2009): 2667–2674; G. T. Lloyd et al., “Quantifying the deep-sea rock and fossil record bias using coccolithophores,” Geological Society, London, Special Publications 358 (2011): 167–177.

  32 A few are known from rocks of the same age in nearby Orkney.

  33 See for example W. J. Sollas and I. G. B. Sollas, “An account of the Devonian fish, Palaeospondylus gunni, Traquair,” Philosophical Transactions of the Royal Society of London B 196 (1904): 267–294; J. A. Moy-Thomas, “The Devonian fish Palaeospondylus gunni Traquair,” Philosophical Transactions of the Royal Society of London B 230 (1940): 391–413; K. S. Thomson et al., “A larval Devonian lungfish,” Nature 426 (2003): 833–834; M. J. Newman and J. L. Den Blaauwen, “New information on the enigmatic Devonian vertebrate Palaeospondylus gunni,” Scottish Journal of Geology 44 (2008): 89–91.

  CHAPTER 5

  1 R. Lee, “The outlook for population growth,” Science 333 (2011): 569–573.

  2 T. Benton, “Oceans of garbage,” Nature 352 (1991): 113.

  3 H. Kaessmann et al., “Great ape DNA sequences reveal a reduced diversity and an expansion in humans,” Nature Genetics 27 (2001): 155–156; H. Kaessmann et al., “Extensive nuclear DNA sequence diversity among chimpanzees,” Science 286 (1999): 1159–1162; Chimpanzee Sequencing and Analysis Consortium, “Initial sequence of the chimpanzee genome and comparison with the human genome,” Nature 437 (2005): 69–87.

  4 C. D. Huff et al., “Mobile elements reveal small population size in ancient ancestors of Homo sapiens,” Proceedings of the National Academy of Sciences of the USA 107 (2010): 2147–2152. I should perhaps add a note here about the term “effective population size” used in studies such as this. The effective population size (Ne) is not the gross number of individuals in a population, but the number that contribute genes to the next generation. This is typically a much smaller number, given that many individuals in a population will die before reproducing, and a few individuals (such as dominant males) will contribute disproportionately to the gene pool—but it’s the number that matters when one is tracking changes in genetic diversity.

  5 S. R. Copeland et al., “Strontium isotope evidence for landscape use by early hominins,” Nature 474 (2011): 76–78.

  6 A. Manica et al., “The effect of ancient population bottlenecks on human phenotypic variation,” Nature 448 (2007): 346–348.

  7 M. H. Wolpoff, “Competitive exclusion among Lower Pleistocene hominids: The single species hypothesis,” Man 6 (1971): 601–614.

  8 R. E. F. Leakey and A. C. Walker, “Australopithecus, Homo and the single species hypothesis,” Nature 261 (1976): 572–574.

  9 K. Harvati et al., “The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and chronology,” PLOS One 6 (2011): e24024, doi:10.1371/journal.pone.0024024.

  10 See for example R. Dennell, “Early Homo sapiens in China,” Nature 468 (2010): 512–513; Y. Hou and L. X. Zhao, “An archeological view for the presence of early humans in China,” Quaternary International 223–224 (2010): 10–19; X. Gao et al., “Revisiting the origin of modern humans in China and its implications for global human evolution,” Science China: Earth Sciences 53 (2010): 1927–1940; and C. Shen et al., “The earliest hominin occupations of the Nihewan Basin of northern China: Recent progress in field investigations,” Asian Paleoanthropology (2010): 169–180.

  11 D. Reich et al., “Genetic history of an archaic hominin group from Denisova Cave in Siberia,” Nature 468 (2010): 1053–1060.

  12 M. Stoneking and J. Krause, “Learning about human population history from ancient and modern genomes,” Nature Reviews Genetics 12 (2011): 603–614.

  13 D. Curnoe, “A 150-year conundrum: Cranial robusticity and its bearing on the origin of Aboriginal Australians,” International Journal of Evolutionary Biology (2011), doi:10.4061/2011/632484.

  14 A. Urbain, “Le kou-prey ou boeuf gris cambodgien,” Bulletin de la Société Zoologique de France 62 (1937): 305–307.

  15 M. V. Erdmann et al., “Indonesian ‘king of the sea’ discovered,” Nature 395 (1998): 335.

  16 V. V. Dung et al., “A new species of living bovid from Vietnam,” Nature 363 (1993): 443–445.

  17 W. Robichaud, “Physical and behavioral description of a captive saola, Pseudoryx nghetinhensis,” Journal of Mammalogy 79 (1998): 394–405.

  18 I have sometimes wondered whether I might compile a list of antelopes and other ungulates (the okapi isn’t an antelope, but a relative of the giraffe) whose names would be useful in such a context. I once placed ADDAX in a competitive setting, much to the chagrin of my opponent, who challenged it and lost. Others worth keeping up your sleeve are GNU, TOPI, KOB, ELAND, PUDU, KUDU, BOK, NYALA, NILGAI, IMPALA, and ORYX. I am sure you can think of lots more.

  19 “Notes,” Nature 64 (1901): 188.

  20 See for example J. B. Buhs, Bigfoot: The Life and Times of a Legend (Chicago: University of Chicago Press, 2009).

  21 There are many recent, excellent accounts of human evolution, and the material in this chapter draws on several. I recommend (in no particular order) C. Stringer, The Origin of Our Species (London: Allen Lane, 2011); D. Falk, The Fossil Chronicles: How Two Controversial Discoveries Changed Our View of Human Evolution (Berkeley: University of California Press, 2011); J. Reader, Missing Links: In Search of Human Origins (Oxford: Oxford University Press, 2011); and A. Gibbons, The First Human: The Race to Discover Our Earliest Ancestors (New York: Anchor, 2007). For the student there is the 2011–2012 edition of R. Jurmain et al., Introduction to Physical Anthropology (Belmont, CA: Wadsworth Cengage Learning)—but for your coffee table it would be hard to beat A. Roberts, Evolution: The Human Story (London: Dorling Kindersley, 2011).

  22 P. Shipman, The Man Who Found the Missing Link: The Extraordinary Life of Eugène Dubois (New York: Simon and Schuster, 2001).

  23 A. C. Haddon, “Eoanthropus dawsoni,” Science 37 (1913): 91–92.

  24 I have borrowed the term “Piltdown committee” a
nd drawn on Dean Falk’s excellent account of events in The Fossil Chronicles: How Two Controversial Discoveries Changed Our View of Human Evolution (Berkeley: University of California Press, 2011). Falk’s account of the possible suppression of Dart’s 1929 monograph on Australopithecus africanus—which remains unpublished to this day—is especially noteworthy.

  25 Those more used to baseball are invited to substitute the appropriate metaphors.

  26 R. Dart, “Australopithecus africanus: The man-ape of South Africa,” Nature 115 (1925): 195–199.

  27 See the correspondence column in Nature 115 (1925): 234–236 for immediate reactions from several members of the Piltdown committee, notably Sir Arthur Keith and Arthur Smith-Woodward, who had to some extent staked their reputations on Piltdown. The debate between Dart and Keith became somewhat acrimonious, as shown by the exchange in Nature 116 (1925): 462–463.

  28 R. Broom, “Some notes on the Taungs skull,” Nature 115 (1925): 569–571.

  29 R. Broom, “A new fossil anthropoid skull from South Africa,” Nature 138 (1936) 486–488; R. Broom, “The dentition of Australopithecus,” Nature 138 (1936): 719; R. Broom, “Discovery of a lower molar of Australopithecus,” Nature 140 (1937): 681–682; R. Broom, “Discovery of teeth of Australopithecus,” Nature 140 (1937): 680; R. Broom, “More discoveries of Australopithecus,” Nature 141 (1938): 828–829; R. Broom, “The Pleistocene anthropoid apes of South Africa,” Nature 142 (1938): 377–379; R. Broom, “Further evidence on the structure of the South African Pleistocene anthropoids,” Nature 142 (1938): 897–899; R. Broom, “Structure of the Sterkfontein ape,” Nature 147 (1941): 86; R. Broom, “Mandible of a young Paranthropus child,” Nature 147 (1941): 607–608; R. Broom, “The origin of man,” Nature 148 (1941): 10–14; R. Broom, “The hand of the ape-man, Paranthropus robustus,” Nature 149 (1942): 513–514; R. Broom, “An ankle-bone of the ape-man, Paranthropus robustus,” Nature 152 (1945): 389–390; R. Broom, “The upper milk molars of the ape-man, Plesianthropus,” Nature 159 (1947): 602; R. Broom and J. T. Robinson, “Size of the brain in the ape-man, Plesianthropus,” Nature 161 (1948): 438; R. Broom, “Another new type of fossil ape-man,” Nature 163 (1949): 57; and R. Broom and J. T. Robinson, “Eruption of the permanent teeth in the South African fossil ape-men,” Nature 167 (1951): 443. Broom died, vindicated but still publishing, at the age of eighty-four—his obituary by W. E. LeGros Clark appeared in Nature 167 (1951): 752. Broom’s discoveries were, like Dart’s, not immune to the view that they were more likely to be fossil apes than hominins—see the letter by E. Schwarz, Nature 138 (1936): 969, countered by Broom, Nature 139 (1937): 326.

  30 Even Sir Arthur Keith was won over, with a gracious admission in Nature 159 (1947): 277.

  31 D. Black, “Tertiary man in Asia—The Chou Kou Tien discovery,” Bulletin of the Geological Society of China 5 (1926): 207–208.

  32 D. Black, On an Adolescent Skull of Sinanthropus pekinensis in Comparison with an Adult of the Same Species and with Other Hominid Skulls Recent and Fossil (Peking: Geological Survey of China, 1931); F. Weidenreich, “The new discovery of three skulls of Sinanthropus pekinensis,” Nature 139 (1937): 269–272.

  33 P. Teilhard de Chardin and W. G. Pei, “The lithic industry of the Sinanthropus deposits in Choukoutien,” Bulletin of the Geological Society of China 11 (1932): 315–364; D. Black, “Evidences of the use of fire by Sinanthropus,” Bulletin of the Geological Society of China 11 (1932): 107–108.

  34 G. H. R. von Koenigswald and F. Weidenreich, “The relationship between Pithecanthropus and Sinanthropus,” Nature 144 (1939): 926–929.

  35 J. S. Weiner et al., “The solution of the Piltdown problem,” Bulletin of the British Museum (Natural History) Geology 2 (1953): 139–146.

  36 B. G. Gardiner, “The Piltdown forgery: A re-statement of the case against Hinton,” Zoological Journal of the Linnean Society 139 (2003): 315–335.

  37 V. Morell, Ancestral Passions: The Leakey Family and the Quest for Humankind’s Beginnings (New York: Touchstone, 1996).

  38 L. S. B. Leakey, “A new fossil skull from Olduvai,” Nature 184 (1959): 491–493.

  39 L. S. B. Leakey et al., “A new species of the genus Homo from Olduvai Gorge,” Nature 202 (1964): 7–9.

  40 R. E. F. Leakey, “Evidence for an advanced Plio-Pleistocene hominid from East Rudolf, Kenya,” Nature 242 (1973): 447–450.

  41 D. Curnoe, “A review of early Homo in southern Africa focusing on cranial, mandibular and dental remains, with the description of a new species (Homo gautengensis, sp. nov.),” Homo: Journal of Comparative Human Biology 61 (2010): 151–177.

  42 Some recently discovered fossils confirm that there were at least two kinds of early Homo. See M. G. Leakey et al., “New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo,” Nature 488 (2012): 201–204.

  43 B. Wood and M. Collard, “The human genus,” Science 284 (1999): 65–71.

  44 L. R. Berger et al., “Australopithecus sediba: A new species of Homo-like australopith from South Africa,” Science 328 (2010): 195–204.

  45 S. Semaw et al., “2.5-million-year-old stone tools from Gona, Ethiopia,” Nature 385 (1997): 333–336; S. P. McPherron et al., “Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikika, Ethiopia,” Nature 466 (2010): 857–860.

  46 J.-L. Arsuaga, “Three new human skulls from the Sima de los Huesos Middle Pleistocene site in Sierra de Atapuerca, Spain,” Nature 362 (1993): 534–537.

  47 J. M. Bermúdez de Castro, “A hominid from the Lower Pleistocene of Atapuerca, Spain: Possible ancestor to Neandertals and modern humans,” Science 276 (1997): 1392–1395. For a general review of hominin variation and taxonomy during this period of time, see G. P. Rightmire, “Homo in the Middle Pleistocene: Hypodigms, variation and species recognition,” Evolutionary Anthropology 17 (2008): 8–21.

  48 F. Brown et al., “Early Homo erectus skeleton from west Lake Turkana, Kenya,” Nature 316 (1985): 788–792.

  49 Once again, for a discussion of these issues see B. Wood and M. Collard, “The human genus,” Science 284 (1999): 65–71.

  50 C. J. Lepre et al., “An earlier origin for the Acheulian,” Nature 477 (2011): 82–85.

  51 R. Ferring et al., “Earliest human occupation of Dmanisi (Georgian Caucasus) dated to 1.85–1.78 Ma,” Proceedings of the National Academy of Sciences of the USA 108 (2011): 10432–10436.

  52 D. Lordkipanidze et al., “Postcranial evidence from early Homo from Dmanisi, Georgia,” Nature 449 (2007): 305–310; L. Gabunia et al., “Découverte d’un nouvel hominidé à Dmanissi (Transcaucasie, Géorgie),” Comptes Rendus Palevol 1 (2002): 243–254.

  53 C. J. Lepre et al., “An earlier origin for the Acheulian,” Nature 477 (2011): 82–85.

  54 R. Dennell and W. Roebroeks, “An Asian perspective on early human dispersal from Africa,” Nature 438 (2005): 1099–1104.

  55 I. McDougall et al., “Stratigraphic placement and age of modern humans from Kibish, Ethiopia,” Nature 433 (2005): 733–736.

  56 C. W. Marean et al., “Early human use of marine resources and pigment in South Africa during the Middle Pleistocene,” Nature 449 (2007): 905–908.

  57 R. L. Cann et al., “Mitochondrial DNA and human evolution,” Nature 325 (1987): 31–36.

  58 J. Wainscoat, “Out of the Garden of Eden,” Nature 325 (1987): 13.

  59 R. E. Green et al., “A draft sequence of the Neandertal genome,” Science 328 (2010): 710–722.

  60 D. Reich et al., “Genetic history of an archaic hominin group from Denisova Cave in Siberia,” Nature 468 (2010): 1053–1060.

  61 M. F. Hammer et al., “Genetic evidence for archaic admixture in Africa,” Proceedings of the National Academy of Science of the USA 108 (2011): 15123–15128; K. Harvati et al., “The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and chronology,” PLOS One 6 (2011): e24024, doi:10.1371/journal.pone.0024024.

  62 I’ve always been puzzled by Genesis 4:17: “A
nd Cain knew his wife; and she conceived, and bare Enoch: and he builded a city, and called the name of the city, after the name of his son, Enoch.” Where did Cain find his wife, and all the other citizens of Enoch? Obviously, they were already there, yet unrecorded, outside Cain’s African Eden.

  63 C. Howell, “Omo research expedition,” Nature 219 (1968): 567–572.

  64 D. C. Johanson and M. Taieb, “Plio-Pleistocene hominid discoveries in Hadar, Ethiopia,” Nature 260 (1976): 293–297.

  65 T. D. White et al., “Australopithecus ramidus, a new species of hominid from Aramis, Ethiopia,” Nature 371 (1994): 306–312.

  66 T. D. White et al., “Ardipithecus ramidus and the paleobiology of early hominids,” Science 326 (2009): 75–86.

  67 M. G. Leakey et al., “New four-million-year-old hominid species from Kanapoi and Allia Bay, Kenya,” Nature 376 (1995): 565–571; Y. Haile-Selassie, “Late Miocene hominids from the Middle Awash, Ethiopia,” Nature 412 (2001): 178–181; B. Senut et al., “First hominid from the Miocene (Lukeino Formation, Kenya),” Comptes rendus de l’Académie des sciences, series 2a, 332 (2001): 137–144.

  68 B. Wood and T. Harrison, “The evolutionary context of the first hominins,” Nature 470 (2011): 347–352.

  69 M. Brunet et al., “A new hominid from the Upper Miocene of Chad, Central Africa,” Nature 418 (2002): 145–151.

  70 C. P. E. Zollikofer et al., “Virtual cranial reconstruction of Sahelanthropus tchadensis,” Nature 434 (2005): 755–759.

  71 M. H. Wolpoff et al., “Sahelanthropus or ‘Sahelpithecus’?,” Nature 419 (2002): 581–582; M. Brunet et al., “Sahelanthropus or ‘Sahelpithecus’?,” Nature 419 (2002): 582.

  CHAPTER 6

  1 Equotes, http://bevets.com/equotesg.htm#G, accessed 4 April 2012.

  2 S. Reuland, Sunbeams from Cucumbers, http://stevereuland.blogspot.com/2006/04/wittlessly-quote-mining.html, accessed 4 April 2012.

  3 Psalms 14:1. I am grateful to Andrew Thaler for pointing out that particular gem.