The Accidental Species: Misunderstandings of Human Evolution

by Henry Gee

  11 S. L. Vartanyan et al., “Holocene dwarf mammoths from Wrangel Island in the Siberian Arctic,” Nature 362 (1993): 337–340.

  12 M. J. Morwood et al., “Further evidence for small-bodied hominins from the Late Pleistocene of Flores, Indonesia,” Nature 437 (2005): 1012–1017.

  13 Dean Falk summarizes the story very well in her book The Fossil Chronicles: How Two Controversial Discoveries Changed Our View of Human Evolution (Berkeley: University of California Press, 2011). This book is especially interesting given that she has been an important player in the debate. Her work comparing the skulls and brains of humans (both normal and microcephalic), Homo floresiensis, and other extinct hominins has led her to conclude that Homo floresiensis represents a distinct species rather than a variant of Homo sapiens. See for example D. Falk et al., “Brain shape in human microcephalics and Homo floresiensis,” Proceedings of the National Academy of Sciences of the USA 104 (2007): 2513–2518; and D. Falk et al., “The brain of LB1, Homo floresiensis,” Science 308 (2005): 242–245. More support comes from D. Argue et al., “Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo?,” Journal of Human Evolution 51 (2006): 360–374.

  14 See for example I. Hershkovitz et al., “Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron syndrome),” American Journal of Physical Anthropology 134 (2007): 198–208; G. D. Richards, “Genetic, physiologic and ecogeographic factors contributing to variation in Homo sapiens: Homo floresiensis reconsidered,” Journal of Evolutionary Biology 19 (2006): 1744–1767; T. Jacob et al., “Pygmoid Australomelanesian Homo sapiens skeletal remains from Liang Bua, Flores: Population affinities and pathological abnormalities,” Proceedings of the National Academy of Sciences of the USA 103 (2006): 13421–13426.

  15 J. Krause et al., “The complete mitochondrial DNA genome of an unknown hominin from southern Siberia,” Nature 464 (2010): 894–897.

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

  17 See Richard Fortey’s book Survivors: The Animals and Plants That Time Has left Behind (London: HarperCollins, 2011) for a charming roundup of living fossils.

  18 C. Oxnard et al., “Post-cranial skeletons of hypothyroid cretins show a similar anatomical mosaic as Homo floresiensis,” PLOS One 5 (2010): e13018, doi:10.1371/journal.pone.0013018.

  19 S. G. Larson et al., “Descriptions of the upper limb skeleton of Homo floresiensis,” Journal of Human Evolution 57 (2009): 555–570; M. W. Tocheri et al., “The primitive wrist of Homo floresiensis and its implications for hominin evolution,” Science 317 (2007): 1743–1745; W. L. Jungers et al., “The foot of Homo floresiensis,” Nature 459 (2009): 81–84.

  20 M. M. Lahr and R. Foley, “Human evolution writ small,” Nature 431 (2004): 1043–1044.

  21 D. Lordkipanidze et al., “Postcranial evidence from early Homo from Dmanisi, Georgia,” Nature 449 (2007): 305–310.

  22 E. M. Weston and A. M. Lister, “Insular dwarfism in hippos and a model for brain size reduction in Homo floresiensis,” Nature 459 (2009): 85–88.

  23 A. D. Gordon et al., “The Homo floresiensis cranium (LB1): Size, scaling and early Homo affinities,” Proceedings of the National Academy of Sciences of the USA 105 (2008): 4650–4655.

  24 I have heard that the voice-over was provided by a prominent evolutionary biologist, though I should emphasize that this is just gossip.

  25 This is a reasonable assumption given that all the great apes—the chimps, the gorillas, and the orangutans—are much more similar to one another, as regards their general features, biology, and life habits, than any one in particular resembles humans. It used to be the case that the apes were placed in a single family, the Pongidae. However, it turns out that chimps are in fact more closely related to humans than are gorillas, with the orangutans at a more remote remove. This means that the term “Pongidae” doesn’t refer to what zoologists call a “natural group”—unless humans are included.

  26 This doesn’t mean that the common ancestor of all creatures living today was the first creature to have evolved. It is possible that other essays in self-reproducing systems appeared, but became extinct and left no trace. Scientists therefore sometimes refer to the common ancestor of all extant life as LUCA, which stands for “last universal common ancestor.”

  27 D. L. Theobald, “A formal test of the theory of universal common ancestry,” Nature 465 (2010): 219–222.

  28 R. D. Martin, “Primate origins: Plugging the gaps,” Nature 363 (1993): 223–234.

  29 This is why the expression “this research raises more questions than it answers” is a cliché.

  30 P. J. Turnbaugh et al., “The Human Microbiome Project,” Nature 449 (2007): 804–810.

  CHAPTER 2

  1 National Health Statistics Report 10, 22 October 2008.

  2 http://en.wikipedia.org/wiki/Human_height, accessed 4 January 2013.

  3 B. C. Msamati and P. S. Igbigbi, “Anthropometric profile of urban adult black Malawians,” East African Medical Journal 77 (2000): 364–368.

  4 UK National Health Service, http://www.ic.nhs.uk/statistics-and-data-collections/health-and-lifestyles-related-surveys/health-survey-for-england/health-survey-for-england-2008-trend-tables, accessed 22 January 2011.

  5 J. Cohen, “Knife-edge of design,” Nature 411 (2001): 529.

  6 I discuss this idea in my book Jacob’s Ladder.

  7 OED, June 2011, http://www.oed.com/view/Entry/65447, accessed 6 September 2011. All the examples of the use of the word “evolution” in this chapter come from that source, unless otherwise stated.

  8 W. Bateson, Materials for the Study of Variation, Treated with Especial Regard to Discontinuity in the Origin of Species (London: Macmillan, 1894), v–vi.

  9 L. Oken, Abriss des Systems der Biologie (1805); this translation in R. J. Richards, The Meaning of Evolution (Chicago: University of Chicago Press, 1992), 39.

  10 Most notably William Bateson, a cofounder of the science of genetics.

  11 J. Z. Young, The Life of Vertebrates (Oxford: Clarendon Press, 1981).

  12 N. Eldredge and S. J. Gould, “Punctuated equilibria: An alternative to phyletic gradualism,” in T. J. M. Schopf, ed., Models in Paleobiology (San Francisco: Freeman, Cooper, 1972), 82–115.

  CHAPTER 3

  1 For example, see K. Chong, “Bacillus cereus in ‘Poon Choi,’” in Food Safety Focus (Hong Kong: Centre for Food Safety), http://www.cfs.gov.hk/english/multimedia/multimedia_pub/multimedia_pub_fsf_40_01.html, accessed 29 March 2012.

  2 “The hidden hordes,” Nature Reviews Microbiology 10 (2010): 517.

  3 L. Rothschild and R. Mancinelli, “Life in extreme environments,” Nature 409 (2002): 1092–1101.

  4 See for example D. W. Griffin, “Terrestrial microorganisms at an altitude of 20,000 m in Earth’s atmosphere,” Aerobiologia 20 (2004): 135–140; A. P. Teske, “The deep subsurface biosphere is alive and well,” Trends in Microbiology 13 (2005): 402–404.

  5 See for example R. C. Blake II et al., “Chemical transformation of toxic metals by a Pseudomonas strain from a toxic waste site,” Environmental Toxicology and Chemistry 12 (1993): 1365–1376; J. Lloyd and J. C. Renshaw, “Bioremediation of radioactive waste: Radionuclide-microbe interactions in laboratory and field-scale studies,” Current Opinion in Biotechnology 16 (2005): 254–260.

  6 W. L. Nicholson et al., “Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments,” Microbiology and Molecular Biology Reviews 64 (2000): 548–572.

  7 E. Szathmáry and J. Maynard Smith, “The major evolutionary transitions,” Nature 374 (1995): 227–232.

  8 J. A. Lake, “Lynn Margulis (1938–2011),” Nature 480 (2011): 458.

  9 L. Margulis, Origin of Eukaryotic Cells (New Haven: Yale University Press, 1971).

  10 J. W. Costerton et al., “Microbial biofilms,” Annual Review of Microbiology 49 (1995): 711–745.

  11 Fo
r a lovely account of stromatolites in their natural habitat, go no further than Richard Fortey’s book Survivors: The Animals and Plants That Time Has Left Behind (London: HarperCollins, 2011).

  12 J. W. Schopf, “Fossil evidence of Archaean life,” Philosophical Transactions of the Royal Society B 361 (2006): 869–885.

  13 P. K. Singh et al., “Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms,” Nature 407 (2000): 762–764.

  14 M. W. Gray et al., “The origin and early evolution of mitochondria,” Genome Biology 2 (2001), http://genomebiology.com/2001/2/6/reviews/1018.

  15 G. I. McFadden and G. G. van Dooren, “Red algal genome affirms a common origin of all plastids,” Current Biology 14 (2004): R514–R516.

  16 T. Kleine et al., “DNA transfer from organelles to the nucleus: The idiosyncratic genetics of endosymbiosis,” Annual Review of Plant Biology 60 (2009): 115–138.

  17 G. I. McFadden and P. Gilson, “Something borrowed, something green: Lateral transfer of chloroplasts by secondary endosymbiosis,” Trends in Ecology and Evolution 10 (1995): 12–17; G. I. McFadden, “Primary and secondary endosymbiosis and the origin of plastids,” Journal of Phycology 37 (2001): 951–959.

  18 F. Martin et al., “The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis,” Nature 452 (2008): 88–92.

  19 J. Whitfield, “Fungal roles in soil ecology: Underground networking,” Nature 449 (2007): 136–138.

  20 Perhaps the most elegant way to lose your lunch is to read Carl Zimmer’s book Parasite Rex (New York: Touchstone, 2001).

  21 J. H. Day, “The life history of Sacculina,” Quarterly Journal of Microscopical Science 77 (1935): 549–583.

  22 S. T. Cole et al., “Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence,” Nature 393 (1998): 537–544; S. T. Cole et al., “Massive gene decay in the leprosy bacillus,” Nature 409 (2001): 1007–1011.

  23 Carl Zimmer has followed his book on parasites (Parasite Rex) with one on viruses—A Planet of Viruses (Chicago: University of Chicago Press, 2012).

  24 D. Raoult et al., “The 1.2-megabase genome sequence of mimivirus,” Science 306 (2004): 1344–1350.

  25 B. La Scola et al., “The virophage as a unique parasite of the giant mimivirus,” Nature 455 (2008): 100–104.

  26 The natural history of LINEs and SINEs can be found in E. S. Lander et al., “Initial sequencing and analysis of the human genome,” Nature 409 (2001): 879–880.

  27 R. O. Prum and A. H. Brush, “The evolutionary origin and diversification of feathers,” Quarterly Review of Biology 77 (2002): 261–295.

  28 P. M. O’Connor and L. P. A. M. Claessens, “Basic avian pulmonary design and flow-through ventilation in non-avian theropod dinosaurs,” Nature 436 (2005): 253–256; F. E. Novas and P. F. Puertat, “New evidence concerning avian origins from the Late Cretaceous of Patagonia,” Nature 387 (1997): 390–392; M. A. Norell et al., “A Velociraptor wishbone,” Nature 389 (1997): 447; M. A. Norell et al., “A nesting dinosaur,” Nature 378 (1995): 774–776.

  29 For a review see M. A. Norell and X. Xu, “Feathered dinosaurs,” Annual Review of Earth and Planetary Sciences 33 (2005): 277–299.

  30 X. Xu et al., “The smallest known non-avian theropod dinosaur,” Nature 408 (2000): 705–708; X. Xu et al., “A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China,” Nature 401 (1999): 262–266.

  31 X. Xu et al., “A gigantic bird-like dinosaur from the Late Cretaceous of China,” Nature 447 (2007): 844–847.

  32 When Gee Minor was a little older—about four—I took her to the Natural History Museum in London to see a traveling exhibition on the new and unfamiliar feathered dinosaurs of China. I had published reports on most of the specimens on display, but had seen them only in photographs, so was excited to see them in real life, or, as it may be, death. One had to pay to get into this special exhibition, and it was tucked away in a side gallery—so it was away from the main dinosaur exhibit and thus patronized by very few visitors. The exhibit consisted of just nine specimens, moodily lit. As I became engrossed in the study of each fossil, Gee Minor whizzed around from fossil to fossil in the manner of a bumblebee flitting between flowers in a herbaceous border. A fossil that particularly engaged my attention was Caudipteryx, preserved on a large tabletop slab, a creature previously featured in Nature under my watch (J. Qiang et al., “Two feathered dinosaurs from northeastern China,” Nature 393 [1998]: 753–761). As I was examining the specimen, deep in thought, a little face popped up on the other side of the slab and said, “Dad, did you punish this in Nature?” Out of the mouths of babes.

  33 For an overview of Archaeopteryx, see P. Shipman, Taking Wing: Archaeopteryx and the Origin of Bird Flight (New York: Touchstone, 1999).

  34 P. Domínguez Alonso et al., “The avian nature of the brain and inner ear of Archaeopteryx,” Nature 430 (2004): 666–669.

  35 P.-J. Chen et al., “An exceptionally well-preserved theropod dinosaur from the Yixian Formation of China,” Nature 391 (1998): 147–152.

  36 X. Xu et al., “An Archaeopteryx-like theropod from China and the origin of Avialae,” Nature 475 (2011): 465–470; L. Witmer, “An icon knocked from its perch,” Nature 475 (2011): 458–459.

  37 F. Zhang et al., “A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers,” Nature 455 (2008): 1105–1108.

  38 C. Y. McLean et al., “Human-specific loss of regulatory DNA and the evolution of human-specific traits,” Nature 471 (2011): 216–219.

  39 N. Humphrey et al., “Human hand-walkers: Five siblings who never stood up” (2005), London School of Economics and Political Science Research Online, http://eprints.lse.ac.uk/id/eprint/463.

  40 W. Enard et al., “Molecular evolution of FOXP2, a gene involved in speech and language,” Nature 418 (2002): 869–872.

  CHAPTER 4

  1 G. Weber, “Top languages: The world’s 10 most influential languages” (2008), http://www.andaman.org/BOOK/reprints/weber/rep-weber.htm, accessed 31 March 2012.

  2 For an absorbing account of the history of the British Empire, see N. Ferguson, Empire: The Rise and Demise of the British World Order and the Lessons for Global Power (London: Allen Lane, 2002).

  3 Niall Ferguson looked at America, too, in Colossus: The Rise and Fall of the American Empire (London: Penguin, 2004).

  4 F. McLynn, 1759: The Year Britain Became Master of the World (London: Vintage, 2008).

  5 N. Ferguson, ed., Virtual History: Alternatives and Counterfactuals (London: Picador, 1997).

  6 D. W. Meinig, The Shaping of America: Atlantic America, 1492–1800 (New Haven: Yale University Press, 1986); D. W. Meinig, The Shaping of America: Continental America, 1800–67 (New Haven: Yale University Press, 1993).

  7 M. Alexander, Old English Literature (New York: Schocken, 1983).

  8 I have two editions of the poem, separated in time by almost exactly a century. The first is a second edition (1898) of the standard text by A. J. Wyatt; the second is the text with the recent translation by the poet Seamus Heaney (London: Faber and Faber, 1999).

  9 J. R. R. Tolkien, Finn and Hengest: The Fragment and the Episode, ed. Alan Bliss (London: HarperCollins, 1982).

  10 S. McBrearty and N. Jablonski, “First fossil chimpanzee,” Nature 437 (2005): 105–108.

  11 Z. Zhou et al., “An exceptionally preserved Lower Cretaceous ecosystem,” Nature 421 (2003): 807–814.

  12 This was kindly demonstrated to me by Jean-Bernard Caron of the Royal Ontario Museum in Toronto.

  13 D. Dashzeveg et al., “Extraordinary preservation in a new vertebrate assemblage from the Late Cretaceous of Mongolia,” Nature 374 (1995): 446–449.

  14 P. A. Allison and D. E. G. Briggs, “Exceptional fossil record: Distribution of soft-tissue preservation through the Phanerozoic,” Geology 21 (1993): 527–530.

  15 R. S. Sansom et al., “Non-random decay of chordate characters causes bias in f
ossil interpretation,” Nature 463 (2010): 797–800.

  16 G. Borgonie et al., “Nematoda from the terrestrial deep subsurface of South Africa,” Nature 474 (2011): 79–82.

  17 N. A. Cobb, Nematodes and Their Relationships, United States Department of Agriculture Yearbook (Washington, DC: US Department of Agriculture, 1914), 472. I am grateful to Roderic Page for tracing this quote.

  18 G. Poinar Jr., “Trends in the evolution of insect parasitism by nematodes as inferred from fossil evidence,” Journal of Nematology 35 (2003): 129–132.

  19 G. Poinar Jr. and A. J. Boucot, “Evidence of intestinal parasites of dinosaurs,” Parasitology 133 (2006): 245–249.

  20 E. P. Hoberg et al., “Out of Africa: Origins of the Taenia tapeworms in humans,” Proceedings of the Royal Society of London B 268 (2001): 781–787.

  21 It is possible that Opabinia is obscurely related to velvet worms (onychophores) and tardigrades (water bears). G. E. Budd, “The morphology of Opabinia regalis and the reconstruction of the arthropod stem group,” Lethaia 29 (1996): 1–14.

  22 For a general review see The Adequacy of the Fossil Record, ed. S. K. Donovan and C. R. C. Paul (Chichester, UK: Wiley, 1998). The thesis of this book is that the incompleteness of the fossil record need not dent its adequacy for solving a variety of paleontological problems.

  23 The literature on the Doushantuo phosphorites is voluminous. For two recent articles see J. A. Cunningham et al., “Distinguishing geology from biology in the Ediacaran Doushantuo biota relaxes constraints on the timing of the origin of bilaterians,” Proceedings of the Royal Society of London B 279 (2012): 2369–2376; and G. Jiang et al., “Stratigraphy and paleogeography of the Ediacaran Doushantuo Formation (ca. 635–551 Ma) in South China,” Gondwana Research 19 (2011): 831–849.

  24 F. H. T. Rhodes and R. Phillips, “The zoological affinities of conodonts,” Biological Reviews 29 (1954): 419–452.

  25 S. Conway Morris, “Typhloesus wellsi (Melton and Scott, 1973), a bizarre metazoan from the Carboniferous of Montana, U.S.A.,” Philosophical Transactions of the Royal Society of London B 327 (1990): 595–624.