5. UC Berkeley paleontologist Charles Marshall said: Personal interview, October 18, 2011. Marshall made this comment after I asked him what he thought of Keller’s theories.
6. Smit told the BBC: This comment comes from an interview Smit did with the BBC program Horizon, in the episode “What Really Killed the Dinosaurs?” You can read a transcript here: http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dino_trans.shtml.
7. the dinosaurs died of fungal infections: See Arturo Casadevall, “Fungal Virulence, Vertebrate Endothermy, and Dinosaur Extinction: Is There a Connection?” Fungal Genetics and Biology 42 (2005): 98–106.
8. Brown University geologist Jessica Whiteside put it: Personal interview, January 12, 2012. See also: J. H. Whiteside, P. E. Olsen, D. V. Kent, S. J. Fowell, and M. Et-Touhami, “Synchrony Between the CAMP and the Triassic-Jurassic Mass-Extinction Event? Reply to Comment of Marzoli et al,” Palaeogeography, Palaeoclimatology, and Palaeoecology 262 (2008): 194–98.
9. CAMP: A helpful map of the CAMP eruption can be found here: http://www.auburn.edu/academic/science_math/res_area/geology/camp/Fig1.jpg.
10. Jennifer McElwain, a paleobotanist at University College Dublin: Personal interview, January 16, 2012.
11. dinofuzz: See Ryan C. McKellar et al., “A Diverse Assemblage of Late Cretaceous Dinosaur and Bird Feathers from Canadian Amber,” Science 16 (2011): 1619–22.
12. they may have been social, like birds: See, for example, D. J. Varricchio, Paul C. Sereno, Zhao Xijin, Tan Lin, Jeffery A. Wilson, and Gabrielle H. Lyon, “Mud-Trapped Herd Captures Evidence of Distinctive Dinosaur Sociality,” Acta Palaeontologica Polonica 53 (2008): 567–78.
CHAPTER FIVE: IS A MASS EXTINCTION GOING ON RIGHT NOW?
1. University of Oregon archaeologist Dennis Jenkins: Personal interview, February 9, 2012. See also Dennis Jenkins et al., “Clovis Age Western Stemmed Projectile Points and Human Coprolites at the Paisley Caves,” Science 337 (2012): 223–28.
2. UC Berkeley biologist Anthony Barnosky has been at the forefront: Personal interview, October 18, 2011.
3. March 3, 2011, issue of Nature: Anthony Barnosky et al., “Has the Earth’s Sixth Mass Extinction Already Arrived?” Nature 471 (2011): 51–57.
4. Peter Ward, a geologist at the University of Washington: Personal interview, September 27, 2011. See also Peter Ward, The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive? (Princeton, NJ: Princeton University Press: 2009).
CHAPTER SIX: THE AFRICAN BOTTLENECK
1. “effective population size”: For more on this concept, see Matthew B. Hamilton’s valuable primer Population Genetics (West Sussex: Wiley Blackwell, 2009), plus you can find a good introduction to this idea in R. Kliman, B. Sheehy, and J. Schultz, “Genetic Drift and Effective Population Size,” Nature Education 1 (2008).
2. human effective population size: N. Takahata, Y. Satta, and J. Klein, “Divergence Time and Population Size in the Lineage Leading to Modern Humans,” Theoretical Population Biology 48 (October 1995): 198–221.
3. Toba catastrophe: Richard Dawkins, The Ancestor’s Tale, A Pilgrimage to the Dawn of Life (Boston: Houghton Mifflin Company, 2004).
4. But, as John Hawks, an anthropologist at the University of Wisconsin, Madison, put it to me: Personal interview, November 29, 2011.
5. according to the anthropologist Ian Tattersall of the American Museum of Natural History: Personal interview, December 13, 2011.
6. we were part of a hominin group: Most of the evolutionary history I describe here comes from Richard Klein’s indispensable evolutionary biology text The Human Career: Human Biological and Cultural Origins (Third Edition) (Chicago: University of Chicago Press, 2009). In this book I’m following today’s accepted scientific practice of referring to humans and our ancestors as “hominins.” Hominids include the greater group of humans and apes (and their ancestors).
7. But as the Stanford paleoanthropologist Richard Klein told me: Personal interview, November 30, 2011.
8. but the University of Utah geneticist Chad Huff recently argued: Chad Huff et al., “Mobile Elements Reveal Small Population Size in the Ancient Ancestors of Homo Sapiens,” PNAS 107 (February 2, 2010): 2147–52.
9. As Hawks explained in a paper he published with colleagues in 2000: Hawks et al., “Population Bottlenecks and Pleistocene Human Evolution,” Molecular Biology and Evolution 17 (2000): 2–22.
10. That’s how speciation creates a genetic bottleneck: It’s worth noting that the definition of “species” can get as messy as evolution itself. For example, two classes of species may look similar but have very different genetic backgrounds, like bats (from the class Mammalia) and birds (from the class Aves); two species can crossbreed and produce viable offspring, like bonobos and chimps; and two very different-looking animals might actually be the same species at different stages in their development, like tadpoles and frogs. Scientists who study phylogeny, the family trees that define a species, use many rubrics to draw boundaries between species, but there are no absolute rules. But when two groups’ genetic makeup, body shape, and behaviors diverge enough, they are generally said to be separate species. There is a great deal of debate over where to draw species lines between ancient human groups, but we can say for certain that today’s H. sapiens descended from a pretty small genetic pool—and speciation could be part of what made that pool smaller.
11. his book Prehistoric Art: Randall White, Prehistoric Art: The Symbolic Journey of Humankind (New York: Abrams, 2003).
12. In his book The Mating Mind: Geoffrey Miller, The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (New York: Anchor Books, 2001).
13. The 10,000 Year Explosion: Gregory Cochran and Henry Harpending, The 10,000 Year Explosion: How Civilization Accelerated Human Evolution (New York: Basic Books, 2010).
14. humans bred themselves to be the ultimate survivors: It seems counterintuitive to say that we’re survivors when most of us have been taught that genetic diversity is vital to species health. Does our low genetic diversity mean that we’re weaker than other species? In some cases, as we’ll see later, it can be a vulnerability. However, the kind of inbreeding that creates low effective population size is not the same thing as inbreeding between close relatives like a brother and sister, which can result in genetic defects. Indeed, as Murdoch University’s geneticists Alan Bittles and Michael Black point out in a paper about human “consanguinity,” or inbreeding, it was long considered acceptable for second cousins and more distant relatives to marry in Western cultures—and is still common in many parts of the world. Such marriages have few deleterious effects, and as we’ve seen, these traditions grow out of what is probably a very ancient human practice in founder populations. Inbreeding between distant relatives seems to be the human norm.
15. DNA extracted from the fossils of Neanderthals and other hominins: Svante Pääbo et al., “A Draft Sequence of the Neanderthal Genome,” Science 328 (May 7, 2010): 710–22.
CHAPTER SEVEN: MEETING THE NEANDERTHALS
1. Neanderthals used tools and fire: See Brian Fagan, Cro-Magnon: How the Ice Age Gave Birth to the First Modern Humans (New York: Bloomsbury Press, 2011).
2. Neanderthals were mostly meat-eaters: Fagan, Cro-Magnon.
3. Richard Klein: Personal interview, November 30, 2011.
4. possibly with red hair: The possibility of some Neanderthals having pale skin and red hair is raised in Carles Lalueza-Fox et al., “A Melanocortin 1 Receptor Allele Suggests Varying Pigmentation Among Neanderthals,” Science 318 (2007): 1453–55.
5. Many Neanderthal skeletons are distorted by broken bones that healed: Joe Alper, “Rethinking Neanderthals,” Smithsonian Magazine (June 2003).
6. a generous estimate: John Hawks, personal correspondence, October 9, 2012.
7. many scientists believe: V. Fabre, S. Condemi, and A. Degioanni, “Genetic Evidence of Geographical Groups Among Neanderthals,” PLoS ONE 4 (2009): e5151.
8. A 60,000-year-old Neanderthal grav
e: Jennifer Viegas, “Did Neanderthals Believe in an Afterlife?” Discovery News (April 20, 2011).
9. Neanderthals talked or even sang: See Steven Mithen, The Singing Neanderthals (Cambridge: Harvard University Press, 2007).
10. two dominant theories: John Relethford, “Genetics of Modern Human Origins and Diversity,” Annual Review of Anthropology 27, (1998): 1–23.
11. Rebecca Cann and her colleagues found a way to support: Rebecca L. Cann et al., “Microbial DNA and Human Evolution,” Nature 325 (1987): 31–36.
12. Popularized by Wolpoff and his colleague John Hawks: See Milford Wolpoff and John Hawks, “Modern Human Origins,” Science 241 (August 12, 1988): 772–74.
13. “out of Africa” migration is based on an artificial political boundary: According to Clive Finlayson, who writes, “The first proto-humans would have gradually expanded into favorable habitats wherever these were.” Clive Finlayson, The Humans Who Went Extinct (Oxford: Oxford University Press, 2009).
14. Hawks has presented compelling genetic evidence: John Hawks, Gregory Cochran, Henry C. Harpending, and Bruce T. Lahn, “A Genetic Legacy from Archaic Homo,” Trends in Genetics 24 (January 2008): 19–23.
15. the truth lies somewhere in between African replacement and multiregionalism: The middle-of-the-road take on all this is often dubbed the “assimilation theory.” Anthropologist Vinayak Eswaran (see Vinayak Eswaran et al., “Genomics Refutes an Exclusively African Origin of Humans,” Journal of Human Evolution 49 [July 2005]: 1–18) and his colleagues take this perspective in a paper in which they argue that genetic evidence suggests that there were two distinct waves of immigration out of Africa—the archaic human one and the H. sapiens one. But as H. sapiens moved out into the world, they assimilated the local Neanderthal peoples, along with their other cousin H. erectus in Asia.
So basically, in the assimilation-theory model, H. sapiens didn’t destroy their kindred, nor were they deeply interrelated with them as in the multiregional theory. They met them as strangers, but forged alliances and formed families with them. Gradually, though, H. sapiens became the dominant culture.
16. Simon Armitage published a paper suggesting that H. sapiens emerged from Africa: Simon Armitage et al., “The Southern Route ‘Out of Africa’: Evidence for an Early Expansion of Modern Humans into Arabia,” Science 331 (2011): 453–56.
17. Svante Pääbo, who led the Neanderthal DNA sequencing project: Svante Pääbo et al., “A High-Coverage Genome Sequence from an Archaic Denisovan Individual,” Science 338 (October 2012): 222–26.
CHAPTER EIGHT: GREAT PLAGUES
1. wiped out over 60 percent of the population of the British Isles: Ole Jørgen Benedictow, The Black Death, 1346–1353: The Complete History (Woodbridge, U.K.: The Boydell Press, 2004).
2. The son of a wealthy wine merchant, Chaucer grew up: All the biographical details here come from Larry Benson, Robert Pratt, and F. N. Robinson, eds., The Riverside Chaucer (New York: Houghton Mifflin, 1986).
3. our own growing societies: We see the first stirrings of modern global culture during the late Middle Ages in Europe, when a growing middle class began laying the foundations for capitalism and global trade communities. As the sociologist Anthony Giddens would have it, this was the moment when the premodern era gave way to the modern. In a sense, today’s world is part of a narrative arc that began during Chaucer’s time. Before that era, urban or global cultures still tended to be exceptions.
Probably the closest historical analogy to the global culture that began stirring to life during Chaucer’s time would have been that of the Silk Road trade route that crossed from China into Europe for over a millennium. Still, the Silk Road culture was also a localized phenomenon, accessible only to nearby regions. Within a few hundred years of Chaucer’s time, the oceans became in essence an enormous Silk Road, uniting every continent in the world.
4. Jo Hays, a historian at Loyola University whose work focuses on pandemics: Personal interview, October 2011.
5. Likewise, the common people began questioning government authorities: Robert S. Gottfried, The Black Death: Natural and Human Disaster in Medieval Europe (New York: The Free Press, 1983), especially chapter 5.
6. After the Black Death, there was a rise: Frances and Joseph Gies, Women in the Middle Ages (New York: Harper Perennial, 1991).
7. SUNY Albany anthropologist Sharon DeWitte: Personal interview, November 30, 2011.
8. sequenced bacterial DNA: Kirsten I. Bos et al., “A Draft Genome of Yersinia pestis from Victims of the Black Death,” Nature 478 (October 27, 2011): 506–10.
9. New York University’s literary historian Ernest Gilman: Personal interview, February 15, 2012. See also Ernest Gilman, Plague Writing in Early Modern England (Chicago: University of Chicago Press, 2009).
10. In the late 1990s, Jared Diamond argued: Jared Diamond, Guns, Germs and Steel: The Fates of Human Societies (New York: W. W. Norton & Co., 1999, originally published in hardback in 1997). Diamond’s argument about the Americas is contained in a couple of chapters where he discusses the conquest of the massive Incan army by Pizarro’s small band of hooligans. Though very much aware of how plagues also played into this scenario, Diamond focuses in these chapters most heavily on how the Inca lacked steel and writing.
11. As Charles Mann explains in his book 1491: See Charles Mann, 1491: The Revelations of the Americas Before Columbus (New York: Vintage, 2005), especially part one, where Mann discusses how historians have arrived at the 90 percent number I mention a few paragraphs later.
12. only today finally being deciphered: One of the main places this decipherment is being done is at the Khipu Database Project at Harvard University. Scholars involved have identified several ways that the knots convey meaning, including size, orientation, color, and shape. They’ve already figured out the numbering system and are now moving on to the written language. You can learn more about the project here: http://khipukamayuq.fas.harvard.edu/.
13. Arizona State University forensic archaeologist Jane Buikstra: Personal interview, February 14, 2012.
14. Paul Kelton, of the University of Kansas: Personal interview, February 2012. See also Paul Kelton, Epidemics and Enslavement: Biological Catastrophe in the Native Southeast 1492–1715 (Lincoln and London: University of Nebraska Press, 2007).
15. David S. Jones, a Harvard historian and medical doctor, sums up the issues: David S. Jones, “Virgin Soils Revisited,” William and Mary Quarterly 60 (October 2003): 703–42.
16. Susan Kent explains in her recent book about the 1918–19 flu epidemic: Susan Kent, The Influenza Pandemic of 1918–1919 (Boston and New York: Bedford/St. Martins, 2013).
17. native cultures and peoples have survived throughout the Americas: Gerald Vizenor, Native Liberty: Natural Reason and Cultural Survivance (Lincoln and London: University of Nebraska Press, 2009).
CHAPTER NINE: THE HUNGRY GENERATIONS
1. Famines have been recorded in historical documents: Cormac Ó Gráda, Famine: A Short History (Princeton and Oxford: Princeton University Press, 2009).
2. Cormac Ó Gráda has spent most of his career: Personal interview, December 8, 2011.
3. This famine had its roots in politics: John O’Rourke, The History of the Great Irish Famine of 1847 (Dublin: James Duffy and Co., Ltd., 1902). This is a fascinating account by a man who gathered together many first-person accounts of the famine, mostly from interviews he did with survivors in the late nineteenth century. He credits “the public press” as being one of the first groups to alert the world to the famine, and place it in a political context.
4. Amartya Sen first advanced this theory in the 1980s: Amartya Sen, Poverty and Famines: An Essay on Entitlement and Deprivation (Oxford: Oxford University Press, 1983).
5. Evan Fraser, a geographer at the University of Guelph: Personal interview, February 16, 2012. See also Evan Fraser, “Social Vulnerability and Ecological Fragility: Building Bridges Between Social and Natural Sciences Using the Irish Potato Famine as a Case Study,”
Conservation Ecology 7 (2003): 9.
6. According to the weekly U.S. Drought Monitor: I’ve pulled these numbers from publicly available statistics on the summer 2012 Midwest drought, available from the U.S. National Climatic Data Center in its August 2012 State of the Climate drought report. This document is available online here: http://www.ncdc.noaa.gov/sotc/drought/#national-overview.
7. Newcastle University historian and demographer Violetta Hionidou: Personal interview, February 15, 2012. See also Violetta Hionidou, Famine and Death in Occupied Greece, 1941–1944 (Cambridge, U.K.: Cambridge University Press, 2006).
8. University of Hong Kong history professor Frank Dikötter: Frank Dikötter, Mao’s Great Famine: The History of China’s Most Devastating Catastrophe, 1958–1962 (New York: Walker and Company, 2011).
9. Intergovernmental Panel on Climate Change’s recent models: You can see these predictions in S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor, and H. L. Miller, eds., Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007 (Cambridge: Cambridge University Press, 2007). It is online at http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-projections-of.html.
10. “You get a famine if the price of food”: Personal correspondence, February 14, 2012.
CHAPTER TEN: SCATTER: FOOTPRINTS OF THE DIASPORA
1. Stories about how cool it is to rip: Yes, I’m joking a little bit here—I don’t think anybody actually talks about ripping faces off in the Old Testament, but there is a lot of chopping off of various body parts and driving stakes through people’s heads and similarly graphic violence against enemies. In Assyrian cuneiform tablets, which were often erected as ceremonial stelae or monoliths in celebration of various kings, it was standard practice to praise the current leader by recounting all his battle victories. Indeed, we get some of the first historical accounts of the Jewish people in one of these stelae, in the Louvre’s collection. On it, King Sargon talks about how great it was to capture and kill thousands of Jews from the northern kingdom of Israel, called Samaria. It’s important to remember that this kind of writing was part of the style of national monuments of the era, and probably didn’t reflect the common people’s sentiments or even the sentiments of the people writing. They were patriotic documents, intended as propaganda. But it was against the backdrop of this kind of propaganda that Exodus was written and compiled, which makes many aspects of the story quite remarkable.
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