Favored Races in the Struggle for Life: Racism and the Speciation Concept

Abstract

Evolutionary speciation, whether it be cladistic or phyletic, has always been associated with race concepts. Biological races are conceived as definable stages of divergence from a common ancestor. However, the species concept in Western science began within a special creationist framework. The sixteenth century European voyages of discovery resulted in special creationist schemes explaining the origin of the new peoples encountered. These were designed to provide the moral justification for their colonization and enslavement. By the seventeenth century, European naturalists were beginning to seriously question the meaning of the variation within the animals and plants they observed within the context of God's role in creation. By the middle of the nineteenth century, “the species question” was the most important intellectual enterprise within biology. Here I discuss how notions of speciation influenced and were influenced by conceptions of race within Homo sapiens.

SPECIES, RACE, AND SPECIAL CREATION

The study of biology in the Western world began within the framework of special creationism. This meant that each species begat offspring after its own kind, especially humans. We have some ideas about how the ancient civilizations (Hebrews, Greeks, Romans) thought about human variation. For the most part, due to the fact that prior to the fourteenth century people did not travel far from their own homes, no concept of race as we understand it today developed in these societies (Snowden 1970; Brace 2005; Graves 2005; McLaughlin 2010).

Neither was there any widespread notion of race anywhere in the world during the fourteenth century. The travelers Marco Polo and Ibn Battuta (a North African explorer from Tangiers) explored vast territories throughout Europe, the Middle East, North Africa, India, and China. Neither of them formulated a race concept relating to the various human populations they observed (Brace 2005; Graves and Goodman 2022).

European notions of how to explain human variation show a marked change after their colonialization of the Western hemisphere and establishment of the transatlantic slave trade. As early as 1520, the Swiss physician Paracelsus argued that Africans were descended from Cain, Europeans from Adam and Eve's son Seth. His argument is considered one of the first stories for the multiple origins of human diversity (polygenism). The term polygenism refers to multiple special creation events that gave rise to the diversity of humanity, and should not be confused with the twentieth century term associated with multilocus quantitative genetics (Caspari 2018). In 1600, the Italian philosopher Giordano Bruno was executed by the Holy Inquisition for both his defense of the heliocentric universe, but in addition he claimed that no thinking man could think that the Ethiopians (a term for anyone of sub-Saharan descent) had the same ancestry as the Jews. Later in 1616, the Italian philosopher Lucillio Vanini claimed that Africans were descended from monkeys (Vanini 1616). In short, Vanini was claiming that different human races were descended from different first pairs (pre-Adamite races). Isaac de la Peyrère in 1655 held that Africans, Asians, and the Amerindians were descendants of the pre-Adamite races (Graves 2005). The views of Africans as degraded races, held by European natural scientists and philosophers, soon began to work their way into European popular culture (Graves 2005).

During this same time period, naturalists began to wrestle with the species concept, as well as how they might be classified. The Italian naturalist, Andrea Cesalpino, introduced the concept of classification by logical division in De Plantis, published in 1583. This concept dominated the thinking of Carolus Linnaeus (1707–1778), who invented his Linnaean hierarchy of classification (class, order, genus, species) and the binomial nomenclature system. The species that were classified by Linnaeus were fixed and unchanging entities. Linnaeus's thinking was derived from the eidos concept of Plato (428–348 BCE). This meant that species reflected a limited number of unchanging universals (essentialism). By the seventeenth century, European naturalists recognized that even within the essentialist species concept variation in living things was real. The English Christian naturalist John Ray (1627–1705) dealt with this problem in plants by recognizing that whatever variations occurred within the lifetime of a plant, if they sprang from the same seed they were members of the same species (Cain 1999). This principle was still the dominant view of species in the eighteenth century. The French naturalist Georges Cuvier (1769–1832) held to the same principle regarding animal species (Mayr 1982).

While Linnaeus did not discuss human varieties in the first edition of Systema Naturae published in 1735; by the 10th edition published in 1758 he mentioned several. Most importantly, he ranked Homo sapiens europaeus (Europeans), Homo sapiens asiaticus (Asians), Homo sapiens americanus (Amerindians), and Homo sapiens afer (Africans) in a hierarchical fashion. Linnaeus based these rankings (H. sapiens europaeus highest and H. sapiens afer lowest) based upon the literature and tales of European explorers. His view reflected the general confusion concerning human variation in this time period. There was no still no general consensus among European naturalists concerning the nature of the species or of human varieties (races). Georges Buffon (1707–1788) introduced the criterion of interfertility as part of the identification of species in his Histoire Naturelle in 1749. Later on, in this work (1766; Histoire Naturelle was published in 44 volumes from 1749 to 1804), he hinted at apes and humans sharing common ancestry. He felt that apes had degenerated from men. He mused “that the orang-outang might simply be the most degenerate of men, one step beyond the Hottentot.” Buffon saw that a gap had arisen between the European and African races through a degenerative process associated with the environment experienced by the two races, but still saw them as members of the same species via the interfertility criterion (Buffon 1766).

Thus, for Buffon, degeneration due to environmental conditions was the explanation for the existing human varieties. However, unlike the varieties of other species, Buffon thought the races of humans remained constant due to some hereditary mechanism (Forgione 2020). Naturalists such as Francois Bernier (France 1684), Gottfried W. von Leibniz (Germany 1690), and Johann Friedrich Blumenbach (Germany 1775, often referred to as “the Father of Anthropology”) thought there was no objective ranking of human races, although they differed on whether racial traits were heritable. On the other hand, Linnaeus (Sweden 1758), Henry Home (England 1774), Samuel Sömmering (Germany 1784), Petrus Camper (Netherlands 1786), Georges Buffon (France 1786), and Christopher Meiners (Germany 1790) felt that races could be objectively ranked, their traits were inheritable, and that Africans (Negroes) were inferior to all other races. The consensus of eighteenth-century naturalists was that there was only one human species, the descendants of the one human pair, Adam and Eve (Graves 2005).

THE SPECIES QUESTION IN THE NINETEENTH CENTURY

At the beginning of the nineteenth century, the essentialist species concept still dominated biology. Jean-Baptiste Lamarck (1744–1829) published a theory of phyletic species transformation early in the century (Lamarck 1809). Lamarck felt this change occurred extremely slowly within a given species lineage. He also deployed the concepts of “use and disuse” as well as the inheritance of acquired characteristics to explain the variation within organic species. He particularly thought that the domesticated breeds (or races) illustrated this principle (Burkhardt 2013). However, Lamarckians in the main were monogenists, and held that the human races belonged to one species (Forgione 2020).

Yet by the middle of the nineteenth century, monogenist ideas of human origins had been replaced by polygenist theories (William Lawrence, UK, 1823; Samuel Morton, USA, 1849; Louis Agassiz, USA, 1850; Josiah Nott, USA, 1855; George R. Gliddon, UK, 1857; Paul Broca, France, 1862; Graves 2005). The polygenists were uniform in their belief that the human races had descended from different original pairs, that racial traits were inheritable, and that Africans (Negroes) were the most inferior of all the races (Graves 2005). There is an unmistakable connection between the ascension of polygenism and the social crisis concerning chattel slavery in the Western world at this time. The Scottish physician Robert Knox emphasized the importance of understanding the origin of human races with regard to the coming “race wars” between them (Knox 1850). In the United States, the connection between polygenism and the institution of chattel slavery was unmistakable. In this regard, four individuals played a critical role in supporting and popularizing this theory (Graves 2005). Louis Agassiz was its chief theorist (1807–1873, “zones of creation”). Samuel Morton was its chief empiricist (1799–1851, craniometry measurements). Josiah Nott (1804–1873, South Carolina, physician) and George R. Gliddon (1809–1857, Egyptologist) were its chief propagandists (Types of Mankind, 1854; Indigenous Races of the Earth, 1857). Nott was acclaimed throughout the south for his lectures on “niggerology” (Haller 1972).

Louis Agassiz was born in Switzerland in 1807. In 1837, he became a leading proponent of the Ice Age theory of catastrophism (Irmscher 2013). This theory held that at the end of each geological period sudden temperature decreases were accompanied by the demise of all existing life. The new geological period was then repopulated with new species by direct intervention of the creator. Agassiz's scientific notoriety made him a highly sought-after scholar. Prior to coming to the United States, Louis Agassiz was not overly concerned with either the species question or the origin and character of human races. In 1846, Agassiz received an invitation to give a series of lectures at the Lowell Institute in Boston (“The plan of creation, especially the animal kingdom”). In 1848, he published Principles of Zoology (with his Boston colleague Dr. Augustus Gould). This work held that there were “zones of creation” each complete with its own unique flora and fauna (including humans; Agassiz and Gould 1848). Agassiz collaborated with Josiah Nott and George R. Gliddon in the publication of Types of Mankind in 1850 (Nott and Gliddon 1854). Its claims were based largely on the collected works of Samuel Morton (who died shortly after in 1851).

It is clear that Charles Darwin appreciated that his ideas concerning descent with modification would come into conflict with the polygenist dogma of the mid-nineteenth century. Agassiz's remarks on this question were read by Darwin. In a letter to his cousin, William Darwin Fox, Darwin wrote: “Agassiz's lectures in the U.S. in which he has been maintaining the doctrine of several species—much I daresay, to the comfort of the slave–holding Southerns” (Darwin 1856; Irmscher 2013). Darwin's mentor Sir Charles Lyell was also concerned about this issue. In 1856, he agonized over the implications of Darwin's species theory. He clearly understood the implications of a theory demonstrating the common descent of all humans: “go back umpteen generations and would blacks and whites find a common ancestor? Itself the descendent of an ape? The idea would give shock to … nearly all men. No university would sanction it; it wd ensure the expulsion of a Prof. already installed.” In that same year, as Darwin prepared the publication of The Origin, he felt that Agassiz “will throw a boulder at me, & many others will pelt me” (Desmond and Moore 1991). This concern played a major role in why Darwin chose not discuss human speciation and race in the first edition of On the Origin of Species in 1859 (Desmond and Moore 1991; Graves 2005).

However, in the first edition of The Origin, Darwin did explain how varieties came about in nonhuman species. Chapters I through V were all about this topic (“Variation Under Domestication”; “Variation Under Nature”; “Struggle for Existence”; “Natural Selection”; “Laws of Variation”). He pointed out how the power of selection produced phenotypic differences: “cultivated plants and animals…generally differ much more from each other, than do individuals of any species or variety in a state of nature” (Darwin 1859). Darwin, as well as Alfred Russell Wallace, both understood that the isolation of subpopulations was an important requirement for new species to form. The example that Darwin presented in The Origin was the birds of the Galapagos islands, while Wallace relied on monkeys, poorly flying birds, and butterflies in the Amazon tributaries. Wallace also saw similar patterns in various species of the Malay Archipelago. Darwin realized that isolation of populations could occur by the formation of mountain ranges, rivers, and deserts over geological time. He also understood that there were intermediate points along the way to the formation of new species. He discussed this in Chapter II of The Origin (“Variation Under Nature”):

Those forms which possess in some considerable degree the character of species, but which are so closely similar to some other forms, or are so closely linked to them by intermediate gradations [emphasis added], that naturalists do not like to rank them as distinct species, are in several respects important to us.

—Charles Darwin

On the Origin of Species, p. 47

His thinking on this is also illustrated in Chapter IV (“Natural Selection”) in which he explained the logical consequences of natural selection. This meant that natural selection would result in the divergence of characters, due to the fact that more living things could be supported in a geographical area the more they diverged in character. Ultimately, this resulted in the formation of new species; thus, all modern species were the result of this “descent with modification.” A careful reader would have remembered that Darwin had already described in the previous chapters what variation within a species might look like during this process (e.g., the formation of varieties). Applying this to all species also meant that all existing humans were descended from a common ancestor.

Natural selection and descent with modification did not immediately take hold as an explanation of human biological diversity. One of the first attempts to deploy evolutionary reasoning to human racial diversity was that of John Jeffries (Jeffries 1869). In reality, Jeffries’ ideas were more Lamarckian than Darwinian, in that he saw the classification of races according to facial angles, and that the progression of facial angles throughout the evolutionary history of the species was responsible for its biological races. Later in the twentieth century, Ernst Haeckel would advance a similar theory (Graves 2005). Finally, it is a common historical/scientific error to associate the social Darwinism of Herbert Spencer with evolutionary theory (or its explanation of speciation). Spencer's ideas were an amalgam of various ideological positions (Lamarckian progressive evolution, Malthusian population thinking, laissez faire capitalism, and an “unknowable” driving force behind the universe). Neither was Galton's Hereditary Genius (1869), the tome that launched the eugenics movement, particularly associated with Darwinian speciation (Graves 2005).

Darwin would return to the issue of the common ancestry of human races with a vengeance in 1871. In Chapter VII (“On the Races of Man”), he directly takes on the polygenist claim concerning the “so-called races” of men as separate species. His arguments against polygenism are summarized in Table 1. Darwin's primary arguments rested upon his concept of descent with modification (therefore common descent) of humans. He noted that humans displayed some differences in both physical and mental capacities, but in the main all groups of humans were more alike to each other than they were different. He also noted that the physical features used to classify humans into races were inconsistently applied and also not constant within so-called races. This had resulted in naturalists of the 18th and 19th centuries classifying the number of races within humans differently, from Virey (two), Blumenbach, Buffon, Hunter, and Agassiz (five, six, seven, and eight, respectively), to Crawford's 60 and Burke's 63 (Darwin 1871).

Table 1.

Darwin's arguments against polygeny in The Descent of Man (1871)

Trait	Claim	Supported then	Supported now
Geographical distribution	Agassiz's zones of creation did not describe human distribution	Yes	Yes
Physical/mental differences	Differences existed between races, but races were more alike than different	Yes	Yes
Racial characters constant	Characters used define races were not consistent, nor constant within supposed races	Yes	Yes
External parasites	External parasite species (e.g., lice) were different by race	Yes	No
Infectious disease	Human races showed differences in their susceptibility to infectious disease	Yes	Yes
Hybridization	Full infertility of human races with each other, offspring showed no loss of viability	Yes	Yes

SPECIATION, RACE, AND THE SYNTHESIS

The intellectual tools necessary to fully understand the process of speciation were in their infancy in the nineteenth century. In particular, to better understand this problem it was necessary to unify natural selection and Mendelian genetics. This began around the turn of the twentieth century, and was mainly complete by mid-century (Mayr and Provine 1980; Bowler 1989). It can be argued that Ronald A. Fisher, John Burdon Sanderson Haldane, and Sewall Wright provided important advances that stimulated the synthesis. However, with regard to our modern understanding of biological theories of race as associated with the speciation, the work of Wright, Theodosius Dobzhansky, and Ernst Mayr were most crucial. Fisher's thinking, outlined in The Genetical Theory of Natural Selection (1931), also played a major role in stimulating the research that would lead to some of the first comprehensive measurements of genetic variation in our species. Dobzhansky addressed the factors that influenced variation in natural populations within the context of Darwinian evolution in Genetics and the Origin of Species, first published in 1937. In the first edition, he discussed race formation as essentially resulting from local adaptation to different environments. By the 3rd edition, published in April 1951, he specifically added a chapter entitled “Race Formation.” In this edition, he provided a formal definition of race as “Genetically distinct allopatric populations of a species are termed geographic races, subspecies, local varieties, or simply races” (Dobzhansky 1951, p. 135). For Dobzhansky, the primary criterion for identifying biological races was whether populations within a species was “distinct.” This was achieved by whether there was a statistical difference in the incidence of genetic variants in the gene pools of the populations in question. He provided the example of the inversion frequencies in Drosophila pseudoobscura associated with elevation in the western United States. He also recognized that this criterion would result in rather arbitrary decisions concerning how many races would exist within a species: “This is a matter of convention and convenience.” While Dobzhansky never made this claim, one could argue using this logic that high altitude adaptation in humans as exhibited in the Eastern Africa, the Himalayas, and the Andes plateau represent three distinct biological races, separate from the rest of our species. Undoubtedly the most important idea that Dobzhansky outlined in this chapter is the point that race is not a static entity but the product of a process. This meant that the evolutionary forces of natural selection, genetic drift, and patterns of isolation shift throughout the lifetime of species. The logical conclusion from this is that racial formations shift over the course of the existence of the species; in some cases biological races would merge, and in others they might result in the formation of new species.

FASCISM, WAR, AND RACE

It is difficult to overestimate the degree to which the thinking of physical anthropologists, evolutionary biologists, and geneticists in the middle of the twentieth century were deeply influenced by socially defined race concepts in this period. By the 1920s, eugenical sterilization of “unfit” individuals had begun to be common practice in both the Western democracies and their fascist counterparts (Sofair and Kaldjian 2000; Graves 2005). The debates about how evolution and genetics might be deployed to improve human societies were fierce. In 1939, the Seventh International Congress of Genetics in Edinburgh saw a walkout of the German, Hungarian, Scandinavian, and Swiss delegations (second or third day); upon the initial printing of the program, the Russian (Soviet) delegation refused to attend. The report of the congress included a “manifesto” authored primarily by American and English geneticists (F.A.E. Crew, J.B.S. Haldane, S.C. Harland, L.T. Hogben, J.S. Huxley, H.J. Muller, J. Needham), which was later signed by others (including G. Dahlberg, Th. Dobzhansky, and C.H. Waddington). The manifesto focused on how the world's population could be improved most effectively by genetic means. The manifesto did not explicitly condemn Nazi race science, nor did it reject eugenical methods. Instead it called for society to understand how such methods could be potentially used to improve health, intelligence, and temperament suited for social behavior (Gruenberg 1939). In 1942, the British anthropologist Ashley Montagu and the Swedish geneticist Gunnar Dahlberg both published books outlining the fallacies of the race concept and its application to the classification of human beings (Dahlberg 1942; Montagu 1942). Dahlberg's book illustrated how natural selection and geographical isolation accounted for genetic and physical differences in humans. He further debunked the Nazi conception of “pure races.” Montagu discussed similar topics, but went further in demonstrating the incapacity of defining biological races in humans using physical features (the principle of discordance).

After the war, with the horrible logic of fascist race science revealed, Theodosius Dobzhansky and Leslie Dunn wrote a popular work entitled Heredity, Race, and Society, published in 1946. This work pointed out that classical schemes of race classification failed to be able to unambiguously place individuals into specific races. Specifically, they demonstrated that you could draw different configurations of racial classification depending upon what genes were utilized (Graves 2005). The consequences of racial genocide in World War II also prompted the victors to address the science of human variation. This was begun by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) in 1949 (Hazard 2012). The first statement published in 1950 was composed by a committee dominated by anthropologists and sociologists and chiefly authored by Montagu. It hinged on the principle of the nonexistence of biological races within humans, and hence the irrationality of any race-specific prejudice. There was considerable pushback against the 1950 statement both by geneticists in the Western democracies and former fascist scientists. The 1951 statement was composed with major input from Julian Huxley, Gunner Dahlberg, Theodosius Dobzhansky, and Leslie Dunn. It disputed Montagu's “nonexistence of biological races idea” and replaced it with the “utility of race as a form of biological classification within humans” but held with the notion that race prejudice was irrational (United Nations Educational, Scientific, and Cultural Organization 1952).

MAYR, ALLOPATRIC SPECIATION, AND RACE

In Animal Species and Evolution, first published in 1963, Ernst Mayr provided virtually all the principles required to fully comprehend the biological concept of race. Most importantly, he stressed the importance of the population in speciation. He relied on the ideas of both Dobzhansky and Wright to define population, specifically that in sexual species, that any two individuals within them must have an equal probability of mating with a member of the other biological sex and producing fertile offspring. Of course, Mayr was simplifying the mating dynamics of real-world populations in this definition, as in some cases sexual selection would result in unequal probabilities of mating success. He also pointed out that a species in both time and space is composed of numerous local populations, each one integrated with the others.

It is the integration of populations with each other that is crucial with regard to understanding his biological concept of race. As populations are distributed in space, it is logical to expect that there will be local adaptation for the conditions which that population is experiencing. Mayr goes on to explain the conditions under which biological races might form; specifically, he talked about the role of mechanisms that maintain genetic diversity (including heterozygosity, heterozygote superiority, epistasis—effect of one gene on the expression of another, opposing selection pressures through time, diversity within the local environment, and gene flow). It is also crucially important to understand the Mayr was writing before the revelations of the neutral theory of molecular evolution were fully understood. Neutral theory demonstrated that much of the genetic change at the level of nucleotide changes in DNA is selectively neutral (Kimura 1968, 1983). Therefore, populations maintain a large amount of genetic variability that is not directly exposed to natural selection.

Mayr also contrasted evolutionary understandings of the species with that of essentialist ones. His Chapter 12, “The Polytypic Species of the Taxonomist,” is very illustrative with regard to how we should understand human biological variation. The first point he makes is that naturalists would be most satisfied if species only existed in one location. This would dispense with the requirement to define varieties, subspecies, ecological races, or geographic races. He lamented about the difficulties of utilizing these descriptions within any given species. These were consistently confused by problems of what traits in these groups resulted from genetic, as opposed to environmental, influences. He proposed that species did not consist of strictly morphologically definable aggregates of subspecies and varieties, or of purely definable ecotypes or ecological races, but simply is best understood as composed of populations that are distributed in space and time. These populations possess morphological as well as physiological and ecological characteristics, such that geographical races were genetic–physiological responses to a local environment.

Mayr was not aware that subsequent genetic and genomic analysis of human variation (1970s to present day) would support much of his initial reasoning concerning the human species. However, at the time he wrote Animal Species and Evolution, he did understand the significance of his analysis of the mechanisms of speciation and the difficulty of using variation within the species to produce an unambiguous classification of biological races within humans. He pointed out, in a fashion similar to Darwin in The Descent of Man, that the anthropologists of his time differed in their classification schemes. In 1950, William Boyd recognized six human races, and Carleton Coon recognized 30. And in 1952, Bertil Lundman classified 37, with 30 additional subraces. This lack of taxonomic agreement (which continues to through the 2020s) is an indication that human biological variation is not really consistent with naming biological races in our species at all. Mayr (1959) held a similar view:

Biologically, it is immaterial how many subspecies and races of man one wants to recognize. The essential point is to recognize the genetic and biological continuity of all these gene pools, localized in space and time, and to recognize the biological meaning of their adaptations and specializations.

MULTIREGIONALISM AND RACIAL FORMATION IN HUMANS

Beginning in the mid-nineteenth century, fossils of extinct hominids began to accumulate. This was taken as proof that Darwin's mechanisms of speciation could be applied to understand human evolution. In the 1940s, a partial reconciliation of the diverse humanoid fossil finds appeared in the form of Franz Weidenreich's multiregional theory of human origins (Weidenreich 1947). In this theory, the modern human biological races were descended from an ancient common ancestor (Homo erectus) and that each race of humans evolved within its current geographical range. H. erectus fossils had been found all over the world (sub-Saharan Africa, China, Java, Malaysia, Saudi Arabia, England, France, Germany, and other European sites). These fossils differed from modern humans by a number of features, including having cranial bones twice as thick and a mean cranial capacity of about 833 cubic centimeters (modern humans mean is 1350 cc; Campbell 1998). Today we know that the African fossils are the oldest (1.8–1.5 million) compared to 1.6 million—53,000 in other parts of the world (McKee et al. 2004). However, the type of radiometric dating tools to accurately determine the age of fossils were unavailable to Weidenreich. His model of human evolution allowed for some gene flow between the regions, but the primary evolutionary events (adaptation) occurred within each region. He also posited that the rate of evolution from H. erectus to H. sapiens most likely differed from region to region. Typical to the white supremacist/Eurocentrism that dominated physical anthropology in this period, Weidenreich saw Europeans as more advanced than other groups of modern humans.

In 1962, Carleton Coon would incorporate Weidenreich's multiregional model into his own ideas, which more explicitly relied on the different rates of evolution by region. Coon supported the idea that Caucasoid (Europeans) and Mongoloids (East Asians) developed into H. sapiens before Negroids (Sub-Saharan Africans) and Australoids (native Australians; Coon 1962). The significance of Coon's claims was immediately picked up to justify ongoing racial segregation in the United States. They were popularized by the arch-segregationist (and his cousin) Carleton Putnam. Neither could Coon claim “objective neutrality” in the controversy generated by his ideas, as he was shown to be in correspondence with his cousin over the relevance of his “science” for the segregationist agenda. He even argued vehemently with evolutionary geneticists such as Theodosius Dobzhansky concerning the validity and application of this theory (Jackson 2001). In the 1970s, Milford Wolpoff and his colleagues revised the “multiregional hypothesis.” In the Wolpoff model, gene flow between the regions undergoing evolution toward H. sapiens played a more significant role (Wolpoff et al. 2000). In this model, H. erectus populations in various regions of the world maintained sufficient gene flow such that the entire species evolved from H. erectus to H. sapiens simultaneously (Wolpoff et al. 2000).

OUT OF AFRICA AND MODERN HUMAN DIVERSITY

Wolpoff and his collaborators were the last serious adherents of multiregionalism. The theory was first postulated in a time period that did not have the scientific tools to accurately test its predictions. In effect, it was an evolutionary theory of human origins that relied primarily on the interpretation of fossil evidence. The problem with the type of physical (phenotypic) evidence that can be derived from fossils is that phenotypes are always influenced by environments. Thus, it is difficult to accurately assess how much contemporary fossils differ from each other in their physical attributes due to environmental and genetic influences. Furthermore, fossil finds of ancient hominids are rare, so the sample sizes required to make accurate inferences between supposed species were always limited. Thus, the coming of new technologies, particularly genomic sequencing of living humans, and eventually ancient fossilized specimens, sounded the death knell for multiregionalism in the last decade of the 20th and first decade of the twenty-first century.

One of the first major genomic findings that gave powerful support to the “out of Africa” replacement model was the study of “mitochondrial Eve” of Cann, Stoneking, and Wilson published in 1987 (Cann et al. 1987). The scientific objections to the mitochondrial Eve hypothesis revolved mainly around the extreme coalescent event that the model predicted (Ayala 1995). The mitochondrial Eve study predicted that all modern humans were descended from one to four sub-Saharan African females within the last 200,000 yr. Ayala 1995 argued that effective population estimates of anatomically modern humans were no less than 10,000 individuals in that time period (Ayala 1995; Kingman 2000). There were other methodological concerns with the original “Eve” study, but over the last 30 yr, an avalanche of additional evidence (fossil, mtDNA, Y-chromosome, and nuclear DNA) have validated the out of Africa replacement model (Campbell et al. 2014). This was possible because the multiregional and out of Africa replacement models make some strikingly different predictions concerning what the genetic diversity of modern humans should look like (Graves 2023). It is particularly problematic for multiregionalism to explain the patterns of heterozygosity and linkage disequilibrium (LD) with distance from Africa found in modern humans. If multiregionalism were true, LD should be roughly equal in all regions. It clearly is not. By the end of the first decade of the twenty-first century, the multiregional hypothesis was completely discredited, replaced by the out of Africa replacement theory by serial founder events (DeGiorgio et al. 2009; Hunley and Cabana 2016).

However, the new revelations resulting from the sequencing of ancient DNA could be interpreted as resurrecting some of the ideas that are adjacent to multiregionalism. David Reich and others view the peopling of the world beginning with H. sapiens migrating out of Africa within the last 100,000 yr, but with both significant regional adaptation and hybridization with archaic human species (such as the Denisovans and Neanderthals; Reich 2018). For Reich and colleagues, modern human populations are the product of gene flow between adapted regional populations. It is unclear, however, if that adaptation might have been sufficient enough to make those regional populations akin to biological races. Thus, the evidence now suggests that out of Africa includes some local adaptation of regional subpopulations as well as episodes of hybridization with archaic human species (H. naledi—Africa; H. floresiensis, H. neanderthalensis—Eurasia; and H. floresiensis Denisovans—East Asia) (Browning et al. 2018; Santander et al. 2019; Wall et al. 2019).

CONCLUSION: DO BIOLOGICAL MODELS OF SPECIATION NECESSARILY SUPPORT RACISM?

No. The modern biological definitions of race revolve around the amount of genetic variation within versus between populations or whether any population within a species can be considered a unique evolutionary or phylogenetic lineage. We have long known that there is more genetic variation within purported human races than between them, and that there are no human populations that can be legitimately thought of as unique evolutionary lineages (Lewontin 1972; Nei and Roychoudhury 1972; Cavalli-Sforza et al. 1992; Templeton 1998; Graves 2018; Graves and Goodman 2022). This means that our species of anatomically modern humans have maintained sufficiently high amounts of gene flow between its regional populations throughout its existence, and show no evidence of any subgroups diverging from the whole species per an allopatric species mechanism.

This lack of strong differentiation in our species is a simply a fact of our evolution. Certainly, biological races could have formed during our migratory journey around the planet; they simply did not. The past history of hominids on this planet, however, suggests that the archaic species most likely did form biological races and underwent either cladistic or phyletic evolution. Those species are gone (although some of their genes are in us). Ancient DNA discoveries are telling us much about their geographic distribution and genetic variation. However, it is highly likely that we will never have enough samples of these species to draw definitive conclusions.

Despite the fact that the evolutionary science of speciation does not support the existence of biological races in modern humans, racism has never really relied on scientific rigor. The history of racist pseudoscience within anthropology, evolutionary biology, and genetics is well known (Brace 2005; Graves 2005). Modern racists are coopting modern genomic science and ancient DNA discoveries to their cause (e.g., Wade 2014; Roth and Lyon 2018). For example, modern white supremacists engage in silly practices of publicly drinking milk, as a boastful demonstration of their lactase persistence alleles, and by extension European ancestry and racial superiority (Harmon 2018). This demonstrates an embarrassing lack of scientific understanding: East Africans, such as the Maasai people, have lactase persistence as well (Ranciaro et al. 2014).

In my view, the most effective measure that can be taken against the spread of racist misconceptions associated with theories of speciation is the active participation of evolutionary biologists in dispelling such misinformation (and disinformation). This can be achieved in part by more intentional discussions concerning how to teach concepts in evolutionary science (particularly speciation, local adaptation, genetic drift; as well as the misappropriation of evolutionary ideas) in general biology and lower division courses. In addition, public understanding can be bolstered by the participation of evolutionary biologists discussing their speciation research (and its relevance) with students and the general public at all stages. Finally, I argue that the best palliative measure against the spread of racist misconceptions in evolutionary science is the transformation of the scientific workforce to accommodate the many dimensions of diversity that define human society (see, for example, Graves et al. 2022). There is nothing necessarily racist about evolutionary science, and with some changes to the way that the science is practiced and discussed, the world could benefit from the many important insights that evolutionary speciation and related ideas offer society (Graves 2022).