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Evolution's Other Narrative

Why science would benefit from a symbiosis-driven history of speciation.

Bradford Harris

2013-11MacroHarrisF1.jpgClick to Enlarge ImageDuring a recent meal with a friend who happens to be a successful engineer, I found myself drawn, as usual, into debate. Although our theological and political views diverge, he and I customarily find common ground in scientific epistemology. However, this time the topic was whether intelligent design should be taught in high schools. When I expressed incredulity at his support for teaching intelligent design, he said, “Brad, just look around us—survival of the fittest can’t be all that’s going on here, and I think it is important to respect people’s sensitivity to that.”

I reminded my friend that, because intelligent design argues for supernatural causes of natural phenomena, teaching it would undermine rational inquiry, together with students’ ability to eventually make the kind of scientific breakthroughs we are enjoying today. I pointed out the U.S. National Institutes of Health’s Human Microbiome Project as an example, which is revealing how human health suffers when the health of the millions of microorganisms with which we’ve coevolved suffers. My friend’s simplistic interpretation of evolution as “survival of the fittest” left him ignorant even of the possibility of projects like this, which are based on evolutionary considerations of symbiosis. Evidently, educators—and certainly evolutionary specialists themselves—must broadcast a more nuanced story of evolutionary theory. Otherwise, future scientists and projects that inform better approaches to human health and global ecology will be sabotaged before they even emerge.

Science education has failed to overcome entrenched cultural ideals rooted not only in religion, but also in political philosophy. For those like my engineer friend trying to comprehend how magnificent structures of life emerge by means of “survival of the fittest,” skepticism is understandable. Popular appreciation for life’s complexity has far outpaced the popular interpretation of the evolutionary source of that complexity, which has remained stuck in 1864, when Herbert Spencer coined the phrase “survival of the fittest.”

When it comes to the story of evolutionary science, people know the name Charles Darwin, but most do not know the names Ivan Wallin or Lynn Margulis—two more recent, groundbreaking evolutionary theorists. Over the past several decades, these and other researchers have revealed that organisms’ cooperation and interdependence contribute more to evolution than competition. Symbiogenesis—the emergence of a new species through the evolutionary interdependence of two or more species—is at least as important in the history of life as survival of the fittest. Such insight has failed to gain traction in American minds—including those of American scientists—because of cultural history traceable back through the popularization of Adam Smith’s individualist philosophy.

Darwinism and Individualism

By the time Darwin published On the Origin of Species in 1859, the Western European and American mind had long been intellectually primed to interpret complexity by reducing perspective to the individual. Adam Smith’s publication of The Wealth of Nations 83 years earlier had set the tone of philosophical and scientific approaches to understanding complex systems. Fundamental to Smith’s philosophy, as economic historian Warren Samuel reminds us, was the notion that large organizations like the economy were to be “comprehended in terms of self-interest or maximization of personal well being.” Smith’s influence on Darwin was as strong as it was on the rest of the reading public.

The appeal of this philosophy was twofold: It morally liberated people to be selfish, and it intellectually liberated them to interpret a range of complicated questions in terms of simpler individual parts. When Darwin presented his theory of evolution in 1859, he stood firmly on the platform of Smith’s individualist philosophy. As the renowned evolutionary biologist Stephen Jay Gould surmised, the essential “Darwinian theory advocates no higher principle beyond individuals pursuing their own self-interest . . . [for] Darwin grafted Adam Smith upon nature to establish his theory of natural selection.” If mid-19th-century readers struggled with the unseen mechanism of evolution, then they could do as Darwin did and conveniently borrow Smith’s economic concept of the “invisible hand.”

For most naturalists and laypeople alike, the logical extension self-interest was endless combat. In the second half of the 19th century, compelling historical reasons existed for this vision. Since Thomas Hobbes published Leviathan in 1651, Western Europeans and later Americans had struggled to reconcile ideals of self-government with social stability, often violently. Humanity’s social institutions might separate it from the violent chaos of nature, but nature’s violent chaos was assumed. The theory of natural selection grew out of and reinforced this assumption, and the most successful circulating English phrases to distill Darwin’s tome depicted violence, not harmony. Nature was understood, through Alfred Lord Tennyson, as “red in tooth and claw.” Similarly, T. H. Huxley tapped the psychological nerve well when he portrayed the history of life as “a continual free fight…the Hobbesian war of each against all.” The English political theorist Herbert Spencer best captured the concept when he defined natural selection as “survival of the fittest.”

Simple and cleanly fused with the entrenched political ideal of individualism, Darwinian natural selection totally dominated the Western perspective on evolution for more than a century. But even before the end of the 19th century, some Western naturalists began interpreting evolutionary principles differently, looking beyond competition to the role of cooperation.

These investigators studied the many “individual” species that resembled a composition of autonomous species or specie parts somehow working in association—for example, lichens, giant green anemones, and termites. In the 1880s, for example, the Scottish biologist Patrick Geddes interpreted the biological relationship between the algal and animal cells in giant green anemones as a special form of speciation. He reasoned that green algal cells were infused into the animal flesh of the anemone cooperatively. Geddes’s chief interest was the evolution of this relationship. In 1882 he published in Nature under the title “Symbiosis of Alga and Animals,” in which he argued that the giant green anemone, which outnumbered competing anemones that lacked algal cells, represented evolutionary adaptation outside the conceptual framework of Darwinism.

Geddes was not the first to use the term symbiosis, but he was among the first to discuss it in terms of evolution. He appreciated that symbiotic associations between “species” could become so integral to their biology that their individual species identity had little meaning outside of the relationship. Although admired briefly by his cohort, however, “Symbiosis of Alga and Animals” was buried beneath his work in other disciplines, such as urban planning. Apparently constrained by his culture’s prevailing individualist perspective, Geddes never fully articulated a theory of symbiotic-driven speciation, nor did any other Western European or American scientists for another two generations.

If an evolutionary theory featuring symbiotic-driven speciation was to emerge, then it would likely do so outside Western Europe and North America. In fact, by 1910 Russian biologists had raced ahead with the idea of symbiotic-driven speciation. In that year enough relevant evidence had accumulated in the Russian scientific community for the botanist Constantin Merezhkowsky to create a new evolutionary term: symbiogenesis. He declared that the term aptly described “the origin of organisms by the combination or by the association of two or several beings which enter into symbiosis.”

The Russians were not merely unswayed by the Western European and American cultural ideal of individualism; many of them were explicitly hostile to it. The well-known Russian naturalist, evolutionary theorist, and political philosopher Peter Kropotkin was highly critical, especially of Huxley’s “Hobbesian war of each against all.” In his travels across Siberia, Kropotkin was impressed by the cooperation he observed among people and animals. Saddled with his own cultural biases tilting toward socialism, Kropotkin was most interested in how the intra- and interspecies relationships of people, reindeer, birds, fish, ants, and numerous other organisms enabled them to survive the harsh Siberian winters.

Outside of their ecological associations, Kropotkin believed, individual organisms were not worth studying from an evolutionary perspective, because isolated individuals were not biologically viable in the unforgiving Siberian environment. In his most popular work, Mutual Aid (1902), Kropotkin wrote that “mutual aid is as much a law of animal life as mutual struggle, but . . . as a factor of evolution, it most probably has a far greater importance.” He explained that “it favors the development of such habits and characters as insure the maintenance and further development of the species.”

According to science historian Liya Nikolaevna Khakhina, Russian evolutionary theorists did not discount Darwinian natural selection, but they did conceive of it differently. By the 1920s, many Russian scientists had come to believe that “symbiosis was the source of evolutionary novelty but natural selection . . . acted on emerging and tightening symbiotic associations.” In other words, according to Khakhina’s notion of speciation, if “symbiosis is the author, natural selection is the editor.”

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