Post-Darwinian Evolution and Chaotic Order

Nature … is fundamentally erratic, discontinuous, and unpredictable. It is full of seemingly random events that elude our models of how things are supposed to work.

—DONALD WORSTER, “The Ecology of Chaos and Harmony”⁸⁶

Survival of the fittest, natural selection, random genetic mutations, competition for resources—we all know how evolution works, right? Not quite. Over the past two decades, a quiet revolution has been taking place in biology. Some of the most fundamental concepts and principles in evolutionary theory are being questioned, challenged, reexamined, and (in some cases) abandoned altogether. A new paradigm is emerging: post-Darwinian evolution.⁸⁷ “Heretical” ideas are being proposed by post-Darwinian evolutionists, such as the self-organization of life, the notion that the environment can beneficially alter the genetic code, and a suite of evolutionary processes to accompany the once hegemonic principle of natural selection. Moreover, many of the developments in this theorizing reflect surprising convergences with another “new” science, chaos theory.

“Put at its simplest, the new paradigm is an insistence on pluralism in evolutionary studies.” That’s how scientists Mae-Wan Ho and Peter Saunders characterize the essence of the new thinking on evolution.⁸⁸ This paradigm is tackling a number of long-standing puzzles in biology—among them, global patterns of emergence and extinction of species, “mimicry” between animals separated by geography (in which two unrelated butterfly species in different parts of the world, for example, have evolved identical appearances), and convergence between the structure of biological and inorganic forms (in which jellyfish larvae, for instance, closely resemble the patterns made by falling drops of ink in water; or the similarity between animal coat markings and the standing wave patterns that can be generated on thin, vibrating plates). Post-Darwinian evolutionary biologists are synthesizing developments in a number of diverse disciplines such as physics, chemistry, mathematics, and molecular and developmental biology as part of their theorizing on these and other phenomena.

One proposal involves the possibility of the self-organization of life—the notion that the proteins, and in turn the enzymes and the cells, necessary for the first rudimentary life-forms may not have arisen randomly. Rather, experiments have shown that such building blocks can form “spontaneously” through the interaction of chemical and physical processes inherent in the molecules themselves and their watery medium. Similarly, convergences in form between distant species or organic and inorganic matter reveal underlying patterning processes that may actually “direct” evolutionary change. Another revolutionary proposal involves what is known as the “fluid genome”: the hypothesis that the environment can beneficially change the genes of an organism. The genetic code was previously thought to be static and inalterable (aside from random mutations), but now biologists are recognizing that a dynamic, complex, two-way interaction between environment and genetics may occur, possibly even leading to the evolution of new species.⁸⁹

Although much of this theorizing is admittedly in its infancy (and even, in a few cases, on the “fringes” of the scientific establishment), some of the most respected names in evolutionary science are participating in the reevaluation of basic tenets of the theory.⁹⁰ World-renowned biologist and evolutionist Edward O. Wilson is at the forefront of the discussion, even going so far as to declare that evolution is, in a sense, a form of religion—“The evolutionary epic is probably the best myth we will ever have”⁹¹—thereby putting an ironic twist on the whole creationism-evolution controversy. Perhaps what is most significant in this entire discussion is not the explanatory power of particular theories (impressive as some of these are), but the spirit of intellectual openness and vision being embraced by many evolutionists, the willingness to reexamine once ironclad principles. Nowhere is this more apparent than in the questioning of the basic principle of natural selection based on random genetic variations. A number of scientists—among them Stephen Jay Gould—have long criticized the attempt to find an adaptive explanation for “every surviving form, structure, or behavior—however bizarre, unnecessarily complex or outright crazy it may appear.”⁹² Of course, the limitations of such “adaptationist” explanations are precisely the problem that orthodox biology confronts when it looks at the “bizarre” behaviors of homosexuality and nonreproductive heterosexuality. If biology is finally to come to terms with these phenomena, such explanations will need to be seriously reevaluated.

There are a number of parallels between post-Darwinian thought and the emerging science of chaos. Chaos theory is, fundamentally, a recognition of the unpredictability and nonlinearity of natural (and human) phenomena, including apparently destructive or “unproductive” events such as natural catastrophes. Although originally developed in the fields of mathematics, physics, and computer science, chaos science was quickly applied to biological phenomena. In fact, the periodic fluctuations of animal and plant populations were among the first examples of “chaotic behavior” to be uncovered in the natural world. Chaos theory has since been successfully used in the analysis of a wide range of natural and social phenomena, including biological systems (from the ecosystem to the cellular level) and evolutionary processes. Indeed, chaos scientist Joseph Ford has stated that “evolution is chaos with feedback.”⁹³ The fractal or “chaotically ordered” structure of nature has even been revealed in the behavior patterns of individual animals and in the “self-organizing” architecture of honeybee combs.⁹⁴

Arrhythmias, discordant harmonies, and aperiodicities are some of the characterizations of “chaotic” natural phenomena that have been offered. These terms are attempts to convey the idea that fundamental principles of “pattern organization” direct, but do not entirely determine, the development or “shape” of biological (and other) entities. The internal dynamics of such systems generate unpredictable, but not random, patterns.⁹⁵ This concept is echoed in recent reappraisals of “adaptationist” explanations for the diversity of plant and animal forms. As one ornithologist studying the proliferation and elaboration of bird plumage has observed, traditional evolutionary theory may be able to account for how a specific pattern, color, or form has developed, but it cannot explain why or how such incredible variety arose in the first place: “Such hypotheses explain a large variety of traits as divergent as a widowbird’s tail, a rooster’s comb, a peacock’s train, or the black bib of a sparrow. While these hypotheses can account for some features of the trait, they cannot account for the enormous diversity in conspicuous traits—why some birds have red heads and others long tails even though the same basic process … may be at work.”⁹⁶ Most current theories of phenomena such as plumage diversity still focus on the putative functional or adaptive role of specific patterns rather than the overall range of variation. However, this is an area where the application of principles from chaos theory might yield fruitful results.⁹⁷

So too for diversity of sexual and gender expression. One of the more important insights to emerge from chaos theory is that the natural world often behaves in seemingly inexplicable or “counterproductive” ways as part of its “normal” functioning. According to Sally Goerner (in her discussion of chaos, evolution, and deep ecology), “Time and again, nonlinear models show that apparently aberrant, illogical behavior is, in fact, a completely lawful part of the system.” Similarly, biologist Donald Worster remarks that “scientists are beginning to focus on what they had long managed to avoid seeing. The world is more complex than we ever imagined … and indeed, some would add, ever can imagine.” More than half a century earlier, evolutionary biologist J. B. S. Haldane presaged these thoughts when he commented that “the universe is not only queerer than we suppose, it is queerer than we can suppose”—words we used to open this book.⁹⁸ Although none of these scientists is referring specifically to homosexuality, the alternate systems of gender and sexuality found throughout the animal kingdom are exactly the sort of “discontinuities” and “irrational” events that should be generated in a “chaotic” system.

Particularly relevant in this respect is Goerner’s statement of one of five basic “principles” of chaos: “Nonlinear systems may exhibit qualitative transformations of behavior (bifurcations). The idea is simple: a single system may exhibit many different forms of behavior—all the result of the same basic dynamic. One equation, many faces. A corollary to this idea is that a system may have … multiple competing forms of behavior, each perhaps a hairsbreadth away, each representing stable mutual-effect organization.”⁹⁹ Transposed to the realm of sexuality, this idea offers the potential for intriguing insights: heterosexuality, homosexuality, and all variants in between can be seen as alternative manifestations of a single sexual “dynamic,” as it were, which is itself part of a much larger nonlinear system. The “flux” of this system is played out in endless and infinitely varying expressions within individual lives, through various communities, between different species, across sequences of time, and so on and so forth.

Though chaos theory has been applied to various social phenomena, it has yet to be used in the analysis of patterns of sexual behavior. It remains to be seen whether something as relatively elusive as sexual and gender expression could even be quantified to the extent required by the rigorous mathematical models of chaos science. Nevertheless, the broader insights offered by chaos theory are readily apparent: seemingly incoherent or counterintuitive phenomena—whether in the realm of inorganic chemistry or “sexual chemistry”—are components of an overall pattern, regardless of whatever meaning (or lack thereof) they may have individually. In essence, deviation from the norm is part of the norm.

Biodiversity = Sexual Diversity

Gaia theory … has a profound significance for biology. It affects even Darwin’s great vision, for it may no longer be sufficient to say that organisms that leave the most progeny will succeed.

—JAMES E. LOVELOCK, “The Earth as a Living Organism”¹⁰⁰

Nearly two decades ago, British scientist James Lovelock published his book Gaia: A New Look at Life on Earth, ushering in a new era in biological thought. What has come to be known as the Gaia hypothesis or Gaia theory has had an immeasurable impact on the way science looks at natural systems in general, and evolution in particular. Gaia theory says that the sum of all living and nonliving matter forms a single self-regulating entity, analogous to a giant living organism. Converging with the results of post-Darwinian evolutionary theory, the Gaia hypothesis has prompted a rethinking of some of the most basic principles of evolution. Cooperation, in addition to competition, is seen as an important force of evolutionary change, while the search for adaptive explanations at the level of the individual has been shifted upward to also include whole species as well as the functioning of the entire biosphere. Although not without controversy, Gaia theory has spawned a number of innovative ideas, many of which are beginning to be empirically and experimentally verified, and has led to important cross-disciplinary collaborations between scientists.¹⁰¹

Once again, these new strands of thought have powerful implications for the way animal homosexuality and, more broadly, systems of sexuality and gender are construed. As Lovelock (quoted above) has observed, reproduction is not necessarily a required component of “survival”—in some instances, it may be beneficial for a species or an ecosystem as a whole if some of its members do not procreate. Of course, it is overly simplistic to equate homosexuality with nonreproduction (since, as we saw in previous chapters, many animals that engage in same-sex activity also procreate). There is also little evidence to support the idea that homosexuality operates as a kind of large-scale “population-regulating” mechanism (perhaps the most obvious “function” that would be ascribed to homosexuality in a Gaian interpretation). Nevertheless, one of the fundamental insights of Gaia theory—the value it accords to “paradoxical” phenomena—is directly applicable to homosexuality and transgender. Indeed, the “mosaic” or mixture of male and female characteristics found in intersexual animals such as gynandromorphs is used by some Gaian theorists as a model of multiplicity within oneness, the transformation of disjuncture into wholeness—in other words, the very image of the earth itself.¹⁰²

Like chaos theory, the Gaia hypothesis recognizes that phenomena that appear inexplicable at the level of an individual organism or population may be part of a larger, complex tapestry: a web of seemingly incongruous forces that interact to produce the flow of life, often in ways that are difficult to fathom. Nowhere is this idea better formulated than in the concept of biodiversity. Stated simply, this is the principle that the vitality of a biological system is a direct consequence of the diversity it contains: “as diversity increases, so does stability and resilience.”¹⁰³ Traditionally, such diversity is thought of strictly in terms of number and types of species—that is, the physical composition of the system, usually expressed in terms of its overall genetic variety. Long-term studies of individual ecosystems have shown, for example, that the health and stability of a natural system is directly linked to the number of different species it contains.¹⁰⁴

However, variability in number of species is not the only way that biological diversity can be expressed. At all levels of the natural world, social and sexual diversity exists—in every type of animal, and between different species, populations, and individuals. As an example, consider just one group of birds, the sandpipers and their relatives.¹⁰⁵ An enormous variety of heterosexual and homosexual mating and social systems are found among the more than 200 species in this group. We find monogamous pairings between birds of the same or opposite sex (Black-winged Stilts, Greenshanks); polygamous associations such as one male mating with more than one female (northern lapwings, curlew sandpipers) or one female mating with more than one male (jacanas), or bisexual trios in which two birds of the same sex bond with each other and with a third individual of the opposite sex (Oystercatchers); and “promiscuous” systems in which birds court and mate with multiple partners of the same or opposite sex without establishing pair-bonds, often involving communal courtship display grounds or leks (Ruffs, Buff-breasted Sandpipers). Even within a particular mating system such as heterosexual “monogamy,” there are many different variations: some species form lifelong pair-bonds (e.g., Black Stilts); others are serially monogamous, forming sequential pairbonds or mating associations with different partners (kentish plovers, sanderlings); others are primarily monogamous but form occasional polygamous trios (Golden Plovers). Some species have largely “faithful” pair-bonds, with birds rarely if ever copulating with individuals other than their mate (Golden Plovers), while in others nonmonogamous matings with birds outside of the pair-bond are routine (Oystercatchers). And even within a given species, there are variations between different geographic areas: lesbian pairs occur in only certain populations of Black-winged and Black Stilts, for example, while snowy plovers exhibit extensive geographic variation in their heterosexual mating patterns, ranging from monogamy to serial polygamy (and numerous versions of each). Within a given population, there is also diversity between individual birds. In Oystercatchers, for example, only some birds participate in homosexual associations, nonmonogamous heterosexual copulations, or serial monogamy, while extensive numbers of nonreproducing birds that do not engage in either heterosexual or homosexual activities are also found in most species. And finally, each individual bird may participate in a variety of sexual and mating behaviors during its lifetime. Among male Ruffs, for example, some birds are exclusively heterosexual for their entire lives, some alternate between periods of heterosexual and homosexual activity or engage in both simultaneously, other individuals participate primarily in same-sex activities for most of their lives, while still others are largely asexual. Similar examples could be furnished from virtually any other animal group, especially now that detailed longitudinal studies are beginning to reveal individual (and idiosyncratic) life-history variations in nearly all organisms.

Scientists are beginning to find evidence that this diversity in social and mating systems contributes directly to the “success” of a species. For instance, among great bustards (a large, storklike bird found in southern Europe and North Africa), flexibility in heterosexual mating systems gives the birds a greater adaptability, enabling them to cope with difficult or variable ecological conditions.¹⁰⁶ And in some species, homosexuality itself appears to be associated with environmental or social changes, in ways that are suggestive but (so far) poorly understood. Male pairing in Golden Plovers, for example, is claimed to be more prevalent in years when severe winter snowstorms have “disrupted” heterosexual pairing, while female coparenting among Grizzlies appears to be characteristic of animals living in conditions of environmental or social flux. In Ostriches, homosexual courtships may be linked to unusually rainy seasons that alter the species’ overall sexual and social patterns. Likewise, same-sex pairs in Ring-billed and California Gulls are more common in newly founded colonies that are experiencing rapid expansion, while homosexual activities in Rhesus and Stumptail Macaques (and a number of other primates) are often associated with changes in the composition or dynamics of the social group.¹⁰⁷

Although the correlations between these factors need to be more systematically investigated—a linear, one-way, cause-and-effect relationship is surely not involved—they do suggest that sexual, social, and environmental variability may be closely allied. Specifically, the capacity for behavioral plasticity—including homosexuality—may strengthen the ability of a species to respond “creatively” to a highly changeable and “unpredictable” world. As primatologist G. Gray Eaton suggests, sexual versatility as both a biological and a cultural phenomenon in animals maybe directly responsible for a species’ success, in ways that challenge conventional views of evolution:

The macaques’ sexual behavior includes both hetero- and homosexual aspects as part of the “normal” pattern. Protocultural variations of some of these patterns have already been discussed but it is well to remember the extreme variation in behavior that characterizes individuals and groups of primates. This plasticity of behavior has apparently played a major role in the evolutionary success of primates by allowing them to adapt to a variety of social and environmental conditions …. The variability and plasticity of the behavior … suggests an optimistic or “ maximal view of human potentialities and limitations” … rather than a pessimistic or minimal view of man as a biological machine functioning on the basis of instinct. This minimal view based on the fang-and-claw school of Darwinism finds little support in the evidence of protocultural evolution in nonhuman primates.¹⁰⁸

This is not to say that such plasticity always has an identifiable “function” in relation to specific environmental or social factors (even though a few such “functions” can be discerned in specific cases, as we saw in previous chapters). Behavioral versatility is best regarded as a manifestation of the larger “chaotic ordering” or nonlinearity of the world, rather than merely a response to it. A broader synergy is involved, a pattern of overall adaptability that can be realized in ways that do not necessarily entail any literal “contribution” to reproduction or any straightforward “improvement” in an animal’s well-being. In other words, it is the presence of behavioral flexibility in a system that is as valuable, if not more so, than its actual concrete “usefulness” or “functionality.”

Taken together, these observations—of sexual diversity, and the strength imparted by such sexual variability—lead to an important conclusion. The concept of biodiversity should be extended to include not only the genetic variety, but also the systems of social organization found within a species or ecosystem. In other words, sexual and gender systems are an essential measure of biological vitality. The more diverse patterns of social/sexual organization that a species or biological system contains—including homosexuality, transgender, and nonreproductive heterosexuality—the stronger that system will be. Mating and courtship patterns are, after all, as much a part of the “complexity” of an ecosystem as the number of species it contains—and same-sex activity is an integral part of those mating and courtship systems in many animals. It stands to reason, then, that a rich mosaic of different social patterns should increase the vitality of a system, even when such patterns themselves are apparently “unproductive” or are found in only a fraction of the population.

In a rain forest that contains many hundreds of thousands of species of mammals, birds, insects, plants, and so on, the “purpose” of yet one more kind of beetle may be difficult to see—except when understood in terms of its contribution to the overall complexity and vitality of the environment. Similarly, the “function” of a particular social or sexual behavior such as homosexual courtship or heterosexual reverse mounting may seem minimal or even nonexistent at the level of a particular species or individual. But its contribution to the overall strength of the system is independent of such “utility” (or lack thereof) and is also independent of the proportion of the population that participates in it. Every individual, every behavior—whether productive or “counterproductive,” comprising 1 percent or 99 percent of the population—has a part to play. Its role is not in the tapestry of life, but as the tapestry of life: its existence is its “function.” Biological diversity is intrinsically valuable, and homosexuality/transgender is one reflection of that diversity.