Alfred Russel Wallace deserves better

During 2009, while we were celebrating Charles Darwin and his The origin of species, sadly, little was said about the critical contribution of Alfred Russel Wallace (1823–1913) to the development of the theory of evolution. Like Darwin, he was a truly remarkable nineteenth century intellect and polymath and, according to a recent book by Roy Davies (The Darwin conspiracy: origins of a scientific crime), he has a stronger claim to the Theory of Evolution by Natural Selection than has Darwin. Here we present a critical comparison between the contributions of the two scientists. Sometimes referred to as ‘The other beetle-hunter’ and largely neglected for many decades, Wallace had a far greater experience of collecting and investigating animals and plants from their native habitats than had Darwin. He was furthermore much more than a pioneer biogeographer and evolutionary theorist, and also made contributions to anthropology, ethnography, geology, land reform and social issues. However, being a more modest, self-deprecating man than Darwin, and lacking the latter’s establishment connections, Wallace’s contribution to the theory of evolution was not given the recognition it deserved and he was undoubtedly shabbily treated at the time. It is time that Wallace’s relationship with Darwin is reconsidered in preparation for 2013, the centenary of Wallace’s death, and he should be recognized as at least an equal in the Wallace-Darwin theory of evolution.     

Tantalizing Tortoises and the Darwin-Galápagos Legend

During his historic Galápagos visit in 1835, Darwin spent nine days making scientific observations and collecting specimens on Santiago (James Island). In the course of this visit, Darwin ascended twice to the Santiago highlands. There, near springs located close to the island’s summit, he conducted his most detailed observations of Galápagos tortoises. The precise location of these springs, which has not previously been established, is here identified using Darwin’s own writings, satellite maps, and GPS technology. Photographic evidence from excursions to the areas where Darwin climbed, including repeat photography over a period of four decades, offers striking evidence of the deleterious impact of feral mammals introduced after Darwin’s visit. Exploring the impact that Darwin’s Santiago visit had on his thinking – especially focusing on his activities in the highlands – raises intriguing questions about the depth of his understanding of the evolutionary evidence he encountered while in the Galápagos. These questions and related insights provide further evidence concerning the timing of Darwin’s conversion to the theory of evolution, which, despite recent claims to the contrary, occurred only after his return to England.     

Darwin and His Pigeons. The Analogy Between Artificial and Natural Selection Revisited

The analogy between artificial selection of domestic varieties and natural selection in nature was a vital element of Darwin’s argument in his Origin of Species. Ever since, the image of breeders creating new varieties by artificial selection has served as a convincing illustration of how the theory works. In this paper I argue that we need to reconsider our understanding of Darwin’s analogy. Contrary to what is often assumed, nineteenth-century animal breeding practices constituted a highly controversial field that was fraught with difficulties. It was only with considerable effort that Darwin forged his analogy, and he only succeeded by downplaying the importance of two other breeding techniques – crossing of varieties and inbreeding – that many breeders deemed essential to obtain new varieties. Part of the explanation for Darwin’s gloss on breeding practices, I shall argue, was that the methods of his main informants, the breeders of fancy pigeons, were not representative of what went on in the breeding world at large. Darwin seems to have been eager to take the pigeon fanciers at their word, however, as it was only their methods that provided him with the perfect analogy with natural selection. Thus while his studies of domestic varieties were important for the development of the concept of natural selection, the reverse was also true: Darwin’s comprehension of breeding practices was moulded by his understanding of the working of natural selection in nature. Historical studies of domestic breeding practices in the eighteenth and nineteenth century confirm that, besides selection, the techniques of inbreeding and crossing were much more important than Darwin’s interpretation allowed for. And they still are today. This calls for a reconsideration of the pedagogic use of Darwin’s analogy too.     

Experimenting with Transmutation: Darwin, the Beagle, and Evolution

Detailed analysis of Darwin’s scientific notes and other writings from the Beagle voyage reveals a focus on endemism and replacement of allied taxa in time and in space that began early in the journey. Though it is impossible to determine exactly when Darwin became a transmutationist, the evidence suggests that he was conversant with the transmutational ideas of Lamarck and others and testing (“experimenting” with) them—before he received a copy of Lyell’s Principles of Geology, vol. 2, in November 1832, in which Lyell describes and disputes Lamarck’s theory. To the two rhea species of Patagonia and the four mockingbird species of the Galapagos, we can now add the living Patagonian cavy (rodent) species, and its extinct putatively related species that Darwin collected at Monte Hermoso (Bahia Blanca) in the Fall of 1832, as a replacement pattern absolutely critical to the development of Darwin’s transmutational thinking. Darwin developed his first transmutational theory by adopting “Brocchi’s analogy” (Rudwick 2008)—i.e. that births and deaths of species are analogous to the births and deaths of individuals. Births and deaths of species, as of individuals, are thus explicable in terms of natural causes. Darwin explored these themes and the replacement of the extinct cavy by the modern species explicitly in his February 1835 essay (Darwin 1835a).

Capitalist Contexts for Darwinian Theory: Land, Finance, Industry and Empire

When socio-economic contexts are sought for Darwin’s science, it is customary to turn to the Industrial Revolution. However, important issues about the long run of England’s capitalisms can only be recognised by taking a wider view than Industrial Revolution historiographies tend to engage. The role of land and finance capitalisms in the development of the empire is one such issue. If we historians of Darwin’s science allow ourselves a distinction between land and finance capitalisms on the one hand and industrial capitalism on the other; and if we ask with which side of this divide were Darwin and his theory of branching descent by natural selection aligned, then reflection on leading features of that theory, including its Malthusian elements, suggests that the answer is often and largely, though not exclusively: on the land side. The case of Wallace, socialist opponent of land capitalism, may not be as anomalous for this suggestion as one might at first think. Social and economic historians have reached no settled consensuses on the long-run of England’s capitalisms. We historians of Darwin’s science would do well to import some of these unsettled states of discussion into our own work over the years to come.     

Why Darwin rejected intelligent design

As a Cambridge University undergraduate Charles Darwin was fascinated and convinced by the argument for intelligent design, as set forth in William Paley’s 1802 classic, Natural Theology. Subsequently, during his five-year voyage on HMS Beagle (1831–1836), Darwin interpreted his biological findings through a creationist lens, including the thought-provoking evidence he encountered during his historic visit to the Galápagos Islands in September and October 1835. After his return to England in 1836 and his subsequent conversion to the idea of organic evolution in March 1837, Darwin searched for a theory that would explain both the fact of evolution and the widespread appearance of intelligent design. His insight into the process of natural selection, which occurred in September 1838, provided this alternative explanation. Darwin’s Origin of Species (1859) exemplifies his skillful deployment of the hypothetico-deductive method in testing and refuting the arguments for intelligent design that he had once so ardently admired.     

Wallace’s Other Line: Human Biogeography and Field Practice in the Eastern Colonial Tropics

This paper examines how the 19th-century British naturalist Alfred Russel Wallace used biogeographical mapping practices to draw a boundary line between Malay and Papuan groups in the colonial East Indies in the 1850s. Instead of looking for a continuous gradient of variation between Malays and Papuans, Wallace chose to look for a sharp discontinuity between them. While Wallace’s “human biogeography” paralleled his similar project to map plant and animal distributions in the same region, he invoked distinctive “mental and moral” features as more decisive than physical ones. By following Wallace in the field, we can see his field mapping practices in action – how he conquered the problem of local particularity in the case of human variation. His experiences on the periphery of expanding European empires, far from metropolitan centers, shaped Wallace’s observations in the field. Taking his cues from colonial racial categories and his experiences collaborating with local people in the field, Wallace constructed the boundary line between the Malay and Papuan races during several years of work in the field criss-crossing the archipelago as a scientific collector. This effort to map a boundary line in the field was a bold example of using the practices of survey science to raise the status of field work by combining fact gathering with higher-level generalizing, although the response back in the metropole was less than enthusiastic. Upon his return to Britain in the 1860s, Wallace found that appreciation for observational facts he had gathered in the field was not accompanied by agreement with his theoretical interpretations and methods for doing human biogeography.     

Celebrate Darwin Day, An Event for Education and Outreach in Evolutionary Biology

Darwin Day is an international celebration of Charles Darwin’s birthday, February 12, and is used as an occasion for education and outreach in evolutionary biology. I describe the history and structure of Darwin Day at the University of Tennessee, one of the oldest Darwin Day organizations in the world. I detail past events including speakers, themes, and advertising ideas that have worked for us and suggestions for getting a Darwin Day started. I encourage interested groups especially those at schools, museums, libraries, nature centers, and other institutions to adapt ideas from our organization to fit their own circumstances and to start planning their own Darwin Days for the celebration of Darwin’s 200th birthday in 2009.     

Joseph Hooker Takes a “Fixed Post”: Transmutation and the “Present Unsatisfactory State of Systematic Botany”, 1844–1860

Joseph Hooker first learned that Charles Darwin believed in the transmutation of species in 1844. For the next 14 years, Hooker remained a “nonconsenter” to Darwin’s views, resolving to keep the question of species origin “subservient to Botany instead of Botany to it, as must be the true relation”. Hooker placed particular emphasis on the need for any theory of species origin to support the broad taxonomic delimitation of species, a highly contentious issue. His always provisional support for special creation waned during the 1850s as he lost faith in its expediency for coordinating the study of plant geography, systematics and physiology. In 1858, Hooker embraced Darwin’s “considerable revolution in natural history,” but only after Darwin had carefully molded his transmutationism to meet Hooker’s exacting specifications.     

Separated at Birth: The Interlinked Origins of Darwin’s Unconscious Selection Concept and the Application of Sexual Selection to Race

This essay traces the interlinked origins of two concepts found in Charles Darwin’s writings: “unconscious selection,” and sexual selection as applied to humanity’s anatomical race distinctions. Unconscious selection constituted a significant elaboration of Darwin’s artificial selection analogy. As originally conceived in his theoretical notebooks, that analogy had focused exclusively on what Darwin later would call “methodical selection,” the calculated production of desired changes in domestic breeds. By contrast, unconscious selection produced its results unintentionally and at a much slower pace. Inspiration for this concept likely came from Darwin’s early reading of works on both animal breeding and physical ethnology. Texts in these fields described the slow and unplanned divergence of anatomical types, whether animal or human, under the guidance of contrasting ideals of physical perfection. These readings, it is argued, also led Darwin to his theory of sexual selection as applied to race, a theme he discussed mainly in his book The Descent of Man (1871). There Darwin described how the racial version of sexual selection operated on the same principle as unconscious selection. He thereby effectively reunited these kindred concepts.     

Brocchi’s Subapennine Fossil Conchology

The Italian geologist Giambattista Brocchi (1771–1826) is presented as a key figure in the historical period preceding young Charles Darwin’s first work on transmutational theory while on the Beagle. The brief biographical account focuses on Brocchi’s writings related to his analogy that species have births and deaths like individuals, and culminates in his most important work, Subapennine Fossil Conchology of 1814. Brocchi’s analogy as an original and fertile way to approach the fossil record was to influence Darwin’s first evolutionary thinking. Relevant passages of the book are presented for the first time in an English translation.     

The Charms of Nature: Darwin on Meaning and Value

I review George Levine’s provocative and highly original book Darwin Loves You. Levine, whose “home discipline” is English Literature, offers a compelling interpretation of Darwin’s works, evaluating their content and Darwin’s prose style to identify a distinctly Darwinian attitude toward nature as a source of meaning and value. Levine believes that Darwin exemplifies the capacity to feel “enchantment” about the natural world, suggesting that, if Darwin’s example were followed, a “Darwinian re-enchantment of the world” would be brought about. This would offer a secular, non-supernatural basis for purpose, meaning, and value. I conclude with a few critical remarks about the scope and cogency of Levine’s proposal.     

Brocchi,Darwin, and Transmutation: Phylogenetics and Paleontology at the Dawn of Evolutionary Biology

Giambattista Brocchi’s (1814) monograph (see Dominici, Evo Edu Outreach, this issue, 2010) on the Tertiary fossils of the Subappenines in Italy—and their relation to the living molluscan fauna—contains a theoretical, transmutational perspective (“Brocchian transmutation”). Unlike Lamarck (1809), Brocchi saw species as discrete and fundamentally stable entities. Explicitly analogizing the births and deaths of species with those of individual organisms (“Brocchi’s analogy”), Brocchi proposed that species have inherent longevities, eventually dying of old age unless driven to extinction by external forces. As for individuals, births and deaths of species are understood to have natural causes; sequences of births and deaths of species produce genealogical lineages of descent, and faunas become increasingly modernized through time. Brocchi calculated that over 50% of his fossil species are still alive in the modern fauna. Brocchi’s work was reviewed by Horner (1816) in Edinburgh. Brocchi’s influence as a transmutational thinker is clear in Jameson’s (1827) “geological illustrations” in his fifth edition of his translation of Cuvier’s Theory of the Earth (read by his student Charles Darwin) and in the anonymous essays of 1826 and 1827 published in the Edinburgh New Philosophical Journal—which also carried a notice of Brocchi’s death in 1827. The notion that new species replace older, extinct ones—in what today would be called an explicitly phylogenetic context—permeates these essays. Herschel’s (1830) discussion of temporal replacement of species and the modernization of faunas closely mirrors these prior discussions. His book, dedicated to the search for natural causes of natural phenomena, was read by Charles Darwin while a student at Cambridge. Darwin’s work on HMS Beagle was in large measure an exploration of replacement patterns of “allied forms” of endemic species in time and in space. His earliest discussions of transmutation, in his essay February 1835, as well as the Red Notebook and the early pages of Notebook B (the latter two written in 1837 back in England), contain Brocchi’s analogy, including the idea of inherent species longevities. Darwin’s first theory of the origin of species was explicitly saltational, invoking geographic isolation as the main cause of the abrupt appearance of new species. We conclude that Darwin was testing the predicted patterns of both Brocchian and Lamarckian transmutation as early as 1832 at the outset of his work on the Beagle.     

“A Great Complication of Circumstances” – Darwin and the Economy of Nature

In 1749, Linnaeus presided over the dissertation “Oeconomia Naturae,” which argued that each creature plays an important and particular role in nature’s economy. This phrase should be familiar to readers of Darwin, for he claims in the Origin that “all organic beings are striving, it may be said, to seize on each place in the economy of nature.” Many scholars have discussed the influence of political economy on Darwin’s ideas. In this paper, I take a different tack, showing that Darwin’s idea of an economy of nature stemmed from the views of earlier naturalists like Linnaeus and Lyell. I argue, in the first section of the paper, that Linnaeus’ idea of oeconomia naturae is derived from the idea of the animal economy, and that his idea of politia naturae is an extension of the idea of a politia civitatis. In the second part, I explore the use of the concept of stations in the work of De Candolle and Lyell – the precursor to Darwin’s concept of places. I show in the third part of the paper that the idea of places in an economy of nature is employed by Darwin at many key points in his thinking: his discussion of the Galapagos birds, his reading of Malthus, etc. Finally, in the last section, I demonstrate that the idea of a place in nature’s economy is essential to Darwin’s account of divergence. To tell his famous story of divergence and adaptation, Darwin needed the economy of nature.     

Extending Darwin’s analogy: Bridging differences in concepts of selection between farmers, biologists, and plant breeders

Darwin developed his theory of evolution based on an analogy between artificial selection by breeders of his day and “natural selection.” For Darwin, selection included what biologists came to see as being composed of (1) phenotypic selection of individuals based on phenotypic differences, and, when these are based on heritable genotypic differences, (2) genetic response between generations, which can result in (3) evolution (cumulative directional genetic response over generations). The use of the term “selection” in biology and plant breeding today reflects Darwin’s assumption—phenotypic selection is only biologically significant when it results in evolution. In contrast, research shows that small-scale, traditionally-based farmers select seed as part of an integrated production and consumption system in which selection is often not part of an evolutionary process, but is still useful to farmers. Extending Darwin’s analogy to farmers can facilitate communication between farmers, biologists, and plant breeders to improve selection and crop genetic resource conservation.     

Symbiogenesis,natural selection,and the dynamic Earth

One century ago, Constantin S. Mereschkowsky introduced the symbiogenesis theory for the origin of chloroplasts from ancient cyanobacteria which was later supplemented by Ivan E. Wallin’s proposal that mitochondria evolved from once free-living bacteria. Today, this Mereschkowsky–Wallin principle of symbiogenesis, which is also known as the serial primary endosymbiosis theory, explains the evolutionary origin of eukaryotic cells and hence the emergence of all eukaryotes (protists, fungi, animals and plants). In 1858, the concept of natural selection was described independently by Charles Darwin and Alfred R. Wallace. In the same year, Antonio Snider-Pellegrini proposed the idea of shifting continents, which was later expanded by Alfred Wegener, who published his theory of continental drift eight decades ago. Today, directional selection is accepted as the major cause of adaptive evolution within natural populations of micro- and macro-organisms and the theory of the dynamic Earth (plate tectonics) is well supported. In this article, I combine the processes and principles of symbiogenesis, natural selection and the dynamic Earth and propose an integrative ‘synade-model’ of macroevolution which takes into account organisms from all five Kingdoms of life.     

Darwin, Herschel, and the role of analogy in Darwin’s origin

In what follows, I consider the role of analogy in the first edition of Darwin’s Origin. I argue that Darwin follows Herschel’s methodology and hence exploits an analogy between artificial and natural selection that allows him generalize selection as a cause of evolutionary change. This argument strategy is not equivalent to an argument from analogy. Reading Darwin’s argument as conforming to Herschel’s two-step methodology of causal analysis followed by generalization allows us to understand the role and placement of Darwin’s discussion of artificial selection in the Origin, without making the mistake of portraying Darwin’s argument for the existence and character of natural selection as an analogical argument.     

Coevolution Between Food-Rewarding Flowers and Their Pollinators

The concept of coevolution was first developed by Darwin, who used it to explain how pollinators and food-rewarding flowers involved in specialized mutualisms could, over time, develop long tongues and deep tubes, respectively. He famously predicted that Angraecum sesquipedale, a long-spurred Malagasy orchid, must be pollinated by a hawkmoth with an exceptionally long tongue. Darwin’s idea of a coevolutionary “race” was championed by contemporary naturalists, including Alfred Wallace, and a hawkmoth fitting the expected tongue-length profile was eventually discovered in Madagascar during the early twentieth century. However, strong empirical support for the mechanism behind Darwin’s coevolutionary model has been forthcoming only in the past two decades. It is now established that selection often strongly favors plants with floral tubes that exceed the length of their pollinator’s tongues. There is also evidence that pollinators gain an energetic benefit from having tongues that enable them to consume most or all of the nectar in deep tubular flowers. Alternative explanations for the evolution of long pollinator tongues, such as evasion of predators that use flowers as ambush sites, are considered much less compelling and lack quantitative support. Another important advance in coevolution research has been the development of approaches that explicitly predict a geographical mosaic of coevolution. The expectation that coevolution can lead to geographical diversification and trait covariation among strongly interacting organisms is strongly supported by studies of long-proboscid fly and oil-bee pollination systems in South Africa. Macro- and microevolutionary studies of pollination systems suggest that coevolution can operate alongside other one-sided evolutionary processes, such as shifts, in shaping plant and pollinator traits.