The Natural Order of Things: Visualizing Evolutionary Theory

October 16 – December 11

/ 1998

A History of Images in the Natural Sciences

In the modern world botanical and zoological prints have become so commonplace that they are barely visible-a decorative cliché in motels and waiting rooms everywhere. It’s easy to forget how beautiful the best of them are, and to forget, too, that they once served not merely as decoration, but also as important scientific tools. In fact, the development of printing process and the accumulation of knowledge about plant and animal species went hand in hand for nearly four centuries.

Scholars of the ancient world, Aristotle and Pliny among them, set themselves the task of recording various aspects of the universe, categorizing organisms, particularly plants, primarily with respect to their usefulness to humans, i.e., as medicinal, edible, or poisonous. By the sixth century a manuscript on plants by the Greek writer Dioscorides, De Materia Medica, contained an invaluable addition: small but detailed drawings of plants to supplement their textual description. A closer relationship between art and science began in the late Middle Ages during what is known as the Age of Herbals (1470-1670). Herbals were books similar in style to Dioscorides’ work but made use of woodcuts to reproduce the plant images.

The first known woodcuts produced for botanical illustrations were contained in Konrad von Megenberg’s Book of Nature (1475). Over the next century, illustrations were used with increasing frequency in texts. Leonard Fuch’s De Historia Stripium Commentarii Insignes (Important Commentaries Concerning the History of Plants, 1542) contained over 500 drawings, including species from America. This document, along with Andreas Vesalius’ De Humani Corporis Fabrica (On the Structure of the Human Body, 1543) are felt to represent the end of the Medieval Age, when science was based on traditional knowledge, and the birth of modern science, based on research and fact. Accurate documentation of individual observations through illustrations played an important role in this transition.

The next step in the co-evolution of illustration and systematics came with the publication of Conrad Gesner’s Historia Animalium (History of Animals, 1551-1587), and his subsequent volumes on fish and plants. Although Gesner made little effort to classify organisms beyond Aristotle’s scheme and the book contains a fair amount of traditional, inaccurate, information, it represented the first effort to describe and picture every animal known in Europe. Gesner also firmly believed that science belonged to all people, and his book was designed to educate. With the inclusion of extensive illustrations, information became available not only to scholars, but also to general readers. Gesner did, however, make a significant contribution to systematics with the publication of his Historica Plantarum (History of Plants), published two centuries after his death. In this document, he is the first to recognize that similar species could be grouped to form genera.

By 1600, local fauna and flora (including 6,000 species of plants) had been reasonably well described, but many fables about fantastic creatures and bizarre behaviors still circulated. Over the next century, however, the breadth and depth of understanding of nature was to change considerably, and books and images changed in corresponding fashion. The early prints lacked detail, but apparently proved so useful or so attractive that some books reused older blocks with new text, while others pressed ahead with increasingly sophisticated printing techniques. By the middle of the seventeenth century detailed engravings augmented with watercolor had become the standard for zoological and botanical texts; they yield reluctantly to photographs in the twentieth century, arguably sacrificing clarity for objectivity.

Advancing techniques in printing coincided with the so-called Age of Exploration-the European voyages of “discovery” that sought to enlarge the base of trade by exploiting new sources of raw materials, land, and labor. Early voyagers collected and brought back specimens which were eagerly studied. Thousands of new plants, animals, and minerals flooded Europe, confusing the existing categories of use and meaning. Aristocrats and royalty formed entire rooms, known as Wunderkammern or cabinets of curiosities, in which to display stuffed animals, shells, and other wonders of nature. The organization of these rooms, sometimes conceived as the entire world in miniature, began the process of sorting or classification that brought a culturally imposed order to the materials of nature.

During the same period the invention of the microscope allowed an examination of the finer structure of plant and animal tissues by a trio of contemporaries: Marcello Malphigi, Anton van Leeuwenhoek, and Robert Hooke. Hooke’s Micrographia (1665) was the first publication dealing exclusively with microscopic observations, and his plates of such structures as the compound eye of the fly, the sting of a bee, and the feathers of birds, awed contemporaries and remained classics for two centuries. More detailed observation and illustration of form lead to an increased understanding of function and process, including the theory of cells. Although new species and new technologies encouraged a century of investigation, the role of science was still largely descriptive.

The 1700s simultaneously saw the initiation of maritime voyages specifically for scientific exploration, and the first comprehensive system of organizing the increasing diversity of organisms. Carolus Linnaeus, a botanist from Sweden, developed a system of binomial nomenclature that identifies each organism as to species and genus, published as Systema Naturae in 1736. Although Linnaeus felt that systematics and nomenclature were absolutely essential to science, he recognized that his classification was artificial, and viewed it as a temporary convenience to be supplanted by a natural system of fundamental relationships that would eventually be discovered. Like most people of his time, however, he believed that species themselves were fixed and immutable.

Continued scientific exploration in the nineteenth century contributed not only knowledge of thousands of new living species, but increasing collections of fossil organisms. These expeditions spawned today’s museums to house collections of preserved specimens, as well as botanical gardens, zoological gardens, and marine stations both to allow the study of living specimens by scientists, and to satisfy the curiosity of the public for the exotic.

Meantime the constant flow of new specimens and advancing techniques in printing fed an ever-growing popular interest in what came to be called natural history. Natural-history prints offered scholars multiple advantages. First, because they were reproducible, images of new species could be widely and quickly disseminated. Second, they permitted manipulation of the image-and emphasis on certain physical characteristics, or even secondary images of particular details such as bone structure or leaf shape. Finally, and perhaps most importantly, they were manipulable as images; individual prints could be grouped or rearranged much more easily than living specimens, and the relationship among species became readily apparent. Books became, in effect, even more compact versions of Wunderkammern.

By the late eighteenth century expeditions routinely included naturalists and artists, who were charged with the study of flora and fauna in every corner of the earth. Often their work was closely linked to the process of colonial domination. As European governments sought to discover the available and exploitable resources in their new territories, these collections and publications conveyed through their detailed exposition and the naming of species a sense of authority and control. The ambitious process of collection and description perhaps finds its high point in the work of the French encyclopedists, who at the end of the eighteenth century produced a massive, multivolume text with elaborate illustrations on topics ranging from physics through biology.

Although the nineteenth century saw the continued publication of beautiful natural history books, they were more and more directed at popular audiences. For naturalists, the focus of attention had already shifted from the accumulation of data to its systematization. Linnaeus’s Systema Naturae, which classified species according to differences in reproductive organs, included no illustrations in his text since that body of data was already well documented.

The same was true of an even more revolutionary volume published just over a century later: Charles Darwin’s The Origin of Species. If Linnaeus asked about the interrelationship of various organisms, Darwin pursued the question of how such a variety of species came into existence. Darwin’s thesis, too, needed no illustration, although it is clear that neither he nor Linnaeus could have arrived at their conclusions in the absence of such an extensive and heavily illustrated body of literature. The knowledge of specific and often minute visible distinctions-the salient details prints and models made directly from specimens can show most clearly-laid the groundwork for theoretical understanding of the natural world.

In the late twentieth century the study of systematics and the use of images in science has taken an entirely new turn. Distinctions made on the basis of observable differences have been superseded by distinctions made on less “visible” grounds: in the structure of DNA, for example, or in behavior or environment. The research of two DePaul faculty members, Dr. Kathleen Helm-Bychowski and Dr. Stan Cohn, exemplifies some of these new directions. Their comments, which follow, describe new paradigms for classification that now render natural history printmaking a beautiful relic of scientific history.

Nancy Clum, Department of Environmental Science

Louise Lincoln, Director, University Gallery