Ernst Haeckel was a German biologist who promoted Darwin's work; he's perhaps best known for his theorizing that "ontogeny recapitulates phylogeny." Today, his scientific theories are considered suspect, and their social applications abhorrent. However, students and enthusiasts of Art Nouveau will find in his masterful illustrations, especially of invertebrates, a stylized natural world, rendered through the filter of celebratory art rather than realism. Present are both the whiplash curves of luscious nouveau, with its choice colors, and the(Secessionist) jungendstil discipline of spare line and form, especially in some of Haeckel's black and white renderings of more angular organisms.
See here for an impressive
gallery of Haeckel's illustration. Another online exhibit, with more detailed background information, is Marine Biological Laboratory's
Art Forms in Nature. According to Curator Ann Weissman:
"His on-the-spot drawings of deep-sea vegetation, aquatic creatures, frogs, birds, and higher animals were turned into more than 1000 engravings. From this treasure trove, a selection of 100 colored lithographs were produced for publication in his 1904 Kunstformen der Natur. This work is considered one of the marvels of 19th century naturalist illustration. With their sinuous lines and tendency to idealize nature, these drawings are also considered a forerunner of the Art Nouveau movement. Indeed Haeckel's most lasting legacy may lie in the field of art. In science, where artistic license is often called fraud, Haeckel's reputation was sorely tarnished...Haeckel aimed Art Forms in Nature at a broad audience rather than specialists. Each of the 100 plates was accompanied by a short, readable commentary that made biological concepts accessible to the public. Moreover Haeckel's use of Art Nouveau techniques made the book even more appealing and 'fashionable.' The publication was an immediate success."
Haeckel's idealizing, aestheticizing turn toward the natural world may be explained in
"Beauty Beyond Belief" (Natural History, Dec. 1998), in which James Hanken notes that "Combining science and art in the study of natural history was not unusual in Haeckel's day. Art historian Beryl Hartley has noted, for example, that beginning in the early nineteenth century, Western landscape painters worked hard to accurately portray individual species of trees and other natural features. The British painter John Constable epitomized the thinking behind this approach when, in 1836, he asked why "landscape painting should not be considered as a branch of natural philosophy of which paintings are but experiments." Equally (if not more) important to Haeckel's art was his fervent belief in evolutionary monism, an extreme worldview that purported to have found in Darwinism the unifying principle for all of life. With its romantic and, at times, mystical notions, monism encouraged artistic expression as a means of venerating the natural world."
The Wiki has this to say of Haeckel's materialist monism: Haeckel "extrapolated a new religion or philosophy called Monism from evolutionary science. In Monism, all economics, politics, and ethics are reduced to "applied biology." His writings and lectures on Monism provided scientific (or quasi-scientific) justifications for racism, nationalism and social Darwinism. It has even been argued that monism thus became the de facto religion of Nazi Germany. Other scholars disagree, arguing that Nazi ideology was not comfortable with evolutionary theory, which argues for a common descent of all human races." Indeed, even Haeckel made the supposition of "'biogenic theory', in which he suggested that the development of races paralleled the development of individuals. He advocated the idea that 'primitive' races were in their infancies and needed the 'supervision' and 'protection' of more 'mature' societies." In his art, too, we can see that the "lower" creatures of the natural world are shown as elevated through human vision, fixed and ordered, put into rational(ized) and perfected form.