19th-century Themes: Identity, Type & Change|
Biologists of the 19th-century encountered a tension between the concepts of type and historical change. What constituted organismal identity? The papers here address how different prominent biologists approached the problem from their own perspectives. Tobais Cheung examines George Cuvier, highlighting concepts of comparative anatomy and the ego. Olivier Lagueux considers interpretations of double-monsters in early nineteenth-century biology, such as Geoffroy's monstrous animal specimens and new animals hard to classify at the time (the 1827 giraffe, the platypus). Igor Popov addresses the problematic relationship of Lamarckism and orthogenesis. Finally, Juan Carlos Zamora profiles Charles Darwin's typological thinking.
- Tobias Cheung, University of Tokyo
"Uncertain Organisms: The Struggle for Identity in Cuvier s Comparative Anatomy"
- The paper focuses on the basic tensions between individuality, organismic life, identity and the role of the human in George Cuvier s (1769-1832) comparative anatomy of animal bodies. In the beginning of the development of the life sciences as natural sciences, his anatomical and theoretical writings highlight the struggle for organismic identity in constructing the other as an animal or a human. Cuvier s conceptual frame of an individual organism transforms the difference of measure (as shape or form) into the one of the skin as a metabolic border between a problematic inside and outside. It foreshadows at the same time the dissolution of the rational Ego in biological units as actors in evolution and ecology.
- Olivier Lagueux, Yale University
"The Giraffe, the Platypus, and Other Misfits: Geoffroy's Work in Classification"
- Őtienne Geoffroy Saint-Hilaire (1772-1844) seems to have been attracted to odd-looking creatures throughout his career. The electric fish, the flamingo, the aye-aye, and mummified cats from the Nile: many of his descriptive papers dealt with extraordinary fishes or mammals. I will follow 3 examples of Geoffroy's classificatory work in detail. First, the famous giraffe offered in 1826 to the King of France and which Geoffroy was mandated to fetch in Marseilles. For the naturalist, this official mission offered the opportunity to examine an exotic animal never seen before in France, and to correct the misconceptions of previous naturalists. With the duck-billed Platypus, Geoffroy got involved in a dispute over the taxonomical status of this bizarre animal, a dispute that took on a diplomatic dimension. Finally, Geoffroy's most original contributions were related to teratology. He proposed a binomial nomenclature and a classification system that came to replace the older categories of monsters "by excess" and "by default".
- Igor Yu. Popov, Russian Academy of Sciences
"Orthogenesis and Lamarckism"
- Orthogenesis ˝ the idea of internal driving force of evolution - quite often is considered as a version of Lamarckism. It really corresponds to some ideas of Lamarck, but a term "orthogenesis" was appeared as a contrast to Lamarckism. It was proposed by W. Haake for the characteristic of regularities in "germinal plasma", postulated by A. Weismann. It means, that the units of inheritance ("determinants") could join each other only in definite combinations, which restrict and regulate variation. This sense of orthogenesis corresponds to the idea of correlations, developed by the greatest antagonist of Lamarck ˝ J. Cuvier. However the term "orthogenesis" has become known due to work of │h. Eimer, which supported Lamarckism. He believed, that environment stimulates variability, but that there was also a predisposition to vary in the certain directions (orthogenesis). Subsequently the relations between Lamarckism and orthogenesis in a history of biology were also complicated, but it seems that orthogenesis developed rather independently from the most known Lamarck's ideas (concept of exercises and the idea of direct influence of environment to evolution). Many adherents of orthogenesis developed saltationism (D. Sobolev, L. Berg, O. Schindewolf, etc.) or emphasised similarity of life cycle of individual and those of a taxon (D. Rosa, A. Vandel, etc.). Both ideas contradict to the concept of Lamarck. The orthogenetic concepts were hardly compatible with Lamarckian ones. However they (like anyone other) could be considered as a kind of Lamarckism, because the treatises of Lamarck are vast and unclear.
- Juan Carlos Zamora, Universidad Nacional Autonoma de Mexico
"Typological Thinking in Darwin's Theory of Descent with Modification"
- The theory of descent with modification proposed by Darwin states that variability and natural selection that occur in populations are the most important causes of a divergent evolution. The historical innovation of considering variation to explain an organic process has led biologists, historians and philosophers to establish a distinction between Darwin┤s population thinking and typological thinking. Even though this dichotomy can be useful, sometimes it has been stated that this opposition implies that Darwin had to abandon all typological thinking before he could formulate his theory. In this paper we examine this implication by analyzing if typological thinking necessarily should be absent in the theory of descent with modification exposed in The Origin of Species.
Darwin stated near the end of Chapter Six, "Difficulties on Theory," of The Origin of Species that: "It is generally acknowledged that all organic beings have been formed on two great laws -- Unity of Type, and the Conditions of Existence. By unity of type is meant that fundamental agreement in structure, which we see in organic beings of the same class, and which is quite independent of their habits of life. On my theory, unity of type is explained by unity of descent." Darwin considered that organisms of the same class have a similar structure, a Unity of Type. In the second half of the nineteenth century, almost all naturalists conceived the existence of four basic types in animals that define each one of the classes or embranchement proposed by Cuvier: Vertebrata, Articulata, Molusca and Radiata. Darwin saw each of these types as the basic structure of the common ancestor of all the members of a class. By applying this same argument to inferior taxonomic categories, he considered that homologies, similarities based in a common structure, reveal ancestor-descendant relations and determine the natural system of classification. And by analyzing how these structural similarities are present in organisms of different time and space, he showed taxonomic, morphological, embriological, paleontological and biogeographical evidence of a ramified evolution.
Thus, even though population thinking permited Darwin to consider variation and natural selection as causes of a divergent evolution, typological thinking led him to conceive multiple evidence of this kind of evolution. Not only this naturalist didn┤t have to abandon typological thinking to structure his theory. Typological thinking was essential in its formulation.
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