Variability of species

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From 1809 , Jean Baptiste Lamarck referred to his theory as the variability of species (syn. Transmutation of species , species change ) , with which he described the transformation of one species into another. The term was used throughout the nineteenth century to refer to evolutionary ideas that preceded Charles Darwin's theory of natural selection . Other proponents of a pre-Darwinian theory of evolution were Étienne Geoffroy Saint-Hilaire , Robert Edmond Grant , and Robert Chambers , who anonymously published the book Vestiges of the Natural History of Creation . Anatomists like Georges Cuvier and Richard Owen or the geologist Charles Lyell led the scientific criticism of the concepts of species change. The discussion of this notion is a significant chapter in the history of evolution and influenced the responses to Darwin.

terminology

Transmutation (for conversion) was one of the terms commonly used for evolutionary ideas during the 19th century, before Charles Darwin published his book On The Origin of Species in 1859. Before Lamarck, the term was used in alchemy to describe the transformation of common metals into gold. Other terms used to denote evolutionary ideas were the evolutionary hypothesis (a term also used by Darwin) and "the theory of lawful gradation," a term used by William Chilton in magazines such as The Oracle of Reason . The term transformation was also used in this context. The concepts denoted by these terms played a role at the beginning of the 19th century in connection with the history of the theory of evolution . The forerunners of evolutionary ideas in the 18th and early 19th centuries had to invent terms with which to describe their ideas. Before the Origin of Species appeared, there was no agreement on terminology. The term “evolution” only established itself late. Herbert Spencer uses the term in his work Social Statics from 1851, there is also at least one other earlier use, but not in the sense in which the word was used from around 1865 to 1870.

The historical development of the theory

The diagram from the book Vestiges of the Natural History of Creation by Robert Chambers, written in 1844, shows a model of evolution in which fish (F), reptiles (R), and birds (B) are twigs on a trunk that leads to mammals ( M) leads.

Jean-Baptiste Lamarck proposed in his 1809 book Philosophy Zoologique a theory of the transmutation of species . Lamarck did not believe that all living things had a common ancestor. Rather, he thought that all simple forms of life were continuously created through spontaneous generation . He also thought that a life force, which he sometimes described as "nerve fluid," drove species to evolve and climb a ladder of complexity. Lamarck noticed that the species were adapted to their environment. He explained this by assuming that the life force caused the organisms to change and that this change was dependent on the use or disuse of the corresponding organs, similar to the way muscles adapt to exercise. He argued that these changes were hereditary, causing slow adaptations to the environment. This mechanism of adaptation through inheritance of acquired traits was increasingly associated with his name and influenced debates about evolution well into the 20th century.

A radical British school of comparative anatomy, which included surgeon Robert Knox and anatomist Robert Edmond Grant , maintained close ties with the Lamarckian school of French transformationists , which included the scientist Saint-Hilaire . Robert Grant tried to find evidence for the theory of descent by examining homologies , thus making contributions in support of the ideas on transmutation and evolution of Lamarck and Erasmus Darwin . As a young student, Darwin worked with Grant on the life cycle of marine animals. He studied geology with Robert Jameson . In the magazine he edited, an article appeared in 1826 in which Lamarck was praised for explaining how higher animals developed from the simplest worm. This passage is believed to be the earliest use of the term evolution in the modern sense. Jameson's geology lectures usually ended with references to the "Origin of the Species of Animals" .

In his ninth Bridgewater treatise , the computer pioneer Charles Babbage outlined his idea that God created the world in such a way that new species arise from it by law, so that no divine miracles are necessary when a new species forms. In 1844, Scottish publisher Robert Chambers anonymously published an influential book called Vestiges of the Natural History of Creation . Chambers believed that the solar system and life on earth had evolved. He claimed that the fossils were evidence of the assumption that animals were evolving, a process that eventually led to humans. The transmutation of the species would therefore be the realization of a predetermined plan inscribed in the laws that govern the world. This idea was less radical than the materialistic ideas of Robert Grant, but the consequence that humans were the last link in the evolution of animals angered much conservative scholars. Chambers' assumptions have been criticized from many quarters. Conservatives like Adam Sedgwick and radical materialists like Thomas Henry Huxley , who rejected the notion of a predetermined world order, searched for and found errors in the book that allowed them to denigrate the scriptures. Darwin lamented the author's “poor intellect” and dismissed it as a “literary curiosity”. However, the great publicity of the debates on Chambers “Vestiges” with its portrayal of evolution as a progressive process had an impact on the later publication of Darwin's theory. It also influenced the young naturalists of the time, including Alfred Russel Wallace, and sparked their interest in the ideas of transmutation.

Opponent of transmutation

This 1847 diagram by Richard Owen shows his outline of a hypothetical archetype for all vertebrates.

Proponents of the idea of ​​a transmutation of species felt closely linked to the radical materialism of the Enlightenment , and conservative scholars often encountered them with hostility. Cuvier, for example, attacked the theories of Lamarck and Saint-Hilaire , claiming in the tradition of Aristotle that the species are immutable. Cuvier believed that the parts that make up an animal are so closely linked that it is impossible to change any part. He believed that the fossils were evidence of mass extinction due to disasters that would be followed by population regrowth. As a result, they are not an indication of a gradual change in a species. He also pointed out the fact that the millennia-old depictions of animals and animal mummies in Egypt did not contain any indication of a change in species compared with modern individuals. The convincing arguments of Cuvier (for the time) and his outstanding reputation meant that the idea of ​​transmutation did not find its way into mainstream science in the 19th century for decades. Natural theology also remained influential in Great Britain . There William Paley wrote the book Natural Theology as a response to the transmutation theories of Erasmus Darwin . It contains the famous watchmaker analogy .

Natural theologians such as the geologists Buckland and Sedgwick regularly attacked the evolutionary ideas of Lamarck and Grant. Sedgwick wrote a particularly rude review of the "Vestiges". Although the geologist Charles Lyell was an opponent of Bible-based geology, he defended the idea of ​​the immutability of species. In his main work Principles of Geology (1830-1833) he criticized and rejected Lamarck's theory of evolution. Rather, he represented a form of progressive creation in which every species has its "place of creation", was created by God for this specific habitat and dies out when it changes.

Another source of opposition to transmutation was the school of naturalists , influenced by German philosophers and naturalists who, like Goethe , Hegel, and Lorenz Oken , were shaped by idealism . Idealists like Louis Agassiz and Richard Owen believed that each species was immutable and represented an idea in God's consciousness. They believed that kinship relationships between species could be discerned from developmental patterns in embryology and fossil remains. But they were also convinced that these relationships pointed to an underlying divine plan in the course of which God, through continuous creation, leads the world to ever greater complexity and which ultimately culminates in man.

Owen developed the idea that there are "archetypes" in God's consciousness that give rise to whole series of species that are related by homologies. Much like vertebrates resemble each other by having extremities. Owen was concerned about the possible political implications of the ideas of a transmutation. He therefore successfully led a public campaign by conservative scholars aimed at isolating Robert Grant from the scientific community. In his famous 1841 treatise, in which he introduced the term "dinosaur" to refer to the giant reptiles whose fossils Buckland and Gideon Mantell discovered, he stated that these reptiles would be evidence that the transmutation theory was wrong because the dinosaurs appeared to be more developed than the modern reptiles. Later, Darwin will make extensive use of the homology studies Owen investigated for his own theory. However, the memory of the rude treatment Grant received and the controversial discussions about the "Vestiges" will have led him to very carefully substantiate his own theory with facts and arguments before he published it.

Used literature

  • Peter J. Bowler: Evolution: The History of an Idea . University of California Press 2003, ISBN 0-520-23693-9
  • Adrian Desmond: Darwin: The Life of a Tormented Evolutionist . WW Norton & Company 1994, ISBN 0-393-31150-3
  • Peter J. Bowler: Making Modern Science . The University of Chicago Press 2005, ISBN 0-226-06861-7
  • Edward J. Larson : Evolution: The Remarkable History of Scientific Theory . Modern Library 2004, ISBN 0-679-64288-9
  • John van Wyhe: Mind the gap: Did Darwin avoid publishing his theory for many years? in: Notes and Records of the Royal Society 61 (2) pg. 177-205. March 27, 2007 PDF

Web links

Individual evidence

  1. ↑ Secord, James A. 2000. Victorian sensation: the extraordinary publication, reception, and secret authorship of the Vestiges of the Natural History of Creation . Chicago, p311
  2. ↑ There are three examples of the word 'evolution' in Social Statics , but none in the sense that is used today in biology. See Herbert Spencer: Social Statics
  3. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. pp = 86-94. ISBN 0-520-23693-9 .
  4. ^ Larson, Edward J. (2004). Evolution: The Remarkable History of Scientific Theory. Modern Library. pp = 38-41. ISBN 0-679-64288-9 .
  5. ↑ Desmond, Adrian; Moore, James (1994). Darwin: The Life of a Tormented Evolutionist. WW Norton & Company. p = 40. ISBN 0-393-31150-3 .
  6. ^ Bowler, Peter J .; More, Iwan Rhys (2005). Making Modern Science. The University of Chicago Press. pp = 120-134. ISBN 0-226-06861-7 .
  7. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. pp = 134-138. ISBN 0-520-23693-9 .
  8. ^ Bowler, Peter J .; More, Iwan Rhys (2005). Making Modern Science. The University of Chicago Press. pp = 142-143. ISBN 0-226-06861-7 .
  9. ↑ Desmond, Adrian; Moore, James (1994). Darwin: The Life of a Tormented Evolutionist. WW Norton & Company. p = 47. ISBN 0-393-31150-3 .
  10. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. pp = 174. ISBN 0-520-23693-9 .
  11. ^ Larson, Edward J. (2004). Evolution: The Remarkable History of Scientific Theory. Modern Library. pp = 5-24. ISBN 0-679-64288-9 .
  12. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. pp = 103-104. ISBN 0-520-23693-9 .
  13. ^ Larson, Edward J. (2004). Evolution: The Remarkable History of Scientific Theory. Modern Library. pp = 37-38. ISBN 0-679-64288-9 .
  14. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. p = 138. ISBN 0-520-23693-9 .
  15. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. pp = 120-134. ISBN 0-520-23693-9 .
  16. ^ Bowler, Peter J. (2003). Evolution: The History of an Idea. University of California Press. pp = 120-134. ISBN 0-520-23693-9 .
  17. ^ Larson, Edward J. (2004). Evolution: The Remarkable History of Scientific Theory. Modern Library. pp = 42-46. ISBN 0-679-64288-9 .
  18. ^ Van Wyhe, John (March 27, 2007). "Mind the gap: Did Darwin avoid publishing his theory for many years?" (PDF). Notes and Records of the Royal Society 61 (2): 177-205. doi: 10.1098 / rsnr.2006.0171 . Retrieved February 7, 2008, pp = 181–182.