Background
Bronn was born on March 3, 1800, at Ziegelhausen (now part of Heidelberg) in the Electoral Palatinate. He was the fifth of seven children of Georg Ernst Bronn, a government forestry official, and Elisabeth Margarethe Bronn.
69117 Heidelberg, Germany
Bronn attended the University of Heidelberg in 1817. He got a doctor's degree in the faculty of medicine in 1821.
Heinrich Georg Bronn's tree-like diagram published in Untersuchungen über die Entwickelungs-Gesetze der organischen Welt in 1858. In describes evolutionary relationships between organisms.
geologist paleontologist scientist
Bronn was born on March 3, 1800, at Ziegelhausen (now part of Heidelberg) in the Electoral Palatinate. He was the fifth of seven children of Georg Ernst Bronn, a government forestry official, and Elisabeth Margarethe Bronn.
Bronn attended elementary school in Ziegelhausen and gymnasium in Heidelberg, and began attending the University of Heidelberg in 1817. He got a doctor's degree in the faculty of medicine in 1821. He studied cameralism and natural history, possibly with the intention of pursuing a civil-service career like his father's. This course of study contrasts with the medical training that was more usual for German morphologists, and it allowed Bronn to range more broadly into applied sciences such as forestry, mining, and plant and animal breeding. Bronn’s most influential teacher at Heidelberg was probably the geologist Karl von Leonhard.
In 1821, after completing his habilitation in natural history and Encyclopädie der Staatswissenschaften (general sciences of the state), Bronn began to teach at Heidelberg at the rank of Privatdocent (lecturer; paid from student fees, not on the state payroll). In 1824 and 1827 Bronn traveled to Switzerland, southern France, Austria, and northern Italy for field research. In 1828, back at Heidelberg, he was promoted to außerordentlicher Professor (extraordinary professor) for topics in commerce and natural history. From 1830 on, he coedited the Jahrbuch (after 1833, the Neues Jahrbuch) für Mineralogie, Geognosie, Geologie, and Petrefaktenkunde (New yearbook for mineralogy, geognosy, geology, and fossil studies), which von Leonhard had founded in 1806. In 1833, he took over the directorship of the zoological collection and responsibility for teaching zoology. Finally, in 1837, he received his promotion to Ordinarius (ordinary, or full professor) and became head of Heidelberg’s first full-fledged institute of zoology, while also retaining responsibility for applied natural history. This places him among the first generation of zoologists to establish their field as a university-based discipline.
Bronn spent the rest of his career at Heidelberg. He rose to the rank of Hofrat (court councilor) in the civil service and served as a university Prorektor in 1859–1860. Bronn’s work in paleontology was honored with a gold medal from the Dutch Scientific Society in Haarlem and a prize from the French Academy of Sciences in 1857.
Bronn made his international reputation as a geologist and paleontologist between 1824 and 1831 with systematic works on fossil shells and zoophytes, and reports on the geology, paleontology, and economy of Heidelberg and of the regions he visited on his scientific travels. From 1835 to 1838 he brought out his Lethæa geognostica, the most complete compendium of fossil species of its time. By organizing fossils first by geological time period, and then taxonomically and geographically within each period, it put the organisms into concrete historical contexts instead of arranging them on a timeless scale of nature or in an abstract system. The arrangement also facilitated the practice, already widespread, of dating geological strata by the fossil species they contained. Other reference works followed, which featured alphabetical indexing and continued to add species and eliminate synonyms.
He also authored a three-volume Handbuch einer Geschichte der Natur (Handbook of a history of nature, 1841–1849), which is not only a reference work but also a general introduction to natural history.
Bronn did not consider himself a narrow specialist on paleontology but was also concerned with zoology as a whole and its emerging position among the academic disciplines. In the interest of providing zoology with a unifying conceptual framework, Bronn devoted his next major project to an encyclopedic Allgemeine Zoologie (General zoology). Here he outlined a view of the animal as a living whole, to which every subdiscipline contributed: anatomy, physiology, biochemistry, animal psychology, biogeography, paleontology, and systematics. The same unifying urge provided the impetus behind Bronn’s well-known series Klassen und Ordnungen des Thierreiches (Classes and orders of the animal kingdom), which was intended to give a complete account of every major animal group. Bronn produced the first three volumes between 1859 and 1862, and it has been continued by many other authors.
Bronn’s prizewinning Untersuchungen über die Entwickelungs-Gesetze der organischen Welt während der Bildungs-Zeit unserer Erd-Oberfläche (Investigations on the developmental laws of the organic world during the formative period of our Earth’s surface), originally written in French in 1855, first appeared in print in an 1858 German version. In it Bronn restated and refined his theory of organic history from Handbuch einer Geschichte der Natur.
Also in 1858, Bronn published Morphologische Studien über die Gestaltungs-Gesetze der Naturkörper überhaupt und der organischen insbesondere (Morphological studies of the formative laws of natural bodies generally and organic ones in particular), an analysis of crystals, embryonic stages, and the diversity of adult forms. By publishing a separate book on this subject, Bronn underscored the distinction between the process of forming an animal body and the historical progression of forms in the fossil record.
Heinrich Georg Bronn was raised a Catholic.
In Handbuch einer Geschichte der Natur Bronn outlined his major theoretical statement on the history of the organic world, the causes and laws of change, and the places of zoology and paleontology among the scientific disciplines. It stresses the unity of the sciences and the bearing of cosmology, geology, physics, and chemistry on the study of life. Beginning with the nebular hypothesis and the origin of Earth as a molten sphere, it argues that the gradually cooling Earth presented progressively more hospitable and diverse environments. Such geological progress, Bronn argued, together with the principle that species must always be adapted to their environments, explains the patterns (or “laws”) of species succession that are documented in the rest of the book.
Based on a study of variation, both in geographic varieties and artificially bred ones, Bronn decided against the possibility of species transformation. If a new species appear suddenly at some point in the fossil record, it must have been produced then and there by some creative force or process. Although the nature and causes of the creative force were unknown, Bronn could describe its effects and discover the laws that governed it. His most fundamental law (Grundgesetz) was that new species always had to be adapted to the environmental conditions they would actually encounter. Other, less fundamental laws saw to it that new creations stayed within taxonomic types, but also pushed their boundaries to make them include higher percentages of modern species, more “perfect,” and more diverse ones, and also to colonize a progression of environments, from the marine to the freshwater, to the terrestrial.
Bronn’s law of adaptation implied that each species was suited to life at a particular time and place, and would gradually become less-well adapted as Earth evolved. Eventually it would diminish in numbers, become extinct, and be replaced by one or more better-adapted and more-advanced species. Because of complex interdependencies among species and environments, each extinction, in turn, triggered further extinctions, then further creations, resulting in continual turnover and improvement of the fauna and flora.
This successional theory of Bronn’s was one of several that were current in the decades before The Origin of Species, but it had several distinctive features. Against Louis Agassiz’s catastrophism, which had envisioned periodic mass extinctions and wholesale fresh creations of more advanced forms, Bronn argued for asynchronous extinctions and gradual species turnover. His detailed tabulations of fossils and their relative ages provided strong evidence against mass, simultaneous extinctions. In contrast, Bronn opposed the steady state uniformitarianism of Charles Lyell, which had gradual species turnover, but no net geological or morphological progress. Bronn’s data also allowed him to document and quantify various forms of advancement in the fossil record. In addition, Bronn also rejected the notion, associated with Naturphilosophie and idealistic morphology, that embryonic development could serve as the model for historical change. Bronn argued that the sequences of fossil forms did not run parallel to embryonic stages and that species did not have life cycles and predetermined life expectancies. Bronn viewed paleontology as a separate subdiscipline, with its own laws and its own data, and paleontologists were to explain organic change with reference to the changing external world, rather than internal, developmental processes.
In Untersuchungen über die Entwickelungs-Gesetze der organischen Welt während der Bildungs-Zeit unserer Erd-Oberfläche (Investigations on the developmental laws of the organic world during the formative period of our Earth’s surface) Bronn restated and refined his theory of organic history from Handbuch einer Geschichte der Natur. It was still a successional theory, rather than an evolutionary one, but the laws of change were much simplified and it was strongly suggested that they were all ultimately reducible to the effects of adaptation to an evolving Earth. Morphological progress was also measured by some new yardsticks, such as increasing “physiological division of labor,” a concept developed by Henri Milne-Edwards, who was one of the judges at the French Academy.
Despite its threat to overturn his own successional theory, Bronn responded constructively to the publication of The Origin of Species in 1859. He translated the second and third editions of Darwin’s book into German in 1860 and 1863, respectively, and he appended his own critical commentary to both of those editions. Bronn also translated Darwin’s book on orchids.
Bronn’s translation of The Origin has often been criticized for rendering Darwin’s new ideas in the language of an older German morphology, which spoke of natural selection leading to increasing “perfection” of form. Darwin’s supporters also objected to Bronn’s commentary, which gave at best an ambiguous endorsement of Darwinism. Still, it was the first translation on the market in any language, and it was instrumental in disseminating Darwin’s theory and initiating discussion in Germany. Starting with the 1867 third German edition (based on Darwin’s fourth), J. Victor Carus took over as Darwin’s principal German translator, and he removed Bronn’s commentary and modernized some of the terminology.
Bronn’s own work had anticipated Darwin’s emphasis on adaptation to changing environments and on the demise of the maladapted, and he was willing to reconsider the fixity of species and even the direction and purposefulness of historical progress. But in his commentary, he complained of Darwin’s inability to explain the origin of the very first species. As long as Darwin still allowed for a mysterious creative force to produce even one species long ago, Bronn argued, he had not really rid science of such forces or ruled out theories such as Bronn’s that relied solely on them. Bronn also raised the problem of orderliness in taxonomy, especially the distinctiveness of species. He thought that there was not, in fact, such a great chaos of unclassifiable species as Darwinian variation ought to produce. Bronn observed that nature had “lawlike means” of maintaining species’ identities and eventually returning varieties to the norm if they were ever altered by environmental influences, hybridization, or artificial selection. In contrast, under Darwin’s theory, such order had to be maintained by natural selection, which carved out recognizable species and higher groups. But Darwin had no direct historical evidence that it always did so and, worst of all, nothing like a law of nature requiring it. The whole scheme seemed to Bronn to be too capricious to be a proper scientific explanation of life. Bronn rejected the theory as it then stood, but predicted that the Darwinians would eventually gain acceptance.
Bronn was married to Luise Bronn, née Penzel, and they had five children.