Louis Agassiz

Jean Louis Rodolphe Agassiz ( born May 28, 1807 in Haut-Vully in the community part Môtier, Canton of Fribourg, Switzerland, † December 14, 1873 in Cambridge, Massachusetts, United States) was a Swiss- American naturalist.

Agassiz was one of the first internationally renowned U.S. scientist and husband of educator Elizabeth Cary Agassiz. He is known primarily for his pioneering studies ice age and its services as ichthyologist ( fish expert ) and high school teachers. He coined the word phrase that glaciers "the great ploughshare of God" were.

In more recent times, Agassiz 's views on the human races were discussed.

• 3.1 The problem of erratic boulders
• 3.2 The development of the ice age theory
• 3.3 Studies on the availability of ice age theory
• 3.4 Acceptance of the ice age theory

• 5.1 Assessment of human races

Early years

Louis Agassiz was the son of a Protestant pastor in Vully -le-Haut (now Haut-Vully ) born in the district Môtier, in Switzerland. First educated at home, he spent four years at a secondary school in Biel / Bienne and then studied in Lausanne. With the aim direction to become a doctor, he studied from 1824 at the Universities of Zurich, Heidelberg and Munich. In Heidelberg and Munich, he was a member of the Corps Helvetia. At the same time, he expanded his knowledge in the natural sciences, especially botany. In 1829 he earned his doctorate as a Doctor of Philosophy in Erlangen and in 1830 as Doctor of Medicine in Munich. After moving to Paris was Alexander von Humboldt and Georges Cuvier his mentors who encouraged him to develop in geology and zoology. He quickly developed a preference for the ichthyology, which was his preferred area of ​​research for the rest of his life.

Early research

First activities ichthyologist

From a research trip to Brazil in the years 1819 to 1820 Johann Baptist von Spix and Carl Friedrich Philipp von Martius had brought back a collection of freshwater fish of the Brazilian rivers, especially the Amazon. Spix died in 1826 without having his findings classified conclusively scientifically and Agassiz was selected by Martius, Spix ' continue working. With the enthusiasm which should characterize him throughout his life, Agassiz devoted to this task. After the completion of the work and the publication in 1829 Agassiz dealt scientifically with the fishes of Lake Geneva. This work he extended in 1830 to all freshwater fish from Central Europe. The first part of the work appeared in 1839 and was completed in 1842.

Professor in Neuchâtel

1832, after his return from Paris, he became a professor at the Lyceum of Neuchatel, where he taught until his emigration to the United States. At Agassiz ' employees in Neuchâtel were Eduard Desor, Amanz Gressly and Carl Vogt.

In Neuchâtel, he devoted himself to the fossil fish which were to be found abundantly in the shale layers of the Swiss canton of Glarus and in the limestone of Monte Bolca, about which, however, no scientific studies were carried out up to that time. Already since 1829 Agassiz had therefore planned, about to publish a scientific paper. This work later formed the basis for his worldwide fame. The five volumes of his Recherches sur les poissons fossil ( " Studies on fish fossils" ) published at intervals in the period 1833-1843. You were illustrated especially by Joseph Dinkel. As part of his research, Agassiz visited the principal museums in Europe and was mainly by Georges Cuvier, whom he met in Paris, encouraged the continuation of his work and support.

Revision of ichthyological classification system

Agassiz soon came to the conclusion that his paleontological work necessitated a new classification of ichthyological classification system. Since the fossils usually only the teeth, scales and fins of the fish reproductions, he designed a classification system that divided fish into four groups. His classification is now obsolete, but it forms the basis of the current system.

When it became obvious that the continuation of the work of Agassiz was limited by financial constraints, he received support from the British Association, and by Lord Francis Egerton, who bought from him 1,290 drawings to hand them over to the Geological Society of London. 1836 Agassiz was honored for his work with the Wollaston medal and appointed two years later as a foreign member of the British Royal Society. In the meantime, he extended his studies on invertebrates. From 1840-1845 he gave his Etudes critiques sur les Mollusques fossil ( " Critical Studies on Fossil Mollusks ", German: " Critical Studies on fossil mollusks " ) out.

Glacier research and the thesis of the Ice Age

The problem of erratic boulders

Since about 1760 geologists engaged intensively with the question of which forces boulders, which are blocks of rock, which were to be found in areas from which they geologically obviously did not come, had been transported over long distances. Particularly striking were the boulders in the north German plain and in the foothills. The common explanation were volcanic processes. Dead-ice depressions were interpreted as crater. 1787 Although Bernhard Friedrich Kuhn had suspected glacier activities as a cause and a similar result by Scottish geologist James Hutton had come. However, their theories were just a little more acceptance as that of the natural scientist Reinhard Bernhardi (1797-1849), who in 1832 represented in an article the opinion that had once extended an ice cap over Europe, which would have been enough to Central Germany. Other scientists were of the view that these huge rocks were worn on ice floes from the north during the flooding of their present localities. For the boulders in the foothills of the Alps has been suggested that large floods they had carried into the foothills of the Alpine peaks. Over the many theories that have been discussed for their explanation, Goethe had his Mephistopheles in Faust II scoff:

The development of the ice age theory

The thesis that once glaciers have covered not only the Swiss Plateau and the Jura, but also large parts of Europe, was set up in 1822 by Ignaz Venetz. Hearing, he found only at Jean de Charpentier, director of the Saline in Bex (Vaud ) in the Swiss Rhone Valley.

It was not until the year 1836 brought a breakthrough in glacier research. At the meeting, Swiss naturalist in Solothurn Charpentier met the naturalist, geologist and botanist Karl Friedrich Schimper, who had been held since 1835 talks about the problem of erratic and his ideas about the " winter world ". Over the next four months, the two developed their ideas further in the Jura, the Black Forest and in the Rhone Valley. This summer, Agassiz visited the Rhone valley and was convinced by Charpentier from the Ice Age theory. From December 1836 to May 1837 worked Agassiz and Schimper together in Neuchâtel. The latter wrote an ode entitled " The Ice Age ", which today is as a concept nor the customary term.

On the evening of July 24, 1837 Agassiz Schimpers lectured theory that the earth was exposed in earlier times ice ages. His fiery speech as chairman before a meeting of the Swiss naturalist in Neuchâtel ( Switzerland ), he headed with the words:

This was followed by Agassiz ' dramatic portrayals " of an epoch freezing cold ", a Siberian winter, which " put on a world that had hitherto been blessed with lush vegetation and populated by large animals " and " a pall over the whole of nature spread. " This speech produced the first tensions between Agassiz one hand and Venetz, Charpentier and Schimper other. In a letter to Schimper to Charpentier complained later that Agassiz had not particularly made ​​clear that Schimper, with Agassiz in Heidelberg and Munich study periods was a close friend, was the actual author of Ice Age thesis.

Despite the considerable reputation, which had already acquired Agassiz as a naturalist, he was provisionally but no supporters for the Ice Age theory. His old patron Alexander von Humboldt advised him in a letter in the same year, on fossil fish return to " his work ... if you do, you make the positive Geology a greater service than with these general considerations ( also a bit icy ) on the upheavals of the primitive world, considerations which, as you well know, only convince those they bring into being. " ( Reinke - Kunze, p 112)

Studies on the availability of ice age theory

From 1836 Agassiz had begun to gather evidence for the shaping of the landscape by glaciers. This research he intensified by the skeptical response to this theory. He traveled not only common in the glacial areas, but could be even build a hut on the Unteraargletscher to watch from there the structure and movement of glaciers. To this end, he drove a number of piles transverse to the flow direction of the glacier the ice, marking their positions on the lateral walls of rock. Based on his experimental field he was able to show that the friction of the ice slows its movement on the rocks and different speeds that occur in the flow direction of a glacier. In 1840 he published the results of his studies in Etudes sur les glaciers ( " studies of glacier "). He discussed not only in the forms of movement of glaciers and their significance for the formation of the Alpine landscape, but also concluded that the Swiss Plateau was once completely covered by ice. The publication of his book led to the final break with Charpentier and Venetz. Although Agassiz pointed out that the essential features of this theory came from his two colleagues, but he published his book before Charpentier its own research results could publish.

1840 Agassiz traveled to England with the intention of returning to his actual field of research, the fossil fish turn. During this journey he presented the ice age theory to the British Association for the Advancement of Science. Together with the leading English geologist William Buckland he came in addition to the conclusion that the landscape of Scotland was formed under the action of glaciers. A similar conclusion he came to the mountain landscapes of England, Wales and Ireland, and he noted that:

The acceptance of the ice age theory

Until the ice age theory found wide acceptance, however, was several decades. Agassiz contributed to his research and his publications significantly to that employed in Europe and later in the United States, numerous scientists with this thesis.

Already his stay in England inspired a whole series of English scientists to think more intensively with this theory. Although written by the British scientist Edward Forbes 1841 Agassiz, he had all the geologists of Great Britain " great glacier " made ​​, however, remained the authoritative time geologist in the UK, Charles Lyell, cautious. During field work in Scotland in 1840 he was persuaded short of Agassiz, but the very next year reported Lyell concerns to: The concept of ice ages seemed his actualistic basic principle too much to argue that the forces that had shaped the earth in the past, in principle, are the same as today. It was not until 1863, Lyell approached the Ice Age teachings with their own contributions again.

On the European continent began more and more scientists to find evidence of glacial reshaping. In Germany, for example, discovered in 1844 by Bernhard Cotta glacier scrapes in the Hohburger mountains east of Leipzig, which convinced him that the ice cap once extended into this region. It is uncertain which scientists as the first had the idea that there have been several ice ages. Presumably it is in turn been Ignaz Venetz. Adolph von Morlot assumed that the ice ages of climatically very warm periods were separated, and the palaeobotanist Oswald Heer in 1865 coined the term " interglacial " for these periods. However, in Germany the real breakthrough came in 1875, two years after Agassiz 's death, when the Swedish scientist Otto Torell lectured before the Geological Society, in what way glacial ice would have advanced from the far north to northern Germany.

Emigration to the USA

In the ten years in which Agassiz grappled intensively with the glaciers and ice age research, he led his systematic research continues. From 1842 to 1846 Agassiz published his Nomenclator Zoologicus, a classification of all zoological species - the product of hard work and research. With the support of the king of Prussia, he went in the fall of 1846 in the United States, there to investigate the natural history and geology of the United States and at the invitation of JA Lowell a series of lectures on zoology in Boston, Massachusetts. The offered financial opportunities led him to settle in the United States and by 1847 to teach as a professor of zoology and geology at Harvard University. After the death of his first wife, married Elizabeth Cabot Agassiz 1850, the writer Cary of Boston, particularly as a champion of women's education made ​​a name for himself. 1852 was followed by a Professor of comparative anatomy in Charlestown (Massachusetts ), which he resigned two years later.

After moving to the USA took the time Aggasiz for scientific studies expended significantly. Yet because of its teaching, he exerted a great influence on the development of geology and zoology in the U.S. from: Agassiz developed a new teaching method by creating the connection of students to nature, so that they could gain the needed knowledge from personal experience, rather than just book knowledge to learn. This enthusiastic, emotionally colored view of nature is the influence of the romantic natural philosophy, particularly Friedrich Schelling, back - finally were Heidelberg and Munich, where Agassiz once studied, have been centers of the German high romance.

At Agassiz ' students included, among other things, David Starr Jordan, Joel Asaph Allen, Joseph Le Conte, Nathaniel Shaler, Alpheus Packard, as well as his own son Alexander Agassiz, who later acquired all his name as a scientist and teacher. In Agassiz ' skill in obtaining donations and grants, the establishment of the Natural History Museum goes back in Cambridge, which was opened in 1859. He was one of the first, which dealt with the influence of the last ice age North America. However, his research focus remained the fish in the area of the United States from 1865 to 1866 he undertook a research expedition to Brazil, from which he brought back numerous exhibits for the museum he founded. 1871-1872 he began also to deal with deep-water investigations.

As a scientist, he was perceived by the general public and was one of the best known and most esteemed teachers of his time. The poet Henry Wadsworth Longfellow wrote on the occasion of his 50th birthday in his honor a poem entitled "The fiftieth birthday of Agassiz ." The Bavarian Academy of Sciences appointed him in 1853 to its foreign members.

Agassiz himself continued his numerous publications, including the two four-volume work Natural History of the United States and Bibliographia Zoologiae et Geologiae.

Agassiz and the theory of evolution

Despite his intense studies of the anatomy and systematics of recent and fossil fish, by which he was familiar with the graded morphological similarities and possible lines of development, Agassiz remained until his death a follower of founded by Georges Cuvier catastrophism and as such a staunch opponent of the theory of evolution that was developed by Charles Darwin. He argued that the ordinary circumstances, that were used by Darwin for his theory of how variability and genetic variation of species, climate change, geological upheavals, and even ice ages, could still only lead to the extinction of species, but never rise to new species. The development of simpler to more complex organisms, as they came to the fore in the sequence of fossils, he led in Neoplatonic type as " thought associations in the divine spirit " back. He was one of the last paleontologist who metaphysically founded the biodiversity by led her back to a creative God. As such, he assumed a constancy of species and tried to replace the facts of the zoogeography by centers of creation (see the history of geology ).

Assessment of human races

In his Swiss time Agassiz was still followers of the monogenesis theory, which is now generally accepted. It says that all people have emerged from a common origin. But during his years in the U.S., he became a follower of the then competing polygenism, alleging that people have evolved independently from different origins in different parts of the world. At this change of opinion contributed his encounters with black slaves who were at that time in the U.S. only minor development opportunities. Agassiz had an extremely unfavorable impression of them, as he described in a letter to his mother.

As far as known, Agassiz expressed in any publication on the subject, but in an article in a liberal Christian magazine, with the headline "The diversity of origin of the human races", with the author - specified LA - his name was therefore merely indicated. So it was not recognizable name and thus the authority of a famous scientist behind this article, which was led by Charles Darwin in his book " The Descent of Man " (1871 ). The distinction of different races, especially by higher civilized races on the one hand and lower races, on the other hand was then prevalent among zoologists. Agassiz wrote at the end of his article:

Even in some of his letters to Agassiz expressed it.

Because of this attitude Agassiz ' wanted 2007, the Swiss parliamentarian Carlo Sommaruga can rename named after the researchers Agassizhorn. Although the Swiss Federal Council condemned racist views Agassiz ', but saw it as no reason for renaming the mountain summit.

Aftereffect

In the last years of his life he made ​​it his goal to establish an institution that can be performed on the zoological studies of living objects. The Philanthropist John Anderson left in 1873 Agassiz a location in front of Massachusetts ' coastal island as well as $ 50,000 to build a station for the study of marine life there. This station lasted the death of Agassiz not very long, but it is considered a forerunner of the Woods Hole Oceanographic Institution, which now exists in the vicinity of the old research station.

At Agassiz, the experts remind mostly due to its glacier studies and as one of the last great zoologist, who opposed Charles Darwin's theory. He died in 1873 in Cambridge. His tomb consists of a rock of the moraine of the Aargletschers on which once stood his research hut.

Honors

In honor of Louis Agassiz ' carries the 3,946 m high in the Bernese Alps Agassizhorn his name. It is separated from the southeastern Finstaarhorn, the highest Bernese peaks through the 3,749 m high Agassizjoch. In addition, a number of animal species have been named by Agassiz. Among the species that bear his name, including Agassiz ' dwarf cichlid ( Apistogramma agassizii ) and the gopher tortoise Gopherus agassizii California. A huge lake that formed at the end of the Pleistocene in North America from glacial melt water and had covered a large part of Canada in Altholozän was called since 1879 Agassiz. Louis Agassiz had described the relationship between the end of the last Ice Age and the emergence of prehistoric lake. A crater on Mars named after him. Likewise, the promontory Agassiz on the Earth's moon.

In 1836 he became a corresponding member of the Royal Prussian Academy of Sciences, two years later he was admitted to the Leopoldina. In addition, he was taken on August 17, 1860 as a foreign member of the Prussian Order Pour le Mérite for Sciences and Arts.

Works

• Selecta Genera et Species Piscium (1829 )
• Recherches sur les poissons fossil (1833-1843) digitized (vol. 1-5)
• Monographies d' échinodermes, Vivans et fossil (1838 - 1842) doi: 10.5962/bhl.title.1833
• Mémoire sur les moules de Mollusques Vivans et fossil (1839 ) doi: 10.5962/bhl.title.1915
• History of the Freshwater Fishes of Central Europe (1839-1842)
• Catalogus systematicus ectyporum echinodermatum Fossilium Musei neocomensis (1840 ) doi: 10.5962/bhl.title.8820
• Études sur les glaciers (1840 )
• Études critiques sur les Mollusques fossil (1840-1845) doi: 10.5962/bhl.title.1126
• Histoire naturelle poissons d' eau douce of de l'Europe centrale (1842 ) doi: 10.5962/bhl.title.1820 doi: 10.5962/bhl.title.5744 doi: 10.5962/bhl.title.5774 doi: 10.5962/bhl.title .12472
• Introduction a une monograph of the fossil poissons du vieux grès rouge (1844 ) doi: 10.5962/bhl.title.5763
• Monograph of the fossil poissons du vieux grès rouge, ou Système Dévonien ( Old Red Sandstone ) des Îles Britanniques et de Russie ( 1844-1845 ) doi: 10.5962/bhl.title.5752
• Anatomy of salmones (1845 ) doi: 10.5962/bhl.title.13843
• Natural History of the United States (1847-1862)
• ( with AA Gould ) Principles of Zoology for the Use of Schools and Colleges, " ( Boston, 1848)
• Bibliographia zoologiæ et geologiæ. A general catalog of all books, tracts, and memoirs on zoology and geology (1848 - 1854) doi: 10.5962/bhl.title.56049 doi: 10.5962/bhl.title.20707
• Lake Superior its physical character, vegetation and animals, Compared with Those of other and similar regions. ( 1850) doi: 10.5962/bhl.title.56214 doi: 10.5962/bhl.title.50379 doi: 10.5962/bhl.title.1827 doi: 10.5962/bhl.title.29144
• The classification of insects from embryological data ( 1850) doi: 10.5962/bhl.title.32965
• Contributions to the natural history of the Acalephae of North America ( 1850) doi: 10.5962/bhl.title.11610
• Directions for collecting fishes and other objects of natural history (1853 ) doi: 10.5962/bhl.title.5767
• ' Contributions to the natural history of the United States of America. (1857 - 1862) doi: 10.5962/bhl.title.12644
• Essay on Classification ( 1859) ( against the theory of evolution ) doi: 10.5962/bhl.title.1831
• Essay on classification. Edited by Edward Lurie (1862 ) doi: 10.5962/bhl.title.6816
• Methods of study in natural history (1863 ) doi: 10.5962/bhl.title.54211 doi: 10.5962/bhl.title.1832 doi: 10.5962/bhl.title.23661 doi: 10.5962/bhl.title.45797 doi: 10.5962/bhl. title.21094 doi: 10.5962/bhl.title.29529
• A Journey in Brazil, along with his wife Elizabeth Cary. 2nd edition (1868 ) doi: 10.5962/bhl.title.19243 doi: 10.5962/bhl.title.1787 doi: 10.5962/bhl.title.4342
• 6th edition (1869 ) doi: 10.5962/bhl.title.4437
• 8th edition (1871 ) doi: 10.5962/bhl.title.4418