Elisabeth Vrba

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Elisabeth Vrba, 2009

Elisabeth Vrba (born May 27, 1942 in Hamburg ) is a South African-American paleontologist and professor of geology and geophysics at Yale University in New Haven (Connecticut) .

She became internationally known in 1980 through a specialist publication in the South African Journal of Science . In this publication she intervened in a debate on evolutionary theory that had been going on since the early 1970s between representatives of gradualism and punctualism in favor of punctualism, and at the same time formulated for the first time the now generally known hypothesis that climate changes occurred in Africa 2.5 to 2 million years ago led to an accelerated "species change" . Their hypothesis, based mainly on studies on fossil antelopes , quickly spread to research into human tribal history , since in this epoch - the transition from Pliocene to Pleistocene - the genus Homo emerged from the genus Australopithecus in Africa .

Together with Stephen Jay Gould , Elisabeth Vrba developed the concept of exaptation in 1982 as a distinction to adaptation .

Career

Elisabeth Vrba was born in Hamburg. She was two years old when her mother with her to Namibia emigrated after her father - a professor of law - at sea like was; A sister of her mother already lived in Namibia. There her mother married a second marriage to a sheep farmer who found a qualified education for girls to be useless. She was nevertheless able to get her wish to attend high school and later the University of Cape Town in South Africa . There she obtained a bachelor's degree in mathematical statistics in 1964 and in zoology in 1965 . Then Vrba moved for a year to the Zoological Institute of the Witwatersrand University in Johannesburg , and from 1967 to 1968 she taught high school students at St. Alban's College in Pretoria . In 1967 she married her husband George.

From 1969 to 1972 Elisabeth Vrba worked - initially free of charge - as an expert for the Transvaal Museum in Pretoria. There, its long-time director, Charles Kimberlin Brain , had assembled a large collection of remains of fossil antelopes , which had to be cleaned and sorted from attached rock. In the course of her doctoral thesis, she learned that antelopes - unlike most other vertebrates - have a distinctive feature from which their affiliation to a certain species can be derived: while male and female animals of many species each other based on their behavior, their The members of an antelope species recognize themselves by the shape of their horns if they recognize their plumage or their fur color (by characteristics that are not passed down fossilized) . This knowledge formed the cornerstone of her reflections on the mechanisms of evolution, formulated from 1980 onwards . The resulting international fame led to her receiving the Star Women of the Year Award in South Africa in 1982 (meaning: Working Woman of the Year).

From 1973 to 1986 Vrba headed the Department of Paleontology and Paleoanthropology of the Transvaal Museum; In 1975 she obtained a doctorate in zoology / paleontology from the University of Cape Town. From 1976 to 1986 she led excavation projects at the Australopithecine site of Kromdraai and at Broederstroom in the South African northwest province . From 1977 to 1986 she was also the museum's deputy director.

In 1986, Elisabeth Vrba switched to a professorship for geology and geophysics at Yale University and has been teaching in the field of biology since 1987. She has also been the curator of vertebrate palaeontology and osteology at the university's Peabody Museum of Natural History since 1987 .

Research topics

UR 501 (original), the second oldest known fossil of the genus Homo , in the hands of Elisabeth Vrba

First she published (1968) on fish skulls . After Elisabeth Vrba began assigning antelope fossils to certain species in 1969, she noticed that the definition of evolutionary success that was customary at the time could not be applied to antelopes: those chronospecies were considered successful that - like the wildebeest - in had split up a particularly large number of successor species. Vrba, on the other hand, found that many wildebeest species were already extinct one million years after their first appearance, while fossil relatives of the Impala , for example, existed for four million years and only a few successor species emerged from them during this time. Together with a colleague, Vrba was also able to demonstrate that among the recent antelopes living in the Kruger National Park , the evolutionarily less successful impalas were much more common than the wildebeest of the various species. At the same time, she noticed that wildebeest specialize in the grasses in dry, open savannahs , while impalas inhabit both savannahs and wooded areas. From this she deduced that food specialists react more sensitively to climate changes in their environment than generalists and can therefore on the one hand react more quickly in terms of species change, but on the other hand are also exposed to a higher risk of extinction . Her data and reflections, published in 1980 in the South African Journal of Science, earned the researcher, who had previously not been recognized internationally, invitations to lectures at numerous renowned universities, including Harvard , Oxford and Cambridge .

Since Elisabeth Vrba now also headed the paleoanthropological collection of the Transvaal Museum and excavations in Kromdraai (where Robert Broom discovered the first fossil of Paranthropus robustus in 1938 ), she noticed parallels in the history of the development of antelopes and hominini : at the same time as around 5 million and 2 million years ago changed 2.5 rapidly bis species composition of antelope again, there were significant changes in the species composition in the apes . At first the lines of development of the chimpanzees and the hominini separated; 2.5 million years ago there was a transition from the "graceful" australopithecines to the "robust" australopithecines of the genus Paranthropus and, parallel to this, the transition from the "delicate" australopithecines to the genus Homo . Vrba attributed these changes in terms of adaptive radiation to climatic changes in Africa; She derived this from the analysis of fossil antelope teeth, the nature of which previously indicated a stay in moist forest areas (with soft leaves for food) and then in dry grassland (with less soft food). Paleoclimatological analyzes later confirmed that the closure of the land bridge between North and South America led to a diversion of ocean currents and about 2.5 million years ago to a cooling in Africa (cf. Cenozoic Ice Age ). At that time, Africa became drier and the rainforest areas decreased.

Their interpretation of the causes of the species change became known in the English-speaking world under the designation "turn-over pulse" hypothesis (for example: hypothesis about the causes that give the impetus for change ). In 1992 she linked this hypothesis with other ecological evolution factors to create a habitat theory of macroevolution . This complements the competitive paradigm (“ Survival of the Fittest ”), according to which individual species are gradually being displaced by other species and eventually become extinct. According to the habitat theory, it is above all dramatic environmental changes that trigger both rapid adaptation - and thus the rapid emergence of new species - and the rapid disappearance of existing species.

Fonts (selection)

  • Role of Environmental Stimuli in Hominid Origins. In: W. Henke, H. Rothe, I. Tattersall (Eds.): Handbook of Palaeoanthropology, Vol. 3: Phylogeny of Hominines. Springer-Verlag, New York 2006, pp. 1-41
  • with David DeGusta: Do species populations really start small? New perspectives from the Late Neogene fossil record of African mammals. In: Phil. Trans. R. Soc. Lond. B. Volume 359, 2004, pp. 285-293
  • Climate, heterochrony, and human evolution. In: Journal of Anthropological Research. Vol. 52, 1996, pp. 1-28
  • with GH Denton, TC Partridge, LH Burckle (eds.): Paleoclimate and Evolution with emphasis on Human Origins. Yale University Press, New Haven, Connecticut, 1995
  • Mammals as a key to evolutionary theory. Plenary Keynote Address, 70th Congress of American Society of Mammalogists, June 1990, Frostburg, Maryland. In: Journal of Mammalogy . Volume 73, No. 1, 1992, pp. 1-28
  • Environment and evolution: alternative causes of the temporal distribution of evolutionary events. In: South African Journal of Science. Volume 81, No. 5, 1985, pp. 229-236

literature

  • Ulf von Rauchhaupt: On you and you with the wildebeest. In: Frankfurter Allgemeine Sonntagszeitung. November 22, 2009, p. 61.

Web links

Commons : Elisabeth Vrba  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Article Vrba, Elisabeth. In: Elizabeth H. Oakes: Encyclopedia of World Scientists. Infobase Publishing, 2007, p. 744 ( digitized version )
  2. ^ Elisabeth S. Vrba: Evolution, species and fossils: how does live evolve? In: South African Journal of Science . Volume 76, No. 2, 1980, pp. 61-84
  3. ^ Elisabeth S. Vrba: The Pulse That Produced Us. In: Natural History. No. 5/1993, pp. 47-51; Full text
  4. ↑ Stephen Jay Gould , Elisabeth S. Vrba: Exaptation - a missing term in the science of form. In: Paleobiology. Volume 8, No. 1, 1982, pp. 4-15
personal data
SURNAME Vrba, Elisabeth
ALTERNATIVE NAMES Vrba, Elisabet S.
BRIEF DESCRIPTION South African-American paleontologist
DATE OF BIRTH May 27, 1942
PLACE OF BIRTH Hamburg