Ernst Mayr: biography of this evolutionary biologist

Ernst Mayr was a great systematic naturalist and ornithologist, known for having contributed to the synthetic theory of evolution and having given a definition of what species are that adapts to the idea of ​​hybridization fertile.

He was a great connoisseur of the work of Charles Darwin and Theodosius Dobzhansky, which allowed him to give evolutionary theory a genetic perspective.

Mayr fought for the recognition of biology as an autonomous science, independent from the rest of the sciences. evidenced by his extensive research career that lasted for 80 years and resulted in numerous books and articles. Here we will see a summary of his life through a biography of Ernst Mayr.

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Brief biography of Ernst Mayr

Ernst Walter Mayr was born on July 5, 1904 in Kempten, Bavaria, Germany., being the second child of the marriage between doctor Otto Mayr and Helene Pusinelli. In his family there was always a great interest in nature and Dr. Mayr used to take his children to the fields to observe nature, something that had a positive impact on the young Ernst Mayr.

Following the family tradition He studied Medicine at the University of Greifswald and, after graduating in 1925, he went to Berlin to pursue a doctorate in Ornithology., a title he obtained in 1926. In the German capital he would also have the opportunity to study Systematic Biology.

His fondness for ornithology had already taken root in him for a long time and, in fact, he even published his first studies on birds in 1923, when he was still studying medicine at Greifswald. The long excursions through the countryside together with his father had helped him avidly observe all kinds of birds. characteristic of the German landscape, taking an interest in its behaviour, ecological relations and the environment in which it they lived.

After completing his training on German soil Ernst Mayr he had the opportunity to spend two years traveling around the Pacific islands, especially New Guinea and the Solomon Islands. It was a scientific expedition, in which he was researching and relating to endemic species of birds of Oceania, with the intention of finding and establishing genetic laws and evolutionary.

Thanks to his observations during the Ernst Mayr expedition, whose journey resembled that of Charles Darwin aboard the Beagle, he was fully convinced of the correctness of the naturalist's evolutionary theory English. However, despite his conviction with the Darwinian postulates, he had doubts as to how it was possible that individuals of the same species, at some point in its evolutionary history, cease to be part of it and give rise to two or more new species and differentiated.

He later went to the United States to work at the Museum of Natural History in New York., where he did research on bird taxonomy from 1931 to 1935. A little later, in 1937, he along with other scientists gave support to the theory of the "modern evolutionary synthesis", which had already been outlined in the book "Genetics and the origin of of the Species” by the Russian-American geneticist Theodosius Dobzhansky, a book that was crucial in spreading evolutionary postulates within the scientific community international.

From 1953 to 1975 he taught Comparative Zoology at Harvard University. In 1961 he became the director of the Harvard Museum of Comparative Zoology. Shortly before entering that institution as a teacher, Mayr he had proposed a new classification for fossils, including those of hominids that had been documented up to that time. This alternative proposal ended up having wide acceptance within the paleontology community.

His wife was Margarete Mayr, who died in 1990, with whom he had two daughters. Ernst Walter Mayer died on February 3, 2005 in Bedford, Massachusetts, United States, after a brief period of age-related illness. At the time of his death he was 100 years old, half a year shy of turning 101 and having known five grandchildren and ten great-grandchildren.

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The biological concept of species

Thanks to his detailed and systematic studies on the birds of New Guinea, Melanesia and Polynesia, Ernst Mayr managed to describe 24 species that had never been documented before, plus 400 subspecies of birds. Thanks to what was observed on these islands and knowing the work of Dobzhansky and Darwin, Mayr developed his own theory of the origin of species, taking many postulates from those evolutionists.

To understand how species arise we must first understand what Mayr's originally proposed definition of species was. For him, a species is a natural group or groups of individuals, which may be in contact or not, which, in case of interbreeding their individuals, they result in fertile offspring in the vast majority of cases. cases.

For example, a German Shepherd and a Chihuahua are the same species because, by crossing them, we have fertile mixed-breed dogs. On the other hand, a mule, a cross between a mare and a donkey, is sterile, demonstrating that the horse and the donkey are different species.

To Ernst Mayr he is credited with the idea of ​​allopatric speciation, which has become the most accepted mechanism to understand the emergence of a new species. According to this idea, species arise when two or more groups of individuals of the same species, although still equal, are isolated from each other because of natural barriers, such as mountains, a river, being on different islands or any geographic impediment that prevents the two populations from establishing contact reproductive.

As the generations go by, combined with the appearance of mutations in both groups of individuals and, Also, the progressive adaptation to their environments, these reproductively isolated groups are increasingly different. As more time passes, these two groups of individuals constitute two genetic lineages so different that there comes a time when they interbreed. two individuals, one from each population, will either have sterile offspring or, directly, will not have a child, meaning that they are already two species different.

Although this idea of ​​how new species arise is the most accepted in the scientific community, it has certain limitations. The first thing is that this definition of species is not applicable to fossil organisms found up to that time nor was it applicable to organisms that reproduce asexually. In addition, there are many cases of hybridization of two different species whose offspring have turned out to be fertile, as would be the case of the coydog, a hybrid of dog and coyote.

Mayr admitted that his original species definition did not fit asexual organisms very well, but the idea of ​​fertile hybridization led him to revamp his species concept. He paid special attention to his original ideas of isolation mechanisms in terms of their function as biological properties of individuals that prevent interbreeding of populations. These mechanisms do not always prevent occasional interbreeding, but they would prevent complete fusion of two species.

To understand it better, let's imagine that two groups of individuals originally from the same species have evolved enough to be considered two distinct species, each with its own niche ecological. It may be the case that the geographical barrier that separated them disappears, allowing both groups to establish accidental reproductive contact. The isolation mechanisms of each of the two groups would make the probability that two individuals, one of each species, have fertile offspring almost remote, although not impossible.

Through these isolation mechanisms, even though both groups had contacts again and, even, interspecific copulation was frequent, there would be very few cases of fertile hybrids and there would even come a time when, no matter how much they copulated, there would be no way to fertilize the females of the other species.

Given this situation, there would be two possible scenarios: one would be that both species, which would have different food sources, share the same habitat, while the other, in the event of feeding on the same, would mean that one of the two species would end up displacing or extincting the other species. other.

Publications and commemorations

The high point in Ernst Mayr's life was the period between 1963 and 1970, when he was working in Comparative Zoology at Harvard University. In this years he published several books on species, evolution and population genetics.

Among his most important books we find "Systematics and the Origin of Species" (1942), in which he combines genetic Darwinism, clarifying what was what the English naturalist could not demonstrate due to the technological limitations of his time, mainly the process of how the species.

Other of his most important works are:

• "Animal Species and Evolution" (1963)
• "Principles of Systematic Zoology" (1980)
• "Growth of Biological Thought" (1982)
• "This Is Biology" (1997)

Throughout his entire career he came to publish some 750 scientific articles and received several honorary degrees from prestigious universities such as Oxford, Cambridge, Harvard, The Sorbonne, Uppsala, and Berlin.

Bibliographic references:

• Mayr, Ernst (1942). Systematics and the Origin of Species, from the Viewpoint of a Zoologist. Cambridge: Harvard University Press. ISBN 978-0-674-86250-0.
• Mayr, Ernst (1945). Birds of the Southwest Pacific: A Field Guide to the Birds of the Area Between Samoa, New Caledonia, and Micronesia. New York: Macmillan.
• Mayr, Ernst (1963). Animal Species and Evolution. Cambridge: Belknap Press of Harvard University Press. ISBN 978-0-674-03750-2.
• Mayr, Ernst (1970). Populations, Species, and Evolution. Cambridge: Belknap Press of Harvard University Press. ISBN 978-0-674-69013-4.
• Mayr, Ernst (1976). Evolution and the Diversity of Life. Cambridge: Belknap Press of Harvard University Press. ISBN 978-0-674-27105-0.
• Mayr, Ernst. & William B. Provine, (eds) (1980). The Evolutionary Synthesis: Perspectives on the Unification of Biology, ISBN 0-674-27225-0
• Mayr, Ernst (1982). The Growth of Biological Thought. Cambridge (Mass.): Belknap P. of Harvard U.P. ISBN 978-0-674-36446-2.