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The two forms of geographic speciation


The theory of geographic speciation
Ernst Mayr Scientist
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How can… such reproductively isolated species originate? I mean, they couldn't originate on one place because what… what would pull them apart at this place? And that is the theory of geographic speciation, these are… new species originate when two populations get geographically isolated and in this isolation either by… by action of the ocean or by… by a vegetational barrier, let's say a… a desert or a savanna, in the case of forest birds… during this period of isolation there is enough genetic turn over in these populations so that eventually these two populations are so different that they react to each other as if they were two different species.

The late German-American biologist Ernst Mayr (1904-2005) was a leading light in the field of evolutionary biology, gaining a PhD at the age of 21. He was also a tropical explorer and ornithologist who undertook an expedition to New Guinea and collected several thousand bird skins. In 1931 he accepted a curatorial position at the American Museum of Natural History. During his time at the museum, aged 37, he published his seminal work 'Systematics and Origin of the Species' which integrated the theories of Darwin and Mendel and is considered one of his greatest works.

Listeners: Walter J. Bock

Walter J. Bock is Professor of Evolutionary Biology at Columbia University. He received his B.Sc. from Cornell and his M.A. and Ph.D. from Harvard. His research lies in the areas of organismal and evolutionary biology, with a special emphasis on functional and evolutionary morphology of the skeleto-muscular system, specifically the feeding apparatus of birds.

Tags: geographic speciation, birds, species, reproduction, ocean

Duration: 49 seconds

Date story recorded: October 1997

Date story went live: 24 January 2008