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Science 13 September 1996:
Vol. 273. no. 5281, pp. 1496 - 1497
DOI: 10.1126/science.273.5281.1496b
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Special News Report

Virginia Morell

Although increasing numbers of biologists believe that new species can form without being isolated by a geographic barrier, geographic speciation remains a powerful generator of diversity. Sometimes it can take a surprising face, however, as in the Amazon basin. The basin's great rivers have been a major species-maker: By dividing populations in two, they create new groups that follow separate evolutionary paths. But a new study points to another kind of barrier as well: ancient ridges now lying buried and nearly invisible under the cloak of forest.




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Science. ISSN 0036-8075 (print), 1095-9203 (online)