Dispersal versus vicariance
Sanmartín, Isabel Department of Biodiversity and Conservation, Real Jardin Botanico, Madrid, Spain.
- Centers of origin and the vicariance paradigm
- Molecular phylogenetics and the resurrection of dispersal
- Dispersal and vicariance: new integrative approaches
- Links to Primary Literature
- Additional Readings
Scientists have long been fascinated by the existence of disjunct (geographically discontinuous) distribution patterns such as the one shown in Fig. 1a, in which the members of a group of organisms are distributed across the southern continents, now separated by thousands of miles of ocean. How did this type of widely scattered distribution originate? Traditionally, two alternative explanations have been proposed: dispersal across a preexisting geographical barrier (for example, a mountain chain); or vicariance, the fragmentation of a widespread ancestral distribution by the appearance of a new barrier. Both biogeographical processes result in the isolation of a population by a geographic barrier, followed by differentiation of a new taxon by allopatric (geographically separated) speciation. However, the barrier in the dispersal explanation is older than the geographic disjunction, whereas the appearance of the geographic barrier is responsible for the geographic disjunction in the vicariance explanation, so it cannot be older than the resulting speciation event. Although vicariance and dispersal are not mutually exclusive processes—the opening of the Gibraltar Strait between North Africa and Iberia in the Pliocene was simultaneously a vicariance event for terrestrial organisms and a dispersal event for marine organisms—the history of biogeography as an evolutionary science could be considered until recently as the history of a debate between dispersal and vicariance explanations.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 42 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information