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Molecular variation in coastal marine taxa and some implications for speciation in the ocean

Mike N. Dawson
University of California, Los Angeles

Wednesday, February 16, 2000
3:00 p.m.—Pacific Forum

Marine faunas are, compared to terrestrial and freshwater faunas, species poor—a dichotomy usually attributed to the relatively distant dispersal of marine planktonic larvae across largely homogenous oceans that contain few barriers to gene flow. Even philopatric organisms may disperse hundreds of kilometers in episodic events such as rafting. The dearth of barriers to gene flow suggests marine species originate primarily in parapatry or sympatry, but allopatric speciation may be an important process, especially in coastal waters.

I will describe the geographic distribution of genetic variation in several marine taxa occupying coastal habitats in the western and/or northeastern Pacific Ocean. These data variously describe (1) widespread populations with little geographic subdivision, (2) intra-specific phylogenies that result from long-term geographic subdivision, and (3) a species complex in which genetic variation can be greater over a few than over hundreds of kilometers. My discussion of these results will refer to coastal geography and hydrography, Plio-Pleistocene climate change, systematics, ecology, life-history, behavior, introduced species, and marine evolution and speciation.

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 Last updated: December 19, 2000