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Zoogeography and Evolution
John C. Briggs
Vol. 20, No. 3 (Sep., 1966), pp. 282-289
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2406630
Page Count: 8
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1. There is good evidence from world-wide distributional patterns of both terrestrial and marine animals that a correlation exists between evolution and distribution. These show that advanced, dominant species apparently come from certain favorable centers and that the more primitive forms are likely to be the most remote in terms of geographic distance or of inaccessibility to invasion. 2. Since it is known that speciation is very active in areas peripheral to the major dispersal centers, we should consider that two kinds of evolution may be taking place-one that may be successful in terms of a phyletic future and one that is unsuccessful. 3. It is known that unsuccessful evolution is the rule in situations that have been described as evolutionary traps or blind alleys. However, if the evidence from widespread zoogeographic patterns and observations made on relatively isolated populations is accepted, unsuccessful evolution may also be characteristic of almost all types of peripheral areas. 4. Many dominant marine shore species that are produced in the Indo-West Pacific evolutionary center are capable of migrating and establishing themselves in the other tropical regions. But, species that arise in the peripheral regions are probably unable to colonize any part of the Indo-West Pacific. 5. The rate at which speciation takes place in the evolutionary centers is apparently very slow. In contrast, the rate in evolutionary traps or other isolated peripheral locations can be exceedingly rapid. 6. The concept of relative ecological stability seems to be important. The extensive tropical regions of the world are the major centers for successful evolution and, at the same time, they contain the most species and therefore have the most stable ecosystems. The stable ecosystem with its high level of competition apparently provides the proper environment for the production of dominant species.
Evolution © 1966 Society for the Study of Evolution