For example, reproductive isolation is weak ... Science 326, 1704–1707 (2009). Via, S. Sympatric speciation in animals: The ugly duckling grows up. Trends in Ecology & Evolution 16, 381 ...

Chimpanzees, for example, show population-specific signatures ... which is a necessary precursor to speciation. Future studies that incorporate ecological, behavioral, and genetic data hold ...

The biological equivalent is "allopatric speciation," an evolutionary process ... geographical change that can be slow or rapid. An example of vicariance is the separation of marine creatures ...