Assertion: bear's population | /r/CapableOf | become isolated
Facets:
value: in northern latitudes
type: LOCATION
value: by glaciation
type: CAUSE
Source sentences:
text: The polar bear is the most recently evolved species and descended from a population of brown bears that became isolated in northern latitudes by glaciation 400,000 years ago.
text: Polar bears are thought to have diverged from a population of brown bears that became isolated during a period of glaciation in the Pleistocene from the eastern part of Siberia (from Kamchatka and the Kolym Peninsula).