Evolution & Geography

There is evidence that the formation of the Isthmus of Panama created a geographic barrier down the middle of a population of snapping shrimp.

Now, 300 million years later, the shrimp on either side have diverged into distinct species.

Scientists believe the formation of the Isthmus of Panama is one of the most important geologic events to happen on Earth in the last 60 million years.

Even though it is only a tiny sliver of land, relative to the sizes of continents, the Isthmus of Panama had an enormous impact on Earth's climate and its environment.

American Redstarts

Long-distance dispersal is a fundamental process in ecology and evolution but the factors that influence these movements remain poorly understood in most species.

Results provide evidence that both natal dispersal and breeding dispersal were influenced by the timing of breeding-season phenology, with both age classes more likely to disperse north in years when the onset of breeding-season phenology occurs earlier than normal.

•VICARIANCE - separation of population by new barriers.

•DISPERSAL - Taxa migration from one region to another.

VICARIANCE & DISPERSAL

•CLADOGENESIS - formation of new group of organisms or higher taxon by evolutionary divergence from an ancestral form.

Archaic H. sapiens

•K is actually the traditional abbreviation for the Cretaceous period•T is the abbreviation for the Tertiary period.

So the K-T boundary is the point in between the Cretaceous and Tertiary periods.

Geologists have dated this period to about 65.5 million years ago.

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