PBS
Pbs Learning Media: Allopatric Speciation
These images from the Smithsonian Institution depict Nancy Knowlton's work with snapping shrimp in Panama. Knowlton found that the closing of the isthmus -- dividing the Pacific Ocean from the Caribbean -- resulted in new species of shrimp.
Tom Richey
Slide Share: Energy Flow and Nutrient Cycle
Read 37 slides on energy flow and the nutrient cycle.