Research Training Program

Emily Armgardt
Seattle University
Seattle, Washington

Ellen Strong, Ph.D.
Supervising Scientist
Department of Invertebrate Zoology

"This experience was unforgettable. Not only the privilege to research at the museum, but also to explore the different departments within the museum really is a dream come true."

Using Freshwater Snail Shells to Understand Evolution

Lake Tanganyika, the second largest lake in Africa, is part of a chain of ancient lakes in the Western Rift Valley of southeast Africa. These lakes formed millions of years ago and provide scientists with unique opportunities to study evolution and species formation within a controlled environment. Lake Tanganyika holds many endemic species, those found exclusively in the lake and nowhere else. Traditionally, the fish of Lake Tanganyika were used to study evolution; but scientists have now begun to examine other animals living in the lake to seek clues to evolution. Gastropod snails are a good organism to study for many reasons and especially those found in Lake Tanganyika because they inhabit almost the entire lake and span all the different habitats present. Snails provide a unique opportunity when studying evolution because their shells provide a record of not only the development of the individual, but also the environmental stresses that occur during the snail's life. Using a scanning electron microscope (SEM), the shells of the snails can be examined at extremely high magnification to reveal the microstructure, or layers that make up the shell. By looking at these layers scientists can see the differences in individuals as well as differences between species. These differences can then be charted and used to determine if similarities and differences in shell microstructure between species in the lake is a reflection of evolution, of the function of the shell, or a combination of both. Scientists can then begin to better understand the relationship between evolution and the functional limitations of not only snail shells but other aminals as well.

This research was supported by a the Alice Eve Kennington Endowment.

Letter of gratitude