This research will address the question: Why and how do individuals with the same genetic constitution sometimes produce strikingly different forms? The problem will be investigated by using spadefoot toad tadpoles as a model system. Spadefoot toad tadpoles are unusual in that any given individual can develop into two different forms. Following ingestion of fairy shrimp or other tadpoles, typical omnivorous tadpoles may alter their behavior and development to assume a distinctive carnivorous form, which then metamorphoses into an adult toad more quickly. The specific goals of the research would be to: (1) determine what developmental and physiological processes cause these two forms to be produced, (2) determine if there is a genetic basis to the variation, and (3) identify the environmental factors that maintain the two forms within the same population. Spadefoot tadpoles are excellent model animals for studying and teaching others about developmental biology and ecology. The planned research is important in that it will address how the environment interacts with an organism's genes during development to produce alternative forms. Such research will provide critical insight into developmental processes and the role of development in enabling organisms to adapt to changing environments.
