Exploration of how chemical signals are produced, transported, and influence behavior of microbes, plants, and animals. Synthetic approach, with emphasis on applications to cell biology, neurobiology, and ecology. Prerequisite: either a minimum grade of 2.5 in either BIOL 220, BIOL 240, B BIO 220, or T BIOL 140, or a minimum grade of 2.0 in BIOL 350.