The Environmental Science Program builds upon a substantial background in science and mathematics obtained through required lower-division prerequisite courses. The knowledge of how natural systems work is applied to solving problems largely created by human activities. Often these problems are represented by disturbances in the functioning of natural systems. Humans are altering their own life-support systems-the air, water, and soil. Scales of disturbances range from the molecular and cellular to individuals, populations, ecosystems, and regional and global levels.