Introduction. What is ecology ? Natural history : life on land. Life in water. Individuals : temperature relations. Water relations. Energy and nutrient relations. Populations : distributing and abundance. Population dynamics. Population growth. Interactions : competition. Exploitation : predation, herbivory, parasitism and disease. Mutualism. Communities and ecosystems : species abundance and diversity. Food webs. Primary production and energy flow. Nutrient cycling and retention. Succession and stability. Large scale ecology. Landscape ecology. Geographical ecology. Global ecology.