The document provides an overview of environmental sciences by discussing its objectives and topics covered. It defines environmental sciences as an interdisciplinary field that studies ecosystems and the relationship between humans and the environment. The key topics covered include ecosystems, biodiversity, sustainability, environmental impact assessment, and environmental law. Examples of ecosystem types like forests, grasslands, deserts, and aquatic ecosystems are described along with their biotic and abiotic components. The biosphere and its interaction with the lithosphere, hydrosphere, and atmosphere are also summarized.