Marine biology is the study of life in the oceans and other saltwater environments, including estuaries and coastal regions. As a course, it explores the diversity of marine organisms, their behaviors, interactions, and adaptations to aquatic habitats. Students learn about various ecosystems, such as coral reefs, deep-sea trenches, and intertidal zones, examining the physical and chemical factors that influence marine life. The course often integrates principles of biology, ecology, oceanography, and environmental science to provide a comprehensive understanding of marine ecosystems. 

Topics covered may include marine biodiversity, conservation, fisheries science, and the impact of human activities on oceanic life. Students also study the physiological and anatomical adaptations of marine organisms, from microscopic plankton to large marine mammals. Research methods, fieldwork, and laboratory techniques are often essential components, giving students hands-on experience in collecting and analyzing marine samples. 

Career opportunities for those studying marine biology range from research and conservation to working in aquariums, marine policy, and environmental management. The course encourages a multidisciplinary approach, combining scientific inquiry with practical applications to address issues like climate change, pollution, and habitat destruction in marine environments.