Marine biology is the branch of science that involves the study of marine organisms, their behaviors, and their interactions with the environment. Because the marine ecosystem is very large there are many sub-fields of marine biology and because of the wide scope of the field there are many specializations that can be preferred by the researchers. The important specializations of Marine Biology includes Marine biotechnology, Aquaculture, Marine molecular biology, Marine ecology, Marine environmental biology, Aquatic toxicology, Marine microbiology and the study of marine mammals like their bioacoustics and vocalization (the study of marine mammal sounds), and population dynamics (studying marine mammalian behaviors and responses to environmental conditions as they impact population). The Specialization may also be done on the basis of particular species, organism or ecosystem. Most involves specializing on particular study of animal groups such as phycology, invertebrate zoology and ichthyology. Hence, Marine biology can be considered a broad field. Marine Biology is closely related to Oceanography. To understand marine organisms and their behaviors completely, one must have a basic understanding of other aspects or disciplines of Oceanography, such as chemical oceanography, physical oceanography, and geological oceanography. Fisheries science, environmental science and conservation science can be considered as offshoots of Marine Biology. The subject- Marine Biology is important since marine life significantly contributes and affects us and our Earth. Marine life is a vast resource of food, medicine and a variety of raw materials. It helps to support recreation and tourism all over the world. Moreover, marine organisms contribute significantly to the oxygen cycle and play an important role in regulation of Earth’s climate.