There are more than 14,000 types of marine fishes, from the huge whale shark to the small pygmy goby (MAY, R.M., 1988). This order of vertebrate creatures comprises the cartilaginous fishes such as sharks, rays and chimaeras, jawless fishes, as well as the bony fishes.
Invertebrates, species without a backbone, include the biggest group of animals on the planet, forming about a billion of species. Aquatic invertebrates alone include thousands of animals, and are an extensively varied group of species, from spiny sea urchins to sessile sponges.

In Marine Biology, as I learn about aquatic species and water pressure, and come to a more comprehensive understanding of these crucial motifs, so assuming a few of the questions that I raise:
What forms of aquatic environments remain to be discovered? What kind of aquatic animals are yet to be discovered and how much of the biodiversity is still unidentified? How have aquatic creatures been formed through interactions with their physical environments & biological communities? What we do not recognize about Seafloor? At last, what are the effects of scientific research done on the sea world, and how will such effects transform aquatic life and aquatic environments? The human being’s future will be drastically affected by such changes, and will depend upon the factor on how intelligently we use that information (UNESCO, 1988).