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Aquatic animals generally conduct gas exchange in water by extracting dissolved oxygen via specialised respiratory organs called gills, through the skin or across enteral mucosae, although some are evolved from terrestrial ancestors that re-adapted to aquatic environments (e.g. marine reptiles and marine mammals), in which case they actually ...
Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million in total. Animals range in size from 8.5 millionths of a metre to 33.6 metres (110 ft) long and have complex interactions with each other and their environments, forming intricate food webs.
Pelagic marine systems regulate the global climate, contribute to the water cycle, maintain biodiversity, provide food and energy resources, and create opportunities for recreation and tourism. [48] Economically, marine systems support billions of dollars worth of capture fisheries, aquaculture, offshore oil and gas, and trade and shipping.
Aquatic animals (8 C, 15 P) B. Brackish water organisms (1 C, ... Pages in category "Aquatic organisms" The following 6 pages are in this category, out of 6 total.
An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. [1]
Marine mammals are aquatic mammals that rely on the ocean for their existence. They include animals such as sea lions, whales, dugongs, sea otters and polar bears. Like other aquatic mammals, they do not represent a biological grouping. [26] The humpback whale is a fully aquatic marine mammal.
Many animals feed on kelp and kelp provides sheltered habitats for yet others. Sea grass is the only type of flowering plant that grows in British seas, but it nonetheless forms vast beds. Invertebrates in coastal Britain are very diverse and include brittle stars , hermit crabs , mussels , prawns , sponges , sea anemones and sea squirts .
Marine biology studies species that live in marine habitats. Most of the Earth's surface is covered by ocean, which is the home to marine life. Oceans average nearly four kilometers in-depth and are fringed with coastlines that run for about 360,000 kilometres. [4] [5] Marine biology can be contrasted with biological oceanography.