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In fish, the long bony cover for the gill (the operculum) can be used for pushing water. Some fish pump water using the operculum. Without an operculum, other methods, such as ram ventilation, are required. Some species of sharks use this system. When they swim, water flows into the mouth and across the gills.
Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills that are protected under gill covers (operculum) on both sides of the pharynx (throat). Gills are tissues that are like short threads, protein structures called filaments. These filaments have many functions including ...
Fish from multiple groups can live out of the water for extended time periods. Amphibious fish such as the mudskipper can live and move about on land for up to several days, or live in stagnant or otherwise oxygen depleted water. Many such fish can breathe air via a variety of mechanisms. The skin of anguillid eels may absorb oxygen directly.
Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including mollusks, crustaceans, insects, fish, and amphibians. Semiterrestrial marine animals such as crabs and mudskippers have gill chambers in which they store water, enabling them to use the dissolved oxygen when they are on land.
Aquatic animals are important to humans as a source of food (i.e. seafood) and as raw material for fodders (e.g. feeder fish and fish meal), pharmaceuticals (e.g. fish oil, krill oil, cytarabine and bryostatin) and various industrial chemicals (e.g. chitin and bioplastics, formerly also whale oil).
The physiology of underwater diving is the physiological adaptations to diving of air-breathing vertebrates that have returned to the ocean from terrestrial lineages. They are a diverse group that include sea snakes, sea turtles, the marine iguana, saltwater crocodiles, penguins, pinnipeds, cetaceans, sea otters, manatees and dugongs.
Marine life can be roughly grouped into autotrophs and heterotrophs according to their roles within the food web: the former include photosynthetic and the much rarer chemosynthetic organisms (chemoautotrophs) that can convert inorganic molecules into organic compounds using energy from sunlight or exothermic oxidation, such as cyanobacteria ...
Human longevity is affected by a complex number of factors, including lifestyle. Through modifiable lifestyle behaviors, including diet, exercise, and limiting sedentary behavior, you can improve ...