User:Hook0601
Brand of laundry detergent pods under the Tide brand / From Wikipedia, the free encyclopedia
A fish (pl.: fish or fishes) is an aquatic, gill-bearing animal with a hard skull that lacks limbs with digits. This includes hagfish, lampreys, and both cartilaginous and bony fish. Approximately 95% of living fish species are ray-finned bony fish; around 99% of those are teleosts. As a group, if tetrapods are excluded, fish are paraphyletic and so do not form a taxonomic group.
Fish | |
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Diversity of various fish including sharks, stingrays, bony fish, jawless fish, and coelacanths. | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Olfactores |
Subphylum: | Vertebrata |
Groups included | |
Cladistically included but traditionally excluded taxa | |
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The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods.
Most fish are ectothermic ("cold-blooded"), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature. Fish can acoustically communicate with each other, most often in the context of feeding, aggression or courtship.
Fish are an important resource for humans worldwide, especially as food. Commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean. They are also caught by recreational fishers, kept as pets, raised by fishkeepers, and exhibited in public aquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies.