#Sea water splash png free
In this gallery "Fish" we have 117 free PNG images with transparent background.
#Sea water splash png download
Here you can download free PNG images on theme: Fish PNG image, free download Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies. They are also caught by recreational fishers, kept as pets, raised by fishkeepers, and exhibited in public aquaria. Commercial and subsistence fishers hunt fish in wild fisheries (see fishing) or farm them in ponds or in cages in the ocean (see aquaculture). With 33,100 described species, fish exhibit greater species diversity than any other group of vertebrates.įish are an important resource for humans worldwide, especially as food. They can be found in nearly all aquatic environments, from high mountain streams (e.g., char and gudgeon) to the abyssal and even hadal depths of the deepest oceans (e.g., gulpers and anglerfish). Fish are abundant in most bodies of water. 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. 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. Many fish of the Paleozoic developed external armor that protected them from predators. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. The traditional term pisces (also ichthyes) is considered a typological, but not a phylogenetic classification. Because in this manner the term " fish" is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. However, traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods (i.e., the amphibians, reptiles, birds and mammals which all descended from within the same ancestry). Tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. They form a sister group to the tunicates, together forming the olfactores. A fish is any member of a group of animals that consist of all gill-bearing aquatic craniate animals that lack limbs with digits.
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