fin
Quick Summary
A fin is an appendage that helps aquatic animals, such as fish, stabilize and steer themselves in the water. Most aquatic vertebrates have a dorsal fin and a pair of anterolateral fins, in addition to their caudal (tail) fin, for balance and control. These fins, along with the skeleton, are crucial for locomotion.12
Fins first appeared during the early evolution of fish. They can be composed of cartilage or bone and are supported by fin rays. Some fish, like ostariophysans, also have an adipose fin, a small fleshy structure located between the dorsal and tail fins. In some cases, fins can also be found on non-living objects like bombs or rockets to aid in stability.2345
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clupeiformDistinguishing characteristicsā¦and sizes of the various fins. If a herring (Clupetta), a pilchard (Sardinops), and a sprat (Sprattus) are held by the leading edge of their dorsal fins, the herringās body orientation is approximately horizontal, because the fin is located at the centre of the back. In contrast, the pilchard hangsā¦
Read Moreā¦and sizes of the various fins. If a herring (Clupetta), a pilchard (Sardinops), and a sprat (Sprattus) are held by the leading edge of their dorsal fins, the herringās body orientation is approximately horizontal, because the fin is located at the centre of the back. In contrast, the pilchard hangsā¦
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crossopterygianForm and functionThe powerful tail fin has three lobes. The posterior end of the notochord extends into the middle lobe, which is by far the smallest. Two pairs of fins, the pectoral and the pelvic, are attached to their respective girdles. The base of each fin is made up ofā¦
Read MoreThe powerful tail fin has three lobes. The posterior end of the notochord extends into the middle lobe, which is by far the smallest. Two pairs of fins, the pectoral and the pelvic, are attached to their respective girdles. The base of each fin is made up ofā¦
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perciformForm and functionā¦their dorsal, anal, and pelvic fins. The dorsal fin is usually divided into two parts, with the first part supported by one or more spiny rays; these rays are believed to have evolved for defense purposes. The pelvic fins are usually present, directly below or a little ahead of theā¦
Read Moreā¦their dorsal, anal, and pelvic fins. The dorsal fin is usually divided into two parts, with the first part supported by one or more spiny rays; these rays are believed to have evolved for defense purposes. The pelvic fins are usually present, directly below or a little ahead of theā¦
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protacanthopterygianExternal characteristicsThe body and fins are streamlined and symmetrical; the body is covered with small smooth (cycloid) scales; the fins are formed from soft supporting rays, without spines. A small, fleshy adipose fin is located between the dorsal fin and the tail. The dorsal fin is located midway alongā¦
Read MoreThe body and fins are streamlined and symmetrical; the body is covered with small smooth (cycloid) scales; the fins are formed from soft supporting rays, without spines. A small, fleshy adipose fin is located between the dorsal fin and the tail. The dorsal fin is located midway alongā¦
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locomotionSoaringā¦surface, its pectoral and pelvic fins, which are analogous to the forelimbs and hind limbs of quadrupeds, are pressed along the side of the body. The greatly enlarged, winglike pectoral fins then spread out as the fish leaves the water. The wind against the fins provides lift to raise theā¦
Read Moreā¦surface, its pectoral and pelvic fins, which are analogous to the forelimbs and hind limbs of quadrupeds, are pressed along the side of the body. The greatly enlarged, winglike pectoral fins then spread out as the fish leaves the water. The wind against the fins provides lift to raise theā¦
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respiratory systemAmphibiansā¦tadpoles use their large tail fins for respiration; the tail fins contain blood vessels and are important respiratory structures because of their large surface area. As amphibian larvae develop, the gills (and in frogs, the tail fin) degenerate, paired lungs develop, and the metamorphosing larvae begin making excursions to theā¦
Read Moreā¦tadpoles use their large tail fins for respiration; the tail fins contain blood vessels and are important respiratory structures because of their large surface area. As amphibian larvae develop, the gills (and in frogs, the tail fin) degenerate, paired lungs develop, and the metamorphosing larvae begin making excursions to theā¦
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