In most biological nomenclature, a scale (Greek lepid, Latin squama) is a small rigid plate that grows out of an animal's skin to provide protection. The Buff Striped Keelback ( Amphiesma stolatum) is a common Species of non-venomous Colubrid Snake found across Asia. Foundations of modern biology There are five unifying principles Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. The skin is the outer covering of living tissue of an animal (or plant In lepidopteran (butterfly and moth) species, scales are plates on the surface of the insect wing, and provide coloration. Lepidoptera is an order of Insect that includes Moths and butterflies. A butterfly is an Insect of the order Lepidoptera. Like all Lepidoptera butterflies are notable for their unusual life cycle with a A moth is an Insect closely related to the Butterfly, both being of the order Lepidoptera. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Scales are quite common and have evolved multiple times with varying structure and function. Convergent evolution describes the acquisition of the same biological trait in unrelated lineages
Scales are generally classified as part of an organism's integumentary system. The Integumentary System is an organ system that protects the body from damage comprising the Skin, Hair, scales, nails, sweat glands and their There are various types of scales according to shape and to class of animal.
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Fish scales
Fish scales are dermally derived, specifically in the mesoderm. Rohu ( Labeo rohita) is a fish of the carp family Cyprinidae, found commonly in rivers and freshwater lakes in and around the South Asia and South-East This fact distinguishes them from reptile scales paleontologically.
Cosmoid scales
True cosmoid scales can only be found on the extinct Crossopterygians. Sarcopterygii (from Greek σαρξ sarx, flesh and πτερυξ pteryx, fin is traditionally the class of lobe-finned Fishes consisting The inner layer of the scale is made of lamellar bone. A lamella is a Gill -shaped structure fine sheets of material held adjacent one another with fluid in-between-(or simply 'welded'-plates On top of this lies a layer of spongy or vascular bone and then a layer of dentinelike material called cosmine. The blood vessels are part of the Circulatory system and function to transport Blood throughout the body Dentin ( BE: dentine) is a calcified tissue of the body and along with enamel, Cementum, and pulp is one of the four The upper surface is keratin. Keratins are a family of fibrous structural proteins; tough and insoluble they form the hard but nonmineralized structures found in Reptiles Birds The coelacanth has modified cosmoid scales that lack cosmine and are thinner than true cosmoid scales. Coelacanth (ˈsiːləkænθ adaptation of Modern Latin Cœlacanthus > cœl-us + acanth-us from Greek κοῖλ-ος + ἄκανθ-α) is the common name for
Ganoid scales
Ganoid scales can be found on gars (family Lepisosteidae) and bichirs and reedfishes (family Polypteridae). In American English the name gar (or garpike) is strictly applied to members of the Lepisosteus, a family including seven living species of fish in two In American English the name gar (or garpike) is strictly applied to members of the Lepisosteus, a family including seven living species of fish in two The bichirs are a family Polypteridae, of archaic-looking ray-finned fishes, the sole family in the order Polypteriformes. The bichirs are a family Polypteridae, of archaic-looking ray-finned fishes, the sole family in the order Polypteriformes. Ganoid scales are similar to cosmoid scales, but a layer of ganoin lies over the cosmine layer and under the enamel. They are diamond-shaped, shiny, and hard.
Placoid scales
Placoid scales are found on cartilaginous fish and sharks. Cartilage is a type of dense Connective tissue. It is composed of specialized cells called chondrocytes that produce a large amount of extracellular matrix Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body These scales, also called denticles, are similar in structure to teeth. Denticles are body surface structures found on some fish and insects
Leptoid scales
Leptoid scales are found on higher order bony fish and come in two forms, ctenoid and cycloid scales.
As they grow, cycloid and ctenoid scales add concentric layers. The scales of bony fishes are laid so as to overlap in a head-to-tail direction, a little like roof tiles, allowing a smoother flow of water over the body and therefore reducing drag. In Fluid dynamics, drag (sometimes called fluid resistance) is the force that resists the movement of a Solid object through a Fluid (a
Cycloid scalesCycloid scales have a smooth outer edge, and are most common on more primitive fish with soft fin rays, such as salmon and carp. Salmon is the common name for several species of Fish of the family Salmonidae. Carp is a common name for various Freshwater Fish of the family Cyprinidae, a very large |
Reptilian scales
Reptile scale types include: cycloid, granular (which appear bumpy), and keeled (which have a center ridge). Reptile skin is covered with scutes or scales which along with other characteristics distinguish reptiles from animals of other classes (except Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers
The scales of all reptiles have an epidermal component (what one sees on the surface), but many lizards have osteoderms underlying the epidermal scale, as do crocodilians and turtles. Snakes, tuataras and many lizards lack osteoderms. The tuatara is a reptile endemic to New Zealand which though it resembles most lizards is actually part of a distinct lineage order Sphenodontia. All reptilian scales have a dermal papilla underlying the epidermal part, and it is there that the osteoderms, if present, would be formed.
Arthropod scales
Butterflies and moths - the order Lepidoptera (Greek "scale-winged") - have membranous wings covered in delicate, powdery scales, which are modified setae. The Heath Fritillary ( Melitaea athalia) is a Butterfly of the Nymphalidae family A butterfly is an Insect of the order Lepidoptera. Like all Lepidoptera butterflies are notable for their unusual life cycle with a A moth is an Insect closely related to the Butterfly, both being of the order Lepidoptera. Lepidoptera is an order of Insect that includes Moths and butterflies. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Seta (plural setae) is a biological term derived from the Latin word for " Bristle " Each scale consists of a series of tiny stacked platelets of organic material, and butterflies tend to have the scales broad and flattened, while moths tend to have the scales narrower and more hair-like. Scales are frequently pigmented, but some types of scales are metallic, or iridescent, without pigments; because the thickness of the platelets is on the same order as the wavelength of visible light the plates lead to structural coloration and iridescence through the physical phenomenon described as thin-film optics. For the drug referred to as "pigment" see Black tar heroin. In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. Iridescence is an Optical phenomenon in which Hue changes with the angle from which a surface is viewed Thin-film optics is the branch of Optics that deals with very thin structured layers of different materials The most common color produced in this fashion is blue, such as in the Morpho butterflies. Blue is a Colour, the Perception of which is evoked by A Morpho butterfly may be one of over 80 species of the Genus Morpho. Other colors can be seen on the Sunset moth. The Madagascan sunset moth, or simply sunset moth, ( Chrysiridia rhipheus) is a day-flying Moth of the Uraniidae family
Bibliography
- Kardong, Kenneth V. (1998). Vertebrates: Comparative Anatomy, Function, Evolution, second edition, USA: McGraw-Hill, 747 pp. The McGraw-Hill Companies Inc, ( is a Publicly traded corporation headquartered in Rockefeller Center in New York City. . ISBN 0-07-115356-X/0-697-28654-1.
References
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