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Manx Shearwater
The Manx shearwater (''Puffinus puffinus'') is a medium-sized shearwater in the seabird family Procellariidae. The scientific name of this species records a name shift: Manx shearwaters were called Manks puffins in the 17th century. Puffin is an Anglo-Norman word (Middle English ''pophyn'') for the cured carcasses of nestling shearwaters. The Atlantic puffin acquired the name much later, possibly because of its similar nesting habits. Taxonomy The shearwaters form part of the family Procellariidae, a widespread group containing nearly 100 species of medium to large seabirds. They have long, narrow wings and the characteristic “tube nose”. Although it was considered a monotypic species, recently an endemic subspecies for the Canary Islands has been proposed ''P. puffinus canariensis''. The large genus ''Puffinus'' includes several species formerly considered to be subspecies of the Manx shearwater, including the yelkouan shearwater, Balearic shearwater, Hutton's shearw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skomer Island
Skomer () or Skomer Island is an island off the coast of Pembrokeshire, in the community of Marloes and St Brides in west Wales. It is well known for its wildlife: around half the world's population of Manx shearwaters nest on the island, the Atlantic puffin colony is the largest in southern Britain, and the Skomer vole (a subspecies of the bank vole) is unique to the island. Skomer is a national nature reserve, a Site of Special Scientific Interest and a Special Protection Area. It is surrounded by a marine nature reserve and is managed by the Wildlife Trust of South and West Wales. Skomer is known for its archaeological interest: stone circles, standing stone and remains of prehistoric houses. Much of the island has been designated an ancient monument. Description The island has an area of . Its highest point is above sea level at Gorse Hill, while the majority of the island sits at around above sea level. Skomer is intersected by a series of slopes and ridges g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lava Shearwater
The lava shearwater (''Puffinus olsoni''), or Olson's shearwater, was a species of shearwater that bred on Lanzarote and Fuerteventura in the Canary Islands. It is known from fossil remains, and was only described in 1990. It was intermediate in size between the Manx shearwater and the little shearwater. The remains of the species are particularly common in lava fields. The species is thought to have survived the arrival of the first settlers in the Canary Islands, and become extinct after the arrival of European settlers in the 15th century. It is suspected that the species became extinct due to hunting pressures and possibly the arrival of introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ... such as rats. References *J. C. Rando, J. A. Alcover (2008) "Evide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. The cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its focus is fixed. Accommodation (the refocusing of light to better view near objects) is accomplished by changing the geometry of the lens. Medical terms related to the cornea often start with the prefix "'' kerat-''" from the Greek word κέρας, ''horn''. Structure The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the healthy cornea does not have or need blood ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (anatomy)
The lens, or crystalline lens, is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as '' accommodation'' (see also below). Accommodation is similar to the focusing of a photographic camera via movement of its lenses. The lens is flatter on its anterior side than on its posterior side. In humans, the refractive power of the lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power. Structure The lens is part of the anterior segment of the human eye. In front of the lens is the iris, which regulates the amount of light entering into the eye. The lens is suspended in place by the suspensory ligament of the lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinal Ganglion Cell
A retinal ganglion cell (RGC) is a type of neuron located near the inner surface (the ganglion cell layer) of the retina of the eye. It receives visual information from photoreceptors via two intermediate neuron types: bipolar cells and retina amacrine cells. Retina amacrine cells, particularly narrow field cells, are important for creating functional subunits within the ganglion cell layer and making it so that ganglion cells can observe a small dot moving a small distance. Retinal ganglion cells collectively transmit image-forming and non-image forming visual information from the retina in the form of action potential to several regions in the thalamus, hypothalamus, and mesencephalon, or midbrain. Retinal ganglion cells vary significantly in terms of their size, connections, and responses to visual stimulation but they all share the defining property of having a long axon that extends into the brain. These axons form the optic nerve, optic chiasm, and optic tract. A s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by synapses and is supported by an outer layer of pigmented epithelial cells. The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rods and cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible for the perception of colour through the use of a range of opsins, as well as high-acuity vision used fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fovea Centralis
The fovea centralis is a small, central pit composed of closely packed cones in the eye. It is located in the center of the macula lutea of the retina. The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading and driving. The fovea is surrounded by the ''parafovea'' belt and the ''perifovea'' outer region. The parafovea is the intermediate belt, where the ganglion cell layer is composed of more than five layers of cells, as well as the highest density of cones; the perifovea is the outermost region where the ganglion cell layer contains two to four layers of cells, and is where visual acuity is below the optimum. The perifovea contains an even more diminished density of cones, having 12 per 100 micrometres versus 50 per 100 micrometres in the most central fovea. That, in turn, is surrounded by a larger peripheral area, which delivers highly comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Vision
Vision is the most important sense for birds, since good eyesight is essential for safe flight. Birds have a number of adaptations which give visual acuity superior to that of other vertebrate groups; a pigeon has been described as "two eyes with wings".Güntürkün, Onur, "Structure and functions of the eye" in Sturkie (1998) 1–18 Birds are theropod dinosaurs,"Avian Visual Cognition", Edited and Published by Dr. Robert G. Cook, Dept. of Psychology, Tufts University. In cooperation with Comparative Cognition Press (September, 2001), http://www.pigeon.psy.tufts.edu/avc/husband/avc3dino.htm and the avian eye resembles that of other reptiles, with ciliary muscles that can change the shape of the lens rapidly and to a greater extent than in the mammals. Birds have the largest eyes relative to their size in the animal kingdom, and movement is consequently limited within the eye's bony socket. In addition to the two eyelids usually found in vertebrates, bird's eyes are protected by a t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puffinus Puffinus -Iceland -flying-6
''Puffinus'' is a genus of seabirds in the order Procellariiformes that contains about 20 small to medium-sized shearwaters. Two other shearwater genera are named: ''Calonectris'', which comprises three or four large shearwaters, and ''Ardenna'' with another seven species (formerly often included within ''Puffinus''). The taxonomy of this group is the cause of much debate, and the number of recognised species varies with the source. The species in this group are long-winged birds, dark brown or black above, and white to dark brown below. They are pelagic outside the breeding season. They are most common in temperate and cold waters. These tubenose birds fly with stiff wings, and use a shearing flight technique to move across wave fronts with the minimum of active flight. Some small species, such as the Manx shearwater, are cruciform in flight, with their long wings held directly out from their bodies. Many are long-distance migrants, perhaps most spectacularly the sooty and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isle Of Man
) , anthem = "O Land of Our Birth" , image = Isle of Man by Sentinel-2.jpg , image_map = Europe-Isle_of_Man.svg , mapsize = , map_alt = Location of the Isle of Man in Europe , map_caption = Location of the Isle of Man (green) in Europe (dark grey) , subdivision_type = Sovereign state , subdivision_name = United Kingdom , established_title = Norse control , established_date = 9th century , established_title2 = Scottish control , established_date2 = 2 July 1266 , established_title3 = English control , established_date3 = 1399 , established_title4 = Revested into British Crown , established_date4 = 10 May 1765 , official_languages = , capital = Douglas , coordinates = , demonym = Manx; Manxman (plural, Manxmen); Manxwoman (plural, Manxwomen) , ethnic_groups = , ethnic_groups_year = 2021 , ethnic_groups_ref = Official census statistics provided by Statistics Isle of Man, Isle of Man Government: * * , religion = , religion_year = 2021 , relig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morten Thrane Brünnich
Morten Thrane Brünnich (30 September 1737 – 19 September 1827) was a Danish zoologist and mineralogist. Biography Brünnich was born in Copenhagen, the son of a portrait painter. He studied oriental languages and theology, but soon became interested in natural history. He contributed his observations of insects to Erik Pontoppidan's ''Danske Atlas'' (1763–81). After being put in charge of the natural history collection of Christian Fleischer he became interested in ornithology, and in 1764 he published ''Ornithologia Borealis'', which included the details of many Scandinavian birds, some described for the first time. The publication of ''Ornithologia Borealis'' was aided by his insight in the collection. Brünnich corresponded with many foreign naturalists including Linnaeus, Peter Simon Pallas and Thomas Pennant. He published his ''Entomologia'' in 1764. He then embarked on a long tour of Europe, spending time studying the fish of the Mediterranean Sea and publishin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
