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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 language, Anglo-Norman word (Middle English ''pophyn'') for the Curing (food preservation), 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 shea ... [...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 (United Kingdom), 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 ... [...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 such as rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...s. References *J. C. Rando, J. A. Alcover (2008) "Eviden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornea
The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea Refraction, 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 (optics), focus is fixed. Accommodation (eye), 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 "''wikt:kerat-, kerat-''" from the Ancient Greek, Greek word κέρας, ''horn''. Structure The cornea has myelinated, unmyelinated nerve endings sensitive to touch, temperature and chemicals; a to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (anatomy)
The lens, or crystalline lens, is a Transparency and translucency, transparent Biconvex lens, biconvex structure in most land vertebrate eyes. Relatively long, thin fiber cells make up the majority of the lens. These cells vary in architecture and are arranged in concentric layers. New layers of cells are recruited from a thin epithelium at the front of the lens, just below the basement membrane surrounding the lens. As a result the vertebrate lens grows throughout life. The surrounding lens membrane referred to as the lens capsule also grows in a systematic way, ensuring the lens maintains an optically suitable shape in concert with the underlying fiber cells. Thousands of suspensory ligaments are embedded into the capsule at its largest diameter which suspend the lens within the eye. Most of these lens structures are derived from the epithelium of the embryo before birth. Along with the cornea, aqueous humour, aqueous, and vitreous humours, the lens Refraction, refracts light, Fo ... [...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 photoreceptor cell, photoreceptors via two intermediate neuron types: Bipolar cell of the retina, 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 ner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retina
The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), 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 photographic film, film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by Chemical synapse, 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: rod cell, rods and cone cell, cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fovea Centralis
The ''fovea centralis'' is a small, central pit composed of closely packed Cone cell, cones in the eye. It is located in the center of the ''macula lutea'' of the retina. The ''fovea'' is responsible for sharp central visual perception, vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading (activity), reading and driving. The fovea is surrounded by the ''parafovea'' belt and the ''perifovea'' outer region. The ''parafovea'' is the intermediate belt, where the Retinal ganglion cell, 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 centra ... [...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". Birds are theropods,"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 sauropsids, with ciliary muscles that can change the shape of the Lens (anatomy), 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 third transparent movable membrane. The eye's internal anatomy is similar ... [...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] |
Calf Of Man
Calf of Man ( ) is a island, off the southwest coast of the Isle of Man. It is separated from the Isle of Man by a narrow stretch of water called the Calf Sound. Like the nearby rocky islets of Chicken Rock and Kitterland, it is part of the historic parish of Rushen and the current parish district of Arbory and Rushen. It has only two seasonal inhabitants. The word 'calf' derives from the Old Norse word ''kalfr'', which means a small island lying near a larger one. One can reach the Calf of Man by boat from either Port Erin or Port St Mary. Cow Harbour and South Harbour are the main landing places. The highest part of the island is in the west where an unnamed peak reaches above sea level. Until 1939, the island was under private ownership by the Keig family, but the island was purchased by Mr F. J. Dickens of Silverdale, Lancashire, who then donated it to the National Trust for it to become a bird sanctuary. In 1951, the Manx Museum & National Trust, which became know ... [...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 publishing h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
