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Audubon's Shearwater
Audubon's shearwater (''Puffinus lherminieri'') is a common tropical seabird in the petrel family. Sometimes known as the dusky-backed shearwater,Carboneras (1992) the specific epithet honours the French naturalist Félix Louis L'Herminier. Certain populations are known variously as Baillon's shearwater, tropical shearwater, Bannerman's shearwater, Mascarene shearwater and Persian shearwater; some of these are considered distinct species by various authors. If they are all placed in ''P. lherminieri'', the North Atlantic little shearwater (otherwise often separated as ''P. baroli'') is generally included here too. Thus, these small shearwaters form a cryptic species complex. Description Audubon's shearwaters are on average in length—about half the size of the greater shearwater (''Puffinus gravis'')—and weigh 170 g. There is some variation between populations, and the normal size and weight range is and . The wingspan is , the tail is around long, the exposed cul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarsus (skeleton)
In the human body, the tarsus is a cluster of seven articulating bones in each foot situated between the lower end of the tibia and the fibula of the lower leg and the metatarsus. It is made up of the midfoot (Cuboid bone, cuboid, medial, intermediate, and lateral cuneiform bone, cuneiform, and navicular) and hindfoot (Talus bone, talus and calcaneus). The tarsus articulates with the bones of the metatarsus, which in turn articulate with the proximal phalanges of the toes. The joint between the tibia and fibula above and the tarsus below is referred to as the ankle, ankle joint proper. In humans the largest bone in the tarsus is the calcaneus, which is the weight-bearing bone within the heel of the foot. Human anatomy Bones The talus bone or ankle bone is connected superiorly to the two bones of the lower leg, the tibia and fibula, to form the ankle, ankle joint or talocrural joint; inferiorly, at the subtalar joint, to the calcaneus or heel bone. Together, the talus and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caribbean
The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Sea and the North Atlantic Ocean) and the surrounding coasts. The region is southeast of the Gulf of Mexico and the North American mainland, east of Central America, and north of South America. Situated largely on the Caribbean Plate, the region has more than 700 islands, islets, reefs and cays (see the list of Caribbean islands). Island arcs delineate the eastern and northern edges of the Caribbean Sea: The Greater Antilles and the Lucayan Archipelago on the north and the Lesser Antilles and the on the south and east (which includes the Leeward Antilles). They form the West Indies with the nearby Lucayan Archipelago (the Bahamas and Turks and Caicos Islands), which are considered to be part of the Caribbean despite not bordering the Caribbe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined .Pacific Ocean . '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the |
Arabian Sea
The Arabian Sea ( ar, اَلْبَحرْ ٱلْعَرَبِيُّ, Al-Bahr al-ˁArabī) is a region of the northern Indian Ocean bounded on the north by Pakistan, Iran and the Gulf of Oman, on the west by the Gulf of Aden, Guardafui Channel and the Arabian Peninsula, on the southeast by the Laccadive Sea and the Maldives, on the southwest by Somalia, and on the east by India. Its total area is 3,862,000 km2 (1,491,000 sq mi) and its maximum depth is 4,652 meters (15,262 ft). The Gulf of Aden in the west connects the Arabian Sea to the Red Sea through the strait of Bab-el-Mandeb, and the Gulf of Oman is in the northwest, connecting it to the Persian Gulf. Name The sea is named after Arabia, the historic name of the region to the west of the sea. The Arabian Sea's name in Arabic is ; in Persian it is دریای عرب; in Urdu it is بحیرہ عرب; in Hindi it is अरब सागर; in Gujarati it is અરબી સમુદ્ર; in Marathi it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by the Southern Ocean or Antarctica, depending on the definition in use. Along its core, the Indian Ocean has some large marginal or regional seas such as the Arabian Sea, Laccadive Sea, Bay of Bengal, and Andaman Sea. Etymology The Indian Ocean has been known by its present name since at least 1515 when the Latin form ''Oceanus Orientalis Indicus'' ("Indian Eastern Ocean") is attested, named after Indian subcontinent, India, which projects into it. It was earlier known as the ''Eastern Ocean'', a term that was still in use during the mid-18th century (see map), as opposed to the ''Western Ocean'' (Atlantic Ocean, Atlantic) before the Pacific Ocean, Pacific was surmised. Conversely, Ming treasure voyages, Chinese explorers in the Indian Oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Little Shearwater
The little shearwater (''Puffinus assimilis'') is a small shearwater in the petrel family Procellariidae. Despite the generic name, it is unrelated to the puffins, which are auks, the only similarity being that they are both burrow-nesting seabirds. Description This shearwater has the typically "shearing" flight of the genus, dipping from side to side on stiff wings with few beats, the wingtips almost touching the water, though in light winds it has a more flapping flight than that of its larger relatives. In flight it looks cross-shaped, with its wings held at right angles to the body, its colouration changing from black to white as the black upperparts and white underparts are alternately exposed as it travels low over the sea. At in length with a wingspan, it is like a small Manx shearwater but has proportionally shorter and broader wings, with a pale area on the inner flight feathers. Its bill is more slender than that of Manx, and its dark eye stands out against the surr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subantarctic
The sub-Antarctic zone is a region in the Southern Hemisphere, located immediately north of the Antarctic region. This translates roughly to a latitude of between 46° and 60° south of the Equator. The subantarctic region includes many islands in the southern parts of the Atlantic, Indian, and Pacific oceans, especially those situated north of the Antarctic Convergence. Sub-Antarctic glaciers are, by definition, located on islands within the sub-Antarctic region. All glaciers located on the continent of Antarctica are by definition considered to be Antarctic glaciers. Geography The sub-Antarctic region comprises two geographic zones and three distinct fronts. The northernmost boundary of the subantarctic region is the rather ill-defined Subtropical Front (STF), also referred to as the Subtropical Convergence. To the south of the STF is a geographic zone, the Subantarctic Zone (SAZ). South of the SAZ is the Subantarctic Front (SAF). South of the SAF is another marine zone, cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allopatric Speciation
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 shearwater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Down Feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding (duvets and featherbeds), pillows and sleeping bags. The discovery of feathers trapped in ancient amber suggests that some species of dinosaur may have possessed down-like feathers. Description and etymology The word ''down'' comes from the Old Norse word ''dúnn'', which had the same meaning as its modern equivalent. The down feather is considered to be the most "straightforward" of all feather types. It has a short or vestigial rachis (shaft), few barbs, and barbules that lack hooks. There are three types of down: natal down, body down and powder down. Natal down is the layer of down feathers that cover most birds at some point in their early development. Precocial nestlings are alre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iris (anatomy)
In humans and most mammals and birds, the iris (plural: ''irides'' or ''irises'') is a thin, annular structure in the eye, responsible for controlling the diameter and size of the pupil, and thus the amount of light reaching the retina. Eye color is defined by the iris. In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm. Structure The iris consists of two layers: the front pigmented fibrovascular layer known as a stroma and, beneath the stroma, pigmented epithelial cells. The stroma is connected to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles ( dilator pupillae), which pull the iris radially to enlarge the pupil, pulling it in folds. The sphincter pupillae is the opposing muscle of the dilator pupillae. The pupil's diameter, and thus the inner border of the iris, changes size when constricting or dilating. The outer border of the iris does not change size. The constricti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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