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Terrestrial Locomotion
Terrestrial locomotion is the method of movement of an organism on land. Organisms employ many different methods of movement for a variety of reasons. Terrestrial locomotion is of great interest to the study of evolution, which determines that aquatic organisms adapted to terrestrial environments. Animal locomotion on land experiences buoyancy and friction to a lesser extent, and gravity to a greater extent. Evolutionary taxonomy establishes three basic forms of terrestrial locomotion: * legged – moving by using appendages * limbless locomotion – moving without legs, primarily using the body itself as a propulsive structure. *rolling – rotating the body over a substrate Some terrains and terrestrial surfaces permit or demand alternative locomotive styles. A sliding component to locomotion becomes possible on slippery surfaces (such as ice and snow), where locomotion is aided by potential energy, or on loose surfaces (such as sand or scree), where friction is low but pur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muybridge Race Horse Animated
Eadweard Muybridge ( ; 9 April 1830 – 8 May 1904, born Edward James Muggeridge) was an English photographer known for his pioneering work in photographic studies of motion, and early work in motion-picture Movie projector, projection. He adopted the first name "Eadweard" as the original Germanic name, Anglo-Saxon form of "Edward", and the surname "Muybridge", believing it to be similarly archaic. A photographer in the 19th century American West, he photographed Yosemite National Park, Yosemite, San Francisco, the newly acquired Alaska, Alaskan Territory, subjects involved in the Modoc War, and lighthouses on the West Coast of the United States, West Coast. He also made his early moving picture studies in California. Born in Kingston upon Thames, Surrey, England, at the age of 20 he emigrated to the United States as a bookseller, first to New York City, then to San Francisco. In 1860, he planned a return trip to Europe, but suffered serious head injuries en route in a sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land Cover
Land cover is the physical material at the land surface of Earth. Land covers include flora, concrete, built structures, bare ground, and temporary water. Earth cover is the expression used by ecologist Frederick Edward Clements that has as its closest modern equivalent vegetation.Makers of American Botany, Harry Baker Humphrey, Ronald Press Company, Library of Congress Card Number 61-18435 The expression continues to be used by the United States Bureau of Land Management. There are two primary methods for capturing information on land cover: field survey, and analysis of remotely sensed imagery. Land change models can be built from these types of data to assess changes in land cover over time. One of the major land cover issues (as with all natural resource inventories) is that every survey defines similarly named categories in different ways. For instance, there are many definitions of "forest"—sometimes within the same organisation—that may or may not incorpora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleat (shoe)
Cleats or studs are protrusions on the sole of a shoe or on an external attachment to a shoe that provide additional traction on a soft or slippery surface. They can be conical or blade-like in shape and can be made of plastic, rubber or metal. The type worn depends on the environment of play: grass, ice, artificial turf, or other grounds. In American English, the term "cleats" is used synecdochically to refer to shoes featuring such protrusions. In Commonwealth English the correct term for shoes with studs is usually boots, especially when referring to football sports. History It is thought that during the Roman Empire, Roman legionaries wore studded sandals that resembled cleats. The caligae (as they were called) were heavy-soled hobnailed military sandal-boots known for being issued to legionary soldiers and auxiliaries throughout the Roman Republic and Empire. Athletes have worn cleats since at least the 1500s. Although there are no images or surviving examples of clea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beavers
Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-largest living rodents, after capybaras, weighing up to . They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet, and tails that are flat and scaly. The two species differ in skull and tail shape and fur color. Beavers can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges. Beavers build dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams restrict water flow, forming ponds, and lodges (usually built in ponds) serve as shelters. Their infrastructure creates wetlands used by many other species, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penguins
Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, is equatorial, with a small portion of its population extending slightly north of the equator (within a quarter degree of latitude). Highly adapted for life in the ocean water, penguins have countershaded dark and white plumage and flippers for swimming. Most penguins feed on krill, fish, squid and other forms of sea life which they catch with their bills and swallow whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey. They spend about half of their lives on land and the other half in the sea. The largest living species is the emperor penguin (''Aptenodytes forsteri''): on average, adults are about tall and weigh . The smallest penguin species is the little blue penguin (''Eudyptula minor''), also known as the fairy peng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Seals
Ice seal, or (in the Southern Hemisphere) pack-ice seal is a general term applied to any one of a number of pinniped species of the family Phocidae whose life cycle is completed largely on or about the sea ice of the Earth's polar regions. The following are widely considered pagophilic or "ice-loving" speciehttp://www.aad.gov.au/default.asp?casid=1380] *Subfamily Monachinae ** Ross seal ** Crabeater seal ** Leopard seal **Weddell seal *Subfamily Phocinae **Bearded seal ** Hooded seal ** Harp seal ** Ringed seal **Ribbon seal The ribbon seal (''Histriophoca fasciata'') is a medium-sized pinniped from the true seal family (Phocidae). A seasonally ice-bound species, it is found in the Arctic and Subarctic regions of the North Pacific Ocean, notably in the Bering Sea and ... ** Spotted seal or larga seal {{SIA Mammal common names ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Climate
The polar climate regions are characterized by a lack of warm summers but with varying winters. Every month a polar climate has an average temperature of less than . Regions with a polar climate cover more than 20% of the Earth's area. Most of these regions are far from the equator and near the poles, and in this case, winter days are extremely short and summer days are extremely long (they could last for the entirety of each season or longer). A polar climate consists of cool summers and very cold winters (or, in the case of ice cap climates, no real summer at all), which results in treeless tundras, glaciers, or a permanent or semi-permanent layer of ice. It is identified with the letter E in the Köppen climate classification. Subtypes There are two types of polar climate: ET, or tundra climate; and EF, or ice cap climate. A tundra climate is characterized by having at least one month whose average temperature is above , while an ice cap climate has no months averaging a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toboggans
A toboggan is a simple sled used in snowy winter recreation. It is also a traditional form of cargo transport used by the Innu, Cree and Ojibwe of North America, sometimes part of a dog train. It is used on snow to carry one or more people (often children) down a hill or other slope for recreation, or as a rescue sled. Designs vary from simple, traditional models to modern engineered composites. A toboggan differs from most sleds or sleighs in that it has no runners or skis (or only low ones) on the underside. The bottom of a toboggan rides directly on the snow. Some parks include designated toboggan hills where ordinary sleds are not allowed and which may include toboggan runs similar to bobsleigh courses. Toboggans can vary depending on the climate and geographical region. Such examples are Tangalooma (Australia) where toboggans are made from Masonite boards and used for travelling down steep sand dunes at speeds up to . Etymology The term toboggan likely comes from an A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Skates
Ice skates are metal blades attached underfoot and used to propel the bearer across a sheet of ice while ice skating. The first ice skates were made from leg bones of horse, ox or deer, and were attached to feet with leather straps. These skates required a pole with a sharp metal spike that was used for pushing the skater forward, unlike modern bladed skates. Modern skates come in many different varieties, each suited to specific conditions or activities. People across the globe wear skates recreationally in ice rinks or on frozen bodies of water, and skates are the standard footwear in many sports, including figure skating, bandy, ice hockey, ringette, rink bandy, rinkball, speed skating and tour skating. History According to a study done by Federico Formenti, University of Oxford, and Alberto Minetti, University of Milan, Finns were the first to develop ice skates some 5,000 years ago from animal bones. This was important for the Finnish populations to save energy in har ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowpack
Snowpack is an accumulation of snow that compresses with time and melts seasonally, often at high elevation or high latitude. Snowpacks are an important water resource that feed streams and rivers as they melt, sometimes leading to flooding. Snowpacks provide water to down-slope communities for drinking and agriculture. High-latitude or high-elevation snowpacks contribute mass to glaciers in their accumulation zones, where annual snow deposition exceeds annual melting. Assessing the formation and stability of snowpacks is important in the study and prediction of avalanches. Scientists study the physical properties of snow under different conditions and their evolution, and more specifically snow metamorphism, snow hydrology (that is, the contribution of snow melt to catchment hydrology), the evolution of snow cover with climate change and its effect on the ice–albedo feedback and hydrology, both on the ground and by using remote sensing. Snow is also studied in a more global c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sliding (motion)
Sliding is a type of motion between two surfaces in contact. This can be contrasted to ''rolling'' motion. Both types of motion may occur in bearings. The relative motion or tendency toward such motion between two surfaces is resisted by friction. This means that the force of friction always acts on an object in the direction opposite to its velocity (relative to the surface it's sliding on). Friction may damage or "wear" the surfaces in contact. However, wear can be reduced by lubrication. The science and technology of friction, lubrication, and wear is known as ''tribology''. Sliding may occur between two objects of arbitrary shape, whereas rolling friction is the frictional force associated with the rotational movement of a somewhat disclike or other circular object along a surface. Generally, the frictional force of rolling friction is less than that associated with sliding kinetic friction. Typical values for the coefficient of rolling friction are less than that of sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scree
Scree is a collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall. Landforms associated with these materials are often called talus deposits. The term ''scree'' is applied both to an unstable steep mountain slope composed of rock fragments and other debris, and to the mixture of rock fragments and debris itself. It is loosely synonymous with talus, material that accumulates at the base of a projecting mass of rock, or talus slope, a landform composed of talus. The term ''scree'' is sometimes used more broadly for any sheet of loose rock fragments mantling a slope, while ''talus'' is used more narrowly for material that accumulates at the base of a cliff or other rocky slope from which it has obviously eroded. Scree is formed by rockfall, which distinguishes it from colluvium. Colluvium is rock fragments or soil deposited by rainwash, sheetwash, or slow downhill creep, usually at the base of gentle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
