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Terrestrial Locomotion
Terrestrial locomotion has evolved as animals adapted from aquatic to terrestrial environments. Locomotion on land raises different problems than that in water, with reduced friction being replaced by the increased effects of gravity. As viewed from evolutionary taxonomy, there are three basic forms of animal locomotion in the terrestrial environment: * legged – moving by using appendages *limbless locomotion – moving without legs, primarily using the body itself as a propulsive structure. *rolling – rotating the body over the 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 location is aided by potential energy, or on loose surfaces (such as sand or scree), where friction is low but purchase (traction) is difficult. Humans, especially, have adapted to sliding over terrestrial snowpack and terrestrial ice by means of ice ska ... [...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 projection. He adopted the first name "Eadweard" as the original Anglo-Saxon form of "Edward", and the surname "Muybridge", believing it to be similarly archaic. Born in Kingston upon Thames, England, at the age of 20 he emigrated to the United States as a bookseller, first to New York City, and eventually to San Francisco. In 1860, he planned a return trip to Europe, and suffered serious head injuries in a stagecoach crash in Texas en route. He spent the next few years recuperating in Kingston upon Thames, where he took up professional photography, learned the wet-plate collodion process, and secured at least two British patents for his inventions. He returned to San Francisco in 1867, a man with a markedly changed personality. In 1868, he exhibited large photographs o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand, for example, aragonite, which has mostly been created, over the past 500million years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Somewhat more rarely, sand may be composed of calciu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitism
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as Armillaria mellea, honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the Orobanchaceae, broomrapes. There are six major parasitic Behavioral ecology#Evolutionarily stable strategy, strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), wikt:trophic, trophicallytransmitted parasitism (by being eaten), Disease vector, vector-transmitted paras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudflow
A mudflow or mud flow is a form of mass wasting involving fast-moving flow of debris that has become liquified by the addition of water. Such flows can move at speeds ranging from 3 meters/minute to 5 meters/second. Mudflows contain a significant proportion of clay, which makes them more fluid than debris flows, allowing them to travel farther and across lower slope angles. Both types of flow are generally mixtures of particles with a wide range of sizes, which typically become sorted by size upon deposition. Mudflows are often called mudslides, a term applied indiscriminately by the mass media to a variety of mass wasting events. Mudflows often start as slides, becoming flows as water is entrained along the flow path; such events are often called flow slides. Other types of mudflows include lahars (involving fine-grained pyroclastic deposits on the flanks of volcanoes) and jökulhlaups (outbursts from under glaciers or icecaps). A statutory definition of "flood-related muds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidewinding
Sidewinding is a type of locomotion unique to snakes, used to move across loose or slippery substrates. It is most often used by the Saharan horned viper, ''Cerastes cerastes'', the Mojave sidewinder rattlesnake, ''Crotalus cerastes'', and the Namib desert sidewinding adder, ''Bitis peringueyi'', to move across loose desert sands, and also by Homalopsine snakes in Southeast Asia to move across tidal mud flats. Any number of caenophidian snakes can be induced to sidewind on smooth surfaces, though the difficulty in getting them to do so and their proficiency at it vary greatly. The method of movement is derived from lateral undulation, and is very similar, in spite of appearances. A picture of a snake performing lateral undulation would show something like a sine wave, with straight segments of the body having either a positive or negative slope. Sidewinding is accomplished by undulating vertically as well as laterally, with the head tracing out an ellipse in a vertical plane n ... [...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. 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 cleats from that time period, the first written documentation of cleats comes from 1526, when "football boots" were listed in King H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beavers
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The two species differ in the shape of the skull and tail 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 impound water and lodges serve as shelters. Their infrastructure creates wetlands used by many other species, and because of their effect on other organisms in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penguins
Penguins ( order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapted for life in the 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 it whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey. They spend roughly 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 penguin, which stands around tall and weighs . Today, larger penguins generally inhabit colder regions, and smaller penguins in ... [...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 **Spotted seal The spotted seal (''Phoca largha''), also known as the larga seal or largha seal, is a member of the family Phocidae, and is considered a "true seal". It inhabits ice floes and waters of the north Pacific Ocean and adjacent seas. It is primarily ... 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 in a polar climate has an average temperature of less than . Regions with 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 (could last for the entirety of each season or longer). A polar climate consists of cool summers and very cold winters, which results in treeless tundra, 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 above . In a tundra climate, even coniferous trees cannot grow, but o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toboggans
A toboggan is a simple sled traditionally used by children. It is also a traditional form of transport used by the Innu and Cree of northern Canada. In modern times, it is used on snow to carry one or more people (often children) down a hill or other slope for recreation. 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 . Design and use Before white colonists arrived in America, toboggan was a Native Indian term fo ... [...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, which are chosen depending on the nature of the requirements needed for the skating activity. They are worn recreationally in ice rinks or on frozen bodies of water across the globe and are used as 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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