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Fruitafossor
''Fruitafossor'' was a termite-eating mammal endemic to North America during the Late Jurassic epoch (around 150 mya). The description is based on a complete skeleton of a chipmunk-sized animal. It was discovered on March 31, 2005, in Fruita, Colorado. It resembled an armadillo (or anteater) and probably ate colonial insects in much the same manner as these animals do today. Other skeletal features clearly show that ''Fruitafossor'' was not related to armadillos, anteaters, or any modern group of mammal. This indicates that specializations associated with feeding on ants or termites have independently evolved many times in mammals: in ''Fruitafossor'', anteaters, numbats, aardwolves, aardvarks, pangolins, and echidnas. Description In 2009, a study by J. R. Foster was published that estimated the body masses of mammals from the Late Jurassic Morrison Formation by using the ratio of dentary length to body mass of modern marsupials as a reference. Foster concludes that ''Fruita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic Magmatic Province. The beginning of the Toarcian Stage started around 183 million years ago and is marked by an extinction event associated with widespread oceanic anoxia, ocean acidification, and elevated temperatures likely caused by the eruption of the Karoo-Ferrar large igneous provinces. The end of the Jurassic, however, has no clear boundary with the Cretaceous and is the only boundary between geological periods to remain formally undefined. By the beginning of the Jurassi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regression Analysis
In statistical modeling, regression analysis is a set of statistical processes for estimating the relationships between a dependent variable (often called the 'outcome' or 'response' variable, or a 'label' in machine learning parlance) and one or more independent variables (often called 'predictors', 'covariates', 'explanatory variables' or 'features'). The most common form of regression analysis is linear regression, in which one finds the line (or a more complex linear combination) that most closely fits the data according to a specific mathematical criterion. For example, the method of ordinary least squares computes the unique line (or hyperplane) that minimizes the sum of squared differences between the true data and that line (or hyperplane). For specific mathematical reasons (see linear regression), this allows the researcher to estimate the conditional expectation (or population average value) of the dependent variable when the independent variables take on a give ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles, like the dinosaurs; an abundance of conifers and ferns; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs, pterosaurs, mosasaurs, and plesiosaurs. The Mesozoic was a time of significant tectonic, climatic, and evolutionary activity. The era witnessed the gradual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecological Niche
In ecology, a niche is the match of a species to a specific environmental condition. Three variants of ecological niche are described by It describes how an organism or population responds to the distribution of resources and competitors (for example, by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (for example, limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey). "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another ndthe relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts". See also Chapter 2: Concepts of niches, pp. 7 ''ff'' A Grinnellian niche is determined by the habitat in which a species lives and its accompanying behavioral adaptations. An Eltonian niche emphasizes that a sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrae
The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic irregular bone whose complex structure is composed primarily of bone, and secondarily of hyaline cartilage. They show variation in the proportion contributed by these two tissue types; such variations correlate on one hand with the cerebral/caudal rank (i.e., location within the backbone), and on the other with phylogenetic differences among the vertebrate taxa. The basic configuration of a vertebra varies, but the bone is its ''body'', with the central part of the body constituting the ''centrum''. The upper (closer to) and lower (further from), respectively, the cranium and its central nervous system surfaces of the vertebra body support attachment to the intervertebral discs. The posterior part of a vertebra forms a vertebral ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xenarthra
Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Extinct xenarthrans include the glyptodonts, pampatheres and ground sloths. Xenarthrans originated in South America during the late Paleocene about 60 million years ago. They evolved and diversified extensively in South America during the continent's long period of isolation in the early to mid Cenozoic Era. They spread to the Antilles by the early Miocene and, starting about 3 Mya, spread to Central and North America as part of the Great American Interchange. Nearly all of the formerly abundant megafaunal xenarthrans became extinct at the end of the Pleistocene. Xenarthrans share several characteristics not present in other placental mammals, which suggest their ancestors were subterranean diggers for insects. The name Xenarthr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olecranon
The olecranon (, ), is a large, thick, curved bony eminence of the ulna, a long bone in the forearm that projects behind the elbow. It forms the most pointed portion of the elbow and is opposite to the cubital fossa or elbow pit. The olecranon serves as a lever for the extensor muscles that straighten the elbow joint. Structure The olecranon is situated at the proximal end of the ulna, one of the two bones in the forearm. When the hand faces forward (supination) the olecranon faces towards the back (posteriorly). It is bent forward at the summit so as to present a prominent lip which is received into the olecranon fossa of the humerus during extension of the forearm. Its base is contracted where it joins the body and the narrowest part of the upper end of the ulna. Its posterior surface, directed backward, is triangular, smooth, subcutaneous, and covered by a bursa. Its superior surface is of quadrilateral form, marked behind by a rough impression for the insertion of the Tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echidna
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the only surviving members of the order Monotremata. The diet of some species consists of ants and termites, but they are not closely related to the true anteaters of the Americas, which (along with sloths and armadillos) are xenarthrans. Echidnas live in Australia and New Guinea. Echidnas evolved between 20 and 50 million years ago, descending from a platypus-like monotreme. This ancestor was aquatic, but echidnas adapted to life on land. Etymology Echidnas are named after Echidna, a creature from Greek mythology who was half-woman, half-snake, as the animal was perceived to have qualities of both mammals and reptiles. An alternative explanation is a confusion with . Physical characteristics Echidnas are medium-sized, solitary ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gopher (animal)
Pocket gophers, commonly referred to simply as gophers, are burrowing rodents of the family Geomyidae. The roughly 41 speciesSearch results for "Geomyidae" on thASM Mammal Diversity Database are all endemic to North and Central America. They are commonly known for their extensive tunneling activities and their ability to destroy farms and gardens. The name "pocket gopher" on its own may refer to any of a number of genera within the family Geomyidae. These are the "true" gophers, but several ground squirrels in the distantly related family Sciuridae are often called "gophers", as well. The origin of the word "gopher" is uncertain; the French ''gaufre'', meaning waffle, has been suggested, on account of the gopher tunnels resembling the honeycomb-like pattern of holes in a waffle; another suggestion is that the word is of Muskogean origin. Description Gophers weigh around , and are about in body length, with a tail long. A few species reach weights approaching . Within any s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mole (animal)
Moles are small mammals adapted to a subterranean lifestyle. They have cylindrical bodies, velvety fur, very small, inconspicuous eyes and ears, reduced hindlimbs, and short, powerful forelimbs with large paws adapted for digging. The word “mole” refers to any species in the family Talpidae, which means “mole” in Latin. Moles are found in most parts of North America, Europe and Asia. Moles may be viewed as pests to gardeners, but they provide positive contributions to soil, gardens, and ecosystem, including soil aeration, feeding on slugs and small creatures that eat plant roots, and providing prey for other wildlife. They eat earthworms and other small invertebrates in the soil. Terminology In Middle English, moles were known as ''moldwarp''. The expression "don't make a mountain out of a molehill" (which means "exaggerating problems") was first recorded in Tudor times. By the era of Early Modern English, the mole was also known in English as ''mouldywarp'', a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossorial
A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees. Prehistoric evidence The physical adaptation of fossoriality is widely accepted as being widespread among many prehistoric phyla and taxa, such as bacteria and early eukaryotes. Furthermore, fossoriality has evolved independently multiple times, even within a single family. Fossorial animals appeared simultaneously with the colonization of land by arthropods in the late Ordovician period (over 440 million years ago). Other notable early burrowers include '' Eocaecilia'' and possibly ''Dinilysia''. The oldest example of burrowing in synapsids, the lineage which includes modern mammals and their ancestors, is a cynodont, '' Thrinaxodon liorhinus'', found in the Karoo of South Africa, estimated to be 251 million years old. Evidence shows that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Popeye
Popeye the Sailor Man is a fictional cartoon character created by Elzie Crisler Segar.Segar, Elzie (Crisler) – Encyclopædia Britannica Article Britannica.com. Retrieved on March 29, 2013.Goulart, Ron, "Popeye", ''St. James Encyclopedia of Popular Culture''. Detroit: St. James Press, 2000. (Volume 4, pp. 87-8).Walker, Brian. ''The Comics: The Complete Collection''. New York: Abrams ComicArts, 2011. (pp. 188-9,191, 238-243) The character first appeared in the daily King Features comic strip '' |
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