|
Paranthropus Robustus
''Paranthropus robustus'' is a species of robust australopithecine from the Early and possibly Middle Pleistocene of the Cradle of Humankind, South Africa, about 2.27 to 0.87 (or, more conservatively, 2 to 1) million years ago. It has been identified in Kromdraai, Swartkrans, Sterkfontein, Gondolin, Cooper's, and Drimolen Caves. Discovered in 1938, it was among the first early hominins described, and became the type species for the genus ''Paranthropus''. However, it has been argued by some that ''Paranthropus'' is an invalid grouping and synonymous with ''Australopithecus'', so the species is also often classified as ''Australopithecus robustus''. Robust australopithecines—as opposed to gracile australopithecines—are characterised by heavily built skulls capable of producing high stresses and bite forces, as well as inflated cheek teeth (molars and premolars). Males had more heavily built skulls than females. ''P. robustus'' may have had a genetic susceptibi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek () 'most' and (; Latinized as ) 'new'. The aridification and cooling trends of the preceding Neogene were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, oscillating between cold Glacial period, glacial periods and warmer Interglacial, int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominin
The Hominini (hominins) form a taxonomic tribe of the subfamily Homininae (hominines). They comprise two extant genera: ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos), and in standard usage exclude the genus '' Gorilla'' ( gorillas), which is grouped separately within the subfamily Homininae. The term Hominini was originally introduced by Camille Arambourg (1948), who combined the categories of ''Hominina'' and ''Simiina'' pursuant to Gray's classifications (1825). Traditionally, chimpanzees, gorillas and orangutans were grouped together, excluding humans, as pongids. Since Gray's classifications, evidence accumulating from genetic phylogeny confirmed that humans, chimpanzees, and gorillas are more closely related to each other than to the orangutan. The orangutans were reassigned to the family Hominidae ( great apes), which already included humans; and the gorillas were grouped as a separate tribe (Gorillini) of the subfamily Homininae. Still, details of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitting Enamel Hypoplasia
Enamel hypoplasia can take a variety of forms, but all types are associated with a reduction of enamel formation due to disruption in ameloblast production. One of the most common types, pitting enamel hypoplasia (PEH), ranges from small circular pinpricks to larger irregular depressions. Pits also vary in how they occur on a tooth surface, some forming rows and others more randomly scattered. PEH can be associated with other types of hypoplasia, but it is often the only defect observed. Causes of PEH can range from genetic conditions to environmental factors, and the frequency of occurrence varies substantially between populations and species, likely due to environmental, genetic and health differences. The most striking example of this is in ''Paranthropus robustus,'' with half of all primary molars, and a quarter of permanent molars, displaying PEH defects, thought to be caused by a specific genetic condition, amelogenesis imperfecta. It is not always clear why PEH forms inst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Susceptibility
Public health genomics is the use of genomics information to benefit public health. This is visualized as more effective preventive care and disease treatments with better specificity, tailored to the genetic makeup of each patient. According to the Centers for Disease Control and Prevention (U.S.), Public Health genomics is an emerging field of study that assesses the impact of genes and their interaction with behavior, diet and the environment on the population's health. This field of public health genomics is less than a decade old. A number of think tanks, universities, and governments (including the U.S., UK, and Australia) have started public health genomics projects. Research on the human genome is generating new knowledge that is changing public health programs and policies. Advances in genomic sciences are increasingly being used to improve health, prevent disease, educate and train the public health workforce, other healthcare providers, and citizens. Public policy Pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in the permanent teeth, permanent set of teeth, making eight premolars total in the mouth. They have at least two Cusp (dentistry), cusps. Premolars can be considered transitional teeth during chewing, or mastication. They have properties of both the canines, that lie anterior and molars that lie Posterior (anatomy), posterior, and so food can be transferred from the canines to the premolars and finally to the molars for grinding, instead of directly from the canines to the molars. Human anatomy The premolars in humans are the maxillary first premolar, maxillary second premolar, mandibular first premolar, and the mandibular second premolar. Premolar teeth by definition are permanent teeth Anatomical terms of location#Proximal and distal, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar (tooth)
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across the mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies among individuals and populations, and in many cases the tooth is missing. The human mouth contains upper (maxillary) and lower (mandibular) molars. They are: maxillary first molar, maxillary second molar, maxillary third mol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cheek Teeth
Cheek teeth or postcanines comprise the molar and premolar teeth in mammals. Cheek teeth are multicuspidate (having many folds or tubercles). Mammals have multicuspidate molars (three in placentals, four in marsupials, in each jaw quadrant) and premolars situated between canines and molars whose shape and number varies considerably among particular groups. For example, many modern Carnivora possess carnassials, or secodont teeth. This scissor-like pairing of the last upper premolar and first lower molar is adapted for shearing meat. In contrast, the cheek teeth of deer and cattle are selenodont. Viewed from the side, these teeth have a series of triangular cusps or ridges, enabling the ruminants' sideways jaw motions to break down tough vegetable matter. Cheek teeth are sometimes separated from the incisors by a gap called a diastema. Cheek teeth in reptiles are much simpler as compared to mammals. Roles and significance Apart from helping grind the food to properly reduce th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bite Force
Bite force quotient (BFQ) is a numerical value commonly used to represent the bite force of an animal adjusted for its body mass, while also taking factors like the allometry effects. The BFQ is calculated as the regression of the quotient of an animal's bite force in newtons divided by its body mass in kilograms. The BFQ was first applied by Wroe et al. (2005) in a paper comparing bite forces, body masses and prey size in a range of living and extinct mammalian carnivores, later expanded on by Christiansen & Wroe (2007). Results showed that predators that take relatively large prey have large bite forces for their size, i.e., once adjusted for allometry Allometry (Ancient Greek "other", "measurement") is the study of the relationship of body size to shape, anatomy, physiology and behaviour, first outlined by Otto Snell in 1892, by D'Arcy Thompson in 1917 in ''On Growth and Form'' and by Jul .... The authors predicted bite forces using beam theory, based on the directly p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (physics)
In continuum mechanics, stress is a physical quantity that describes Force, forces present during Deformation (physics), deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to Tension (physics), ''tensile'' stress and may undergo Elongation (materials science), elongation. An object being pushed together, such as a crumpled sponge, is subject to Compression (physics), ''compressive'' stress and may undergo shortening. The greater the force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Stress has Dimension (physics), dimension of force per area, with SI Units, SI units of newtons per square meter (N/m2) or Pascal (unit), pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while Strain (mechanics), ''strain'' is the measure of the relative deformation (mechanics), deformation of the material. For example, when a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gracility
Gracility is slenderness, the condition of being gracile, which means slender. It derives from the Latin adjective ''gracilis'' (Masculine (grammar), masculine or Feminine (grammar), feminine), or ''gracile'' (Grammatical gender, neuter), which in either form means slender, and when transferred for example to discourse takes the sense of "without ornament", "simple" or various similar connotations. In ''Glossary of Botanic Terms'', B. D. Jackson speaks dismissively of an entry in earlier dictionary of A. A. Crozier as follows: "Gracilis (Lat.), slender. Crozier has the needless word 'gracile'". However, his objection would be hard to sustain in current usage; apart from the fact that ''gracile'' is a natural and convenient term, it is hardly a neologism. The ''Shorter Oxford English Dictionary'' gives the source date for that usage as 1623 and indicates the word is misused (through association with ''grace'') for "gracefully slender". This misuse is unfortunate at least, because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australopithecus
''Australopithecus'' (, ; or (, ) is a genus of early hominins that existed in Africa during the Pliocene and Early Pleistocene. The genera ''Homo'' (which includes modern humans), ''Paranthropus'', and ''Kenyanthropus'' evolved from some ''Australopithecus'' species. ''Australopithecus'' is a member of the subtribe Australopithecina, which sometimes also includes ''Ardipithecus'', though the term "australopithecine" is sometimes used to refer only to members of ''Australopithecus''. Species include ''Australopithecus garhi, A. garhi'', ''Australopithecus africanus, A. africanus'', ''Australopithecus sediba, A. sediba'', ''Australopithecus afarensis, A. afarensis'', ''Australopithecus anamensis, A. anamensis'', ''Australopithecus bahrelghazali, A. bahrelghazali'', and ''Australopithecus deyiremeda, A. deyiremeda''. Debate exists as to whether some ''Australopithecus'' species should be reclassified into new genera, or if ''Paranthropus'' and ''Kenyanthropus'' are synonymous with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synonym (taxonomy)
In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The Botanical nomenclature, botanical and Zoological nomenclature, zoological codes of nomenclature treat the concept of synonymy differently. * In nomenclature, botanical nomenclature, a synonym is a Binomial nomenclature, scientific name that applies to a taxon that now goes by a different scientific name. For example, Carl Linnaeus, Linnaeus was the first to give a scientific name (under the currently used system of scientific nomenclature) to the Norway spruce, which he called ''Pinus abies''. This name is no longer in use, so it is now a synonym of the current scientific name, ''Picea abies''. * In zoology, moving a species from one genus to another results in a different Binomial nomenclature, binomen, but the name is considered an alternative combination rather than a synonym. The concept of synonymy in zoology is reserved f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
