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Third Trochanter
In human anatomy, the third trochanter is a bony projection occasionally present on the proximal femur near the superior border of the gluteal tuberosity. When present, it is oblong, rounded, or conical in shape and sometimes continuous with the gluteal ridge. It generally occurs bilaterally without significant side to side dimorphism. A structure of minor importance in humans, the incidence of the third trochanter varies from 17 to 72% between ethnic groups and it is frequently reported as more common in females than in males. Structures analogous to the third trochanter are present in other mammals, including some primates, but also in horses. It is called the third trochanter in reference to the greater and lesser trochanters that are always present on the femur. Function Its function is to provide an attachment for the ascending tendon of the gluteus maximus muscle. It may function as (1) a reinforcement mechanism for the proximal femoral diaphysis in response to increas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femoral head, top of the femur fits into a socket in the pelvis called the hip joint, and the bottom of the femur connects to the shinbone (tibia) and kneecap (patella) to form the knee. In humans the femur is the largest and thickest bone in the body. Structure The femur is the only bone in the upper Human leg, leg. The two femurs converge Anatomical terms of location, medially toward the knees, where they articulate with the Anatomical terms of location, proximal ends of the tibiae. The angle at which the femora converge is an important factor in determining the femoral-tibial angle. In females, thicker pelvic bones cause the femora to converge more than in males. In the condition genu valgum, ''genu valgum'' (knock knee), the femurs conve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ardipithecus Ramidus
''Ardipithecus ramidus'' is a species of australopithecine from the Afar region of Early Pliocene Ethiopia 4.4 million years ago (mya). The species ''A. ramidus'' is the type species for the genus ''Ardipithecus''. There is an older species in this same genus, ''Ardipithecus kadabba''. ''A. ramidus'', unlike modern hominids, has adaptations for both walking on two legs (bipedality) and life in the trees (arboreality). However, it would not have been as efficient at bipedality as humans, nor at arboreality as non-human great apes. Its discovery, along with Miocene apes, has reworked academic understanding of the chimpanzee–human last common ancestor from appearing much like modern-day chimpanzees, orangutans and gorillas to being a creature without a modern analogue. The facial anatomy (specifically the reduced sexual dimorphism of the canines) suggests that ''A. ramidus'' males were less aggressive than those of modern chimps, which is correlated to increased parental care an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourth Trochanter
The fourth trochanter is a shared characteristic common to archosaurs. It is a protrusion on the posterior-medial side of the middle of the femur shaft that serves as a muscle attachment, mainly for the '' musculus caudofemoralis longus'', the main retractor tail muscle that pulls the thighbone to the rear. The fourth trochanter is considered homologous with the internal trochanter, an asymmetrical ridge-like structure that extends down from the femoral head and is edged by an intertrochanteric fossa in other reptiles such as lizards. The fourth trochanter can be characterized by its position further down the shaft, symmetrical nature, and lack of an intertrochanteric fossa. The ''caudofemoralis'' attachment crest first separated from the femoral head in the Erythrosuchidae, large basal archosauriform predators of the early Triassic period. Shortly afterwards, eucrocopodan archosauriforms (such as ''Euparkeria ''Euparkeria'' (; meaning "Parker's good animal", named in h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Derived Trait
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Determining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primitive (phylogenetics)
In phylogenetics, a primitive (or ancestral) character, trait, or feature of a lineage or taxon is one that is inherited from the common ancestor of a clade (or clade group) and has undergone little change since. Conversely, a trait that appears ''within'' the clade group (that is, is present in any subgroup within the clade but not all) is called advanced or derived. A clade is a group of organisms that consists of a common ancestor and all its lineal descendants. A primitive trait is the original condition of that trait in the common ancestor; advanced indicates a notable change from the original condition. These terms in biology contain no judgement about the sophistication, superiority, value or adaptiveness of the named trait. "Primitive" in biology means only that the character appeared first in the common ancestor of a clade group and has been passed on largely intact to more recent members of the clade. "Advanced" means the character has evolved within a later subgroup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominid
The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); '' Gorilla'' (the eastern and western gorilla); '' Pan'' (the chimpanzee and the bonobo); and ''Homo'', of which only modern humans (''Homo sapiens'') remain. Numerous revisions in classifying the great apes have caused the use of the term ''hominid'' to change over time. The original meaning of "hominid" referred only to humans (''Homo'') and their closest extinct relatives. However, by the 1990s humans and other apes were considered to be "hominids". The earlier restrictive meaning has now been largely assumed by the term ''hominin'', which comprises all members of the human clade after the split from the chimpanzees (''Pan''). The current meaning of "hominid" includes all the great apes including humans. Usage still varies, however, and some scientis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common descent, common ancestor after having been subjected to adaptation (biology), adaptive modifications for different purposes as the result of natural selection. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this from Aristotle's biology onwards, and it was explicitly analysed by Pierre Belon in 1555. A common example of homologous structures is the forelimbs of vertebrates, where the bat wing development, wings of bats and origin of avian flight, birds, the arms of primates, the front flipper (anatomy), flippers of whales, and the forelegs of quadrupedalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene followed the Oligocene and preceded the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by distinct global events but by regionally defined transitions from the warmer Oligocene to the cooler Pliocene Epoch. During the Early Miocene, Afro-Arabia collided with Eurasia, severing the connection between the Mediterranean and Indian Oceans, and allowing the interchange of fauna between Eurasia and Africa, including the dispersal of proboscideans and Ape, hominoids into Eurasia. During the late Miocene, the conn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryopithecus
''Dryopithecus'' is a genus of extinct great apes from the middle–late Miocene boundary of Europe 12.5 to 11.1 million years ago (mya). Since its discovery in 1856, the genus has been subject to taxonomic turmoil, with numerous new species being described from single remains based on minute differences amongst each other, and the fragmentary nature of the holotype specimen makes differentiating remains difficult. There is currently only one uncontested species, the type species ''D. fontani'', though there may be more. The genus is placed into the tribe Dryopithecini, which is either an offshoot of orangutans, African apes, or is its own separate branch. A male specimen was estimated to have weighed in life. ''Dryopithecus'' likely predominantly ate ripe fruit from trees, suggesting a degree of suspensory behaviour to reach them, though the anatomy of a humerus and femur suggest a greater reliance on walking on all fours (quadrupedalism). The face was similar to gorillas, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacholapithecus
''Nacholapithecus kerioi'' was an ape that lived 15-14 million years ago during the Middle Miocene. Fossils have been found in the Nachola formation in northern Kenya. The only member of the genus ''Nacholapithecus'', it is thought to be a key genus in early hominid evolution. Similar in body plan to ''Proconsul'', it had a long vertebral column with six lumbar vertebrae, no tail, a narrow torso, large upper limbs with mobile shoulder joints, and long feet. Together with other Kenyapithecinae such as '' Equatorius'', '' Kenyapithecus'', and '' Griphopithecus'', ''Nacholapithecus'' displayed synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ... with '' Anoiapithecus''. Taxonomy ''Nacholapithecus'' was initially classified as belonging in '' Kenyapithecus'', then attri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proconsul (mammal)
''Proconsul'' is an extinct genus of primates that existed from 21 to 17 million years ago during the Miocene epoch. Fossil remains are present in Eastern Africa, including Kenya and Uganda. Four species have been classified to date: Proconsul africanus, ''P. africanus'', ''P. gitongai'', ''Proconsul major, P. major'' and ''P. meswae''. The four species differ mainly in body size. Environmental reconstructions for the Early Miocene ''Proconsul'' sites are still tentative and range from forested environments to more open, arid grasslands. The gibbon and great apes, including humans, are held in evolutionary biology to share a common ancestral lineage, which may have included ''Proconsul''. Its name, meaning "before Consul" (Consul being a certain chimpanzee that, at the time of the genus's discovery, was on display in London), implies that it is ancestral to the Common chimpanzee, chimpanzee. It might also be ancestral to the rest of the apes. Description The genus had a mixture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
