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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. 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 increased ground reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Femur
The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with the tibia (shinbone) and patella (kneecap), forming the knee joint. By most measures the two (left and right) femurs are the strongest bones of the body, and in humans, the largest and thickest. Structure The femur is the only bone in the upper leg. The two femurs converge medially toward the knees, where they articulate with the proximal ends of the tibiae. The angle of convergence of the femora is a major factor in determining the femoral-tibial angle. Human females have thicker pelvic bones, causing their femora to converge more than in males. In the condition ''genu valgum'' (knock knee) the femurs converge so much that the knees touch one another. The opposite extreme is ''genu varum'' (bow-leggedness). In the general ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourth Trochanter
The fourth trochanter is a shared characteristic common to archosaurs. It is a knob-like feature 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'') evolved, losing the intertrochanteric fossa and acquiri ... [...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". Clade analysis ... [...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 remain. Several revisions in classifying the great apes have caused the use of the term ''"hominid"'' to vary over time. The original meaning of "hominid" referred only to humans (''Homo'') and their closest extinct relatives. However, by the 1990s humans, apes, and their ancestors 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 scientists and la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. 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 flippers of whales and the forelegs of Quadrupedalism, four-legged vertebrates like Canidae, dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adaptation (biology), adapted to different purposes as the result of descent with modification from a Common descent, common ancestor. 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, Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first 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 is preceded by the Oligocene and is followed by 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 a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During ... [...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, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nacholapithecus
''Nacholapithecus kerioi'' was an ape that lived 14-15 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 with '' Anoiapithecus''. Taxonomy Nacholapithecus was initially classified as belonging in ''Kenyapithecus'', then attributed to ''Equatorius'' (with ''Equatorius'' perhaps grouped into a sub-family ''Equatorinae'', instead of both species in ''Afropithecini''), finally recognised by Ishida ''et al.'' (1999) as a separate genus. Classified perhaps as a member of the family '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proconsul (mammal)
''Proconsul'' is an extinct genus of primates that existed from 21 to 14 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: ''P. africanus'', ''P. gitongai'', ''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 chimpanzee. It might also be ancestral to the rest of the apes. Description The genus had a mixture of Old World monkey and ape characteristics, so its plac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
