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Diarthrognathus
''Diarthrognathus'' ("Two joint jaw") is an extinct genus of tritheledontid cynodonts, known from fossil evidence found in South Africa and first described in 1958 by A.W. Crompton.Rieppel, Olivier. Evolutionary Theory and the Creation Controversy', p. 190 (Springer, 2010). The creature lived during the Early Jurassic period, about 200 million years ago. It was carnivorous and small, slightly smaller than ''Thrinaxodon'', which was under long. ''Diarthrognathus'' possesses a jaw structure that is similar to both mammals and more basal synapsids. Its primitive jaw joint is located between the quadrate and articular bones, and its derived, mammalian jaw joint is located between the squamosal and dentary bones. The articular and quadrate bones evolved to become two of the middle-ear bones in mammals.The Mesozoic Era: Age of Dinosaurs', p. 183 (Britannica Educational Publishing, Rosen Publishing Group, 2010). The transition exemplified by ''Diarthrognathus'' suggests that natural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tritheledontidae
Tritheledontidae, the tritheledontids or ictidosaurs, is an extinct family of small to medium-sized (about 10 to 20 cm long) cynodonts. They were highly mammal-like, specialized cynodonts, although they still retained a few reptile-like anatomical traits. Tritheledontids were mainly carnivorous or insectivorous, though some species may have developed omnivory. Their skeletons show that they had a close relationship to mammals. Tritheledontids or their closest relatives may have given rise to the mammaliaforms. The tritheledontids were one of the longest lived non-mammalian therapsid lineages, living from the late Triassic to the Jurassic period. Tritheledontids became extinct in the Jurassic period, possibly due to competition with prehistoric mammals such as the eutriconodonts. They are known from finds in South America and South Africa, indicating that they may have lived only on the supercontinent of Gondwana. The family Tritheledontidae was named by South Afr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tritheledontid
Tritheledontidae, the tritheledontids or ictidosaurs, is an extinct family of small to medium-sized (about 10 to 20 cm long) cynodonts. They were highly mammal-like, specialized cynodonts, although they still retained a few reptile-like anatomical traits. Tritheledontids were mainly carnivorous or insectivorous, though some species may have developed omnivory. Their skeletons show that they had a close relationship to mammals. Tritheledontids or their closest relatives may have given rise to the mammaliaforms. The tritheledontids were one of the longest lived non-mammalian therapsid lineages, living from the late Triassic to the Jurassic period. Tritheledontids became extinct in the Jurassic period, possibly due to competition with prehistoric mammals such as the eutriconodonts. They are known from finds in South America and South Africa, indicating that they may have lived only on the supercontinent of Gondwana. The family Tritheledontidae was named by South African paleon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cynodont
Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extinct ancestors and close relatives (Mammaliaformes), having evolved from advanced probainognathian cynodonts during the Late Triassic. Non-mammalian cynodonts occupied a variety of ecological niches, both as carnivores and as herbivores. Following the emergence of mammals, most other cynodont lines went extinct, with the last known non-mammaliaform cynodont group, the Tritylodontidae, having its youngest records in the Early Cretaceous. Description Early cynodonts have many of the skeletal characteristics of mammals. The teeth were fully differentiated and the braincase bulged at the back of the head. Outside of some Crown group, crown-group mammals (notably the therians), all cynodonts probably laid eggs. The temporal fenestrae#Fenestra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachygenelus
''Pachygenelus'' is a genus of extinct cynodont. Fossils have been found from the Karoo basin in South Africa and date back to the Early Jurassic. The genus was named in 1913 on the basis of a partial lower jaw found from South Africa, with the type species being named ''P. monus''. A new species, ''P. milleri'', was named in 1983 and distinguished from the type species in possessing an accessory posterior cusp on the lower postcanines. Description ''Pachygenelus'' had both an articular- quadrate and dentary-squamosal jaw joint characteristic of ictidosaurs. Only mammals possess the dentary-squamosal articulation, while all other tetrapods possess the typical arcticular-quadrate articulation. Thus the jaw of ''Pachygenelus'' can be seen as transitional between non-mammalian synapsids and true mammals. Another feature of ''Pachygenelus'' that is shared with mammals is plesiomorphic prismatic enamel, or enamel arranged into strengthened prisms. The upper and lower tooth rows o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lower Jurassic
The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.7 ±0.8 Ma. Certain rocks of marine origin of this age in Europe are called " Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias and Carboniferous limestone from South Wales was used throughout North Devon/N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandible
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone is the skull's only movable, posable bone, sharing Temporomandibular joint, joints with the cranium's temporal bones. The mandible hosts the lower Human tooth, teeth (their depth delineated by the alveolar process). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels. Amongst other functions, the jawbone is essential for chewing food. Owing to the Neolithic Revolution, Neolithic advent of agriculture (), human jaws evolved to be Human jaw shrinkage, smaller. Although it is the strongest bone of the facial skeleton, the mandible tends to deform in old age; it is also subject to Mandibular fracture, fracturing. Surgery allows for the removal of jawbone fragments (or its entirety) as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammaliaform
Mammaliaformes ("mammalian forms") is a clade of synapsid tetrapods that includes the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts during the Late Triassic. It is defined as the clade originating from the most recent common ancestor of Morganucodonta and the crown group mammals; the latter is the clade originating with the most recent common ancestor of extant Monotremata, Marsupialia and Placentalia. Besides Morganucodonta and the crown group mammals, Mammaliaformes also includes Docodonta and ''Hadrocodium''. Mammaliaformes is a term of phylogenetic nomenclature. In contrast, the assignment of organisms to class (biology), class Mammalia has traditionally been founded on phenotypic trait, traits and, on this basis, Mammalia is slightly more inclusive than Mammaliaformes. In particular, trait-based taxonomy generally includes ''Adelobasileus'' and ''Sinoconodon'' in Mammalia, though they fall outside the Ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duane Gish
Duane Tolbert Gish (February 17, 1921 – March 5, 2013) was an American biochemist and a prominent member of the creationist movement. A young Earth creationist, Gish was a former vice-president of the Institute for Creation Research (ICR) and the author of numerous publications about creation science. Gish was called "creationism's T. H. Huxley" for the way he "relished the confrontations" of formal debates with prominent evolutionary biologists, usually held on university campuses, while abandoning formal debating principles, in a style that came to be known as the Gish gallop. A creationist publication noted in his obituary that "it was perhaps his personal presentation that carried the day. In short, the audiences liked him." Early life and education Gish, a twin, was born in White City, Kansas, the youngest of nine children. He served in World War II, attaining the rank of captain, and was awarded the Bronze Star. He earned a Bachelor of Science degree from Univers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creationism
Creationism is the faith, religious belief that nature, and aspects such as the universe, Earth, life, and humans, originated with supernatural acts of Creation myth, divine creation, and is often Pseudoscience, pseudoscientific.#Gunn 2004, Gunn 2004, p. 9, "The ''Concise Oxford Dictionary'' says that creationism is 'the belief that the universe and living organisms originated from specific acts of divine creation.'" originally published in Creation/Evolution Journal , Volume 6 , No. 2 , Summer 1986. In its broadest sense, creationism includes various religious views,#Stewart 2010, Haarsma 2010, p. 168, "Some Christians, often called 'Young Earth creationists,' reject evolution in order to maintain a semi-literal interpretation of certain biblical passages. Other Christians, called 'progressive creationists,' accept the scientific evidence for some evolution over a long history of the earth, but also insist that God must have performed some miracles during that history to crea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ameghiniana
''Ameghiniana'' is a peer-reviewed scientific journal covering palaeontology published by the Asociación Paleontológica Argentina. It is named after the 19th century Italian Argentine palaeontologist Florentino Ameghino. The discovery of many dinosaurs found in Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ... and South America have first been published in ''Ameghiniana''; examples of this are '' Argentinosaurus'' and '' Herrerasaurus''. Abstracting and indexing The journal is abstracted and indexed in: References External links * Asociación Paleontológica Argentina Paleontology journals Geology of Argentina Academic journals established in 1957 Quarterly journals Academic journals published by learned and professional societies of Argentina English- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which is intentional, whereas natural selection is not. Genetic diversity, Variation of traits, both Genotype, genotypic and phenotypic, exists within all populations of organisms. However, some traits are more likely to facilitate survival and reproductive success. Thus, these traits are passed the next generation. These traits can also become more Allele frequency, common within a population if the environment that favours these traits remains fixed. If new traits become more favoured due to changes in a specific Ecological niche, niche, microevolution occurs. If new traits become more favoured due to changes in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution Of Mammalian Auditory Ossicles
The evolution of mammalian auditory ossicles was an evolutionary process that resulted in the formation of the mammalian middle ear, where the three middle ear bones or ossicles, namely the incus, malleus and stapes (a.k.a. "the anvil, hammer, and stirrup"), are a defining characteristic of mammals. The event is well-documented and important academically as a demonstration of transitional fossil, transitional forms and exaptation, the re-purposing of existing structures during evolution. The ossicles evolved from skull bones present in most tetrapods, including amphibians, sauropsids (which include extant taxon, extant reptiles and birds) and early synapsids (which include ancestors of mammals). The reptilian quadrate bone, quadrate, articular bone, articular and columella (auditory system), columella bones are homologs of the mammalian incus, malleus and stapes, respectively. In reptiles (and early synapsids by association), the eardrum is connected to the inner ear via a single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
