Cat Gap
The cat gap is a period in the fossil record of approximately 25 million to 18.5 million years ago in which there are few fossils of cats or cat-like species found in North America. The cause of the "cat gap" is disputed, but it may have been caused by changes in the climate ( global cooling), changes in the habitat and environmental ecosystem, the increasingly hypercarnivorous trend of the cats (especially the nimravids), volcanic activity, evolutionary changes in dental morphology of the Canidae species present in North America, or a periodicity of extinctions called van der Hammen cycles. Cat evolution All modern carnivorans, including cats, evolved from miacoids, which existed from approximately 66 to 33 million years ago. There were other earlier cat-like species but ''Proailurus'' (meaning "before the cat"; also called "Leman's Dawn Cat"), which appeared about 30 million years ago, is generally considered the first "true cat". The increase in disparity th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Fossil Record
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good understanding of the pattern of diversification of life on Earth. In addition, the record can predict and fill gaps such as the discovery of '' Tiktaalik'' in the arctic of Canada. Paleontology includes the study of fossils: their age, method of formation, and evolutionary significance. Specimens are sometimes considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years to 4.1 billion years old. Early edition, published online before print. Th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Miacoidea
Miacoidea ("small points") is a former paraphyletic superfamily of extinct placental mammals that lived during the Paleocene and Eocene epochs, about 66-33,9 million years ago.K. D. Rose, A. E. Chew, R. H. Dunn, M. J. Kraus, H. C. Fricke and S. P. Zack (2012"Earliest Eocene mammalian fauna from the Paleocene-Eocene Thermal Maximum at Sand Creek Divide, southern Bighorn Basin, Wyoming."University of Michigan Papers on Paleontology 36:1-122 This group had been traditionally divided into two families of primitive carnivorous mammals: Miacidae (the miacids) and Viverravidae (the viverravids). These mammals were basal to order Carnivora, the crown-group within the Carnivoramorpha. Biology Miacoids were mostly small carnivorous mammals, superficially reminiscent of martens or civets. They probably fed on invertebrates, lizards, birds and smaller mammals like shrews and rodents, while others may have been insectivores. Some species were arboreal, others lived on the ground. Their t ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Cope's Rule
Cope's rule, named after American paleontologist Edward Drinker Cope, postulates that population lineages tend to increase in body size over evolutionary time. It was never actually stated by Cope, although he favoured the occurrence of linear evolutionary trends. It is sometimes also known as the Cope–Depéret rule, because Charles Depéret explicitly advocated the idea. Theodor Eimer had also done so earlier. The term "Cope's rule" was apparently coined by Bernhard Rensch, based on the fact that Depéret had "lionized Cope" in his book. While the rule has been demonstrated in many instances, it does not hold true at all taxonomic levels, or in all clades. Larger body size is associated with increased fitness for a number of reasons, although there are also some disadvantages both on an individual and on a clade level: clades comprising larger individuals are more prone to extinction, which may act to limit the maximum size of organisms. Function Effects of growth Directi ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram depicting the hypothetical relationships among the organisms, reflecting their inferred evolutionary history. The tips of a phylogenetic tree represent the observed entities, which can be living taxa or fossils. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the taxa represented on the tree. An unrooted tree diagram (a network) makes no assumption about directionality of character state transformation, and does not show the origin or "root" of the taxa in question. In addition to their use for inferring phylogenetic pa ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Clades
In biology, a clade (), also known as a monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed ''monophyletic'' (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms that the molecular biology arm of cladistics has revealed ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Smilodon
''Smilodon'' is an extinct genus of Felidae, felids. It is one of the best known saber-toothed predators and prehistoric mammals. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats, belonging to the extinct subfamily Machairodontinae, with an estimated date of Speciation, divergence from the ancestor of living cats around 20 million years ago. ''Smilodon'' was one of the last surviving machairodonts alongside ''Homotherium''. ''Smilodon'' lived in the Americas during the Pleistocene to early Holocene epoch (2.5 Year#mya, mya – at latest 8,200 years ago). The genus was named in 1842 based on fossils from Brazil; the generic name means or combined with . Three species are recognized today: ''S. gracilis'', ''S. fatalis'', and ''S. populator''. The two latter species were probably descended from ''S. gracilis'', which itself probably evolved from ''Megantereon''. The hundreds of specimens obtained from the La Brea T ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Felidae
Felidae ( ) is the Family (biology), family of mammals in the Order (biology), order Carnivora colloquially referred to as cats. A member of this family is also called a felid ( ). The 41 extant taxon, extant Felidae species exhibit the greatest diversity in fur patterns of all terrestrial carnivores. Cats have retractile claws, slender muscular bodies and strong flexible forelimbs. Their teeth and facial muscles allow for a powerful bite. They are all obligate carnivores, and most are solitary predators ambushing or stalking their prey. Wild cats occur in Africa, Europe, Asia and the Americas. Some wild cat species are adapted to forest and savanna habitats, some to arid environments, and a few also to wetlands and mountainous terrain. Their activity patterns range from nocturnal and crepuscular to Diurnality, diurnal, depending on their preferred prey species. Reginald Innes Pocock divided the extant Felidae into three subfamilies: the Pantherinae, the Felinae and the Acin ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Barbourofelidae
Barbourofelidae (or Barbourofelinae) is an extinct family (biology), family (or subfamily) of carnivorans of the suborder Feliformia, sometimes known as false saber-toothed cats, that lived in North America, Eurasia and Africa during the Miocene epoch (22.8—7 million years ago) and existed for about . Thought to be an independent lineage from the Nimravidae and Machairodontinae, which had all attained elongated canines, recent research argues that it may be a subfamily of the Nimravidae. Over the recent years, this hypothesis has been gaining more support among experts. Taxonomy The type genus, ''Barbourofelis'', was originally described by Schultz et al. (1970) and assigned to a new tribe, Barbourofelini, within the felid subfamily Machairodontinae, along with the other sabre-toothed cats. Subsequently, the tribe was reassigned to the Nimravidae by Tedford (1978) and raised to a subfamily by Bryant (1991). However, a number of studies in the early 2000s identified a closer aff ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Nimravidae
Nimravidae is an extinct family (biology), family of carnivorans, sometimes known as false saber-toothed cats, whose fossils are found in North America and Eurasia. Not considered to belong to the true cats (family Felidae), the nimravids are generally considered closely related and classified as a distinct family in the suborder Feliformia. Fossils have been dated from the Middle Eocene through the Late Oligocene epochs (Bartonian through Chattian stages, 41.03–25.9 million years ago), spanning about . The barbourofelids, which were formerly classified as a subfamily of the Nimravidae, were reassigned to their own distinct family Barbourofelidae in 2004. However in the 2020s, some studies suggest the barbourofelids are a branch of the nimravids, suggesting that this debate might not be settled yet. If accepted, the family would have persisted until the Late Miocene, and would extend their spatial distribution to Africa. Taxonomy The family Nimravidae was named by American pale ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Saber-toothed Cat
Machairodontinae (from Ancient Greek μάχαιρα '' machaira,'' a type of Ancient Greek sword and ὀδόντος ''odontos'' meaning tooth) is an extinct subfamily of carnivoran mammals of the cat family Felidae, representing the earliest diverging major branch of the family. Machairodonts varied in size from comparable to lynxes to exceeding that of lions. The Machairodontinae contain many of the extinct predators commonly known as "saber-toothed cats", including those with greatly elongated upper maxillary canines, such as the famed genus ''Smilodon'' and '' Megantereon,'' though the degree of elongation was variable, and in some machairodontines like '' Dinofelis'' the length of the upper canines was much more modest. Sometimes, other carnivorous mammals with elongated teeth are also called saber-toothed cats, although they do not belong to the felids. Besides the machairodonts, other saber-toothed predators also arose in the nimravids, barbourofelids, machaeroidine ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilisations. Its 4.7 billion people constitute roughly 60% of the world's population. Asia shares the landmass of Eurasia with Europe, and of Afro-Eurasia with both Europe and Africa. In general terms, it is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a social constructionism, historical and cultural construct, as there is no clear physical and geographical separation between them. A commonly accepted division places Asia to the east of the Suez Canal separating it from Africa; and to the east of the Turkish straits, the Ural Mountains an ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Bering Land Bridge
Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72° north latitude in the Chukchi Sea; and on the south by the tip of the Kamchatka Peninsula. It includes the Chukchi Sea, the Bering Sea, the Bering Strait, the Chukchi and Kamchatka peninsulas in Russia as well as Alaska in the United States and Yukon in Canada. The area includes land lying on the North American Plate and Siberian land east of the Chersky Range. At various times, it formed a land bridge referred to as the Bering land bridge, that was up to wide at its greatest extent and which covered an area as large as British Columbia and Alberta together, totaling about , allowing biological dispersal to occur between Asia and North America. Today, the only land that is visible from the central part of the Bering land bridge are the Diomede Islands, the Pribilof Islands of St. Paul and St. Georg ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |