Mammal - Wikipedia"Mammalian" redirects here. For the 2. 01. 0 documentary film, see Mammalian (film). Mammals are any vertebrates within the class. Mammalia ( from Latinmamma "breast"), a clade of endothermicamniotes distinguished from reptiles (including birds) by the possession of a neocortex (a region of the brain), hair, three middle ear bones, and mammary glands. Females of all mammal species nurse their young with milk, secreted from the mammary glands. Mammals include the biggest animals on the planet, the great whales. The basic body type is a terrestrial quadruped, but some mammals are adapted for life at sea, in the air, in trees, underground or on two legs. ![]() ![]() The largest group of mammals, the placentals, have a placenta, which enables the feeding of the fetus during gestation. Mammals range in size from the 3. With the exception of the five species of monotreme (egg- laying mammals), all modern mammals give birth to live young. Most mammals, including the six most species- rich orders, belong to the placental group. The largest orders are the rodents, bats and Soricomorpha (shrews and allies). The next three biggest orders, depending on the biological classification scheme used, are the Primates (apes and monkeys), the Cetartiodactyla (whales and even- toed ungulates), and the Carnivora (cats, dogs, seals, and allies). Living mammals are divided into the Yinotheria (platypus and echidnas) and Theriiformes (all other mammals). Peripheral arterial disease is a debilitating and progressive disorder that affects millions of people worldwide (American College of Cardiology et al. Vasc Med 16(6. There are around 5. In some classifications, extant mammals are divided into two subclasses: the Prototheria, that is, the order Monotremata; and the Theria, or the infraclasses Metatheria and Eutheria. The marsupials constitute the crown group of the Metatheria, and include all living metatherians as well as many extinct ones; the placentals are the crown group of the Eutheria. While mammal classification at the family level has been relatively stable, several contending classifications regarding the higher levels—subclass, infraclass and order, especially of the marsupials—appear in contemporaneous literature. Much of the changes reflect the advances of cladistic analysis and molecular genetics. Findings from molecular genetics, for example, have prompted adopting new groups, such as the Afrotheria, and abandoning traditional groups, such as the Insectivora. The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade. Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. No classification system is universally accepted; McKenna.From millions of real job salary data. 0 salary data. Average salary is Detailed starting salary, median salary, pay scale, bonus data report. The early synapsid mammalian ancestors were sphenacodontpelycosaurs, a group that produced the non- mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the sauropsid line that led to today's reptiles and birds. The line following the stem group Sphenacodontia split- off several diverse groups of non- mammalian synapsids—sometimes referred to as mammal- like reptiles—before giving rise to the proto- mammals (Therapsida) in the early Mesozoic era. The modern mammalian orders arose in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non- avian dinosaurs, and have been among the dominant terrestrial animal groups from 6. Some mammals are intelligent, with some possessing large brains, self- awareness and tool use. Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent- marking, alarm signals, singing, and echolocation. Mammals can organize themselves into fission- fusion societies, harems, and hierarchies, but can also be solitary and territorial. Most mammals are polygynous, but some can be monogamous or polyandrous. In human culture, domesticated mammals played a major role in the Neolithic revolution, causing farming to replace hunting and gathering, and leading to a major restructuring of human societies with the first civilizations. They provided, and continue to provide, power for transport and agriculture, as well as various commodities such as meat, dairy products, wool, and leather. Mammals are hunted or raced for sport, and are used as model organisms in science. Mammals have been depicted in art since Palaeolithic times, and appear in literature, film, mythology, and religion. Defaunation of mammals is primarily driven by anthropogenic factors, such as poaching and habitat destruction, though there are efforts to combat this. Classification[edit]. The orders Rodentia (blue), Chiroptera (red) and Soricomorpha (yellow) together comprise over 7. Rodentia Chiroptera Soricomorpha Primates Carnivora Artiodactyla Diprotodontia Lagomorpha Didelphimorphia Cetacea Dasyuromorphia Afrosoricida Erinaceomorpha Cingulata Peramelemorphia Scandentia Perissodactyla Macroscelidea Pilosa Monotremata Proboscidea. Mammal classification has been through several iterations since Carl Linnaeus initially defined the class. ![]() No classification system is universally accepted; Mc. Kenna & Bell (1. Wilson & Reader (2. George Gaylord Simpson's "Principles of Classification and a Classification of Mammals" (AMNH Bulletin v. Since Simpson's classification, the paleontological record has been recalibrated, and the intervening years have seen much debate and progress concerning the theoretical underpinnings of systematization itself, partly through the new concept of cladistics. Though field work gradually made Simpson's classification outdated, it remains the closest thing to an official classification of mammals.[2]Most mammals, including the six most species- rich orders, belong to the placental group. The three largest orders in numbers of species are Rodentia: mice, rats, porcupines, beavers, capybaras and other gnawing mammals; Chiroptera: bats; and Soricomorpha: shrews, moles and solenodons. The next three biggest orders, depending on the biological classification scheme used, are the Primates including the apes, monkeys and lemurs; the Cetartiodactyla including whales and even- toed ungulates; and the Carnivora which includes cats, dogs, weasels, bears, seals and allies.[3] According to Mammal Species of the World, 5,4. These were grouped into 1,2. In 2. 00. 8, the International Union for Conservation of Nature (IUCN) completed a five- year Global Mammal Assessment for its IUCN Red List, which counted 5,4. Definitions [edit]The word "mammal" is modern, from the scientific name Mammalia coined by Carl Linnaeus in 1. Latinmamma ("teat, pap"). In an influential 1. Timothy Rowe defined Mammalia phylogenetically as the crown group of mammals, the clade consisting of the most recent common ancestor of living monotremes (echidnas and platypuses) and therian mammals (marsupials and placentals) and all descendants of that ancestor.[5] Since this ancestor lived in the Jurassic period, Rowe's definition excludes all animals from the earlier Triassic, despite the fact that Triassic fossils in the Haramiyida have been referred to the Mammalia since the mid- 1. If Mammalia is considered as the crown group, its origin can be roughly dated as the first known appearance of animals more closely related to some extant mammals than to others. Ambondro is more closely related to monotremes than to therian mammals while Amphilestes and Amphitherium are more closely related to the therians; as fossils of all three genera are dated about 1. Middle Jurassic, this is a reasonable estimate for the appearance of the crown group.[7]T. S. Kemp has provided a more traditional definition: "synapsids that possess a dentary–squamosal jaw articulation and occlusion between upper and lower molars with a transverse component to the movement" or, equivalently in Kemp's view, the clade originating with the last common ancestor of Sinoconodon and living mammals.[8] The earliest known synapsid satisfying Kemp's definitions is Tikitherium, dated 2. Ma, so the appearance of mammals in this broader sense can be given this Late Triassic date.[9][1. Mc. Kenna/Bell classification[edit]In 1. Malcolm C. Mc. Kenna and Susan K. Bell, which has resulted in the Mc. Kenna/Bell classification. Their 1. 99. 7 book, Classification of Mammals above the Species Level,[1. The authors worked together as paleontologists at the American Museum of Natural History, New York. Mc. Kenna inherited the project from Simpson and, with Bell, constructed a completely updated hierarchical system, covering living and extinct taxa that reflects the historical genealogy of Mammalia.[2]Extinct groups are represented by a dagger (†). Class Mammalia. Subclass Prototheria: monotremes: echidnas and the platypus. America’s First Free- Roaming Genetically Engineered Insects Are Coming to New York. Diamondback moths may be a mere half- inch in length, but their voracious appetite for Brussels sprouts, kale and cauliflower make them a major pain for farmers. This week, the U. S. Department of Agriculture approved a potential solution: moths genetically engineered to contain a special gene that makes them gradually die off. A field trial slated to take place in a small area of upstate New York will become the first wild release of an insect modified using genetic engineering in the US. The moths have been engineered by the British biotech firm Oxitec, the same company that last year caused a stir with its plans to release genetically modified, Zika- fighting mosquitoes in the Florida Keys. The diamond back moths take a similar approach to the mosquitoes, modifying male mosquitoes to limit the population over time by passing on a gene to offspring when it mates with wild females that causes female moths to die before they reach maturity. The technique is a riff on an approach used to manage agricultural pests since the 1. Using radiation, scientists made insects like the screwworm unable to produce viable offspring. By 1. 98. 2, screwworm was eradicated from the US using this alternative to pesticides. In “Silent Spring” Rachel Carson suggested this approach was the solution to the dangers of harmful pesticides agricultural producers required to protect their crops. The problem was that it did not work on every insect—in many cases, it simply left irradiated insects too weak to compete for mates with their healthier kin. Diamondback moths are a sizable problem for farmers, and a problem that’s growing as the moths develop resistance to traditional pesticides. They do about $5 billion in damage to cruciferous crops worldwide every year. In the upcoming trial, a team at Cornell University will oversee the release of the genetically engineered moths in a 1. Cornell in Geneva, New York. After a review found that the field trial is unlikely to impact either the environment or humans, the USDA issued a permit that allows for the release of up to 3. It is caterpillars that damage crops, so the plan to release adult males that produce unviable offspring should not cause any additional crop damage. And any surviving moths will likely be killed off by pesticides or upstate New York’s frigid winter, according to the report submitted to the USDA. The plan to release modified mosquitoes in the Keys attracted much local ire—after initially getting the greenlight from the FDA, the project was ultimately stalled by a local vote and forced to find a new location for a trial. In upstate New York, too, the moths have stirred up a debate over GMOs for the past several years, though the plan has not been met with quite the same level of opposition. The approval process through the USDA rather than the FDA, too, was much swifter. In laboratory and greenhouse trials, the modified mosquito was reportedly effective in decreasing the overall population. But tests still need to determine how it will fare in open air. Oxitec has released its engineered mosquitoes Brazil, Grand Cayman, and Panama, and still plans to go ahead with a field trial in the Keys. In December, the company announced plans for field trials of a genetically modified Mediterranean fruit fly in Western Australia. It is also working on genetically engineering several other agricultural pests, including Drosophila suzukii and the Olive fly.[MIT Technology Review].
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