Pangolins hold clues to how COVID-19 began—and might end
They're small spiny mammals that look like anteaters with scales.
May 8, 2020
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They're small spiny mammals that look like anteaters with scales.
May 8, 2020
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A new paper in Biology Methods & Protocols indicates that researchers in Germany have developed a new system to display epitopes in mammal cells for immunization studies. They believe that this method can help scientists ...
Dec 12, 2023
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American scientists believe a new procedure to repair severed nerves could result in patients recovering in days or weeks, rather than months or years. The team used a cellular mechanism similar to that used by many invertebrates ...
Feb 3, 2012
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(Medical Xpress)—The temperature-regulation research of Stanford biologists H. Craig Heller and Dennis Grahn has led to a device that rapidly cools body temperature, greatly improves exercise recovery, and could help explain ...
Aug 30, 2012
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University of Minnesota Medical School and College of Biological Sciences researchers have made a key discovery showing that male sex must be maintained throughout life.
Jul 20, 2011
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Although most victims survive the 735,000 heart attacks that occur annually in the U.S., their heart tissue is often irreparably damaged—unlike many other cells in the body, once injured, heart cells cannot regenerate. ...
Mar 8, 2019
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Eating fructose appears to alter cells in the digestive tract in a way that enables it to take in more nutrients, according to a preclinical study from investigators at Weill Cornell Medicine and NewYork-Presbyterian. These ...
Aug 18, 2021
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Sharing a home with a pet appeared to act as a buffer against psychological stress during lockdown, a new survey shows.
Sep 25, 2020
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(Medical Xpress) -- The phrase "eat dirt" takes on a whole new meaning when used by biologists, who have widely observed that humans, birds and mammals all engage in geophagy. A new Cornell study concludes that in humans, ...
Jun 10, 2011
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(Medical Xpress)—Apes, including humans, lack an enzyme called uricase that breaks down uric acid. Because we lack uricase, we are predisposed to developing gout. After reconstructing ancient versions of the enzyme found ...
Mammals (formally Mammalia) are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain.
Mammals are divided into three main categories depending how they are born. These categories are, monotremes, marsupials and placentals. Except for the five species of monotremes (which lay eggs), all mammal species give birth to live young. Most mammals also possess specialized teeth, and the largest group of mammals, the placentals, use a placenta during gestation. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart.
There are approximately 5,400 species of mammals, distributed in about 1,200 genera, 153 families, and 29 orders (though this varies by classification scheme). Mammals range in size from the 30–40-millimetre (1.2–1.6 in) Bumblebee Bat to the 33-metre (110 ft) Blue Whale.
Mammals are divided into two subclasses, the prototheria, which includes the oviparous monotremes, and the theria, which includes the placentals and live-bearing marsupials. Most mammals, including the six largest orders, belong to the placental group. The three largest orders, in descending order, are Rodentia (mice, rats, and other small, gnawing mammals), Chiroptera (bats), and Soricomorpha (shrews, moles and solenodons). The next three largest orders include the Carnivora (dogs, cats, weasels, bears, seals, and their relatives), the Cetartiodactyla (including the even-toed hoofed mammals and the whales) and the Primates to which the human species belongs. The relative size of these latter three orders differs according to the classification scheme and definitions used by various authors.
Phylogenetically, Mammalia is defined as all descendants of the most recent common ancestor of monotremes (e.g., echidnas and platypuses) and therian mammals (marsupials and placentals). This means that some extinct groups of "mammals" are not members of the crown group Mammalia, even though most of them have all the characteristics that traditionally would have classified them as mammals. These "mammals" are now usually placed in the unranked clade Mammaliaformes.
The mammalian line of descent diverged from an amniote line at the end of the Carboniferous period. One line of amniotes would lead to reptiles, while the other would lead to synapsids, including mammals. The first true mammals appeared in the Triassic period. Modern mammalian orders appeared in the Palaeocene and Eocene epochs of the Palaeogene period.
This text uses material from Wikipedia, licensed under CC BY-SA