Brain size riddle solved as humans exceed evolutionary trend
The largest animals do not have proportionally bigger brains—with humans bucking this trend—a study published in Nature Ecology & Evolution has revealed.
The largest animals do not have proportionally bigger brains—with humans bucking this trend—a study published in Nature Ecology & Evolution has revealed.
Plants & Animals
Jul 8, 2024
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In the fight to mitigate climate change and deforestation in the tropics, timber plantations have emerged as a promising strategy for reforesting degraded land and connecting patches of natural forest. Often, these are species ...
Ecology
Jul 29, 2024
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A team of paleontologists and natural science specialists from the U.K., the U.S. and France reports that ancient fossil evidence uncovered on Scotland's Isle of Skye suggests small mammals living millions of years ago may ...
One of the most important controversies about human evolution and expansion is when and by what route the first hominins arrived in Europe from the African continent. Now, geological dating techniques at the Orce sites (Baza ...
Evolution
Jul 12, 2024
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Mammals that have evolved more developed brains tend to have a smaller size difference between males and females of that species, according to new research led by the University of Bath and published in Nature Communications.
Plants & Animals
Jul 25, 2024
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While human activity has had a massive effect on the natural world, a new study from North Carolina State University finds that climate is still the most influential factor in determining where mammals can thrive. The work ...
Plants & Animals
Jul 26, 2024
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Cut marks on fossils could be evidence of humans exploiting large mammals in Argentina more than 20,000 years ago, according to a study published July 17, 2024 in the open-access journal PLOS ONE by Mariano Del Papa of National ...
Paleontology & Fossils
Jul 17, 2024
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British dormice have declined by a shocking 70% between 2000 and 2022, according to the latest report by the national dormouse monitoring program. But my research indicates that this decline might not be that catastrophic.
Plants & Animals
Aug 4, 2024
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In one of the largest studies of cancer susceptibility across bird species, researchers at Arizona State University describe an intriguing relationship between reproductive rates and cancer susceptibility.
Plants & Animals
Jul 31, 2024
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Cape fur seals with rabies have infected at least seven people in South Africa and vaccinations will be trialed to try to contain what is the first documented outbreak of the disease in a marine mammal population, a coastal ...
Ecology
Jul 31, 2024
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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