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Why do humans have chins?
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What sets Homo sapiens apart from other animals? Among other things, our chins do. That piece of bone sticking out from your jaw is somewhat of a mystery - one that's inspired a diversity of wild theories to explain its purpose, according to a paper published this month in Evolutionary Anthropology. The author of the paper dismisses a number of these explanations, such as the possibility that the chin serves as a sexual signal (such traits usually only appear in one sex - like the mane of a male lion). Another proposal is that the chin acts to protect your throat - an idea the paper's author also shoots down, because for this to be a substantial advantage, humans would have to be constantly punching each other in the face. So the mystery rem ...
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14018 |
duddy |
8 years ago |
Where is our third eyelid?
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Some mammals, such as camels, polar bears, and seals, have full nictitating membranes. That is the transparent or translucent third eyelid that can be drawn across the eye for protection and to moisten it while maintaining visibility. In humans, the plica semilunaris (also known as the semilunar fold) and its associated muscles are thought to be homologous to the nictitating membranes seen in other animals. In most primate species, a plica semilunaris is present, but a fully developed nictitating membranes still exists in lemurs and lorisiform primates. Unlike the upper and lower eyelids, the nictitating membrane moves horizontally across the eyeball (shown below). In some diving animals, such as beavers and manatees, it moves across the e ...
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2559 |
bio_man |
4 years ago |
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5995 |
savio |
10 years ago |
What mechanism allowed early terrestrial animals to transition from water to land?
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A new study finds that Mudskipper fish carry water in their mouths in order to eat prey outside of water. As seen in the video below, the hidden water is expelled at the moment of eating and it serves as a suction to move the water and their meal back toward the esophagus. The water suction, or “hydrostatic” tongue, may serve as the evolutionary bridge that allowed our aquatic ancestors to begin feeding on land.
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35977 |
duddy |
9 years ago |
What causes the rattle in a rattlesnake's tail?
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Rattlesnakes are a group of venomous snakes native to the Americas known for their loud rattling tail. The tip of their tail, known as the rattle (middle), vibrates to deter predators or serves as a warning to passers-by. The rattle is composed of a series of hollow, interlocked segments made of keratin, which are created by modifying the scales that cover the tip of the tail. The contraction of special "shaker" muscles in the tail causes these segments to vibrate against one another, making the rattling noise (which is amplified because the segments are hollow) in a behavior known as tail vibration. The muscles that cause the rattle to shake are some of the fastest known, firing 50 times per second on average, sustained for up to three hour ...
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5976 |
bio_man |
6 years ago |
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5902 |
duddy |
8 years ago |
We were born to fight
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The bones of the male human face evolved their shape to withstand fistfights, according to a recent scientific study.
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19149 |
duddy |
9 years ago |
Unusual defence mechanism
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While the video may look like a trick an owner could teach their animal to do, some birds actually do play dead to avoid predation. If they feel in danger, they will essentially 'play dead' since predators are more interested in live, healthy prey than dead prey.
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3405 |
savio |
10 years ago |
Two-headed snake
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This two headed albino milk snake was born two years ago in Florida. The condition is known as Polycephaly and occurs when monozygotic twins fail to separate completely. Most organisms with this condition will not live for long, but occasionally you will get cases like this one, where the snake(s?) seem healthy enough and can live for years. The heads act independently of one another, and will fight over food given the opportunity. ...
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4281 |
duddy |
10 years ago |
Turns out that fish oil only benefits those who have the right genes
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Most foods today are fortified with essential oils like omega-3 fatty acids. Naturally, these oils are found in fish, and are known to benefit many parts of the body, including the eyes, brain, heart, and joints. So, are these so-called beneficial oils important for people who lack the DNA profile needed to metabolise them? It turns out that the extra omega-3 might not do much good at all. According to a study published in Science, Inuit people living in Greenland whose traditional diet of fish and marine mammals have the right enzymes in their bodies needed to metabolise these foods that are very high fat content. The researchers reported that their DNA that was most different was on chromosome 11, specifically among genes that control the ...
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15449 |
duddy |
8 years ago |
This synthetic organism survives with less than 500 genes
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This week in Science, researchers led by genome sequencing pioneer Craig Venter report engineering a bacterium to have the smallest genome - and the fewest genes - of any freely living organism. Known as Syn 3.0, the new organism has a genome whittled down to the bare essentials needed to survive and reproduce, just 473 genes. However, the function of 149 of Syn 3.0's 473 genes remain unknown. As Syn 3.0's name suggests, it’s not the first synthetic life made by Venter. In 2010, Venter's team reported that they had synthesized the sole chromosome of Mycoplasma mycoides - a bacterium with a relatively small genome - and transplanted it into a separate mycoplasma called M. capricolum, from which they had previously extracted the DNA. After s ...
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10763 |
duddy |
8 years ago |
This sweet fruit grows in the most unbelievable place
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The Brazilian Jaboticaba tree well and truly takes advantage of all the surface area on its trunk by growing its sweet, grape-like fruits all over it. It's said to have evolved its trunk-fruit so animals could reach them and distribute the seeds.
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4166 |
duddy |
9 years ago |
These aren't snakes, people - they are lizards
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Four species of legless lizard have been identified in the sand dunes of Antioch, California. This picture introduces Anniella grinnelli, one of the recently found species. It has a bright yellow belly and a lilac back with deep purple lines, and was named after Joseph Grinnell, the first director of the Berkeley Zoology Museum.
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2600 |
duddy |
10 years ago |
The best camouflage
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The Buff-tip moth ( Phalera bucephala) is a remarkable species that has developed a unique strategy to evade predators. When at rest, this moth cleverly disguises itself as a broken stick, blending seamlessly with its surroundings. The moth's wings are intricately patterned and colored to mimic the texture and appearance of a twig, complete with jagged edges and bark-like markings. This exceptional camouflage allows the Buff-tip moth to remain virtually invisible to predators such as birds and small mammals that may otherwise consider it a potential meal. By adopting this disguise, the moth gains a significant advantage in survival, as it can confidently rely on its remarkable mimicry to go undetected in its natural habitat. This fascinating ...
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5211 |
duddy |
10 years ago |
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4679 |
ehd123 |
9 years ago |
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