|
Subject |
Comments |
Views |
Author |
Date Written |
What two drifting continental plates look like
|
view preview
This is what it looks like to swim between two continental plates. The Silfra fissure in Iceland separates the North American and Eurasian plates, which drift two cm away from each other every year, causing earthquakes about once per decade.
|
|
|
2 |
2168 |
duddy |
10 years ago |
What really causes an 'ice age'?
|
view preview
I learned about something called axial precession in astronomy class several years ago, which is the idea that as something rotates along its axis, it will slowly trace out a cone if the weight of the object isn't equally distributed. In the case of Earth, Earth isn't a perfect sphere as many of us may think it is -- it actually bulges out in the middle enough for it to allow this phenomenon to occur. At the time, all I really took from this concept was how fascinating it is for the north axial pole to move 1° every 72 years from where it is now, and complete one full cycle every 26 000 years. However, I never managed to understand how this concept could fit in to my understanding of why ice ages [1] occur, and why they too follow a specific ...
|
|
|
3 |
2790 |
bio_man |
11 years ago |
|
1 |
6075 |
savio |
11 years ago |
What does a box and these fish have in common?
|
view preview
Their name and shape!Ostraciidae is a family of squared, bony fish closely related to the pufferfishes and filefishes. Members of this family occur in a variety of different colors (e.g. right - Hawaiian Blue Boxfish, Ostracion meleagris and the Yellow Boxfish, Ostracion cubicus), and are notable for the hexagonal or "honeycomb" patterns on their skin. Boxfish swim in a rowing manner. Their hexagonal plate-like scales are fused together into a solid, triangular or box-like carapace, from which the fins, tail, eyes and mouth protrude. Because of these heavy armoured scales, Ostraciidae are limited to slow movements, but few other fish are able to eat the adults. Some boxfish also secrete poisons from their skin into the surrounding water, fu ...
|
|
|
0 |
6207 |
bio_man |
7 years ago |
What do elephants and fish have in common?
|
view preview
Nothing, except for this fish, appropriately named the elephantnose fish ( Gnathonemus petersii) for its peculiar, elongated spout. The fish is widespread in the flowing waters of West Africa and hunts insect larva at dawn and dusk. Its nose is actually a sensitive extension of its mouth, that it uses for self-defense, communication, navigation, and finding worms and insects to eat. This organ is covered in electroreceptors, as is much of the rest of its body. The elephantnose uses a weak electric field, which it generates with specialized cells called electrocytes, which evolved from muscle cells, to find food, to navigate in dark or turbid waters, and to find a mate. The elephantnose fish live to about 6 to 10 years. ...
|
|
|
2 |
5543 |
duddy |
8 years ago |
What color is a toucan's skull?
|
view preview
Well, obviously it's white, but take a look at its bill! The attractive 7.5-inch-long bill is possessed by both male and female toucans. Interestingly, they use them during a mating ritual, pitching fruit to one another, but has very limited use as an excavation tool. Toucans make their nests in tree hollows found in rain forest regions of Southern Mexico, Central and South America, and the Caribbean region to which they are native. ...
|
|
|
2 |
1160 |
bio_man |
6 years ago |
What causes the rattle in a rattlesnake's tail?
|
view preview
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 ...
|
|
|
0 |
6026 |
bio_man |
7 years ago |
What causes the brown staining of some childrens teeth?
|
view preview
The brownish staining of a child's tooth enamel is due to excessive ingestion of fluoride. Fluoride is a mineral compound that is useful in preventing dental caries. It is thought to work by strengthening the mineral composition of tooth enamel making it more resistant to acid attacks. It may also reduce the acid-producing ability of microorganisms in dental plaque. The water supply may naturally provide fluoride, or it may be added. Mild fluorosis causes white mottling of the teeth; severe cases show brown staining and usually occur in areas where the level of fluoride in the water is many times greater than the recommended level of 0.7 to 1.2 parts per million. ...
|
|
|
2 |
3788 |
duddy |
11 years ago |
What are the most poisonous plants?
|
view preview
Plants are essential for any ecosystem, being both a food source and habitat for living things. Although plants are stationary, many are dangerous to touch or eat, making you sick or cause a bad reaction. Some of the most poisonous plants are described below: Abrus Precarious or Rosary Pea (Left) This plant has beans that contain a deadly poison. Ironically, their seeds are often used in jewelry and rosary making, but are not harmful when touched, only if chewed or scratched. The poison is known to stop protein synthesis, leading to organ failure. Ricinus Communis or the Castor Bean (Center) The castor bean plant comes from Africa and its seed is the source of castor oil used all over the world. However, the seeds contain a deadly poison called ...
|
|
|
0 |
10600 |
bio_man |
7 years ago |
What accounts for blue blood found in invertebrates
|
view preview
Hemocyanins are proteins that transport oxygen throughout the bodies of some invertebrate animals. These metalloproteins contain two copper atoms that reversibly bind a single oxygen molecule (O 2). They are second only to hemoglobin in frequency of use as an oxygen transport molecule. Unlike the hemoglobin in red blood cells found in vertebrates, hemocyanins are not bound to blood cells but are instead suspended directly in the hemolymph. Oxygenation causes a color change between the colorless Cu(I) deoxygenated form and the blue Cu(II) oxygenated form. ...
|
|
|
1 |
5289 |
bio_man |
11 years ago |
What a flame looks like in microgravity
|
view preview
Flames look a little different in space. On Earth, gravity causes a candle flame to be teardrop-shaped, and carries soot to the flame's tip, making it yellow. In microgravity, where these forces are absent, the flame is spherical, soot-free, and blue.
|
|
|
0 |
3583 |
duddy |
9 years ago |
Using millipedes to repel mosquitoes
|
view preview
Researchers studying a group of wedge-capped capuchin monkeys that live in tropical forests of central Venezuela have discovered that the monkeys protect themselves against the annual merciless onslaught of mosquitoes exactly as humans do: by rubbing themselves with mosquito repellent. But while humans may reach desperately for spritzers or bottles or laughably overhyped ''protective'' skin-so-softeners, the capuchins have learned to poke around in tree bark or termite mounds to extract a wriggling specimen of Orthoporus dorsovittatus, a millipede rich with powerful defensive chemicals called benzoquinones. The capuchin monkey will then proceed to anoint itself head to foot with the repellent secretions by massaging the four-inch-long millipe ...
|
|
|
0 |
4917 |
duddy |
10 years ago |
Unusual defence mechanism
|
view preview
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.
|
|
|
3 |
3479 |
savio |
11 years ago |
|
1 |
1901 |
duddy |
10 years ago |
Toxic meat
|
view preview
African spur-winged geese ( Plectropterus gambensis) become so toxic after eating blister beetles that consuming their flesh can kill a human. Blister beetles (family Meloidae) are toxic due to the presence of a chemical compound called cantharidin. Cantharidin is a potent toxin that these beetles produce and store in their bodies as a defense mechanism against predators. It acts as a powerful irritant and blistering agent when it comes into contact with skin or mucous membranes. The toxicity of blister beetles serves as a deterrent to potential predators, helping them avoid being eaten. ...
|
|
|
0 |
2990 |
duddy |
10 years ago |
|