In a paper published in the journal Proceedings of the Royal Society B, researchers at Brown University and the University of Utah undertook an exhaustive specimen-by-specimen analysis to confirm that land-based vertebrates suffered catastrophic losses as the Permian drew to a close. From the ashes, the survivors, a handful of genera labeled "disaster taxa," were free to roam more or less unimpeded, with few competitors in their respective ecological niches. This lack of competition, the researchers write, caused vicious boom-and-bust cycles in the ecosystems, as external forces wreaked magnified havoc on the tenuous links in the food web. As a result, the scientists conclude from the fossil record that terrestrial ecosystems took up to 8 million years to rebound fully from the mass extinction through incremental evolution and speciation.

"It means the (terrestrial ecosystems) were more subject to greater risk of collapse because there were fewer links" in the food web, said Jessica Whiteside, assistant professor of geological sciences at Brown and co-author on the paper.

The boom-and-bust cycles that marked land-based ecosystems' erratic rebound were like "mini-extinction events and recoveries," said Randall Irmis, a co-author on the paper, who is a curator of paleontology at the Natural History Museum of Utah and an assistant professor of geology and geophysics at Utah.

The hypothesis, in essence, places ecosystems' recovery post-Permian squarely on the repopulation and diversification of species, rather than on an outside event, such as a smoothing out of climate. The analysis mirrors the conclusions reached by Whiteside in a paper published last year in Geology, in which she and a colleague argued that it took up to 10 million years after the end-Permian mass extinction for enough species to repopulate the ocean — restoring the food web — for the marine ecosystem to stabilize. 

"It really is the same pattern" with land-based ecosystems as marine environments, Whiteside said. The same seems to hold true for plants, she added.

Some studies have argued that continued volcanism following the end-Permian extinction kept ecosystems' recovery at bay, but Whiteside and Irmis say there's no physical evidence of such activity.

The researchers examined nearly 8,600 specimens, from near the end of the Permian to the middle Triassic, roughly 260 million to 242 million years ago. The fossils came from sites in the southern Ural Mountains of Russia and from the Karoo Basin in South Africa. The specimen count and analysis indicated that approximately 78 percent of land-based vertebrate genera perished in the end-Permian mass extinction. Out of the rubble emerged just a few species, the disaster taxa. One of these was Lystrosaurus, a dicynodont synapsid (related to mammals) about the size of a German shepherd. This creature barely registered during the Permian but dominated the ecosystem following the end-Permian extinction, the fossil record showed. Why Lystrosaurus survived the cataclysm when most others did not is a mystery, perhaps a combination of luck and not being picky about what it ate or where it lived. Similarly, a reptilian taxon, procolophonids, were mostly absent leading to the end-Permian extinction, yet exploded onto the scene afterward.

"Comparison with previous food-web modeling studies suggests this low diversity and prevalence of just a few taxa meant that links in the food web were few, causing instability in the ecosystem and making it susceptible to boom-bust cycles and further extinction," Whiteside said.

The ecosystems that emerged from the extinction had such low animal diversity that it was especially vulnerable to crashes spawned by environmental and other changes, the authors write. Only after species richness and evenness had been re-established, restoring enough population numbers and redundancy to the food web, did the terrestrial ecosystem fully recover. At that point, the carbon cycle, a broad indicator of life and death as well as the effect of outside influences, stabilized, the researchers note, using data from previous studies of carbon isotopes spanning the Permian and Triassic periods.

"These results are consistent with the idea that the fluctuating carbon cycle reflects the unstable ecosystems in the aftermath of the extinction event," Whiteside said.

source ; physorg

Here, we offer a rundown of some of the world's favorite tasty critters.

Palm Weevil Larva

Where It's Eaten: Nigeria, Papua New Guinea, Malaysia.
How: A rural staple that's high in protein, potassium, and calcium, this fat grub is eaten in one of several ways: straight from the tree; skewered and roasted over hot coals; or fried in sago flour and then wrapped in a sago leaf, like a tamale.
Taste: coconut (raw) or bacon (cooked).

Where It's Eaten: Australia, Colombia, Thailand.
How: In Australia, honeypot ants--which gorge themselves until their bellies swell to the size of grapes with a nectar-like substance--are eaten raw as sweet treats by aborigines. In Colombia, a variety of leaf-cutter ant, called hormigas culonas or "big-assed ants," is eaten toasted, like popcorn or peanuts. Red ants and their eggs are consumed sautéed or in salads in Thailand.
Taste: Lemony, vinegary, or sweet-and-sour, respectively.

Where It's Eaten: Mexico, Southern Africa.
How: High in vitamin B but releasing such a stink that it has to be seeped out (by soaking in warm water) before being eaten, these critters are at the center of a Jumil Festival near Taxco, in Mexico. There, folks harvest the bugs in the woods and either eat them alive--they apparently live for a while even after being beheaded--or ground up with chiles in tacos, before crowning a Jumil Queen. In Africa, they are beheaded, squeezed (to empty out a green gland), and then boiled and sun-dried, and eaten as snacks.
Taste: Like a blend of cinnamon and iodine.

Where It's Eaten: Cambodia and Venezuela.
How: Tarantula spiders--technically arachnids, not insects--are commonly fried in oil, salt, and sugar, and sometimes garlic, till crisp, then sold as street food in Cambodia, where they are eaten whole. The legs are crunchy, while the fat little abdomens are gooey. In the jungles of Venezuela, the Piaroa people consider the Goliath bird-eating tarantulas--which can grow to the size of a dinner plate--to be a delicacy and roast them over a fire.
Taste: Crab-like and nutty.

Where It's Eaten: West Africa, Australia, parts of South America.
How: Often eaten raw as tasty snacks, termites are plucked right out of whatever wood they are feasting on or caught en masse around lights, where they also like to swarm. Then they are sold at markets and brought home to be roasted over hot coals or fried in oil.

Taste: Like carrots.

Where It's Eaten: New Zealand.
How: Resembling big, fat maggots but treated as a delicacy in New Zealand, these fellas are eaten either as a raw snack or sautéed as a special meal by their fans who find them burrowing into the rotting wood of tree trunks. The grubs eat the wood, making them rich in protein and therefore even more desirable.
Taste: Like peanut butter.

Where It's Eaten: Japan.
How: Called hachinoko, the pale yellow larvae of wasps or bees are harvested carefully from nests, cooked in soy sauce and sugar, and eaten as a crunchy snack--often with a sprinkling of cooked adult wasps in the mix, too.
Taste: Sweet and crunchy.

Where It's Eaten: Japan, China, all over Asia, in many parts of the U.S.
How: Periodical cicadas spend most of their lives--up to 17 years--living underground and sucking sap from tree roots. But when they emerge to reproduce and die, plenty of folks (including a great many throughout parts of the U.S.) are waiting to catch them before their skins harden, so they can boil or fry them and eat them--kind of as we would with shrimp--as an integrated part of a meal. The singing critters are low in fat and contain 30 to 40 percent protein. Annual cicadas, meanwhile, live anywhere from two to seven years and are caught with much more ease and eaten in much the same way--boiled, fried, or sautéed.
Taste: Asparagus or clammy potato.

Where It's Eaten: Indonesia.
How: Boiled or fried as a special treat, these mosquito-eaters are caught by brandishing a slender palm-wood stick dipped in sticky tree sap and then just waiting for them to land.
Taste: Similar to soft-shell crab.

Where They're Eaten: Mexico.
How: The eggs of the giant black Liometopum ant, sometimes called "insect caviar," are harvested from agave plant roots. They're either boiled or fried in butter to be eaten in tacos, or are presented in a bowl with a side of tortillas for the popular dish escamoles.
Taste: Buttery and nutty, with the consistency of cottage cheese.

Where It's Eaten: Botswana, South Africa, Zimbabwe.
How: Many types of caterpillars are eaten all over the world. In parts of Africa, the specific type of fat blue-and-green spiky caterpillar that lives in the mopane tree is prized as a protein-packed free food. After being squeezed to expel green slime from its gut, the worm is dried in the sun or smoked and almost always served with sauce or in a stew to lend it some flavor.
Taste: Bland to buttery.

Where It's Eaten: Mexico.
How: Roasted to a crunch and tossed with chile and lime, chapulines sit in huge mounds at street stands and in markets in Oaxaca. Vendors sell them to folks who consume them by the handful, just like chips.
Taste: Salty and spicy.

Where It's Eaten: Vietnam, China, Korea.
How: The silkworm itself is an edible byproduct of the silk industry, as manufacturers only use the bugs' cocoons to make the cloth. These squirmy little guys are seasoned and boiled in Korea, and fried in China and Vietnam.
Taste: Briny, similar to dried shrimp, with a chewy consistency.

Where It's Eaten: Thailand.
How: These massive critters are a popular snack in Thailand, commonly found in Bangkok street stalls, where they are eaten whole, fried with spicy sauce, or steamed. They're also available roasted and sealed in a can.
Taste: Briny and fruity with a fish-like consistency.

Where It's Eaten: Vietnam, Thailand, China.
How: Also technically an arachnid, not an insect, the scorpion is usually served as street food--scooped up alive and wriggling, skewered on a kebab, and deep-fried in oil.
Taste: Like soft-shell crab or shrimp in its shell.

Hiccups are involuntary spasms of the diaphragm — the muscular membrane in your chest that figures importantly in breathing. A spell of them ensues when that muscle gets irritated, often by the presence of too much food in the stomach, or too little.

Weirdly, though, hiccups are as useless as they are annoying; they serve no apparent purpose. One hypothesis suggests they may be a remnant of a primitive sucking reflex. Whatever the ancient function, they are little more than a nuisance now — something to be gotten rid of via a variety of creative folk remedies.

We spend roughly one-third of our lives asleep. No human can go without it for more than a handful of days, and yet sleep may be the least understood of all our activities.

It certainly allows for a lot of body "maintenance work," from production of chemicals that get used during waking hours to the self-organization of neurons in the developing brain. REM sleep, with its high neuronal activity, occurs for longer each night during periods of brain growth.

Several theories point to sleep as a state vital to memory and learning. It may help ingrain episodic memories into long-term storage, and it also may simply give our mental waking activities a much-needed break.

Okay, technically speaking, dying isn't an everyday activity. It is, however, done by a whole bunch of people every day. Why?

We die because our cells die. Though they replace themselves over and over again for 70-odd years, they can't do so forever. Inside each cell, telomeres at the end of our chromosomes contain genetic information that gets clipped away with each cell division. Telomeres start out long enough to handle a great many scissor snips. But eventually, they run out of length, the information they held is lost and the cells can't divide anymore.

Luckily, scientists are working on how to extend the lives of human beings, and think they could someday double the average lifespan.

Hey, wait a second… how do two eyes produce 3-D vision?

It's actually a trick of the mind (or three tricks, to be exact). First, our brains utilize "binocular disparity" — the slight difference between the images seen by our left and right eyes. Our brains use the two skewed versions of a scene to reconstruct its depth.

For a close-up object, the brain registers the "convergence" of our eyes, or the angle they swing through to focus on the object, to decide how far away it is.

When glancing at things on the go, we subconsciously gauge distance by registering "parallax." That's the difference in speed at which closer and farther objects seem to move as you pass them.

Turns out, the cheek-reddening reaction is a universal human response to social attention. Everyone does it — some more than others. Common blushing triggers include meeting someone important, receiving a compliment and experiencing a strong emotion in a social situation.

Blush biology works like this: Veins in the face dilate, causing more blood to flow into your cheeks and producing a rosy complexion. However, scientists are stumped as to why all that happens, or what function it serves.

It's weird, when you think about it, that swapping spit seems romantic. Turns out it's a biological instinct.

Kissing allows people to use smell and taste to assess each other as potential mates. People's breath and saliva carry chemical signals as to whether they are healthy or sick, and in the case of females, whether they're ovulating — all important messages for potential partners in reproduction.

Furthermore, the skin around peoples' noses and mouths is coated with oils that contain pheromones, chemicals that broadcast information about a person's biological makeup. When people pick up each other's pheromones during a sloppy kiss, they'll subconsciously become either more or less sexually attracted to each other depending on what they detect.

Alongside the chemosensory cues exchanged during kisses, psychologists also believe the actual physical act of kissing helps couples bond. This theory is supported by the fact that oxytocin — a hormone that increases most peoples' feelings of sociality, love and trust — floods brains when mouths kiss.

The answer may stink, but everything we eat or drink gives us gas. In fact, it's normal to fart up to half a gallon (1.9 liters), or about 15 to 20 toots worth of gas each day.

Particularly fragrant flatulence, however, comes from colonies of bacteria shacked up inside our lower intestinal tract. In the process of converting our meals into useful nutrients, these food-munching microbes produce a smelly by-product of hydrogen sulfide gas—the same stench that emanates from rotten eggs.

Just like the rest of us, the bacteria like munching on sugary foods best. The types of sugar naturally present in milk, fruit — and, of course, beans — produce the most farts.

The punchline of a joke hits you, and with it comes a funny feeling: You're suddenly overcome by the urge to yell out spastically, over and over. Laughing is weird. Why do we do it?

Psychologists think this behavioral response serves as a signal to others by spreading positive emotions, decreasing stress and contributing to group cohesion. For those same reasons, chimps and orangutans smile and laugh during social play too.

In fact, many hypothesize that laughing evolved from panting. When our prehuman ancestors wrestled playfully with each other, they got all panty… and that eventually turned into getting laughy.