Kanazawa’s theory is that intelligence—particularly our ability for on-the-spot problem solving and reasoning—arose as an adaptation to deal with the unusual and unexpected, such as a sudden forest fire.

Since disasters like that are rare in daily life, responding to them wouldn’t likely be something our ancestors were hard-wired to "know" how to do. Surviving the fire required both the ability to think up a new behavior, and the willingness to try it out.

Passed down via genetics, those two traits are still the calling cards of an intelligent brain—expressed as a tendency toward adopting nontraditional social values and preferences, Kanazawa says in his new study, published in the March 2010 issue of Social Psychology Quarterly.

As a result of their iconoclastic ancestry, he suggests, people with higher levels of intelligence are more likely to adopt social values and behaviors that are relatively new to human life—liberalism, atheism, staying up late, and (for men) monogamy, for example.

Link

The oldest dinosaur fossil ever found dates back around 230 million years. But the fossils of around a dozen specimens of a new animal called Asilisaurus kongwe, or silesaur, found in Tanzania lead researchers to believe dinosaurs diverged from another evolutionary line around 243 million years ago.

“Back then it was a very large river system, maybe something like the Mississippi today,” said lead author and University of Texas at Austin paleontologist Sterling Nesbitt. During that time, Africa, South America, Antarctica, Australia and India were all one giant continent called Gondwana.

Though silesaurs are very closely related to dinosaurs, they lack the open hip-sockets that are universal in dinosaurs. The Asilisaurus was a small, four-legged creatures with a long tail. Their beak-like jaws and leaf-shaped teeth helped the animals eat the soft, fibrous leaves of the primordial palms, ferns and conifers that were prevalent during the Triassic period. That suggests that, while the animal may not have been exclusively vegetarian, a good portion of its diet came from plants, he said.

The silesaur changes the conventional wisdom that the dinosaur’s closest relatives were predators. Link

In chimpanzees, he points out, dominant apes will oftentimes extend an open hand to distressed subordinates as a sort of calming gesture; and in some chimp communities, individuals will clasp hands overhead as they manually groom each other. In humans, in contrast, it’s most often the subordinate who initiates the handshake, particularly toward dominant people they wish to impress.

Link | Photo: US House of Representatives

Scientists have discovered what may be the world’s oldest set of footprints. The fossil record may be evidence of a four-legged animal’s first steps on land 397 million years ago:

Scientists tell the journal Nature that the fossil trackways even retain the impressions left by the "toes" on the animals’ feet.

The team says the find means that land vertebrates appeared millions of years earlier than previously supposed. [...]

They represent the movements of many animals as they scurried around what would have been a tropical muddy shoreline in the Middle Devonian Period of Earth history.

Slabs of carbonate rock are dappled with prints that range in size and detail. Some indentations are obscured where successive animals have trampled over the same patch of ground; but others retain exquisite features of the pads and digits that made them.

Link

Our forebears abandoned their easier foraging habits, traveling longer distances through a tropical landscape to acquire sufficient food to survive. Adding meat to their diets meant more calories, but finding prey also took more work. Their activity level increased and with it their need to dissipate body heat to avoid tissue damage. By 1.6 mya, protohumans had long legs for sustained walking and running. Along with that trait came naked skin and a large number of eccrine sweat glands, which produce moisture that removes body heat through evaporative cooling. The hairs on our head also help to combat overheating, by shielding our big brain from direct sun.

Link | Photo: US Department of Energy

Prions are rogue version of a protein called PrP. Like all proteins, they are made up of chains of amino acids that fold into a complex three-dimensional structure. Prions are versions of PrP that have folded incorrectly and this misfolded form, called PrPSc, is social, evangelical and murderous. It converts normal prion proteins into a likeness of its abnormal self, and it rapidly gathers together in large clumps that damage and kill surrounding tissues.

Li has found that variation can creep into populations of initially identical prions. Their amino acid sequence stays the same but their already abnormal structures become increasingly twisted. These “mutant” forms have varying degrees of success in different environments. Some do well in brain tissue; others thrive in other types of cell. In each case, natural selection culls the least successful ones. The survivors pass on their structure to the “next generation”, by altering the folds of normal prion proteins.

Scientists are not ready to classify prions as living things, even though this discovery may lead to some refinements in the definition of life. Link

While sickle cell anemia is the best known of these evolutionary diseases, it is not the only one. Migraines, depression and bipolar disorder are all passed down genetically, and there’s a good reason these traits that seem to be negative haven’t been eradicated through the millenia.

Migraines

Migraines don’t just cause majorly painful headaches, they also stimulate the nervous system, making people far more sensitive to light and sound. While this doesn’t really help modern day migraine sufferers, it could help save someone’s life in prehistoric times. Scientists speculate that migraines allowed prehistoric men and women to be one step ahead of their predators and their prey, making them more fit for survival.

Source Image Via Migraine Chick [Flickr]

Depression

While between 30 to 50 percent of all people suffer from depression at some point, it doesn’t seem the condition would offer any advantages. Surprisingly, depression actually helps people focus on their problems and then think more clearly about the possible solution to the issues that are bothering them.

Studies show that people who are depressed tend to score better on complex problems in intelligence tests than those who are not. Side effects of depression, such as lack of sexual interest and lack of appetite, can even help prevent distractions from our problem solving abilities.

Source Image Via Darkwood67 [Flickr]

Bipolar Disorder

Bipolar disorder works in a much different manner. When individuals inherit severe bipolar disorders, they can have a hard time concentrating, making sound decisions, feeling comfortable in social situations and organizing their time. But, when someone gets the right combination of the genes that cause bipolar disorder, they can see increased creativity, courage and productivity.

Source Image Via Ventolinmono [Flickr]

In order to make lunge-feeding work, you have to have a really big mouth to capture enough water in one gulp. But in order to have a big mouth, you need a big body. And in order to keep that big body running, you need to get a lot of food. And in the very act of getting that food–diving deep, lunging open-mouthed, and then pushing a school-bus-sized volume of water forwards–requires a lot of energy on its own.

This type of feeding might explain the size of whales.

If the scientists are right, they may have discovered one of the big ironies in evolution. Lunge-feeding may have allowed whales to become the biggest animals ever to roam the planet. But this was not an open-ended invitation.r. Once whales got large enough, lunge feeding itself became so costly it prevented them from getting any bigger.

Link

Most mammals can sprint faster than humans — having four legs gives them the advantage. But when it comes to long distances, humans can outrun almost any animal. Because we cool by sweating rather than panting, we can stay cool at speeds and distances that would overheat other animals. On a hot day, the two scientists wrote, a human could even outrun a horse in a 26.2-mile marathon.

Why would evolution favor the distance runner? The prevailing theory is that endurance running allowed primitive humans to incorporate meat into their diet. They may have watched the sky for scavenging birds and then run long distances to reach a fresh kill and steal the meat from whatever animal was there first.

Other research suggests that before the development of slingshots or bows, early hunters engaged in persistence hunting, chasing an animal for hours until it overheated, making it easy to kill at close range. A 2006 report in the journal Current Anthropology documents persistence hunting among modern hunter-gatherers, including the Bushmen in Africa.[...]

There is other evidence that evolution favored endurance running. A study in The Journal of Experimental Biology last February showed that the short toes of the human foot allowed for more efficient running, compared with longer-toed animals. Increasing toe length as little as 20 percent doubles the mechanical work of the foot. Even the fact that the big toe is straight, rather than to the side, suggests that our feet evolved for running.

Link via Instapundit | Image: U.S. Secret Service

The grandmother hypothesis suggests that humans have “given up” their reproductive potential in later years in order to invest in the children they already have as well as their grandchildren. Naturally, this is an unconscious, biological adaptation that emerges over many generations and is not the result of individual decision-making. For such a hypothesis to be confirmed it would have to be demonstrated that children are significantly more likely to survive when a grandmother is present than when she isn’t.

Dr. Lummaa has done just that in her study published in the journal Nature, demonstrating that children are 12% more likely to survive to adulthood when they have a grandmother’s support than when they don’t.

Let’s hear it for grandmas! Link

In apes—both modern apes and, presumably, the ancient ancestors of Ardipithecus—males find mates the good old-fashioned apish way: by fighting with other males for access to fertile females. Success, measured in number of offspring, goes to macho males with big sharp canine teeth who try to mate with as many ovulating females as possible. Sex is best done quickly—hence those penis bristles, which accelerate ejaculation—with the advantage to the male with big testicles carrying a heavy load of sperm. Among females, the winners are those who flaunt their fertility with swollen genitals or some other prominent display of ovulation, so those big alpha dudes will take notice and give them a tumble, providing a baby with his big alpha genes.

Let’s suppose that some lesser male, with poor little stubby canines, figures out that he can entice a fertile female into mating by bringing her some food. That sometimes happens among living chimpanzees, for instance when a female rewards a male for presenting her with a tasty gift of colobus monkey.

Among Ardipithecus’s ancestors, such a strategy could catch on if searching for food required a lot of time and exposure to predators. Males would be far more successful food-providers if they had their hands free to carry home loads of fruits and tubers—which would favor walking on two legs. Females would come to prefer good, steady providers with smaller canines over the big fierce-toothed ones who left as soon as they spot another fertile female. The results, says Lovejoy, are visible in Ardipithecus, which had small canines even in males and walked upright.

Jamie Shreeve of NGM Blog Central has the story: Link

White and his colleagues found so many teeth of different Ardipithecus individuals that they could compare male and female canines with some confidence. The male teeth turn out to be surprisingly blunted. This result suggests that hominids shifted away from a typical ape social structure early in our ancestry. If this was a result of males forming long-term bonds with females and helping raise young, this shift was able to occur while hominids were still living a very ape-like life. Ardipithecus existed about 2 million years before the oldest evidence of stone tools, suggesting that technology was not the trigger for the evolution of nice hominid guys.

There have been a couple of hominid bones found that are even older than Ardipithecus, but none with enough fossils to even begin reconstructing a skeleton. Link -via Metafilter

A private owner has donated a fossil that could change the way we think about Tyrannosaurus and their development.

Some scientists believed the T.Rex evolved to its enormous size, then its arms shrank, when they were no longer needed.  The new discovery, though, shows that the tiny-armed killing machine may have evolved from a much smaller killing-machine-with-tiny-arms.  This totally rearranges the previous T.Rex evolution paradigm.

The 125 million-year-old fossil dinosaur, unearthed in China and dubbed Raptorex kriegsteini, is “as close to the proverbial missing link on a lineage as we might ever get for tyrannosaurs,” Sereno said.

Link

(As a special bonus, check out the religious debate in the comments.)

From the Upcoming ueue, submitted by HeartlessMachine.

Given the possibility of being deceived, it would have been rather foolish of our ancestors to take at face value a person’s verbal or behavioral expressions of remorse. Instead, over tens of thousands of years, uncontrollable blushing would have evolved as a fairly reliable predictor of the actor’s future behavior. In other words, if the behavior or situation at issue made the person feel so uncomfortable that his or her facial veins dilated—a physiological response that for many people is attended by a somewhat unpleasant tingling sensation—the blusher would probably avoid repeating that behavior in the future. Thus, blushing seems to be an appeasement display. Interestingly, this evolutionary hypothesis is aligned with a recent argument advanced by neuroscientist Mark Changizi in his book The Vision Revolution (BenBella, 2009). Among other things, Changizi claims that our species unusually strong color vision evolved so that we could detect subtle hue changes in other peoples’ skin, thereby deducing their emotions.

Link

Image by flickr user SanFranAnnie used under creative commons license.

Trying to plumb the canine mind is a favorite pastime of dog owners. “Everyone feels like an expert on their dog,” says Alexandra Horowitz, a cognitive scientist at Barnard College and author of the new book Inside of a Dog: What Dogs See, Smell, and Know. But scientists had carried out few studies to test those beliefs–until now.

This fall, [Duke University anthropologist Brian] Hare is opening the Duke Canine Cognition Center, where he is going to test hundreds of dogs brought in by willing owners. Marc Hauser, a cognitive psychologist at Harvard University, recently opened his own such research lab and has 1,000 dogs lined up as subjects. Other facilities are operating in the U.S. and Europe.

What they’ve found out so far is that dogs can learn over 200 distinctive human words, but they may mean different things to a dog than to humans. And the intelligent, friendly, and obedient behavior we see in dogs evolved because those things are advantageous to the dog, even though we see them as advantageous to us. Link -via Metafilter

(image credit: D.L. Anderson)

If you could travel back to 130 million years ago, you might not be impressed with the earliest flowers. “They didn’t look like they were going anywhere,” Dr. Doyle said.

Those early flowers were small and rare, living in the shadows of far more successful nonflowering plants. It took many millions of years for flowers to hit their stride. Around 120 million years ago, a new branch of flowers evolved that came to dominate many forests and explode in diversity. That lineage includes 99 percent of all species of flowering plants on Earth today, ranging from magnolias to dandelions to pumpkins. That explosion in diversity also produced the burst of flower fossils that so puzzled Darwin.

Genetic research is providing answers to how plants can switch on genes that control how different plants parts grow, and to use sexual reproduction to increase genetic diversity. Link

One of the first traits that differentiated humans from our ancestors was upright gait. There are several hypotheses about the emergence of this trait, but it seems to have offered a way to move more efficiently in open environments such as the savanna. Although our earliest human ancestors were very apelike in terms of their brains, their upright gait had changed their pelvis to look much like our modern one. This reshaped pelvis came with a narrower birth canal, making childbirth more difficult.

Meanwhile the new roaming grounds afforded advantages in acquiring resources and negotiating social relationships to those with flexible, problem-solving behavior. Over time, natural selection increased brain size in these early humans. But at some point, the selection for bigger and bigger brains collided head-on, so to speak, with the narrow pelvis. If babies’ heads got any bigger, they would get stuck in the birth canal and kill both mother and child. Although natural selection worked to maximize what could be done—for instance, babies’ heads compress as they twist their way around the bones in the pelvis—there simply is not enough room for a big, mature brain to pass through.

Therefore, Bock explains, human baby brains continue to develop substantially after birth and it takes longer for them to learn how to walk.

Link

Image by flickr user BadrNaseem used under creative commons license

“Crying is a highly evolved behavior,” said researcher Oren Hasson, an evolutionary biologist at Tel Aviv University in Israel. “My analysis suggests that by blurring vision, tears lower defenses and reliably function as signals of submission, a cry for help, and even in a mutual display of attachment and as a group display of cohesion.”

Crying as a social behavior? What do you think? Link -via Digg

Depressed people often think intensely about their problems. These thoughts are called ruminations; they are persistent and depressed people have difficulty thinking about anything else. Numerous studies have also shown that this thinking style is often highly analytical. They dwell on a complex problem, breaking it down into smaller components, which are considered one at a time.

This analytical style of thought, of course, can be very productive. Each component is not as difficult, so the problem becomes more tractable. Indeed, when you are faced with a difficult problem, such as a math problem, feeling depressed is often a useful response that may help you analyze and solve it. For instance, in some of our research, we have found evidence that people who get more depressed while they are working on complex problems in an intelligence test tend to score higher on the test.

Link via Instapundit

Photo credit: Guillermo Perales Gonzalez

First the ancestral plant must have adapted to move its tentacles and leaves in a particular direction, giving it a greater chance of sticking to and engulfing a passing insect.

Next it sped up how quickly it detected prey and tried to respond.

Then the plant would have had to find a way to become selective, so it only tried to trap live prey and not any detritus that landed upon it.

Finally, it must have evolved its tentacles into sensory hairs and teeth that detect and wrap around prey, respectively, while also losing its sticky glands and growing new digestive glands capable of digesting the victim’s corpse.

The adaptations led to the plant’s ability to eat larger insects for more nutrition. Link -via the Presurfer

The shell itself is made from broadened and flattened ribs, fused to parts of the turtle’s backbone (so that unlike in cartoons, you couldn’t pull a turtle out of its shell). The shoulder blades sit underneath this bony case, effectively lying within the turtle’s ribcage. In all other back-boned animals, whose shoulder blades sit outside their ribs (think of your own back for a start). The turtle’s torso muscles are even more bizarrely arranged.

Ed Yong looks at turtle anatomy and how this weird configuration evolved from the basic vertebrate plan. Link

Forget DNA! Scientists have re-traced our evolutionary tree and confirmed human’s relationship to fellow apes through laughter.

Who says you can’t learn anything by tickling chimps?

To investigate that, Marina Davila Ross of the University of Portsmouth in England and colleagues carried out a detailed analysis of the sounds evoked by tickling three human babies and 21 orangutans, gorillas, chimps and bonobos.

After measuring 11 traits in the sound from each species, they mapped out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online Thursday in the journal Current Biology.

They also concluded that while human laughter sounds much different from the ape versions, its distinctive features could well have arisen from shared ancestral traits.

After measuring 11 traits in the sound from each species, they mapped out how these sounds appeared to be related to each other. The result looked like a family tree. Significantly, that tree matched the way the species themselves are related, the scientists reported online Thursday in the journal Current Biology.

Link

From the Upcoming ueue, submitted by Gauldar.

Seagrasses, which thrive in shallow water, spread rapidly through these newly formed environments. The researchers think that the ancestors of modern seahorses followed.

Horizontally swimming fish living in seagrass beds don’t blend into the environment well and are easily picked off by predators.

A solution seems to have evolved in seahorse ancestors: the upright body shape, which enables seahorses to seamlessly blend in with surrounding seagrass.

Link

(Photo: Robert Sisson / NGS)

Paleontologist Jorn Hurum lead a team of scientists to analyze a 47-million-year-old fossil above (named "Ida") and came up with this intriguing conclusion: it is a critical missing-link species in the evolution of primates!

The fossil, he says, bridges the evolutionary split between higher primates such as monkeys, apes, and humans and their more distant relatives such as lemurs.

"This is the first link to all humans," Hurum, of the Natural History Museum in Oslo, Norway, said in a statement. Ida represents "the closest thing we can get to a direct ancestor."

Ida, properly known as Darwinius masillae, has a unique anatomy. The lemur-like skeleton features primate-like characteristics, including grasping hands, opposable thumbs, clawless digits with nails, and relatively short limbs.

"This specimen looks like a really early fossil monkey that belongs to the group that includes us," said Brian Richmond, a biological anthropologist at George Washington University in Washington, D.C., who was not involved in the study.

Link | Ida’s official website – Thanks Marilyn!

Knowledge on evolution fills many books, which can be intimidating to someone just beginning to learn about it. Geeks are Sexy has a post explaining in layman’s terms how evolution works and the reason why the theory is so important as a tool when examining the world. The basics boil down to four statements:

* Variation, which arises through mutation, exists within and between populations for every trait.
* More individuals are born into a population than can survive (usually because of the scarcity of resources).
* Traits are passed down from parents to their offspring.
* Individuals most fit to survive in their environment generally do (Natural Selection).

Of course, there’s a lot more which is easier to absorb once you have the basics. Link

From the Upcoming ueue, submitted by Geeksaresexy.

Why are snails so slow? Roberto Nespolo and Paulina Artacho of the Southern University of Chile may have the answer: turns out, evolution favors slower snails because they are more energy efficient.

Testing the biological hypothesis of the “energetic definition of fitness,” which purports that the less energy an animal spends, the more it will have for survival and reproduction, the researchers measured the size and standard metabolic rate (the amount of energy required for maintenance) of nearly 100 garden snails. After seven months, the researchers found that surviving snails had a metabolic rate 20 percent lower than that of the dead snails—and no correlation between snail size and rate of survival.

Link

From the Upcoming ueue, submitted by philosophile.

Link

From the Upcoming ueue, submitted by Andrea.

… scientists have discovered that the "rosada" – or pink – iguana is a species in its own right after comparing its genes with other land iguanas on the Galapagos.

There were also physical differences, besides the striking pink and black-striped colouring. Pink iguanas had flat head scales, unlike other land iguanas, and a thick fatty crest on the back of the neck with small conical scales.

Link