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Friday, 3 July 2009

Past and present, june 2009

Today:

  1. Culture May Be Encoded in DNA
  2. Early domestic animals were surprisingly well bred
  3. Spanish scientists develop echolocation in humans
Short Stories:
  1. 'The world's oldest manufactured beads' are older than previously thought
  2. China's earliest known carving found in central Henan Province
  3. New fossil primate suggests common Asian ancestor, challenges primates such as 'Ida'
  4. Monkey 'stock market' prone to fluctuations too
  5. The end of war: Deep down we're peaceful(link only)
This is going to be relatively short post, because I'm quite tired today. The focus is the evolution of our knowledge about our ancestors. I think that if we compare what we know about our past today with what was known 10 or 15 years ago, we'd see that now, even though we have much more information, we're much less secure about its interpretation. Or to be precise we have theories, on which we can rely with certain probability, but we are much more comfortable with the surprises that might (and eventually do) come.

Culture May Be Encoded in DNA

Knowledge is passed down directly from generation to generation in the animal kingdom as parents teach their children the things they will need to survive. But a new study has found that, even when the chain is broken, nature sometimes finds a way.

Zebra finches, which normally learn their complex courtship songs from their fathers, spontaneously developed the same songs all on their own after only a few generations.

“We found that in this case, the culture was pretty much encoded in the genome,” said Partha Mitra of Cold Spring Harbor Laboratory in New York, co-author of a study in Nature on Sunday.

Birds transmit their songs through social interactions, as humans do for languages, dances, cuisine and other cultural elements. Though birds and humans have clearly followed different evolutionary paths, birdsong culture can still inform theories of human culture.

Normally, male finches learn their complex courtship songs (MP3) from their uncles and fathers. But if there are no vocal role models around, the song will deviate from the traditional song and be harsh to female finch ears (MP3). Each bird, then, must learn from his father or uncles.

Mitra’s team wanted to find out what would happen if an isolated bird raised his own colony. As expected, birds raised in soundproof boxes grew up to sing cacophonous songs.

But then scientists let the isolated birds give voice lessons to a new round of hatchlings. They found that the young males imitated the songs — but they tweaked them slightly, bringing the structure closer to that of songs sung in the wild. When these birds grew up and became tutors, their pupils’ song continue to conform, with tweaks.

After three to four generations, the teachers were producing strapping young finches that belted out normal-sounding songs.

You can listen to the progression below, but keep in mind that the elements that are important to female finches — duration of beats, rise and fall of pitch — can be difficult for the untrained human ear to pick up on. (QuickTime works best for these)

  • birds raised in isolation (MP3)
  • first generation (MP3)
  • second generation (MP3)
  • third generation (MP3)
  • fourth generation (MP3)
  • wild birds (MP3, MP3)

“It all happened so fast, and there was so little difference between the colony and in the one-to-one tutoring environment,” said lead author Olga Fehér of City College of New York. “So the process is pretty much hardwired. And the interesting thing was also that they could only get so close in a single generation, so the three to four generations were necessary for the phenotype to emerge.”

Though there are approximately 6,000 different languages in the world, they all share certain structural and syntactic elements. Even when a language arises spontaneously, as it did in the 1970s among deaf school children in Nicaragua, it adheres to these stereotypical human language features. source

My comment: I find this one rather fascinating since I also believe that our DNA encodes much more than we currently have established. And this is a fine experiment, because it shows that although songs are inherited by the father, the first generation won't know it. It will need whole 3 generations to "get back to normal". It's like the Nature's fail-safe mechanism-social interactions and learning are better, but if anything happens, don't worry. Nice.

Early domestic animals were surprisingly well bred

THEY may not have known about genes and Darwinism, but our ancestors knew how to drive the evolution of once-wild beasts to serve their own needs. A spate of studies published last week show how domestication suddenly gave horses coats of many colours, cows the extra genes to produce milk and fight infection - and even shrank sheep's horns.

The studies also support what archaeologists have long argued about the domestication of wild beasts: that sheep were probably the first farmed animals, about 11,000 years ago, followed by cattle. Then, around 5500 years ago humans tamed horses, giving riders hitherto unmatched military might, speed and mobility.

Ludwig led a team which analysed six genes linked with coat colour in 89 horse fossils, originating from 40,000 years ago to the Middle Ages, which were collected from sites ranging from Spain to China.

The genetic analysis revealed that before about 5500 years ago, almost all horses had reddish-brown or black coats (Science, vol 324, p 485). Then, in what is now Ukraine, Romania and Russia, there was an explosion in colour when humans tamed horses and bred animals with a new range of coat colours, from chestnut to cream, white and dappled.

Our impact on the ancestors of sheep was no less dramatic, show several studies, including one led by Massimo Palmarini of the University of Glasgow in the UK. By analysing harmless "stowaway viruses" in the genetic material of sheep, Palmarini's team was able to distinguish ancient from modern breeds (Science, vol 324, p 532).

They found that sheep were domesticated in two waves. Examples of the first wave still survive as semi-wild breeds, such as the shaggy Soay and Orkney breeds on Scottish islands. The second wave started about 6000 years ago, when farmers in what is now Iraq and Iran began selecting for characteristics such as reduced moulting and smaller horns. Their more ancient, shaggier counterparts were exiled to the fringes of Europe, where they became semi-wild again.

Also, the first analyses of the entire cow genome show that with domestication came a big spurt in the diversity of genes linked with milk production, musculature and immunity to bacterial infection. "There are several areas of the genome you can see that clearly differentiate between beef breeds and dairy breeds," says Harris Lewin of the University of Illinois at Urbana-Champaign, who leads the international cow-genome sequencing project. source

My comment: Cannot comment too much here, I just find it fascinating that once humans figured how to selectively breed, they mastered the technology so quickly. It's amazing that they figured it on the first place, of course. But I must say the numbers are somewhat questionable to me. Because this is so soon. I mean, 5000 years ago is really quite soon. And if they figured how to do it 11000 years ago, then why dis they have to wait for 6000 years to domesticate horses? I think we might have some missing information here-like that horses were domesticated earlier, but then the knowledge "disappeared" for a while.

Spanish scientists develop echolocation in humans

June 30th, 2009

A team of researchers from the University of Alcalá de Henares (UAH) has shown scientifically that human beings can develop echolocation, the system of acoustic signals used by dolphins and bats to explore their surroundings. Producing certain kinds of tongue clicks helps people to identify objects around them without needing to see them, something which would be especially useful for the blind.

The team led by this scientist has started a series of tests, the first of their kind in the world, to make use of human beings’ under-exploited echolocation skills.

In the first study, published in the journal Acta Acustica united with Acustica, the team analyses the physical properties of various sounds, and proposes the most effective of these for use in echolocation. “The almost ideal sound is the ‘palate click, a click made by placing the tip of the tongue on the palate, just behind the teeth, and moving it quickly backwards, although it is often done downwards, which is wrong”, Martínez explains.

The researcher says that palate clicks “are very similar to the sounds made by dolphins, although on a different scale, as these animals have specially-adapted organs and can produce 200 clicks per second, while we can only produce three or four”. By using echolocation, “which is three-dimensional, and makes it possible to ‘see’ through materials that are opaque to visible radiation” it is possible to measure the distance of an object based on the time that elapses between the emission of a sound wave and an echo being received of this wave as it is reflected from the object.

In order to learn how to emit, receive and interpret sounds, the scientists are developing a method that uses a series of protocols. This first step is for the individual to know how to make and identify his or her own sounds (they are different for each person), and later to know how to use them to distinguish between objects according to their geometrical properties “as is done by ships’ sonar”.

Some blind people had previously taught themselves how to use echolocation “by trial and error”. The best-known cases of these are the Americans Daniel Kish, the only blind person to have been awarded a certificate to act as a guide for other blind people, and Ben Underwood, who was considered to be the world’s best “echolocator” until he died at the start of 2009.

However, no special physical skills are required in order to develop this skill. “Two hours per day for a couple of weeks are enough to distinguish whether you have an object in front of you, and within another two weeks you can tell the difference between trees and a pavement”, Martínez tells SINC.

The scientist recommends trying with the typical “sh” sound used to make someone be quiet. Moving a pen in front of the mouth can be noticed straightaway. This is a similar phenomenon to that when travelling in a car with the windows down, which makes it possible to “hear” gaps in the verge of the road.

The next level is to learn how to master the “palate clicks”. To make sure echoes from the tongue clicks are properly interpreted, the researchers are working with a laser pointer, which shows the part of an object at which the sound should be aimed.

Another of the team’s research areas involves establishing the biological limits of human echolocation ability, “and the first results indicate that detailed resolution using this method could even rival that of sight itself”. In fact, the researchers started out by being able to tell if there was someone standing in front of them, but now can detect certain internal structures, such as bones, and even “certain objects inside a bag”.

ВръзкаThe scientists recognise that they are still at the very early stages, but the possibilities that would be opened up with the development of echolocation in humans are enormous. This technique will be very practical not only for the blind, but also for professionals such as firemen (enabling them to find exit points through smoke), and rescue teams, or simply people lost in fog. source

My comment: Now, that's totally cool. When I read about people who can echolocate I was totally amazed. It's hard to believe that someone can learn to uses sounds to orients him/herself so easily and so quickly. If you read trough the article, you'll see that it take month of quite little practice (2 hours a day is hardly a lot of practise for a new sensory input-you practice a lot more with your eyes and ears). And the results are quite astonishing. And if we go further-if you can learn to use simple sounds to "see" bones, what could happen if you learn how to use EM radiation (ok, our eyes see the visible part of the spectrum, but we can feel infrared as warm, so we can do it). It gives a whole new meaning of the idea of "aura-reading", right?

Short stories:

'The world's oldest manufactured beads' are older than previously thought

May 5th, 2009
(PhysOrg.com) -- A team of archaeologists has uncovered some of the world’s earliest shell ornaments in a limestone cave in Eastern Morocco. The researchers have found 47 examples of Nassarius marine shells, most of them perforated and including examples covered in red ochre, at the Grotte des Pigeons at Taforalt.

The fingernail-size shells, already known from 82,000-year-old Aterian deposits in the cave, have now been found in even earlier layers. While the team is still awaiting exact dates for these layers, they believe this discovery makes them arguably the earliest shell ornaments in prehistory.

The shells are currently at the centre of a debate concerning the origins of modern behaviour in . Many regard the shell bead ornaments as proof that anatomically modern humans had developed a sophisticated symbolic material culture. Up until now, Blombos cave in South Africa has been leading the ‘bead race’ with 41 Nassarius shell beads that can confidently be dated to 72,000 years ago.

Aside from this latest discovery unearthing an even greater number of beads, the research team says the most striking aspect of the Taforalt discoveries is that identical shell types should appear in two such geographically distant regions. As well as Blombos, there are now at least four other Aterian sites in Morocco with Nassarius shell beads. The newest evidence, in a paper by the authors to be published in the next few weeks in the Journal of Quaternary Science Reviews, shows that the Aterian in Morocco dates back to at least 110,000 years ago.

Research team leader, Professor Nick Barton, from the Institute of Archaeology at the University of Oxford, said: ‘These new finds are exciting because they show that bead manufacturing probably arose independently in different cultures and confirms a long suspected pattern that humans with modern symbolic behaviour were present from a very early stage at both ends of the continent, probably as early as 110,000 years ago.’source

China's earliest known carving found in central Henan Province
ZHENGZHOU, April 28 (Xinhua) -- Chinese archaeologists say they have identified the country's earliest known carving -- a deer antler sculpted into the shape of a bird -- dating back 12,000 to 15,000 years.

The fossilized grey figurine, which is 2.1 centimeters long, 1.2 centimeters high and 0.6 centimeters thick, was found in Xuchang County in China's central Henan Province in March.

It is made from evenly-heated antler, and vividly carved with amicrolithic cutting tool.

"The carving technique is more exquisite than the western carvings of its time," said Li Zhanyang, head of the archeological team in Xuchang, and a researcher with the Henan Institute of Cultural Relics and Archeology.

Carvings of the late Paleolithic Age have been found in western countries, such as 30,000-year-old ivory horse and mammoth carvings at Vogelherd Cave in Germany, and human profile carvings at a cave in La Marche, France, that are about 10,000 years old.

The bird figurine was unique in its feet that were carved with symmetrical sockets that enable it to stand stably, said Li. "This demonstrates that human beings already had a good grip of the equilibrium principal then."

Li said the bird carving might have been left by hunters when they were very active in Henan Province around the Last Glacial Maximum period, which started about 25,000 years ago. It could have been a totem to represent good luck and freedom.

The bird carving is not the first find at that site. In 2007 and2008, Chinese archaeologists announced that they found more than 30,000 relics in Xuchang, including human skull fossils dating back 80,000 to 100,000 years.source

New fossil primate suggests common Asian ancestor, challenges primates such as 'Ida'

July 1st, 2009

According to new research published online in the Proceedings of the Royal Society B (Biological Sciences) on July 1, 2009, a new fossil primate from Myanmar (previously known as Burma) suggests that the common ancestor of humans, monkeys and apes evolved from primates in Asia, not Africa as many researchers believe.

A major focus of recent paleoanthropological research has been to establish the origin of anthropoid primates (monkeys, apes and humans) from earlier and more primitive primates known as prosimians (lemurs, tarsiers and their extinct relatives). Prior to recent discoveries in China, Thailand, and Myanmar, most scientists believed that anthropoids originated in Africa. Earlier this year, the discovery of the fossil primate skeleton known as "Ida" from the Messel oil shale pit in Germany led some scientists to suggest that anthropoid primates evolved from lemur-like ancestors known as adapiforms.

According to Dr. Chris Beard-- a paleontologist at Carnegie Museum of Natural History in Pittsburgh, Pennsylvania and a member of the international team of researchers behind the Myanmar anthropoid findings--the new primate, Ganlea megacanina, shows that early anthropoids originated in Asia rather than Africa. These early Asian anthropoids differed radically from adapiforms like Ida, indicating that Ida is more closely related to modern lemurs than it is to monkeys, apes and humans.

The 38-million-year-old Ganlea megacanina fossils, excavated at multiple sites in central Myanmar, belong to a new genus and species. The name of the new species refers to a small village, Ganle, near the original site where the fossils were found, and the greatly enlarged canine teeth that distinguish the animal from closely related primates. Heavy dental abrasion indicates that Ganlea megacanina used its enlarged canine teeth to pry open the hard exteriors of tough tropical fruits in order to extract the nutritious seeds contained inside.

Two other amphipithecids, Pondaungia and Myanmarpithecus, were previously discovered in Myanmar, while a third, named Siamopithecus, had been found in Thailand. A detailed analysis of their evolutionary relationships shows that amphipithecids are closely related to living anthropoids and that all of the Burmese amphipithecids evolved from a single common . source

Monkey 'stock market' prone to fluctuations too

Monkeys might not deal in stocks and shares, but they do trade commodities, and now it seems that monkey exchange rates are influenced by supply and demand.

Grooming acts as a common currency among non-human primates, says Ronald Noë at the University of Strasbourg, France. It is exchanged for food, greater tolerance from dominant members of the group – and even for sex.

To see how the exchange system works, Noë's team created an artificial market in groups of vervet monkeys by introducing a plastic box filled with food that only one subordinate female was trained to open.

An hour after the female opened the box, the biologists noted that she was rewarded by being groomed more often and for longer by other group members, and that she could afford to groom dominant group members less often.

Next, the team halved the importance of the female's ability to provide food, by introducing a second lunch box that only a second female could open. The first female's grooming "stock value" decreased, while the second monkey's rose, until both arrived at roughly the same value and were groomed for the same amount of time. source



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