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Saturday, 27 November 2010

Miracles of life, 2010

Today:

  1. Dolphins learn to 'walk on water'
  2. How smart are killer whales? Orcas have 2nd-biggest brains of all marine mammals
  3. Heroic altruistic ants face death alone to save colony
  4. Ravens console each other after fights 
  5. Scientists discover first multicellular life that doesn't need oxygen (!!!)
  6. World's largest, most complex marine virus is major player in ocean ecosystems: researce
  7.  First case of animals making their own carotene
As you can see today's edition is dedicated to life in all of its forms and complexity. Enjoy!

Dolphins learn to 'walk on water'

By Matt Walker, Editor, Earth News 
Wild dolphins in Australia are naturally learning to "walk" on water.
Six dolphins have now been seen mastering the technique - furiously paddling their tail fluke, forcing their body out and across the water.
The dolphins seem to walk on water for fun, as it has no other obvious benefit, say scientists working for the Whale and Dolphin Conservation Society.
That makes the behaviour a rare example of animals "culturally transmitting" a playful rather than foraging behaviour.
Only a few species are known to create their own culture - defined as the sharing or transmitting of specific novel behaviours or traditions between a community of animals.
The discovery was made by Whale and Dolphin Conservation Society (WDCS) scientist Dr Mike Bossley, who has spent 24 years studying dolphins living in the Port River in Adelaide, Australia.
In past years, Dr Bossley has witnessed two wild adult female dolphins, named Billie and Wave for research purposes, attempting to walk on water.
Now four other dolphins, including young infants, have been recorded trying to learn the trick from the two adults, and have been seen practising, less successfully, in the river.
The behaviour, when a dolphin beats its tail fluke repeatedly, so it lifts its body vertically out of the water and then along the surface, is more commonly seen among captive dolphins trained to perform tricks.
A composite image showing Bianca the dolphin attempting to tail-walk on 10 Oct, 2010
A composite image showing Bianca the dolphin attempting to tail-walk on 10 Oct, 2010
In the wild it is extremely rare.
 source 
My comment: It's absolutely amazing how little we know about non-human intelligence. And I think that this article leave very little place for doubt about the intelligence of dolphins. Because while many species are observed until now to use tools and show creativity when it comes to food, not so much do that just for fun. Although that's not completely truth since I have seen baby goats do tricks just for the fun of it. But then the behavior do not pass over to different generations. The mother goat doesn't show new tricks to her babies. While dolphins do. Which maybe make them unique. Or maybe not. Because the more we observe the subtler demonstration of intelligence we find in all species.

How smart are killer whales? Orcas have 2nd-biggest brains of all marine mammals

March 8, 2010 By Kevin Spear
Neuroscientist Lori Marino and a team of researchers explored the brain of a dead killer whale with an MRI and found an astounding potential for intelligence.

Killer whales, or orcas, have the second-biggest brains among all ocean mammals, weighing as much as 15 pounds. It's not clear whether they are as well-endowed with as humans, but scientists have found they are amazingly well-wired for sensing and analyzing their watery, three-dimensional environment.
Scientists are trying to better understand how killer whales are able to learn local dialects, teach one another specialized methods of hunting and pass on behaviors that can persist for generations -- longer possibly than seen with any other species except humans.
These researchers have yet to find evidence that an orca in the wild has ever killed a person.
Human interaction with captive killer whales has come under scrutiny since Feb. 24, when a large male orca with a checkered past killed a trainer at SeaWorld Orlando by dragging her into a tank.
Years of tediously difficult research has given scientists some understanding of killer whales -- but also has made them aware of how little they know about the creatures.For starters, there's puzzlement over exactly how to categorize them.
They swim the world's oceans -- they are more widely distributed than any whale, dolphin or porpoise -- in at least three distinct populations. There are fish-eating orcas that stay in one area, flesh-eaters that wander more widely along coasts, and a third group that roams the deep-blue waters.
The three groups have starkly different diets, languages, hunting techniques and manners of behaving around other marine life, and they don't seem to interact much with one another.

Yet the orcas' DNA tells a different story. Instead of the world's varied populations having genetics that spread outward like a tree with several main branches, theirs is but a single, nearly straight trunk, except for a mismatched pair of genes here and there.
If genetic variety isn't what makes these killer-whale groups so different, scientists suspect, their enormous brains might be the telltale factor.Hal Whitehead, a biology professor at Dalhousie University in Nova Scotia, awakened the world of cetacean research in 2001 when he co-authored a controversial paper that suggested no species other than humans are as "cultural" as orcas."Culture is about learning from others," Whitehead said. "A cultural species starts behaving differently than a species where everything is determined genetically."
One example of a killer-whale culture, he said, is the teaching of a particularly difficult and dangerous hunting technique observed by researchers on Antarctic islands. They watched as mothers repeatedly pushed their young onto beaches in pursuit of seals and sometimes had to drag their stranded young back into the water.
" also are quite conservative animals," he added. "If this is the way they do things, then they are quite loath to do it another way."That last point, he said, is important to consider when it comes to orcas held in captivity.
Equally remarkable to researchers is the orca's ability to communicate with whistles and pulsed calls, and to "see" by making a clicking sound that works like sonar.Many cetaceans -- whales, dolphins and porpoises included -- have these abilities to some degree. But orcas learn local and complex languages that are retained for many generations. And their bio-sonar, or echolocation, abilities also amaze researchers.
Professor Whitlow Au, of the University of Hawaii's Marine Mammal Research Program, finished a study recently adding to evidence that orcas can use their bio-sonar not just to find fish in murky water and not just to single out salmon, but to identify their favorite meal: Chinook salmon.
Sam Ridgway, a neurobiologist and research veterinarian at San Diego's National Marine Mammal Foundation, which works for the Navy, said the orca brain has a relatively smaller amount of cerebral cortex -- the gray matter involved in memory, attention and thought -- than the human brain does. But it has large-diameter myelinated axons, which carry nerve impulses."The bigger the axon, the faster the nerve impulses travel."
Patrick Hof, vice chairman of the Department of Neuroscience at New York's Mount Sinai School of Medicine, summed up the orca noodle as a "big brain, a really big brain" with enormous capacity.
 source 
My comment: Very interesting. I didn't have any idea how complex orcas society actually is. I knew they take care of the offspring together, but that was all. If they have different languages and habits and all those capacity for intellect, I don't understand how it could be allowed for people to keep them in captivity. We need to study them and sometimes watching them in their natural habitat is not enough, but should we keep them for entertainment? Basically, we make slaves of them. And that's so sad.

Heroic altruistic ants face death alone to save colony

By Matt Walker Editor, Earth News

Ants live altruistically, but some die altruistically too.
When ants of the species Temnothorax unifasciatus get sick, they abandon their nest, walking far away from their relatives to die alone.
They perform this act of heroism to prevent the illness that is killing them from spreading to the colony.
The discovery, published in Current Biology, is the first time that such behaviour has been shown in ants or any other social insect.
Such behaviour has been reported in dogs, cats, elephants and even people.
But because it happens occasionally, it cannot be quantifiably studied.
So Prof Heinze decided to set up an experiment to study the phenomenon in ants, which he also noticed would occasionally leave the colony for no apparent reason.
The researchers exposed a colony of Temnothorax unifasciatus ants reared in their laboratory to the spores of a lethal parasitic fungus called Metarhizium anisopliae.
Most of the workers who died from the fungal infection permanently left the nest hours or days before death, and died in a foraging area far from their nest mates.
"Our study suggests that infected ants at least in some species walk away from a colony and die alone, rather than risk infecting others," Prof Heinze told the BBC.
Crucially, the researchers were able to rule out the possibility that the fungus itself caused the diseased ants to walk away.
Many parasites manipulate their hosts in order to increase their own transmission.
Flu viruses make people cough, while in ants, one cordyceps fungus effectively turns its victims into zombies, impelling ants to climb up a stem where they die.

But by exposing the ants to CO2, the researchers artificially reduced their lifespan.
Uninfected ants who survived this treatment, but still knew they would die prematurely, also left the nest before death took hold, proving the fungus itself did not drive them out.
"Another interesting finding was that the workers left the nest voluntarily and were not carried away by other workers," he writes in the same issue of the journal. By choosing to face death alone, the ants were making a truly altruistic act.
That is important because the exact opposite has been found in the bumblebee, another social insect.
Bees infected by fly larvae move out of the hive into colder air.
But in doing so, the cold temperatures slow the lifecycle of the parasite.
So the infected bees are actually trying to extend their own lives, rather than save their nest mates.
The heroic act by the terminally ill ants is the latest in a line of extraordinary behaviours discovered among social insects.
In order to help protect close relatives, termites have been found to explode during fights, bees die after stinging, while the members of another species of ant have been found to condemn themselves to death by sealing in a nesting colony from the outside. source
My comment: How about that?! I think the line between humans and all other species gets tinner with every new discovery. After all, how much people would go away from their home and city, to die alone, just to be able to save the others? Few will do it. But not everyone. So it's amazing the little ants do that automatically. Amazing and little sad. 

Ravens console each other after fights

May 18, 2010 by Lin Edwards
 (PhysOrg.com) -- A new study investigating the behavior of ravens has found strong evidence that after conflicts bystanders appear to console and relieve the distress of victims with whom they have a relationship, and that victims are likely to seek affiliations with bystanders. The results suggest ravens may be sensitive to the emotions of others.
Many species of birds fight aggressively from time to time over resources, to assert , and so on, but such conflicts can waste valuable energy, cause injuries, and damage relationships that are usually mutually beneficial. One way of reducing the cost of conflicts is through reconciliation and through consoling victims, but until relatively recently such behaviors were thought to be unique to humans.
Previous studies of rooks have shown that pair-bonded birds do show such behaviors, so the researchers chose ravens to see if the same kinds of behaviors occurred in birds that were not paired, because ravens live up to ten years in socially complex before pairing off.
A statistical analysis of the observations showed the affiliations were randomly timed and did not appear to be a deliberate attempt to reduce the tension. Victims soliciting affiliations were at greater risk of renewed aggression by their attacker immediately after conflict, but if they solicited affiliations from other members of the flock renewed aggression was less likely to occur. The researchers also found that victims did not attack other birds, so there was little risk involved in approaching them, and many members of the flock offered affiliation spontaneously, especially if they were related or regularly spent a lot of time together. Surprisingly, unsolicited affiliations did not reduce the likelihood of renewed aggression.
 source
My comment:Interesting, but I wonder if the statistics actually points to compassion and so on or to merely random affiliation between individual birds. But still, I find it interesting that even birds can show compassion. After all, they are so small. But it's very interesting that the victims affiliate with bystanders and not with aggressors, as one would naively expect. Obviously whatever they fight for is important enough to keep them separated.  

Scientists discover first multicellular life that doesn't need oxygen

April 7, 2010 by Lisa Zyga
PhysOrg.com) -- Oxygen may not be the staple of modern complex life that scientists once thought. Until now, the only life forms known to live exclusively in anoxic conditions were viruses, bacteria and Archaea. But in a new study, scientists have discovered three new multicellular marine species that appear to have never lived in aerobic conditions, and never metabolized oxygen.
The discovery of the new species, which live buried in sediment under the Mediterranean , is significant in that it marks the first observation of multicellular organisms, or metazoans, that spend their entire lifecycle under permanently anoxic conditions. A few metazoans have been known to tolerate anoxic conditions, but only for limited periods of time.
The team of Italian and Danish researchers, Roberto Danovaro, et al., that discovered the new life forms has identified the creatures as belonging to the animal phylum Loricifera, the most recently described animal phylum. Loriciferans, which have a length of less than one millimeter, typically live in sediment. The three new organisms belong to different genera (Spinoloricus, Rugiloricus, and Pliciloricus), although their species have not yet been named.
Despite belonging to previously known taxonomic groups, the new species possess some radical differences compared with other metazoans. Most significantly, the new species do not have mitochondria, the cellular organelles that use and sugar to generate the cell’s energy. Instead, the new loriciferans have organelles that resemble hydrogenosomes, which are used by some single-celled eukaryotes to generate energy without oxygen. However, this is the first time that these organelles have been observed in multicellular organisms. Previous research has indicated that hydrogenosomes may have evolved from mitochondria, while other research suggests they evolved independently.
The researchers focused on an area called the L’Atalante basin, which is located off the southern coast of Greece. As the scientists explain, this type of “deep hypersaline anoxic basin” was created by the flooding of mineral sediments from 5.5 million years ago. For the past 50,000 years, the basin has possessed a dense hypersaline brine layer up to 60 meters thick. The brine serves as a physical barrier that prohibits oxygen exchange between the water and , making the basin completely oxygen-free. In addition, the basin is rich in methane and hydrogen sulphide, and is also home to a diverse assembly of prokaryotes that have adapted to these conditions.
Because previous studies have reported the presence of cadaverous metazoans that had sunk to anoxic deep-sea sediments in the Black Sea, the researchers here stained the newly collected specimens with Rose Bengal, a protein binding stain that colors living organisms with a much greater intensity than deceased organisms, demonstrating that the new species were indeed alive. In addition, the scientists observed specimens of the undescribed species of both genera Spinoloricus and Rugiloricus that had a large oocyte in their ovary, which showed a nucleus containing a nucleolus, providing evidence of reproduction. source
My comment: WOW! I didn't know that lurks underneath the Black Sea. I had suspicions about the flooding of Black Sea, but that's much more than I ever hoped for. Because if you think about it, that organism is hardly Earh-like. For a little explanation, Black Sea depths are like very few other places on the world (another example are the blue holes on the Bahamas) - they are essentially deadly for anything we know. There's no oxigen, only methan and sulfur. It's the closest thing to alien world with normal temperature we can imagine on Earth. And still, there are living organisms in it! What's more, this is a multicellular oragnism. I wonder if there are bigger organisms as well. And what kind of odd creatures they will be! But in any case, if we believe the theory that the Black Sea was flooded approximately 5-7000 years ago, that means that we observed evolution in under 10 000 years! How cool is that! 

World's largest, most complex marine virus is major player in ocean ecosystems: research

October 25, 2010
UBC researchers have identified the world's largest marine virus--an unusually complex 'mimi-like virus' that infects an ecologically important and widespread planktonic predator.
Cafeteria roenbergensis has a genome larger than those found in some cellular organisms, and boasts genetic complexity that blurs the distinction between "non-living" and "living" entities.
"Virus are classically thought of small, simple organisms in terms of the number of genes they carry," says UBC professor Curtis Suttle, an expert in marine microbiology and environmental virology and lead author of the study.
"Much of the we found in this virus you would only expect to find in living, cellular organisms, including many genes required to produce DNA, RNA, proteins and sugars."
The findings are reported in this week's issue of the .
Viruses cannot replicate outside of living host cells and they depend on proteins provided by the cell, a boundary that is often used to delineate "non-living" from "living" organisms. Giant viruses challenge this definition, as they still need a cell to replicate, but encode in their own genome most of the proteins required for replication.
Discovered in Texas coastal waters in the early 1990s, Curtis and his team where able to determine that the pathogen's genome contains approximately 730,000 base pairs. That makes Cafeteria roenbergensis virus the largest known marine virus, and the second largest known virus, after the fresh water-borne Acanthamoeba polyphaga , which weighs in at 1.2 million base pairs.
Cafeteria roenbergensis virus also infects a major marine zooplankter which occupies a key position in marine food webs.source
My comment: 730 000 base pairs. Pretty big virus is that. As I already have said, I think we know way too little about viruses and their role in the life cycle. So every new discovery is another door opened to our understanding of life itself. 


First case of animals making their own carotene

April 29, 2010

The insects known as aphids can make their own essential nutrients called carotenoids, according to University of Arizona researchers.

No other animals are known to make the potent antioxidants. Until now scientists thought the only way animals could obtain the orangey-red compounds was from their diet. source




 

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