A Bit More Detail

Assorted Personal Notations, Essays, and Other Jottings

Posts Tagged ‘science

[FORUM] What do you think about bringing extinct species back from the dead?

The CBC feature “Species de-extinction plagued by ‘looming questions,’ expert says” does a good job outlining the problems associated with using preserved DNA to bring back extinct species.

Axel Moehrenschlager, a biologist at the Centre for Conservation Research at the Calgary Zoo and an associate professor of biology at the University of Calgary, says that de-extinction is a fascinating possibility, but one that should be approached cautiously.

“There are potentially many issues in bringing a species back … But our primary concern is, if we were to bring something back, why are we doing it? Are we doing it because it’s something cool to do, or because it’s valuable for the ecosystem?” Moehrenschlager said an interview that airs on CBC’s Quirks & Quarks on Saturday.

Moehrenschlager was part of an international team of scientists that published a paper in March in the journal Trends in Ecology and Evolution that outlined 10 vital questions that scientists should ask before selecting candidate species for de-extinction.

“One of the things about species – when you put species back – is that they do things in that ecosystem and those things can potentially be useful or could be potentially damaging,” he says.

“In some cases bringing a species back could restore an ecological function that has been lost. But in other cases, in the wrong environment, it could make extinct species invasive and very damaging.”

What of hybrid species? Mammoth-elephant hybrids would be likely, but also wouldn’t be natives to the wild.

There’s also the huge ethical issue of bringing back smart species. Mammoths, if modern elephants are anything to go by, would have been quite smart animals deeply embedded in a culture. How can this culture possibly be recreated? And you just know that someone is going to try to bring back the Neanderthals and Denisovans …

What do you think about species de-extinction? Is it a good idea, or is it merely inevitable?

Written by Randy McDonald

May 10, 2014 at 8:48 pm

[LINK] “New Evidence Sexuality Is Innate: Study Finds Gay Men Respond to Male Pheromones”

Via Towleroad’s Daniel Villarreal I came across Vice‘s report of a Chinese study on the biology of sexual orientation.

Wen Zhou of the Chinese Academy of Sciences set up an experiment in which participants looked at a video in which human figures rendered in a connect-the-dots style [. . .] were shown walking. Participants were then asked to guess whether the figures were masculine or feminine. When exposed to androstadienone, heterosexual women were more likely to suggest that the wire figure was a man—but the pheromone had no effect on heterosexual men.

Perhaps most importantly, homosexual men also responded to that pheromone, suggesting that gay men innately perceive (and are perhaps affected by) male pheromones.

Straight men, meanwhile, were more likely to perceive the figure as feminine when exposed to estratetraenol. Straight women showed no effect, while lesbian and bisexual women showed a response somewhere in between. To keep everything on the straight and narrow, the pheromones were masked with the smell of cloves in all cases.

“We were able to demonstrate qualitatively that androstadienone signals masculinity to heterosexual males and homosexual males, whereas estratetraenol signals femininity to heterosexual males, without the recipients being aware of the odors,” Zhou wrote in a study about his findings, published in Cell. “Importantly, the specific sexual information conveyed by androstadienone and estratetraenol strongly supports them as human sex pheromones.”

Essentially, the findings suggest that humans can “perceive” someone’s biological sex based on these pheromones, but that the effect only works with those people a person might be attracted to.

Written by Randy McDonald

May 8, 2014 at 8:14 pm

[BLOG] Some Tuesday links

  • io9 notes that apparently circumbinary planets and their moons–planets orbiting two stars which themselves closely orbit each other–might be better-suited to life than planets orbiting single stars.
  • Centauri Dreams’ Paul Gilster reacts to Karl Schroeder’s Lockstep, an imagining of a far future where slower-than-light travel is compensated for by hibernation technology.
  • The Dragon’s Gaze links to Kevin Luhman’s discovery paper for nearby brown dwarf WISE J085510.83-071442.5.
  • A Fistful of Euros reports on the Ukrainian release of intercepted communications between the Russian ambassador and separatists.
  • Mathew Ingram describes the role played by blogger Eliot Higgins in, through his sterling research, is undermining traditional models of journalism.
  • Language Log’s Victor Mair reports on the linguistic diversity within greater Tibet.
  • Marginal Revolution’s Tyler Cowen predicts that Russia will undermine the Ukrainian government to the point that the entire country will align with Russia, not just fragments.
  • John Moyer makes the case for reading Beowulf. (It’s like Die Hard!)
  • The New APPS Blog notes that some Fox affiliates seem to be cutting oddly to commercials whenever the new Cosmos mentions human evolution.
  • Otto Pohl notes the Soviet Mennonite writers of the 1930s.
  • Savage Minds starts a discussion (through Alex Posecznick) about the ways in which anthropologists resemble hipsters.
  • Window on Eurasia links to a few article, one describing the current events as a delayed reaction to the Soviet split of 1991, another noting the de-Ukrainianization of Crimean schools, another noting Crimea’s potential for instability, another observing persecution of religious minorities including Ukrainian Catholics in Crimea, and noting separatism among the Karakalpak of western Uzbekistan.

[BRIEF NOTE] On the intelligent crows of Aesop’s Fables

The Aesop’s Fable of The Crow and the Pitcher was proven by science. In the paper “Using the Aesop’s Fable Paradigm to Investigate Causal Understanding of Water Displacement by New Caledonian Crows”, investigators determined that the famously intelligent New Caledonian crow can interrogate questions of volume as well as young humans.

Understanding causal regularities in the world is a key feature of human cognition. However, the extent to which non-human animals are capable of causal understanding is not well understood. Here, we used the Aesop’s fable paradigm – in which subjects drop stones into water to raise the water level and obtain an out of reach reward – to assess New Caledonian crows’ causal understanding of water displacement. We found that crows preferentially dropped stones into a water-filled tube instead of a sand-filled tube; they dropped sinking objects rather than floating objects; solid objects rather than hollow objects, and they dropped objects into a tube with a high water level rather than a low one. However, they failed two more challenging tasks which required them to attend to the width of the tube, and to counter-intuitive causal cues in a U-shaped apparatus. Our results indicate that New Caledonian crows possess a sophisticated, but incomplete, understanding of the causal properties of displacement, rivalling that of 5–7 year old children.

Virginia Morell interviewed one of these researchers, Sarah Jelbert, for National Geographic News. An excerpt:

How did you come up with your idea to give the Aesop’s Fable test to the crows?

Our study was based on the fantastic work of two other researchers, Christopher Bird and Nathan Emery. [They showed that rooks would use stones to raise the water level in a tube so that they could reach a worm.] Dropping stones into water isn’t something New Caledonian crows do in the wild; no animal does. But it is also a completely natural thing, and so is a fair test of animals’ cognition.

We trained six crows to drop small stones into tubes. And then we gave them different tests to see how much they understand or can learn about the cause and effect of water displacement. Would they understand that dropping stones into water in a tube [to get a piece of meat to float to the top] is different from dropping them into sand in a tube? Or that hollow objects have a different effect from solid ones?

They did very well at four of the six tests, where they were able to apply their natural understanding of cause and effect and the properties of objects. They understood that solid objects sink and hollow ones float, for instance, and that it doesn’t make any sense to drop stones into sand. But they were incredibly poor at the counterintuitive test, which involved a U-[shaped] tube; they had to infer that there was a connection between the two tubes, but none of them could do this.

And what do their successes and failures at these tests tell us about the cognitive abilities of New Caledonian crows?

We’re trying to understand the cognitive mechanisms of animal minds, and to do that you need to look at tests that animals can pass and those that they fail. In human psychology, researchers have discovered that the way people make mistakes is often most informative about how they think. The errors give away how they are solving problems. Is this true for animals, too? Or do they have a completely different way of conceptualizing problems? By looking at the errors the crows make, we may get a better understanding of how they successfully solve problems.

Jelbert reserved judgement as to whether or not the crows took the tricks they learned into the wild.

Written by Randy McDonald

April 24, 2014 at 3:29 am

[LINK] “Neanderthals Lived in Small, Isolated Populations, Gene Analysis Shows”

This analysis, reported by National Geographic News‘ Dan Vergino, is fascinating. The sample size is small–three Neanderthals and one Denisovan–but the preliminary conclusions are quite noteworthy. How were ancient humans different from each other? We’re learning.

Compared to Neanderthals, humanity appears to have evolved more when it comes to genes related to behavior, suggests a team headed by Svante Pääbo, a pioneer in ancient genetics at Germany’s Max Planck Institute for Evolutionary Anthropology. Their study was published today in the Proceedings of the National Academy of Sciences.

They note in particular that genes linked to hyperactivity and aggressive behavior in modern humans appear to be absent in Neanderthals. Also missing is DNA associated with syndromes such as autism.

“The paper describes some very interesting evolutionary dynamics,” said paleoanthropologist John Hawks of the University of Wisconsin at Madison.

The Neanderthal genes suggest that sometime after one million to 500,000 years ago, Neanderthal numbers decreased and the population stayed small, Pääbo’s group determined. A small population size would have been bad news for Neanderthals, Hawks said, because it would have meant that “natural selection had less power to weed out bad mutations.”

Pääbo and colleagues looked at the genes of two ancient Neanderthals, one from Spain and one from Croatia. They compared the DNA of those individuals to that of a third Neanderthal who had lived in Siberia and whose DNA had been analyzed in an earlier study, and to the DNA of several modern humans.

Written by Randy McDonald

April 23, 2014 at 7:16 pm

[BLOG] Some Wednesday links

  • The Dragon’s Tales links to news of remarkably thorough reconstruction of Neanderthal and Denisovan genomes.
  • Eastern Approaches visits eastern Ukraine’s Donbas region.
  • Geocurrents’ Martin Lewis notes that Pakistan still apparently lays claim to the former Muslim-run princely state of Junagadh in Gujarat.
  • Joe. My. God. and Towleroad both note a proposed bill before the Russian parliament that would require the fingerprinting of all HIV-positive people in a national database.
  • The Power and the Money’s Noel Maurer notes a continuing crisis in the availability of rental spaces in the American housing market, linking it to low-density zoning.
  • Torontoist notes the sad loss of a pet pigeon on Queen Street West.
  • Towleroad notes continuing controversy over the use of the HIV drug Truvada as a prophylactic against infection.
  • The Volokh Conspiracy visits controveries over affirmative action in the United States where different minorities (here, Asian-Americans) have different claims.
  • Window on Eurasia visits the increasingly problematic lot of Crimean Tatars in their Russian-occupied homeland, notes that traditionally pro-Russian Belarus is newly wary of its eastern partner, and quotes from a journalist who predicts catastrophe from a Russian pursuit of empire.

[CAT] “What Are Cats Thinking?”

Writing at Slate, David Grimm writes about the state of research into cat intelligence. It seems that it’s not very advanced, largely because cats have a different sort of intelligence from us (and from dogs).

In 1998, [Ádám Miklósi] and Duke University biological anthropologist Brian Hare independently showed that dogs can understand human pointing. Both labs conducted experiments demonstrating that when a volunteer pointed at one of two cups containing a treat, dogs almost always went for the correct cup. Though it may seem a simple test, our closest relatives, chimpanzees, fail miserably; they ignore the volunteer, pick cups at random, and rarely score above chance. The ability to follow a pointed finger isn’t just a neat trick; it shows that dogs may have a rudimentary “theory of mind”—an ability to understand what another animal is thinking (in this case, that the human volunteer was trying to show them something). The skill is so important to our species that without it, we would have trouble learning and interacting with the world around us. That’s why so many labs have begun studying the canine mind; dogs, the thinking goes, may provide clues to the evolution of the human mind.

But what about cats? Miklósi, I was surprised to learn, had also conducted the pointing test with felines. Like Agrillo, he had a hard time getting cats to cooperate in his laboratory—so he went to their homes instead. Even then, most of the animals weren’t interested in advancing science; according to Miklósi’s research paper, seven of the initial 26 test subjects “dropped out.” But those that did participate performed nearly as well as dogs had. Cats too, it appears, may have a rudimentary theory of mind.

But when Miklósi took the study a step further, he spotted an intriguing difference between cats and dogs. This time, he and his colleagues created two puzzles: one solvable, the other impossible. In the solvable puzzle, the researchers placed food in a bowl and stuck it under a stool. Dogs and cats had to find the bowl and pull it out to eat. Both aced the test. Then the scientist rigged the exam. They again placed the bowl under a stool, but this time they tied it to the stool legs so that it could not be pulled out. The dogs pawed at the bowl for a few seconds and then gave up, gazing up at their owners as if asking for help. The cats, on the other hand, rarely looked at their owners; they just kept trying to get the food.

Now before you conclude that cats are dumber than dogs because they’re not smart enough to realize when a task is impossible, consider this: Dogs have lived with us for as many as 30,000 years—20,000 years longer than cats. More than any other animal on the planet, dogs are tuned in to the “human radio frequency”—the broadcast of our feelings and desires. Indeed, we may be the only station dogs listen to. Cats, on the other hand, can tune us in if they want to (that’s why they pass the pointing test as well as dogs), but they don’t hang on our every word like dogs do. They’re surfing other channels on the dial. And that’s ultimately what makes them so hard to study. Cats, as any owner knows, are highly intelligent beings. But to science, their minds may forever be a black box.

Written by Randy McDonald

April 22, 2014 at 12:56 am

Posted in Science

Tagged with , , , ,

[BLOG] Some Monday science links

  • Centauri Dreams’ Paul Gilster notes that there is a class for bright F-class stars to host Earth-like worlds, and observes that the ESA’s Rosetta probe is set to rendezvous with Comet 67P/Churymov-Gerasimenko.
  • D-Brief suggests that mitochondrial damage might be responsible for so-called “Gulf War syndrome”.
  • The Dragon’s Gaze notes that the Kepler satellite can detect large exomoons, links to a paper suggesting that Jupiters aren’t needed to deliver water to the surfaces of rocky habitable-zone planets, and observes that the geological cycles of the Earth are necessary for life.

Written by Randy McDonald

March 31, 2014 at 7:07 pm

[LINK] On cosmic inflation, the Big Bang, and Andrei Linde

CBC’s article

The new results were announced by a collaboration that includes researchers from the Harvard-Smithsonian Center for Astrophysics, the University of Minnesota, Stanford University, the California Institute of Technology and NASA’s Jet Propulsion Laboratory. The team plans to submit its results to a scientific journal this week, said its leader, John Kovac of Harvard.

For their research, astronomers scanned about 2 percent of the sky for three years with a telescope at the South Pole, chosen for its very dry air to aid in the observations.

They were looking for a specific pattern in light waves within the faint microwave glow left over from the Big Bang. The pattern has long been considered evidence of the rapid growth spurt, known as inflation. Kovac called it “the smoking gun signature of inflation.”

The scientists say the light-wave pattern was caused by gravitational waves, which are ripples in the interweaving of space and time that sprawls through the universe. If confirmed, the new work would be the first detection of such waves from the birth of the universe, which have been called the first tremors of the Big Bang.

Arizona State’s Krauss cautioned that it’s possible that the light-wave pattern is not a sign of inflation, although he stressed that it’s “extremely likely” that it is. It’s “our best hope” for a direct test of whether the rapid growth spurt happened, he said.

The New Yorkergoes into more detail, here too.

What went viral about all this is the video of physicist Andrei Linde, the man who suggested the theory of cosmic inflation in the first place, being informed at his door of the news of his theory’s confirmation.

This joyous video has just under 1.6 million views as of this posting.

Written by Randy McDonald

March 19, 2014 at 4:00 am

[LINK] “Making Babies with 3 Genetic Parents Gets FDA Hearing”

Dina Fine Maron’s Scientific American article concerning new technologies that could marry DNA from three individuals, creating three-parent children, is a good overview of the technology’s position in the United States right now. (I’m for it, for whatever it’s worth, in that preventing inherited mitochondrial DNA diseases in children is a good thing.)

Scientists have already had successes with this type of reproductive approach in monkeys and in human embryos, and are now eager to launch human clinical trials. First, however, they must get the green light from the U.S. Food and Drug Administration, which will convene a public hearing before an advisory committee on February 25.

The technology, called oocyte modification (but sometimes nicknamed “three-parent IVF”), involves scooping out potentially mutated mitochondrial DNA (mtDNA) from a woman’s egg and replacing it with the mtDNA of an unaffected donor woman. The process is designed to prevent the transmission of some debilitating inherited mitochondrial diseases, which can result in vision loss, seizures and other maladies. Such inherited diseases, often unfortunately known by acronyms for complex medical names that include LHON, for Leber’s Hereditary Optic Neuropathy, along with MELAS, MERRF and NARP, occur in about one in every 5,000 live births and are incurable.

Once the mtDNA has been swapped out, the egg could be fertilized in the lab by the father’s sperm and the embryo would be implanted back into mom where pregnancy would proceed. The resulting child would be the genetic offspring of the intended mother but would carry healthy mitochondrial genes from the donor.

[. . .]

Scientists already have evidence for the promise of this type of oocyte modification. Shoukhrat Mitalipov of the Oregon Health & Science University and his colleagues created human embryos in this way, although they did not implant those embryos to make babies. Their findings were published in October 2012 in Nature. Other work from that same team also found that in monkeys the process could lead to the birth of healthy offspring that remained free of complications into adulthood. (Scientific American is part of Nature Publishing Group).

[. . .]

But wading into this type of approach is also fraught with ethical issues. Marcy Darnovsky, executive director of the Center for Genetics and Society, fears that this reproductive approach could soon lead to tampering with other traits, such as intelligence or sports ability. “Life is full of slippery slopes and we need brakes,” she says. “This is described as saving lives but it is not aimed at people who are sick,” she adds. The FDA advisory committee does not plan to consider ethical issues at this meeting. Instead it will focus on the scientific aspects of future clinical trial considerations, including long-term risk of carryover of abnormal mtDNA, the potential benefits and harm to mothers and future children, and the need for multigenerational follow-up in any trials (because female children could pass on mitochondrial disease to future offspring). “Our job will be purely to air the issue and bring it out into the open,” says Evan Snyder, chair of the committee and director of the Stem Cell and Regenerative Biology Program at Sanford–Burnham Medical Research Institute in La Jolla, Calif. “We’re not going to come out at the end of the meeting and say we are advocating for clinical trials or any particular technique. This is educational,” he says.

Written by Randy McDonald

February 27, 2014 at 8:47 pm

Follow

Get every new post delivered to your Inbox.

Join 360 other followers