Comment

Comment by doone on Thursday

EVOLUTION SHAPES NEW RULES FOR ANT BEHAVIOR

From PhysOrg:

In ancient Greece, the city-states that waited until their own harvest was in before attacking and destroying a rival community's crops often experienced better long-term success. It turns out that ant colonies that show similarselectivity when gathering food yield a similar result. The latest findings from Stanford biology Professor Deborah M. Gordon's long-term study of harvester ants reveal that thecolonies that restrain their foraging except in prime conditions also experience improved rates of reproductive success. Importantly, the study provides the first evidence of natural selection shaping collective behavior, said Gordon, who is also a senior fellow at the Stanford Woods Institute for the Environment.

A long-held belief in biology has posited that the amount of food an animal acquires can serve as a proxy for its reproductive success. The hummingbirds that drink the most nectar, for example, stand the best chance of surviving to reproduce. But the math isn't always so straightforward. The harvester ants that Gordon studies in the desert in southeast Arizona, for instance, have to spend water to obtain water: an ant loses water while foraging, and obtains water from the fats in the seeds it eats. The ants use simple positive feedback interactions to regulate foraging activity. Foragers wait near the opening of the nest, and bump antennae with ants returning with food. The faster outgoing foragers meet ants returning with seeds, the more ants go out to forage. (Last year, Gordon, Katie Dektar, an undergraduate, and Balaji Prabhakar, a professor of computer science and of electrical engineering at Stanford, showed that the ants' "Anternet" algorithm follows the same rules as the protocols that regulate data traffic congestion in the Internet).

More here.

Posted by Azra Raza at 05:50 AM | Permalink

Comment by doone on May 15, 2013 at 9:46am

The Neanderthals’ Handicaps

MAY 14 2013 @ 7:03PM

Priscilla Long presents some theories as to what led to the demise of our evolutionary cousins – shorter lifespans and climate change among them:

Because they had bigger bodies, they required more calories to survive than we do. They may have lacked sewing skills. Neither Neandertals nor Homo sapiens lived long (the rare 30-year-old Neandertal was old), but at some point, for reasons not really understood, the life spans of Homo sapiens began to increase. More longevity provided a grandparent generation to impart knowledge, skills, and more resources to the group.

Another discovery bearing on the subject are the extreme climate fluctuations that occurred between 65,000 and 25,000 years ago. The Neandertals had bodies and cultures adapted to ice and snow. This time of fluctuation involved such rapid climate change that in one lifetime “all the plants and animals that a person had grown up with could vanish and be replaced with unfamiliar flora and fauna,” writes Wong. The environmental stress may have decimated their ranks to below zero population growth.

Comment by doone on May 14, 2013 at 9:40am

Our Asian Origins infographic by Newscientist.

Comment by doone on May 2, 2013 at 5:39pm

Why Do Birds Walk So Weird?

Favorite 

Tags

 Submitted by: Unknown (via National Geographic)

4 185

SHARE:  7  

The crouched stance developed to compensate for the growth of larger forelimbs that eventually made flight possible, according to new research that digitally "fleshed out" fossils to show physical changes over the eons as bipedal dinosaurs evolved into birds.

Comment by doone on April 10, 2013 at 9:18am

EVOLUTION WITHOUT DARWIN

What if a young Charles Darwin, stricken with seasickness, had been washed over the side of HMS Beagle on a dark and stormy night in 1832? Peter Bowler's dramatic opening paragraph, complete with a nod and wink to Edward Bulwer-Lytton, sets a scene that would have averted the far higher drama that ensued from the publication in 1859 of On the Origin of Species. How would biological science's role in history have differed? By 1900, Bowler argues, scientifically informed opinion would have absorbed the idea that living forms evolve, without recognising that this happens through natural selection. In fact, as Bowler has demonstrated in his previous work on the history of evolutionary thought, that is pretty much what did happen. Although Darwin's theory of natural selection transformed the understanding of life by turning all eyes to evolution, the subsequent decades saw a successful effort to sideline it in favour of less disturbing candidates for mechanisms of change. People were ready to accept the idea of evolutionary transformation as long as it seemed orderly, progressive and purposeful. Lamarckian ideas, suggesting that individuals could improve themselves through their own striving and then pass on these improvements to their offspring, were a popular alternative. Other theories proposed that living forms were shaped by inner laws that guided change in beneficial directions.

more from Marek Kohn at Literary Review here.

Posted by Morgan Meis at 08:50 AM | Permalink

Comment by doone on March 31, 2013 at 8:18am

Dino Style

MAR 30 2013 @ 7:20PM

When it came to sex, dinosaurs had a hard time:

The plated, spiked stegosaurs are perhaps the most perplexing paramours of all. Consider Kentrosaurus, a cousin of the more famous Stegosaurus. This armored dinosaur sported huge spikes on its lower back and hips that must have looked dangerous to males in the mood. I asked my paleontologist friend Heinrich Mallison of the Museum of Natural History in Berlin to evaluate the possibility that Kentrosaurus mated in the leg-over-back position using computer models he had previously developed to study how flexible the animal was. Mallison tested dinosaur sex positions in three dimensions and concluded that the traditional dinosaur sex position did not work forKentrosaurus. If a male tried to throw his leg over the back of a crouching female, he would castrate himself on her sharp spikes. One hip spike in particular seemed to be placed to strike fear in the hearts of stegosaur suitors.

Recent Dish on the kinks of the animal kingdom here.

Comment by doone on March 8, 2013 at 12:18pm

How Can We Save The Rhino?

MAR 8 2013 @ 9:59AM

Kevin Charles Redmon warns that the illegal “rhino horn trade is flourishing”:

Twenty years ago, a kilo of horn went for $4,700. Today, it sells for $65,000, making it more valuable than either gold or cocaine. Poaching is on the rise, and by some accounts, the number of endangered (but not yet extinct) white rhino killed doubles each year. By 2035, African wildlands could be devoid of the animal.

One possible, controversial way to avoid this fate? Horn farming:

“Rhino horn is composed entirely of keratin and regrows when cut,” writes [Duan] Biggs [a postdoctoral research fellow at the University of Queensland]. “Sedating a rhino to shave its horn can be done for as little as $20.” A white rhino produces about a kilo of horn per year, and the current global demand could be met by “farming” as few as 5,000 animals on a private, well-guarded preserve. (Natural rhino death “would also provide hundreds of horns annually,” even as the herd continues to grow at a rate near 10 percent.) The millions of dollars generated by the legal enterprise could be used to fund further conservation efforts, such as wildland preservation, sustainable rural development, and field research.

Comment by Michel on March 8, 2013 at 11:08am

Reversible Evolution Demonstrated in Dust Mites:

In evolutionary biology, there is a deeply rooted supposition that you can't go home again: Once an organism has evolved specialized traits, it can't return to the lifestyle of its ancestors.

There's even a name for this pervasive idea. Dollo's law states that evolution is unidirectional and irreversible. But this "law" is not universally accepted and is the topic of heated debate among biologists.

Now a research team led by two University of Michigan biologists has used a large-scale genetic study of the lowly house dust mite to uncover an example of reversible evolution that appears to violate Dollo's law.

The study shows that tiny free-living house dust mites, which thrive in the mattresses, sofas and carpets of even the cleanest homes, evolved from parasites, which in turn evolved from free-living organisms millions of years ago.

"All our analyses conclusively demonstrated that house dust mites have abandoned a parasitic lifestyle, secondarily becoming free-living, and then speciated in several habitats, including human habitations," according to Pavel Klimov and Barry OConnor of the U-M Department of Ecology and Evolutionary Biology.

Their paper, "Is permanent parasitism reversible?—Critical evidence from early evolution of house dust mites," is scheduled to be published online today in the journal Systematic Biology.

Journal Article (not available just yet... we'll update the link) http://sysbio.oxfordjournals.org/content/early/recent

Dollow's "law" for the curious: https://en.wikipedia.org/wiki/Dollo%27s_law_of_irreversibility

About the Photo: This is a computer-compiled image from a focus stack of 67 individual focal planes. Mite size: 0.3mm
Photo Credit: Jacopo Werther
Licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.

Via DNA Fish on Facebook.

Comment by Marianne on February 20, 2013 at 10:07pm

I love that quote from Judith Hayes and I so entirely agree...

Comment by Davy on February 20, 2013 at 7:09pm

Good one!

• ‹ Previous
• 1
• 2
• 3
• …
• 21
• Next ›
• Page