Later On

A blog written for those whose interests more or less match mine.

Posts Tagged ‘evolution

Metal-eating superworms

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Very interesting. Photo at the link. The story:

Newly evolved “superworms” that feast on toxic waste could help cleanse polluted industrial land, a new study says.

These hardcore heavy metal fans, unearthed at disused mining sites in England and Wales, devour lead, zinc, arsenic, and copper.

The earthworms excrete a slightly different version of the metals, making them easier for plants to suck up. Harvesting the plants would leave cleaner soil behind.

“These worms seem to be able to tolerate incredibly high concentrations of heavy metals, and the metals seem to be driving their evolution,” said lead researcher Mark Hodson of the University of Reading in England.

“If you took an earthworm from the back of your garden and put it in these soils, it would die,” Hodson said.

DNA analysis of lead-tolerant worms living at Cwmystwyth, Wales, show they belong to a newly evolved species that has yet to be named, he said.

Two other superworms, including an arsenic-munching population from southwest England, are also likely new to science, Hodson said.

“It’s a good bet they are also different species, but we haven’t categorically proved that,” he said.

Continue reading.

Written by Leisureguy

25 December 2008 at 9:15 am

Posted in Daily life, Science

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Evolution in action

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One reason to believe in evolution: you can see it happening.

Scientists at the Instituto Gulbenkian de Ciencia (IGC) and the Faculty of Science of the University of Lisbon, in Portugal, have shown that populations of the worm Caenhorabditis elegans become resistance to pesticides in 20 generations, that is, in only 80 days. These findings, published last month in the journal PLoS ONE(*) open the way for future research into improved use of pesticides and antibiotics in pest and parasite control.

Patrícia Lopes and co-workers followed 20 generations of the worm C. elegans in the presence of Levamisole, a widely-used pesticide that acts on the nervous system, is lethal, but also affects fecundity and mobility, when present at lower doses. They found that Levamisole markedly reduced fecundity, survival and the frequency of males. Indeed, these almost disappeared in the population: from an initial frequency of 30%, they reached 0% by the 10th generation. The researchers showed that this drastic decrease in male frequency was not due to males being more susceptible to the pesticide than females. Rather, the pesticide affected the worms’ mobility and, consequently, their ability to find a mate.

However, the populations of worms were able to adapt to the new Levamisole environment, so that by the 10th generation, survival and fecundity had recovered, and the frequency of males increased again by the 20th generation. The ability to lose males in a population and still reproduce is only possible because C. elegans is a hermaphrodite species, that is, within a population, some worms are both male and female and can thus breed on their own, a process called ‘selfing’.

The researchers then placed the adapted worms into the original, pesticide-free environment and found that the worms survived perfectly. Scientists say that there were no adaptation costs to the population. Says Elio Sucena, group leader at the IGC and co-author of this study, ‘These findings have implications for managing the application of pesticides: if we had found that the survival of adapted worms in the original environment was impaired too, this would have meant that, by maintaining areas where the pesticide is not spread, resistance to the pesticide could be controlled, and the efficacy of the pesticide increased’.

Sara Magalhães, group leader at the University of Lisbon, points out that ‘As a result of the widespread use of pesticides and antibiotics, resistance to these chemicals has developed in many species. Our ability to manage this resistance entails being able to dissect the genetic changes underlying the acquisition of resistance. Ourapproach, using experimental evolution, allows us to manipulate several factors, such as population size, environmental stability and genetic background in our efforts to tackle and understand pesticide resistance, not only of C. elegans but also other pests and parasites’.

Source: Instituto Gulbenkian de Ciencia

Written by Leisureguy

18 December 2008 at 12:58 pm

Posted in Daily life, Science

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Why everyone should learn the theory of evolution

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Interesting article in the Scientific American:

Charles Darwin did not think of himself as a genius. “I have no great quickness of apprehension or wit which is so remarkable in some clever men …” he remarked in one passage of his autobiography. Fortunately for the rest of us, he was profoundly wrong in his assessment. So on February 12 the world will mark the bicentennial birthday of a scientist who holds a rightful place alongside Galileo, Copernicus, Newton and Einstein.

Darwin’s genius—and, yes, genius is the right word—is manifest in the way his theory of evolution can tie together disparate biological facts into a single unifying framework. Evolutionary geneticist Theodosius Dobzhansky’s oft-cited quotation bears repeating here: “Nothing in biology makes sense, except in the light of evolution.”

Yet it is also worth noting during this anniversary year that Darwin deserves a lot better than he gets. When the popular press needs an iconic image of a brilliant scientist, it invariably recycles the famous photograph of Albert Einstein having a bad hair day. (Einstein accompanies John Lennon and Andy Warhol on Forbes’s list of top-earning deceased celebrities.) Darwin’s failure to achieve icon status is the legacy of creationists and neocreationists and of the distortion of his ideas by the eugenics movement a century ago.

But Darwin is so much more than just a quaint, Victorian historical figure whose bust in the pantheon deserves a place among those of other scientific greats. Theory needs to explain past, present and future—and Darwin’s does all three in a form that requires no simplifying translation. His theory is readily accessible to any literate person who allots a pleasurable interlude for On the Origin of Species, its prose sometimes bordering on the poetic: “… from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”

Most important, Darwin’s legacy has a direct bearing on …

Continue reading. And see also this timeline/slide show on the theory of evolution.

Written by Leisureguy

15 December 2008 at 10:05 am

Posted in Daily life, Science

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Good response to crackpot anti-evolutionist

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Airtightnoodle has a good post that provides a link to this page: a detailed takedown of an anti-evolution book—a book that, alas, depends heavily on nonsense to make its argument.

Written by Leisureguy

24 August 2008 at 10:01 am

Posted in Daily life, Science

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Evolution of sub-optimal solutions

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Interesting indeed:

“Survival of the fittest” is the catch phrase of evolution by natural selection. While natural selection favors the most fit organisms around, evolutionary biologists have long wondered whether this leads to the best possible organisms in the long run.

A team of researchers at The University of Texas at Austin, led by Drs. Matthew Cowperthwaite and Lauren Ancel Meyers, has developed a new theory, which suggests that life may not always be optimal.

Genetic mutations create the raw material that natural selection acts upon. The short-term fate of a mutation is often quite clear. Mutations that make organisms more fit tend to persist through generations, while harmful mutations tend to die off with the organisms that possess them. The long-term consequences of mutations, however, are not well understood by evolutionary biologists. The researchers have shown that what may be good in the short run, may hinder evolution in the long run.

The team developed computer models of RNA molecules evolving by mutation and natural selection. RNA molecules, which are very similar to DNA, play key roles in essential life processes and serve as the genetic material for some of our deadliest viruses, including influenza and HIV.

Their computer models show …

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Written by Leisureguy

21 July 2008 at 11:37 am

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More technology from evolved structures

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Hundreds of millions of years of trial and error do indeed produce amazing structures. I mentioned earlier the bumps on the fins of the humpback whale, now imitated on fan blades. And now the teeth of the marine worm get close attention. (Scary photo at link—and you can enlarge it, too.)

Researchers in California and New Hampshire report the first detailed characterization of the protein composition of the hard, fang-like jaws of a common marine worm. Their work could lead to the design of a new class of super-strong, lightweight materials for use as construction and repair materials for spacecraft, airplanes, and other applications.

In the new study, Chris C. Broomell and colleagues note that Nereis virens, also known as the sandworm or ragworm, is a burrowing marine worm found in shallow waters in the North Atlantic region. Researchers remain intrigued by the remarkable hardness of its jaws and long pincers, which rivals that of human teeth and exceed the hardness of many synthetic plastics. But little is known about the exact chemical composition of these structures.

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Written by Leisureguy

14 July 2008 at 11:34 am

Posted in Science, Technology

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Rejoice, Creationists!

with 15 comments

“Ask and it shall be given,” as Jesus said. You have asked (repeatedly) for transitional forms in the fossil record, and more and more are found. These provide strong evidence of Evolution, which I assume you will now accept. The latest (with photo at the link):

Hidden away in museums for more that 100 years, some recently rediscovered flatfish fossils have filled a puzzling gap in the story of evolution and answered a question that initially stumped even Charles Darwin.

Opponents of evolution have insisted that adult flatfishes, which have both eyes on one side of the head, could not have evolved gradually. A slightly asymmetrical skull offers no advantage. No such fish — fossil or living — had ever been discovered, until now.

All adult flatfishes–including the gastronomically familiar flounder, plaice, sole, turbot, and halibut–have asymmetrical skulls, with both eyes located on one side of the head. Because these fish lay on their sides at the ocean bottom, this arrangement enhances their vision, with both eyes constantly in play, peering up into the water.

This remarkable arrangement arises during the youth of every flatfish, where the symmetrical larva undergoes a metamorphosis to produce an asymmetrical juvenile. One eye ‘migrates’ up and over the top of the head before coming to rest in the adult position on the opposite side of the skull.

Opponents of evolution, however, insisted that this curious anatomy could not have evolved gradually through natural selection because there would be no apparent evolutionary advantage to a fish with a slightly asymmetrical skull but which retained eyes on opposite sides of the head. No fish–fossil or living–had ever been discovered with such an intermediate condition.

But in the 10 July 2008 issue of Nature, Matt Friedman, graduate student in the Committee on Evolutionary Biology at the University of Chicago and a member of the Department of Geology at the Field Museum, draws attention to several examples of such transitional forms that he uncovered in museum collections of underwater fossilized creatures from the Eocene epoch–about 50 million years ago.

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Written by Leisureguy

9 July 2008 at 12:23 pm

Posted in Daily life, Religion, Science

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Good news for Creationists

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Creationist have repeatedly asked for fossil evidence of the evolutionary step of animals going from sea-dwellers to land-dwellers. Good news: it’s been found! An article by Sid Perkins in Science News:

New fossils of an ancient, four-limbed creature help fill in the blanks of the evolutionary transition between fish and the first land-adapted vertebrates.

Fossils of creatures that span the water-to-land transition of vertebrates are few and far between. One of those pioneers, Ventastega curonica, was first described in 1994 but previously has been known only from fragmentary remains unearthed from 365-million-year-old rocks at a site in western Latvia. Fossils found at the site during subsequent excavations now allow scientists to more fully reconstruct the creature, says Per Ahlberg, a paleontologist at Uppsala University in Sweden.

The new remains — including most of the creature’s skull, the braincase, half of the bones in its forelimb and a quarter of its pelvic girdle — suggest that Ventastega was an evolutionary intermediate between Tiktaalik, a four-limbed fish that lived about 382 million years ago (SN: 6/17/06, p. 379), and subsequent tetrapods such as Acanthostega, which were capable of walking on land.

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Written by Leisureguy

26 June 2008 at 7:52 am

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Yet another “transitional form”

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One argument made by Creationist/ID supporters is that there are gaps in the fossil record—where, they ask, are the transitional forms showing how one species evolved into another? And, of course, as more and more transitional forms are discovered, they are somehow not convinced, but keep asking the questions. We now have transitional forms of fish moving onto land, what became whales moving into water, and now this report of a frog/salamander ancestor.

Written by Leisureguy

23 May 2008 at 9:40 am

Posted in Religion, Science

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Another intermediate evolutionary form

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One thing that evolution deniers talk about is the lack in the fossil record of intermediate forms (e.g., from fish to land animal; from land animal to whale). Of course, when such forms are in fact discovered, they seldom say, “Oh. Guess I was wrong. I need to rethink this. Perhaps a tribal document telling a creation myth thousands of years old might be incorrect about the actual origins or various species.” Here’s the latest:

Scientists have discovered the missing link between whales and their four-footed ancestors. The result is reported in this week’s issue of the journal Nature. The research is funded by the National Science Foundation (NSF).

Scientists since Darwin have known that whales are mammals whose ancestors walked on land. In the past 15 years, researchers led by Hans Thewissen of the Northeastern Ohio Universities Colleges of Medicine and Pharmacy (NEOUCOM) have identified a series of intermediate fossils documenting whale’s dramatic evolutionary transition from land to sea.

But one step was missing: The identity of the land ancestors of whales.

Now Thewissen and colleagues have discovered the skeleton of Indohyus, an approximately 48-million-year-old even-toed ungulate from the Kashmir region of India, as the closest known fossil relative of whales.

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Written by Leisureguy

26 December 2007 at 1:22 pm

Posted in Religion, Science

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Evolution and a critic of it

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From Respectful Insolence (and interesting comments at the link):

There are certain bloggers who can reliably be counted on to deliver the stupid. We’ve met several of them over the time this blog’s been in existence. One such blogger, the born again Christian named LaShawn Barber, has been particularly good at it, although we’ve only met her a couple of times before, likening the NAACP to the white nationalist teen duo Prussian Blue as a means of trolling and saying rather odd things about Ted Haggard. Those were bad enough, but now she’s even more out of her depth than usual as she decides to pontificate about something about which it is brain-fryingly obvious that she knows nothing.

Yes, she thinks she knows enough about evolution to criticize it. She even thinks she knows enough to call it a “delusion.” She’s wrong, of course:

One doesn’t have to believe in the God of the Bible to hold the view that life’s complexity is evidence of an intelligent agent. The idea that an undirected, random series of events caused something as wonderfully complex, specifically magnificent, and infinitely beautiful as life is, to put it mildly, ludicrous. Living things look designed because they were designed.

Here we go again. It’s the old argument from incredulity. Just because Barber can’t understand how evolution works, she finds it “ludicrous.” Far more ludicrous is her arrogance in thinking that, just because she can’t understand evolution, it must mean that a supernatural force did it. Then she further reveals her ignorance by asserting:

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Written by Leisureguy

2 December 2007 at 11:17 am

Posted in Religion, Science

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Evidence for evolution

with 32 comments

Although Creationists stubbornly resist acknowledging evolution, this is going to be hard to explain:

… When [Darwin] suggested, in The Descent of Man (1871), that humans and apes shared a common ancestor, it was a revolutionary idea, and it remains one today. Yet nothing provides more convincing evidence for the “theory” of evolution than the viruses contained within our DNA. Until recently, the earliest available information about the history and the course of human diseases, like smallpox and typhus, came from mummies no more than four thousand years old. Evolution cannot be measured in a time span that short. Endogenous retroviruses provide a trail of molecular bread crumbs leading millions of years into the past.

Darwin’s theory makes sense, though, only if humans share most of those viral fragments with relatives like chimpanzees and monkeys. And we do, in thousands of places throughout our genome. If that were a coincidence, humans and chimpanzees would have had to endure an incalculable number of identical viral infections in the course of millions of years, and then, somehow, those infections would have had to end up in exactly the same place within each genome. The rungs of the ladder of human DNA consist of three billion pairs of nucleotides spread across forty-six chromosomes. The sequences of those nucleotides determine how each person differs from another, and from all other living things. The only way that humans, in thousands of seemingly random locations, could possess the exact retroviral DNA found in another species is by inheriting it from a common ancestor.

Molecular biology has made precise knowledge about the nature of that inheritance possible. With extensive databases of genetic sequences, reconstructing ancestral genomes has become common, and retroviruses have been found in the genome of every vertebrate species that has been studied. Anthropologists and biologists have used them to investigate not only the lineage of primates but the relationships among animals—dogs, jackals, wolves, and foxes, for example—and also to test whether similar organisms may in fact be unrelated.

The entire article is worth reading, but given this smoking-gun quality of evidence for the fact of evolution, how will Creationists respond? (Beyond stubborn, pig-headed, blind denial, I mean.)

Written by Leisureguy

28 November 2007 at 1:30 pm

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Creationists accept SUPER-evolution

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This is safe for work if you turn off the soundtrack, which is not really needed. Super-evolution: one pair of rhinoceruses on Noah’s Ark gave rise to 100-200 species in two centuries. (Very prolific, eh?: a new species arising on average each year, just among rhinoceruses.) Here’s the video:

Written by Leisureguy

13 November 2007 at 10:58 am

Posted in Humor, Religion, Science

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From gestures to words to language

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Mind Hacks:

Science News reviews two books that propose a thought-provoking hypothesis about the evolution of language: that our ability to communicate verbally evolved from hand gestures.

The first book, Talking Hands is a study on a sign language developed by a Bedouin community only a short time ago that is used widely by both deaf and hearing members of the community.

As a relatively new phenomenon, it has allowed researchers to study a spontaneously created language as it develops.

The book also touches on the evolution of language and notes that while primates typically have poor control over their vocal chords, they have a precise control over their hands allowing huge scope for symbolic representation.

The second book, The Gestural Origin of Language directly addresses the issue and argues that sign, not spoken languages, are the original mode of human communication.

Armstrong and Wilcox, building on their earlier work with Stokoe, get around this problem by redefining language itself. In their hands, as it were, language is considered an embodied system whereby bodily gestures become ritualized and conventionalized into an accepted communication system. Given that our ancestors were tree-dwelling primates, our hands are well adapted to create four-dimensional space-time representations of the four-dimensional world. This ability was especially amenable to exploitation once our hominin forebears became bipedal and gained additional freedom of hand movement. With conventionalization, gestures become simplified and may lose their iconic aspect, but they are readily maintained through cultural transmission.

In this view, speech itself is a gestural system, composed of movements of the lips, velum and larynx, and the blade, body and root of the tongue. This is consistent with the so-called “motor theory of speech perception” developed at the Haskins Laboratories (a private research institute in New Haven, Connecticut) during the 1960s, which holds that the perception of speech is not so much an acoustic phenomenon as the recovery, through sound, of speech gestures. The arbitrary nature of speech sounds is not a fundamental property of language but is rather the consequence of the medium through which the gestures are expressed. The authors aptly quote the linguist Charles Hockett: “When a representation of some four-dimensional hunk of life has to be compressed into the single dimension of speech, most iconicity is necessarily squeezed out.” The concentration on speech may have created a myopic view of what language is really all about.

It’s a challenging hypothesis that asks us to reconsider that spoken language, often quoted as the defining feature of humanity, may be a relatively recent form of communication.

On a purely aesthetic level, I find sign language beautiful and utterly mesmerising and after a quick search on YouTube it seems there is a healthy online signing community.

One of my favourites is a video of someone signing Dusty Springfield’s Son of a Preacherman.

Written by Leisureguy

15 October 2007 at 4:19 pm

Posted in Daily life, Science

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