Tuesday, 16 February 2016
Electrons in slo mo?
Scientists discover electrons moving like honey in graphene
February 12, 2016 by Ben Robinson
Electrons which act like slow-pouring honey have been observed for the first time in graphene, prompting a new approach to fundamental physics.
Electrons are known to move through metals like bullets being reflected only by imperfections, but in graphene they move like in a very viscous liquid, University of Manchester researchers have found.
The possibility of a highly viscous flow of electrons in metals was predicted several decades ago but despite numerous efforts never observed, until now as reported in the journal Science.
The observation and study of this effect allows better understanding of the counterintuitive behaviour of interacting particles, where the human knowledge and developed mathematical techniques are lacking.
One-atom thick material graphene, first explored a decade ago by a team at The University of Manchester, is renowned for its many superlative properties and, especially, exceptionally high electrical conductivity.
It is widely believed that electrons in graphene can move 'ballistically', like bullets or billiard balls scattering only at graphene boundaries or other imperfections.
The reality is not quite so simple, as found by a Manchester group led by Sir Andre Geim in collaboration with Italian researchers led by Prof Marco Polini.
They observed that the electric current in graphene did not flow along the applied electric field, as in other materials, but travelled backwards forming whirlpools where circular currents appeared.Such behaviour is familiar for conventional liquids such as water which makes whirlpools when flowing around obstacles, for example, in rivers.
The scientists measured the viscosity of this strange new liquid in graphene, which consists not of water molecules but electrons. To the researchers surprise, the electron fluid can be 100 times more viscous than honey, even at room temperature.
The scientific breakthrough is important for understanding of how materials work at increasing smaller sizes required by the semiconducting industry because such whirlpools are more likely to appear at micro and nanoscale.
The observation also questions our current understanding of the physics of highly conductive metals, especially graphene itself.
The simultaneous existence of such seemingly incompatible properties, with electrons behaving like bullets and a liquid in the same material prompts a fundamental rethinking about our understanding of materials properties.
Professor Polini commented: "Giving decades long efforts to find even minor signs of a viscous flow in metals, we were flabbergasted that graphene exhibited not just some small blip on an experimental curve but the clear qualitative effect, a large backflow of electric current."
Sir Andre Geim, who received a Nobel Prize for graphene, added: "Graphene cannot stop amazing us. Now we need to think long and hard how to connect such contradictory behaviour as ballistic motion of electrons, which is undoubtedly seen in graphene, with this new quantum weirdness arising from their collective motion. A strong adjustment of our understanding of the physics is due."
February 12, 2016 by Ben Robinson
Electrons which act like slow-pouring honey have been observed for the first time in graphene, prompting a new approach to fundamental physics.
Electrons are known to move through metals like bullets being reflected only by imperfections, but in graphene they move like in a very viscous liquid, University of Manchester researchers have found.
The possibility of a highly viscous flow of electrons in metals was predicted several decades ago but despite numerous efforts never observed, until now as reported in the journal Science.
The observation and study of this effect allows better understanding of the counterintuitive behaviour of interacting particles, where the human knowledge and developed mathematical techniques are lacking.
One-atom thick material graphene, first explored a decade ago by a team at The University of Manchester, is renowned for its many superlative properties and, especially, exceptionally high electrical conductivity.
It is widely believed that electrons in graphene can move 'ballistically', like bullets or billiard balls scattering only at graphene boundaries or other imperfections.
The reality is not quite so simple, as found by a Manchester group led by Sir Andre Geim in collaboration with Italian researchers led by Prof Marco Polini.
They observed that the electric current in graphene did not flow along the applied electric field, as in other materials, but travelled backwards forming whirlpools where circular currents appeared.Such behaviour is familiar for conventional liquids such as water which makes whirlpools when flowing around obstacles, for example, in rivers.
The scientists measured the viscosity of this strange new liquid in graphene, which consists not of water molecules but electrons. To the researchers surprise, the electron fluid can be 100 times more viscous than honey, even at room temperature.
The scientific breakthrough is important for understanding of how materials work at increasing smaller sizes required by the semiconducting industry because such whirlpools are more likely to appear at micro and nanoscale.
The observation also questions our current understanding of the physics of highly conductive metals, especially graphene itself.
The simultaneous existence of such seemingly incompatible properties, with electrons behaving like bullets and a liquid in the same material prompts a fundamental rethinking about our understanding of materials properties.
Professor Polini commented: "Giving decades long efforts to find even minor signs of a viscous flow in metals, we were flabbergasted that graphene exhibited not just some small blip on an experimental curve but the clear qualitative effect, a large backflow of electric current."
Sir Andre Geim, who received a Nobel Prize for graphene, added: "Graphene cannot stop amazing us. Now we need to think long and hard how to connect such contradictory behaviour as ballistic motion of electrons, which is undoubtedly seen in graphene, with this new quantum weirdness arising from their collective motion. A strong adjustment of our understanding of the physics is due."
Civil War V :The Dino to Bird controversy.
Study challenges bird-from-dinosaur theory of evolution - was it the other way around?:
(PhysOrg.com) -- A new study just published in the Proceedings of the National Academy of Sciences provides yet more evidence that birds did not descend from ground-dwelling theropod dinosaurs, experts say, and continues to challenge decades of accepted theories about the evolution of flight.
A new analysis was done of an unusual fossil specimen discovered in 2003 called "microraptor," in which three-dimensional models were used to study its possible flight potential, and it concluded this small, feathered species must have been a "glider" that came down from trees. The research is well done and consistent with a string of studies in recent years that pose increasing challenge to the birds-from-dinosaurs theory, said John Ruben, a professor of zoology at Oregon State University who authored a commentary in PNAS on the new research.
The weight of the evidence is now suggesting that not only did birds not descend from dinosaurs, Ruben said, but that some species now believed to be dinosaurs may have descended from birds.
"We're finally breaking out of the conventional wisdom of the last 20 years, which insisted that birds evolved from dinosaurs and that the debate is all over and done with," Ruben said. "This issue isn't resolved at all. There are just too many inconsistencies with the idea that birds had dinosaur ancestors, and this newest study adds to that."
Almost 20 years of research at OSU on the morphology of birds and dinosaurs, along with other studies and the newest PNAS research, Ruben said, are actually much more consistent with a different premise - that birds may have had an ancient common ancestor with dinosaurs, but they evolved separately on their own path, and after millions of years of separate evolution birds also gave rise to the raptors. Small animals such as velociraptor that have generally been thought to be dinosaurs are more likely flightless birds, he said.
"Raptors look quite a bit like dinosaurs but they have much more in common with birds than they do with other theropod dinosaurs such as Tyrannosaurus," Ruben said. "We think the evidence is finally showing that these animals which are usually considered dinosaurs were actually descended from birds, not the other way around."
Another study last year from Florida State University raised similar doubts, Ruben said.
In the newest PNAS study, scientists examined a remarkable fossil specimen that had feathers on all four limbs, somewhat resembling a bi-plane. Glide tests based on its structure concluded it would not have been practical for it to have flown from the ground up, but it could have glided from the trees down, somewhat like a modern-day flying squirrel. Many researchers have long believed that gliders such as this were the ancestors of modern birds.
"This model was not consistent with successful flight from the ground up, and that makes it pretty difficult to make a case for a ground-dwelling theropod dinosaur to have developed wings and flown away," Ruben said. "On the other hand, it would have been quite possible for birds to have evolved and then, at some point, have various species lose their flight capabilities and become ground-dwelling, flightless animals - the raptors. This may be hugely upsetting to a lot of people, but it makes perfect sense."
In their own research, including one study just last year in the Journal of Morphology, OSU scientists found that the position of the thigh bone and muscles in birds is critical to their ability to have adequate lung capacity for sustained long-distance flight, a fundamental aspect of bird biology. Theropod dinosaurs did not share this feature. Other morphological features have also been identified that are inconsistent with a bird-from-dinosaur theory. And perhaps most significant, birds were already found in the fossil record before the elaboration of the dinosaurs they supposedly descended from. That would be consistent with raptors descending from birds, Ruben said, but not the reverse.
OSU research on avian biology and physiology has been raising questions on this issue since the 1990s, often in isolation. More scientists and other studies are now challenging the same premise, Ruben said. The old theories were popular, had public appeal and "many people saw what they wanted to see" instead of carefully interpreting the data, he said.
"Pesky new fossils...sharply at odds with conventional wisdom never seem to cease popping up," Ruben wrote in his PNAS commentary. "Given the vagaries of the fossil record, current notions of near resolution of many of the most basic questions about long-extinct forms should probably be regarded with caution."
(PhysOrg.com) -- A new study just published in the Proceedings of the National Academy of Sciences provides yet more evidence that birds did not descend from ground-dwelling theropod dinosaurs, experts say, and continues to challenge decades of accepted theories about the evolution of flight.
A new analysis was done of an unusual fossil specimen discovered in 2003 called "microraptor," in which three-dimensional models were used to study its possible flight potential, and it concluded this small, feathered species must have been a "glider" that came down from trees. The research is well done and consistent with a string of studies in recent years that pose increasing challenge to the birds-from-dinosaurs theory, said John Ruben, a professor of zoology at Oregon State University who authored a commentary in PNAS on the new research.
The weight of the evidence is now suggesting that not only did birds not descend from dinosaurs, Ruben said, but that some species now believed to be dinosaurs may have descended from birds.
"We're finally breaking out of the conventional wisdom of the last 20 years, which insisted that birds evolved from dinosaurs and that the debate is all over and done with," Ruben said. "This issue isn't resolved at all. There are just too many inconsistencies with the idea that birds had dinosaur ancestors, and this newest study adds to that."
Almost 20 years of research at OSU on the morphology of birds and dinosaurs, along with other studies and the newest PNAS research, Ruben said, are actually much more consistent with a different premise - that birds may have had an ancient common ancestor with dinosaurs, but they evolved separately on their own path, and after millions of years of separate evolution birds also gave rise to the raptors. Small animals such as velociraptor that have generally been thought to be dinosaurs are more likely flightless birds, he said.
"Raptors look quite a bit like dinosaurs but they have much more in common with birds than they do with other theropod dinosaurs such as Tyrannosaurus," Ruben said. "We think the evidence is finally showing that these animals which are usually considered dinosaurs were actually descended from birds, not the other way around."
Another study last year from Florida State University raised similar doubts, Ruben said.
In the newest PNAS study, scientists examined a remarkable fossil specimen that had feathers on all four limbs, somewhat resembling a bi-plane. Glide tests based on its structure concluded it would not have been practical for it to have flown from the ground up, but it could have glided from the trees down, somewhat like a modern-day flying squirrel. Many researchers have long believed that gliders such as this were the ancestors of modern birds.
"This model was not consistent with successful flight from the ground up, and that makes it pretty difficult to make a case for a ground-dwelling theropod dinosaur to have developed wings and flown away," Ruben said. "On the other hand, it would have been quite possible for birds to have evolved and then, at some point, have various species lose their flight capabilities and become ground-dwelling, flightless animals - the raptors. This may be hugely upsetting to a lot of people, but it makes perfect sense."
In their own research, including one study just last year in the Journal of Morphology, OSU scientists found that the position of the thigh bone and muscles in birds is critical to their ability to have adequate lung capacity for sustained long-distance flight, a fundamental aspect of bird biology. Theropod dinosaurs did not share this feature. Other morphological features have also been identified that are inconsistent with a bird-from-dinosaur theory. And perhaps most significant, birds were already found in the fossil record before the elaboration of the dinosaurs they supposedly descended from. That would be consistent with raptors descending from birds, Ruben said, but not the reverse.
OSU research on avian biology and physiology has been raising questions on this issue since the 1990s, often in isolation. More scientists and other studies are now challenging the same premise, Ruben said. The old theories were popular, had public appeal and "many people saw what they wanted to see" instead of carefully interpreting the data, he said.
"Pesky new fossils...sharply at odds with conventional wisdom never seem to cease popping up," Ruben wrote in his PNAS commentary. "Given the vagaries of the fossil record, current notions of near resolution of many of the most basic questions about long-extinct forms should probably be regarded with caution."
The Crisis continues II
Denton, Still a Theory in Crisis, Part 2:
February 16, 2016 Posted by Barry Arrington
This is the second of a series of posts reviewing Michael Denton’s new book Evolution: Still a Theory in Crisis.
“Gaps among known species are sporadic and often small. Gaps among known orders, classes, and phyla are systematic and almost always large.” George Gaylord Simpson, “The History of Life,” in ed. Sol Tax, Evolution After Darwin (Chicago: University of Chicago Press, 1960), 1:149.
“Unfortunately, the origins of most higher categories are shrouded in mystery; commonly new higher categories appear abruptly in the fossil record without evidence of transitional ancestral forms.” D.M. Raup and Steven M. Stanley, Principles of Paleontology (San Francisco: W.H. Freeman and Co., 1971), 306.
“The known fossil record fails to document a single example of phyletic evolution accomplishing a major morphologic transition and hence offers no evidence that the gradualistic model can be valid.” Steven M. Stanley, Macroevolution: Pattern and Process (San Francisco: W. H. Freeman, 1979), 39.
As I noted in part one of this series, Dr. Denton has no doubt that Darwinian evolution occurs. Nor should he. The term “bauplan” comes from the German “building plan” or “building scheme,” and is often translated in biology as “body plan.” In chapter 2 (entitled Galápagos), Denton explains that the biosphere is replete with examples of minor variations of bauplans – such as the beaks of the finches of the Galápagos islands made famous by Darwin – that are doubtless due to purely Darwinian processes. These minor variations of bauplans are often classified under the term “microevolution.”
Before we go any further, let us anticipate an objection. Darwinists who post in these pages often howl in indignation over the term “microevolution.” They say the term is never used by “real” biologists. Perhaps they do not consider George Gaylord Simpson to be a “real” biologist:
“Micro-evolution involves mainly changes within potentially continuous populations, and there is little doubt that its materials are those revealed by genetic experimentation. Macro-evolution involves the rise and divergence of discontinuous groups, and it is still debatable whether it differs in kind or only in degree from microevolution.” George Gaylord Simpson, Tempo and Mode in Evolution (New York: Columbia University Press, 1944), 97
Or Stephen Jay Gould:
“As a Darwinian, I wish to defend Goldschmidt’s postulate that macroevolution is not simply microevolution extrapolated . . .” Stephen Jay Gould, The Return of Hopeful Monsters, Natural History, 86 (June/July 1977), 24, 30
Or Douglas H. Erwin and James W. Valentine:
“Explanations of the Cambrian radiation of invertebrate marine phyla and classes have focused on species selection or traditional microevolutonary processes.” Douglas H. Erwin and James W. Valentine, “‘Hopeful Monsters,’ Transposons, and the Metazoan Radiation,” Proceedings of the National Academy of Sciences, USA 81 (September 1984): 5482-5483
Eminent biologists have recognized and referred to the distinction between microevolution and macroevolution for nearly one hundred years. Let us hope that we can dispense with the “real biologists don’t use the term ‘microevolution’” canard once and for all.
Denton uses the Galápagos finch beaks as an example of microevolution. The finches of the various islands are closely related in terms of nest architecture, egg coloration and DNA. Yet in other respects, including their beak morphology, they can be quite different. Denton quotes Darwin’s correct inference regarding the origin of these differences: “Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends.” Darwin was also correct about the causal mechanism that resulted in these changes: “Darwin also inferred (again rightly, as the work of subsequent researchers on Galápagos has amply confirmed) that the major causal mechanism responsible for their adaptive divergence—the shaping of their beaks for example—is the simple mechanism of natural selection.”
Denton concludes that evolution on this scale is caused by purely Darwinian mechanisms:
As far as the evolution of finch beaks is concerned, there is no need either at the morphological or genetic level to call for any causal agency other than cumulative selection. Here I concur with classic Darwinism. The beaks are clearly adaptations and their evolution is entirely explicable within a classic functionalist framework. . . . The lesson of the Galápagos, and one of the repeated mantras of Evolution: A Theory in Crisis (see Chapters 2 and 4) is simply this: Cumulative selection will work its magic as long as the novelty of interest is adaptive and there is a functional continuum (at the morphological or genetic level) leading from a putative ancestor species or structure A to a descendant species or structure B.
(emphasis in the original)
In summary, Denton has absolutely no problem with attributing evolutionary change to Darwinian mechanisms so long as the two conditions Darwin himself asserted are necessary are in place: (1) the novelty is adaptive (otherwise there is nothing for natural selection to “select” for); and (2) there is a functional continuum – there can be no “gaps” in functional intermediates.
This brings us to another important term: “saltation.” In Origin of Species Darwin quoted six times the Latin sentence natura non facit saltus. It means “nature does not take jumps.” The word saltus means “leap” or “jump,” and in evolutionary theory a drastic or sudden change in an a line of organisms (a “jump”) is called a “saltation.” Thus, Darwin himself asserted that his theory does not allow for saltations. Stephen Jay Gould added in his 2002 The Structure of Evolutionary Theory that Darwinian evolution requires variation for natural selection to act upon, AND that variation must, by definition, be very small. Otherwise, it would be the variation itself, and not natural selection, that would account for the evolutionary change.
Thus Darwinists, beginning with Darwin himself, have always insisted that the theory absolutely requires the “functional continuum” to which Denton alludes. Saltations are not possible under the theory. Gould goes so far as to say “For this reason . . . saltationist (or macromutational) theories have always been viewed as anti-Darwinian.” Stephen Jay Gould, The Structure of Evolutionary Theory (Cambridge, MA: Belknap Press [Harvard], 2002), 111.
Functionalist evolutionary theory demands a continuous chain of functional intermediates for natural selection to work at all:
Darwin’s interminable series of transitional forms is necessary for straightforward mechanistic reasons (how else can one get from A to B by cumulative selection?), but it is also essential if the sole agency of change is to be natural selection. Where a complex adaptation—no matter how complex—can be reached in a series of tiny adaptive steps, then natural selection can indeed function, in Dawkins’s description, as a blind watchmaker and change A into B no matter how complex the transition, without any other causal agency being involved.
But what if the continuous chain of functional intermediates is missing? Here we get to the nub of the matter, because Denton claims that
many of the taxa-defining homologs actualized during the course of evolution have never been shown to be adaptive and even in the case of those homologs which are apparently adaptive, functional continuums are either unknown or very hard to envisage.
And if this is the case, certain conclusions follow ineluctably:
To acknowledge their absence [i.e., the absence of a continuous chain of functional intermediates] is to acknowledge that the paths of evolution must have been ordered and directed by additional causal factors, i.e., that cumulative selection is not the sole or even the major directive agency.
Denton writes that this “need for adaptive continuums brings us to the nub of the problem, the core contention of Evolution: A Theory in Crisis, and the major point defended here: Practically all the novel, taxa-defining homologs of all the main taxa are not led up to via adaptive continuums. Moreover, as argued later in this book, many of these novel Bauplans do not convey any obvious impression of being adaptive . . .”
Denton concludes the chapter with this delightful observation of fine irony:
It is ironic that the very evidence for believing that microevolution has indeed occurred in cases like the finches—an empirically known or readily envisaged continuum of forms leading from an ancestral form A to descendant form B—is precisely the evidence that is lacking when attempting to account for macroevolution and the origin of the defining features (feathers, hands, mammary glands, hair, the placenta, flowers, body plan, etc.) of the major taxa.
February 16, 2016 Posted by Barry Arrington
This is the second of a series of posts reviewing Michael Denton’s new book Evolution: Still a Theory in Crisis.
“Gaps among known species are sporadic and often small. Gaps among known orders, classes, and phyla are systematic and almost always large.” George Gaylord Simpson, “The History of Life,” in ed. Sol Tax, Evolution After Darwin (Chicago: University of Chicago Press, 1960), 1:149.
“Unfortunately, the origins of most higher categories are shrouded in mystery; commonly new higher categories appear abruptly in the fossil record without evidence of transitional ancestral forms.” D.M. Raup and Steven M. Stanley, Principles of Paleontology (San Francisco: W.H. Freeman and Co., 1971), 306.
“The known fossil record fails to document a single example of phyletic evolution accomplishing a major morphologic transition and hence offers no evidence that the gradualistic model can be valid.” Steven M. Stanley, Macroevolution: Pattern and Process (San Francisco: W. H. Freeman, 1979), 39.
As I noted in part one of this series, Dr. Denton has no doubt that Darwinian evolution occurs. Nor should he. The term “bauplan” comes from the German “building plan” or “building scheme,” and is often translated in biology as “body plan.” In chapter 2 (entitled Galápagos), Denton explains that the biosphere is replete with examples of minor variations of bauplans – such as the beaks of the finches of the Galápagos islands made famous by Darwin – that are doubtless due to purely Darwinian processes. These minor variations of bauplans are often classified under the term “microevolution.”
Before we go any further, let us anticipate an objection. Darwinists who post in these pages often howl in indignation over the term “microevolution.” They say the term is never used by “real” biologists. Perhaps they do not consider George Gaylord Simpson to be a “real” biologist:
“Micro-evolution involves mainly changes within potentially continuous populations, and there is little doubt that its materials are those revealed by genetic experimentation. Macro-evolution involves the rise and divergence of discontinuous groups, and it is still debatable whether it differs in kind or only in degree from microevolution.” George Gaylord Simpson, Tempo and Mode in Evolution (New York: Columbia University Press, 1944), 97
Or Stephen Jay Gould:
“As a Darwinian, I wish to defend Goldschmidt’s postulate that macroevolution is not simply microevolution extrapolated . . .” Stephen Jay Gould, The Return of Hopeful Monsters, Natural History, 86 (June/July 1977), 24, 30
Or Douglas H. Erwin and James W. Valentine:
“Explanations of the Cambrian radiation of invertebrate marine phyla and classes have focused on species selection or traditional microevolutonary processes.” Douglas H. Erwin and James W. Valentine, “‘Hopeful Monsters,’ Transposons, and the Metazoan Radiation,” Proceedings of the National Academy of Sciences, USA 81 (September 1984): 5482-5483
Eminent biologists have recognized and referred to the distinction between microevolution and macroevolution for nearly one hundred years. Let us hope that we can dispense with the “real biologists don’t use the term ‘microevolution’” canard once and for all.
Denton uses the Galápagos finch beaks as an example of microevolution. The finches of the various islands are closely related in terms of nest architecture, egg coloration and DNA. Yet in other respects, including their beak morphology, they can be quite different. Denton quotes Darwin’s correct inference regarding the origin of these differences: “Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends.” Darwin was also correct about the causal mechanism that resulted in these changes: “Darwin also inferred (again rightly, as the work of subsequent researchers on Galápagos has amply confirmed) that the major causal mechanism responsible for their adaptive divergence—the shaping of their beaks for example—is the simple mechanism of natural selection.”
Denton concludes that evolution on this scale is caused by purely Darwinian mechanisms:
As far as the evolution of finch beaks is concerned, there is no need either at the morphological or genetic level to call for any causal agency other than cumulative selection. Here I concur with classic Darwinism. The beaks are clearly adaptations and their evolution is entirely explicable within a classic functionalist framework. . . . The lesson of the Galápagos, and one of the repeated mantras of Evolution: A Theory in Crisis (see Chapters 2 and 4) is simply this: Cumulative selection will work its magic as long as the novelty of interest is adaptive and there is a functional continuum (at the morphological or genetic level) leading from a putative ancestor species or structure A to a descendant species or structure B.
(emphasis in the original)
In summary, Denton has absolutely no problem with attributing evolutionary change to Darwinian mechanisms so long as the two conditions Darwin himself asserted are necessary are in place: (1) the novelty is adaptive (otherwise there is nothing for natural selection to “select” for); and (2) there is a functional continuum – there can be no “gaps” in functional intermediates.
This brings us to another important term: “saltation.” In Origin of Species Darwin quoted six times the Latin sentence natura non facit saltus. It means “nature does not take jumps.” The word saltus means “leap” or “jump,” and in evolutionary theory a drastic or sudden change in an a line of organisms (a “jump”) is called a “saltation.” Thus, Darwin himself asserted that his theory does not allow for saltations. Stephen Jay Gould added in his 2002 The Structure of Evolutionary Theory that Darwinian evolution requires variation for natural selection to act upon, AND that variation must, by definition, be very small. Otherwise, it would be the variation itself, and not natural selection, that would account for the evolutionary change.
Thus Darwinists, beginning with Darwin himself, have always insisted that the theory absolutely requires the “functional continuum” to which Denton alludes. Saltations are not possible under the theory. Gould goes so far as to say “For this reason . . . saltationist (or macromutational) theories have always been viewed as anti-Darwinian.” Stephen Jay Gould, The Structure of Evolutionary Theory (Cambridge, MA: Belknap Press [Harvard], 2002), 111.
Functionalist evolutionary theory demands a continuous chain of functional intermediates for natural selection to work at all:
Darwin’s interminable series of transitional forms is necessary for straightforward mechanistic reasons (how else can one get from A to B by cumulative selection?), but it is also essential if the sole agency of change is to be natural selection. Where a complex adaptation—no matter how complex—can be reached in a series of tiny adaptive steps, then natural selection can indeed function, in Dawkins’s description, as a blind watchmaker and change A into B no matter how complex the transition, without any other causal agency being involved.
But what if the continuous chain of functional intermediates is missing? Here we get to the nub of the matter, because Denton claims that
many of the taxa-defining homologs actualized during the course of evolution have never been shown to be adaptive and even in the case of those homologs which are apparently adaptive, functional continuums are either unknown or very hard to envisage.
And if this is the case, certain conclusions follow ineluctably:
To acknowledge their absence [i.e., the absence of a continuous chain of functional intermediates] is to acknowledge that the paths of evolution must have been ordered and directed by additional causal factors, i.e., that cumulative selection is not the sole or even the major directive agency.
Denton writes that this “need for adaptive continuums brings us to the nub of the problem, the core contention of Evolution: A Theory in Crisis, and the major point defended here: Practically all the novel, taxa-defining homologs of all the main taxa are not led up to via adaptive continuums. Moreover, as argued later in this book, many of these novel Bauplans do not convey any obvious impression of being adaptive . . .”
Denton concludes the chapter with this delightful observation of fine irony:
It is ironic that the very evidence for believing that microevolution has indeed occurred in cases like the finches—an empirically known or readily envisaged continuum of forms leading from an ancestral form A to descendant form B—is precisely the evidence that is lacking when attempting to account for macroevolution and the origin of the defining features (feathers, hands, mammary glands, hair, the placenta, flowers, body plan, etc.) of the major taxa.
Bacteria:Known troublemakers for design deniers
Derbyshire VI: Behe's Bacterial Flagellum--Still Stirring Up Trouble for Darwin's Defenders:
Jonathan Witt February 18, 2005 2:50 PM
John Derbyshire is on The Corner arguing that we can never safely infer that certain biological structures were designed. To a reader who asserted that organizational complexity cannot arise from impersonal processes, Derbyshire replies, "How do you know it can't? It is true that the genesis of organizational complexity is not currently well understood; but to leap from that to telling me we shall NEVER be able to find a natural-law explanation for it is just dogma."
Derbyshire's argument is worth confronting because it represents the opinion of leading Darwinists. Biologist Kenneth Miller, for instance, routinely makes just such an argument. Design theorist William Dembski responds thus:
Miller claims that the problem with anti-evolutionists like Michael Behe and me is a failure of imagination -- that we personally cannot "imagine how evolutionary mechanisms might have produced a certain species, organ, or structure." He then emphasizes that such claims are "personal," merely pointing up the limitations of those who make them. Let's get real. The problem is not that we in the intelligent design community, whom Miller incorrectly calls "anti-evolutionists," just can't imagine how those systems arose.
The problem is that Ken Miller and the entire biological community haven't figured out how those systems arose. It's not a question of personal incredulity but of global disciplinary failure (the discipline here being biology) and gross theoretical inadequacy (the theory here being Darwin's).
The particular mechanism Miller has in view here is the bacterial flagellum. Click here and scroll down for a good, brief description and animation of the bacterial flagellum, and here for an enlarged view with its parts labeled. Biochemist Michael Behe made this little engine that could famous by showing that it was irreducibly complex, like a mouse trap: "If any one of the components of the mousetrap (the base, hammer, spring, catch, or holding bar) is removed, then the trap does not function." With even four of these parts, it's utterly useless. The mousetrap is irreducibly complex.
What does irreducible complexity have to do with Darwinian evolution? Evolution by mutation and natural selection must proceed by one slight, functional improvement at a time. So how can it build an irreducibly complex propeller motor one step at a time if the motor can't propel at all until all of its parts are in place? It can't. Something else built it.
Behe's argument doesn't assume that none of the other parts could ever be used for anything else. The spring on a mousetrap could be taken and used in some other device. The base with cheese on it could feed a mouse. Several but not all of the parts of a bacterial flagellum--while completely useless as a rotary propulsion machine--can be used to transport proteins across a membrane. But this hardly provides a credible Darwinian pathway.
Imagine if a boy told a girl he could climb to Mars because there supposedly existed a natural ladder stretching from one planet to the other? The girl is skeptical, pointing out that nobody on earth has ever found such a ladder. The boy screams, "That's an argument from ignorance! Scientists are finding all sorts of new things all the time. Look! The moon! The moon is one step along the way. You see, everything is falling into place." The Darwinists' desperate efforts to spin away the clear significance of the bacterial flagellum is strangely akin to this sort of reasoning. Dembski explains:
Darwin's theory, without which nothing in biology is supposed to make sense, in fact offers no insight into how the flagellum arose. If the biological community had even an inkling of how such systems arose by naturalistic mechanisms, Miller would not -- a full six years after the publication of Darwin's Black Box by Michael Behe -- be lamely gesturing at the type three secretory system as a possible evolutionary precursor to the flagellum.
Miller and Derbyshire are like the boy convinced of the natural ladder to Mars, who finds the moon and yells "Ah ha! Now who dares to play the skeptic!" Well, design theorists do. Consider this passage from a peer-edited paper by biologist Scott Minnich and philosopher of science Stephen Meyer, in which they discuss recent evidence for the delicately orchestrated and information-rich proteins of the bacterial flagellum:
[I]f anything, TTSSs [Type Three Secretory Systems] generate more complications than solutions to this question. As shown here, possessing multiple TTSSs causes interference. If not segregated one or both systems are lost. Additionally, the other thirty proteins in the flagellar motor (that are not present in the TTSS) are unique to the motor and are not found in any other living system. From whence, then were these protein parts co-opted?
Also, even if all the protein parts were somehow available to make a flagellar motor during the evolution of life, the parts would need to be assembled in the correct temporal sequence similar to the way an automobile is assembled in factory. Yet, to choreograph the assembly of the parts of the flagellar motor, present-day bacteria need an elaborate system of genetic instructions as well as many other protein machines to time the expression of those assembly instructions. Arguably, this system is itself irreducibly complex. In any case, the co-option argument tacitly presupposes the need for the very thing it seeks to explain--a functionally interdependent system of proteins.
Now one letter writer, responding to Behe's column in The New York Times, complained that we only describe the bacterial flagellum as an outboard motor because we have no better analogy, not because it is an outboard motor. The letter writer argues that believing this molecular motor was designed is like the astronomer Percival Lowell mistaking Martian canyons for canals. The suggestion is that false design inferences have been made, so surely all of the design inferences in the natural sciences are false. In this case, the fallacious argument--a favorite among Darwinists--is doubly silly because the Martian canyons turned out to be far simpler, far less specified, than engineered canals; while the bacterial flagellum has turned out to be far more sophisticated than our outboard motors.
As Minnich and Meyer note, the discovery of molecular motors is opening a whole new field, where biology and engineering meet:
To paraphrase the original rendition of the Department of Energy's Genomes to Life web site, "the molecular machines present in the simplest cells, produced by evolution, dwarf the engineering feats of the 20th century." The dissection of the complexity and sophistication of ... machines like the bacterial flagellum are indeed a testimony to the power of modern molecular biological techniques. Yet, the elegant structural properties, efficiency, and the highly controlled genetic programming to produce these machines was neither anticipated nor predicted. The potential applications of this knowledge are legion and have spawned a new discipline focused on nanotechnology.
One needn't go far for examples. Here at Physics Today, well trained physicists are standing around this astonishing little machine, the bacterial flagellum, like neighborhood mechanics getting a chance to take apart and learn from a NASCAR racing engine.
Derbyshire, Miller and other Darwinists are mixed up about the direction of things. The more we KNOW about the bacterial flagellum, the less and less it is anything the Darwninian mechanism could produce. Moreover, there are strongly affirmative grounds for inferring design from the presence of irreducibly complex machines and circuits. Every time we know the causal history of an irreducibly complex system (like the NASCAR racing engine or an electronic circuit), it always turn out to have been the product of an intelligent cause.
Finally, the list of known biological mechanisms that appear irreducibly complex isn't shrinking, it's growing.
Jonathan Witt February 18, 2005 2:50 PM
John Derbyshire is on The Corner arguing that we can never safely infer that certain biological structures were designed. To a reader who asserted that organizational complexity cannot arise from impersonal processes, Derbyshire replies, "How do you know it can't? It is true that the genesis of organizational complexity is not currently well understood; but to leap from that to telling me we shall NEVER be able to find a natural-law explanation for it is just dogma."
Derbyshire's argument is worth confronting because it represents the opinion of leading Darwinists. Biologist Kenneth Miller, for instance, routinely makes just such an argument. Design theorist William Dembski responds thus:
Miller claims that the problem with anti-evolutionists like Michael Behe and me is a failure of imagination -- that we personally cannot "imagine how evolutionary mechanisms might have produced a certain species, organ, or structure." He then emphasizes that such claims are "personal," merely pointing up the limitations of those who make them. Let's get real. The problem is not that we in the intelligent design community, whom Miller incorrectly calls "anti-evolutionists," just can't imagine how those systems arose.
The problem is that Ken Miller and the entire biological community haven't figured out how those systems arose. It's not a question of personal incredulity but of global disciplinary failure (the discipline here being biology) and gross theoretical inadequacy (the theory here being Darwin's).
The particular mechanism Miller has in view here is the bacterial flagellum. Click here and scroll down for a good, brief description and animation of the bacterial flagellum, and here for an enlarged view with its parts labeled. Biochemist Michael Behe made this little engine that could famous by showing that it was irreducibly complex, like a mouse trap: "If any one of the components of the mousetrap (the base, hammer, spring, catch, or holding bar) is removed, then the trap does not function." With even four of these parts, it's utterly useless. The mousetrap is irreducibly complex.
What does irreducible complexity have to do with Darwinian evolution? Evolution by mutation and natural selection must proceed by one slight, functional improvement at a time. So how can it build an irreducibly complex propeller motor one step at a time if the motor can't propel at all until all of its parts are in place? It can't. Something else built it.
Behe's argument doesn't assume that none of the other parts could ever be used for anything else. The spring on a mousetrap could be taken and used in some other device. The base with cheese on it could feed a mouse. Several but not all of the parts of a bacterial flagellum--while completely useless as a rotary propulsion machine--can be used to transport proteins across a membrane. But this hardly provides a credible Darwinian pathway.
Imagine if a boy told a girl he could climb to Mars because there supposedly existed a natural ladder stretching from one planet to the other? The girl is skeptical, pointing out that nobody on earth has ever found such a ladder. The boy screams, "That's an argument from ignorance! Scientists are finding all sorts of new things all the time. Look! The moon! The moon is one step along the way. You see, everything is falling into place." The Darwinists' desperate efforts to spin away the clear significance of the bacterial flagellum is strangely akin to this sort of reasoning. Dembski explains:
Darwin's theory, without which nothing in biology is supposed to make sense, in fact offers no insight into how the flagellum arose. If the biological community had even an inkling of how such systems arose by naturalistic mechanisms, Miller would not -- a full six years after the publication of Darwin's Black Box by Michael Behe -- be lamely gesturing at the type three secretory system as a possible evolutionary precursor to the flagellum.
Miller and Derbyshire are like the boy convinced of the natural ladder to Mars, who finds the moon and yells "Ah ha! Now who dares to play the skeptic!" Well, design theorists do. Consider this passage from a peer-edited paper by biologist Scott Minnich and philosopher of science Stephen Meyer, in which they discuss recent evidence for the delicately orchestrated and information-rich proteins of the bacterial flagellum:
[I]f anything, TTSSs [Type Three Secretory Systems] generate more complications than solutions to this question. As shown here, possessing multiple TTSSs causes interference. If not segregated one or both systems are lost. Additionally, the other thirty proteins in the flagellar motor (that are not present in the TTSS) are unique to the motor and are not found in any other living system. From whence, then were these protein parts co-opted?
Also, even if all the protein parts were somehow available to make a flagellar motor during the evolution of life, the parts would need to be assembled in the correct temporal sequence similar to the way an automobile is assembled in factory. Yet, to choreograph the assembly of the parts of the flagellar motor, present-day bacteria need an elaborate system of genetic instructions as well as many other protein machines to time the expression of those assembly instructions. Arguably, this system is itself irreducibly complex. In any case, the co-option argument tacitly presupposes the need for the very thing it seeks to explain--a functionally interdependent system of proteins.
Now one letter writer, responding to Behe's column in The New York Times, complained that we only describe the bacterial flagellum as an outboard motor because we have no better analogy, not because it is an outboard motor. The letter writer argues that believing this molecular motor was designed is like the astronomer Percival Lowell mistaking Martian canyons for canals. The suggestion is that false design inferences have been made, so surely all of the design inferences in the natural sciences are false. In this case, the fallacious argument--a favorite among Darwinists--is doubly silly because the Martian canyons turned out to be far simpler, far less specified, than engineered canals; while the bacterial flagellum has turned out to be far more sophisticated than our outboard motors.
As Minnich and Meyer note, the discovery of molecular motors is opening a whole new field, where biology and engineering meet:
To paraphrase the original rendition of the Department of Energy's Genomes to Life web site, "the molecular machines present in the simplest cells, produced by evolution, dwarf the engineering feats of the 20th century." The dissection of the complexity and sophistication of ... machines like the bacterial flagellum are indeed a testimony to the power of modern molecular biological techniques. Yet, the elegant structural properties, efficiency, and the highly controlled genetic programming to produce these machines was neither anticipated nor predicted. The potential applications of this knowledge are legion and have spawned a new discipline focused on nanotechnology.
One needn't go far for examples. Here at Physics Today, well trained physicists are standing around this astonishing little machine, the bacterial flagellum, like neighborhood mechanics getting a chance to take apart and learn from a NASCAR racing engine.
Derbyshire, Miller and other Darwinists are mixed up about the direction of things. The more we KNOW about the bacterial flagellum, the less and less it is anything the Darwninian mechanism could produce. Moreover, there are strongly affirmative grounds for inferring design from the presence of irreducibly complex machines and circuits. Every time we know the causal history of an irreducibly complex system (like the NASCAR racing engine or an electronic circuit), it always turn out to have been the product of an intelligent cause.
Finally, the list of known biological mechanisms that appear irreducibly complex isn't shrinking, it's growing.
Soft bodies mean hard luck For Darwinian apologists
Derbyshire III: Soft Bodies a Femme Fatale for Darwinism
Jonathan Witt February 15, 2005 11:14 AM
As we saw in Derbyshire II, the pattern of the fossil record doesn't fit the Darwinian prediction of a gradually branching tree of life, even where punctuated equilibrium is invoked to shoehorn the transitional intermediates into those gaps John Derbyshire puts such faith in.
The problem gets even uglier when Darwinists try to explain away the fossil record leading up to the Cambrian Explosion. What story do these strata tell? Animals didn't exist; and then they did--not just dozens of species but dozen of phyla. If you want some idea of how large a category phyla is, consider that sharks, mice, humans and otters are all members of the same phylum.
If natural selection working on random genetic mutation built this menagerie of animals, it had to do it one extraordinarily tiny, functional improvement at a time, one generation at a time, over tens and even hundreds of millions of years. If we had even a tiny fraction of a fraction of the Precambrian life forms, we would have so many transitional forms we would be hard-pressed to draw the line between one phylum and another, so thoroughly would they bleed one form into the other. But we find no such fossil pattern in the Precambrian.
Derbyshire suggests that the precursors of the many Cambrian phyla were soft-bodied and so never fossilized: "[S]oft body parts hardly ever get fossilized," he writes. "We are working from a pretty scanty data set here."
The problem is, many soft-bodied creatures did fossilize, and they tell a different story from the one Darwin told. Consider this passage in which Meyer et al., marshall evidence from mainstream evolutionists working in paleobiology:
While clearly the fossil record does not preserve soft body parts of organisms as frequently as hard body parts, it has preserved enough soft body animals and organs to render this version of the artifact hypothesis suspect. Indeed, entirely soft-bodied representatives of several phyla have been identified in the Cambrian. Soft-bodied organisms are also preserved in Precambrian strata around the world. Even so, these Precambrian organisms do not represent plausible transitional intermediates to representatives of the Cambrian phyla. In each case the jump in complexity (as measured by the number of cell types, for example) and the morphological disparity between the Precambrian and Cambrian organisms appears far too great. (See Section IV.B. below). Furthermore, the postulation of exclusively soft-bodied ancestors for hard-bodied Cambrian organisms seems implausible on anatomical grounds.54 Many phyla such as brachiopods and arthropods could not have evolved their soft parts first and then added shells later, since their survival depends in large part upon their ability to protect their soft parts from hostile environmental forces. Instead, soft and hard parts had to arise together.55 As Valentine notes in the case of brachiopods, "the brachiopod Baupl?�ne cannot function without a durable skeleton."56 To admit that hard-bodied Cambrian animals had not yet evolved their hard-bodied parts in the Precambrian effectively concedes that credible precursor animals themselves had not yet evolved. 57 As Chen and Zhou explain: "[A]nimals such as brachiopods and most echinoderms and mollusks cannot exist without a mineralized skeleton. Arthropods bear jointed appendages and likewise require a hard, organic or mineralized outer covering. Therefore the existence of these organisms in the distant past should be recorded either by fossil tracks and trails or remains of skeletons. The observation that such fossils are absent in Precambrian strata proves that these phyla arose in the Cambrian." (356-357)
There are other tactics for avoiding the growing body of paleontological evidence against Darwinism. Meyer deals with many of those in a peer-reviewed biology journal article here. A spirited rebuttal is here. Discovery Institute fellows show why the rebuttal lacks force here and here. A short, introductory piece on the controversy over the Cambrian Explosion is here. A collection of eye-opening quotations from mainstream paleontologists is here. Journalists seeking to comment on these issues can quickly distinguish themselves merely by doing their homework.
More to come on Derbyshire and the evidence for intelligent design.
Jonathan Witt February 15, 2005 11:14 AM
As we saw in Derbyshire II, the pattern of the fossil record doesn't fit the Darwinian prediction of a gradually branching tree of life, even where punctuated equilibrium is invoked to shoehorn the transitional intermediates into those gaps John Derbyshire puts such faith in.
The problem gets even uglier when Darwinists try to explain away the fossil record leading up to the Cambrian Explosion. What story do these strata tell? Animals didn't exist; and then they did--not just dozens of species but dozen of phyla. If you want some idea of how large a category phyla is, consider that sharks, mice, humans and otters are all members of the same phylum.
If natural selection working on random genetic mutation built this menagerie of animals, it had to do it one extraordinarily tiny, functional improvement at a time, one generation at a time, over tens and even hundreds of millions of years. If we had even a tiny fraction of a fraction of the Precambrian life forms, we would have so many transitional forms we would be hard-pressed to draw the line between one phylum and another, so thoroughly would they bleed one form into the other. But we find no such fossil pattern in the Precambrian.
Derbyshire suggests that the precursors of the many Cambrian phyla were soft-bodied and so never fossilized: "[S]oft body parts hardly ever get fossilized," he writes. "We are working from a pretty scanty data set here."
The problem is, many soft-bodied creatures did fossilize, and they tell a different story from the one Darwin told. Consider this passage in which Meyer et al., marshall evidence from mainstream evolutionists working in paleobiology:
While clearly the fossil record does not preserve soft body parts of organisms as frequently as hard body parts, it has preserved enough soft body animals and organs to render this version of the artifact hypothesis suspect. Indeed, entirely soft-bodied representatives of several phyla have been identified in the Cambrian. Soft-bodied organisms are also preserved in Precambrian strata around the world. Even so, these Precambrian organisms do not represent plausible transitional intermediates to representatives of the Cambrian phyla. In each case the jump in complexity (as measured by the number of cell types, for example) and the morphological disparity between the Precambrian and Cambrian organisms appears far too great. (See Section IV.B. below). Furthermore, the postulation of exclusively soft-bodied ancestors for hard-bodied Cambrian organisms seems implausible on anatomical grounds.54 Many phyla such as brachiopods and arthropods could not have evolved their soft parts first and then added shells later, since their survival depends in large part upon their ability to protect their soft parts from hostile environmental forces. Instead, soft and hard parts had to arise together.55 As Valentine notes in the case of brachiopods, "the brachiopod Baupl?�ne cannot function without a durable skeleton."56 To admit that hard-bodied Cambrian animals had not yet evolved their hard-bodied parts in the Precambrian effectively concedes that credible precursor animals themselves had not yet evolved. 57 As Chen and Zhou explain: "[A]nimals such as brachiopods and most echinoderms and mollusks cannot exist without a mineralized skeleton. Arthropods bear jointed appendages and likewise require a hard, organic or mineralized outer covering. Therefore the existence of these organisms in the distant past should be recorded either by fossil tracks and trails or remains of skeletons. The observation that such fossils are absent in Precambrian strata proves that these phyla arose in the Cambrian." (356-357)
There are other tactics for avoiding the growing body of paleontological evidence against Darwinism. Meyer deals with many of those in a peer-reviewed biology journal article here. A spirited rebuttal is here. Discovery Institute fellows show why the rebuttal lacks force here and here. A short, introductory piece on the controversy over the Cambrian Explosion is here. A collection of eye-opening quotations from mainstream paleontologists is here. Journalists seeking to comment on these issues can quickly distinguish themselves merely by doing their homework.
More to come on Derbyshire and the evidence for intelligent design.
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