In February 2012, The Journal of Medical Ethics prepublished electronically an article by two academics from an Australian Centre for Applied Philosophy and Public Ethics. Their paper had the title: "After-birth abortion: why should the baby live?" It developed arguments that many considered to legitimise infanticide for handicapped children. A vigorous debate ensued, with strong criticisms of the paper and its authors. The journal was also criticized for giving a platform to such views, which appeared to add so little to previous cases of advocacy of infanticide. Its editor, Julian Savulescu, contributed this on 28 February 2012:
"As Editor of the Journal, I would like to defend its publication. The arguments presented, in fact, are largely not new and have been presented repeatedly in the academic literature and public fora by the most eminent philosophers and bioethicists in the world, including Peter Singer, Michael Tooley and John Harris in defence of infanticide, which the authors call after-birth abortion. The novel contribution of this paper is not an argument in favour of infanticide - the paper repeats the arguments made famous by Tooley and Singer - but rather their application in consideration of maternal and family interests. The paper also draws attention to the fact that infanticide is practised in the Netherlands."
Consequently, on 2 March 2012, an "open letter" was produced by the authors that was intended to dampen down the flames:
"the article was supposed to be read by other fellow bioethicists who were already familiar with this topic and our arguments. [. . .] We started from the definition of person introduced by Michael Tooley in 1975 and we tried to draw the logical conclusions deriving from this premise. It was meant to be a pure exercise of logic: if X, then Y. We expected that other bioethicists would challenge either the premise or the logical pattern we followed, because this is what happens in academic debates. [. . .] However, we never meant to suggest that after-birth abortion should become legal. This was not made clear enough in the paper. Laws are not just about rational ethical arguments, because there are many practical, emotional, social aspects that are relevant in policy making (such as respecting the plurality of ethical views, people's emotional reactions etc). But we are not policy makers, we are philosophers, and we deal with concepts, not with legal policy."
Moving to the present, the article has now been formally published in an issue of the journal wholly devoted to the debate. Papers are included that present different views on the issues. Professor Udo Schuklenk authored a paper on academic freedom, from the perspective of one who is also an editor of a bioethics journal. In this paper, he expresses concerns about the flak that "academic bioethicists and academic bioethics journals are subjected to by political activists applying pressure from outside of the academy." He identifies two activists that he considers to be abusing academic freedom. The first is Wesley J. Smith, who writes the Human Exceptionalism Blog. The second is Michael Cook, editor of BioEdge. The main complaint appears to be that they are reading articles in academic journals but critiquing them in the public square. Defences of this practice have been made, along with corrections of misinformation, by Wesley J. Smith and by Michael Cook. However, there is also a criticism of the two authors of the controversial academic paper. He does not like their attempt to distinguish a philosophical argument from public policy:
"It is reasonable to demand that those who suggest that this is a purely academic exercise ask themselves why they came up with very practical conclusionsâ€”that now somehow they don't mean us (and their many critics) to take very seriously. [. . .] Still, bioethics analyses offering practical conclusions are not theoretical games. Michael Tooley and Peter Singer who have defended similar views for decades can undoubtedly tell many a story about harsh criticism and threats to their persons, but until today - to the best of my knowledge - they have not declared their views a mere thought experiment, undertaken for the sake of it, not really meant to be taken seriously, etc. They do take responsibility for views they hold, and they are right in doing so. Respect for free speech has a flipside, requiring of us to take responsibility for the views that we defend. On what other grounds could we expect our views to be taken seriously. What kind of debate could we reasonably have with discussants who - when cornered - will say 'I didn't really mean it'?" (page 305)
There is therefore some common ground here: it is entirely reasonable to infer that ethical stances lead directly to policy implications. This connection would appear to be clearly implied in the workplace of the two authors: the Centre for Applied Philosophy and Public Ethics. However, there are divergences of view over the issue of academic freedom.
"When all is said and done, this is an academic freedom issue. It has to do with ensuring both that we are able to ask difficult questions, and that we are able to defend conclusions that most people will disagree with. For what it is worth, the infanticide debate is not even a paradigmatic example of the culture wars between the religious and the secularists. Secular bioethicists such as the late Mary Anne Warren have been highly critical of the utilitarian rationale offered in this context. To her birth is a crucial marker event conferring moral standing to the newborn. Academics have always challenged assumptions taken for granted by the mainstream." (pages 305-306)
Academic freedom and academic responsibility go together. We do not have freedom to ignore views that we think are taboo. Anyone discussing issues of abortion and infanticide should take seriously reasons why people affirm the sanctity of life. This requires grappling with issues like mankind being made in the image of God. It is not a case of expecting ethicists to agree with these views, but they need to understand the arguments and engage with them. If they are expunged from academic discourse because these views are "religious", then the result is an imposition on the scope of discussion. This is a denial of academic freedom on upholders of the sanctity of human life who are not allowed to bring such arguments into their academic work. However, the words "sanctity" and "image" are lacking in these papers.
The root problem is that academic ethicists have absorbed a secularised worldview. Over a decade ago, Wesley J. Smith described it in this way:
"Mainstream bioethics reached a consensus long ago that religious values are divisive in a pluralistic society and thus have little place in the formulation of public policy. Those who believe in abortion rights but also hold that all born humans are equally endowed with moral worth, along with those who subscribe to the "do no harm" ethos of the Hippocratic oath, have little impact, since mainstream bioethics rejects Hippocratic medicine as paternalistic and shrugs off equal human moral worth as a relic of the West's religious past."
In this academic ethicists have adopted the philosophical naturalism of academia in general. This turns science into scientism and humans into molecular machines. Everything about humanity has to be portrayed through the reductionist filter of scientism. Our consciousness, our values and our sense of free agency must all be 'explained' via material causation. This straitjacket is illustrated in a recent article (in the Wall Street Journal)on the views of Dr Leon Kass, who has often found himself in a minority among bioethicists when it comes to abortion, euthanasia, embryonic research, cloning and other right-to-life questions.
"Take the concept of human dignity. In a 2008 essay highly critical of Dr. Kass's work on the Bush bioethics council, the Harvard psychologist Steven Pinker questioned the value of dignity as a moral guide. "Dignity is a phenomenon of human perception," Mr. Pinker wrote. "Certain signals in the world trigger an attribution in the perceiver." The perception of human dignity, Mr. Pinker went on, is no different from how "converging lines in a drawing are a cue for the perception of depth." That such an outlook is both blinkered and dangerous, Dr. Kass thinks, should be obvious to anyone who has ever been in love or felt other great emotions. "There's no doubt that the human experience of love," he says, is mirrored by "events that are measurable in the brain. But anybody who has ever fallen in love knows that love is not just an elevated level of some peptide in the hypothalamus.""
Academics adopting the secular materialist worldview will always find themselves demolishing traditional values. They have failed to develop any ethical principles based on secular materialist foundations and they end up as pragmatists, postmodernists or social constructivists. Their conclusions about infanticide are entirely predictable. What is controversial is not that they say such things, but that they are so hostile to philosophical theism appearing in the pages of their academic journals. This is the crunch issue for academic freedom that has yet to be recognised.
After-birth abortion: why should the baby live?
Alberto Giubilini, Francesca Minerva
Journal of Medical Ethics, 2013; 39(5), 261-263 | doi:10.1136/medethics-2011-100411
Abstract: Abortion is largely accepted even for reasons that do not have anything to do with the fetus' health. By showing that (1) both fetuses and newborns do not have the same moral status as actual persons, (2) the fact that both are potential persons is morally irrelevant and (3) adoption is not always in the best interest of actual people, the authors argue that what we call 'after-birth abortion' (killing a newborn) should be permissible in all the cases where abortion is, including cases where the newborn is not disabled.
In defence of academic freedom: bioethics journals under siege
Journal of Medical Ethics, May 2013, 39(5), 303-306 | doi:10.1136/medethics-2012-100801
Abstract: This article analyses, from a bioethics journal editor's perspective, the threats to academic freedom and freedom of expression that academic bioethicists and academic bioethics journals are subjected to by political activists applying pressure from outside of the academy. I defend bioethicists' academic freedom to reach and defend conclusions many find offensive and 'wrong'. However, I also support the view that academics arguing controversial matters such as, for instance, the moral legitimacy of infanticide should take clear responsibility for the views they defend and should not try to hide behind analytical philosophers' rationales such as wanting to test an argument for the sake of testing an argument. This article proposes that bioethics journals establish higher-quality requirements and more stringent mechanisms of peer review than usual for iconoclastic articles.
Klinghoffer, D. What Darwin's Enforcers Will Say About Darwin's Doubt: A Prediction (Evolution News & Views, 8 May 2013)
In InvestigateDaily, a report on intelligently designed DNA. The implication, either "God" or space aliens.
Dr. Meyer's interview with Michael Medved on ENV by David Klinghoffer.
Click HERE for the interview.
See the interview on Youtube at GivingAnAnswer.
Coming May 16th...Michael Ruse and Fuz Rana...
Sixty years have passed since Watson and Crick unveiled the structure of the DNA double helix and tentatively explained how it encodes hereditary information. The Central Dogma of genetics soon followed: that "DNA makes RNA makes protein" makes cells and organisms. Once this "River out of Eden" was flowing, the story of life was deemed to be essentially understood. Genes were considered to provide the blueprint of life and the task of filling in the details had begun. The blueprint motif was prominent in media coverage of the Human Genome project - any who questioned its veracity were regarded as subverting science. But is the consensus position robust? At least one commentator (Philip Ball in Nature) is prepared to say that it is misleading.
"But I can tell that the usual tidy tale of how 'DNA makes RNA makes protein' is sanitized to the point of distortion. Instead of occasional, muted confessions from genomics boosters and popularizers of evolution that the story has turned out to be a little more complex, there should be a bolder admission - indeed a celebration - of the known unknowns." (page 419)
In 1953, Francis Crick and James Watson described the double helix structure of DNA. (source here)
Numerous discoveries have been "unsettling old assumptions". First, the ENCODE project has put the spotlight on regulation rather than transcription. Not only are genes transcribed (about 1% of the human genome) but so also is at least 80% of the human genome. Numerous regulatory roles have been determined for many of these RNA transcripts, and every week brings more examples of functionality to our attention. Not only do these findings challenge "the old idea that much of the genome is junk", they also show us that we are only beginning to understand the genome's role in the cell.
"According to evolutionary biologist Patrick Phillips at the University of Oregon in Eugene, projects such as ENCODE are showing scientists that they don't really understand how genotypes map to phenotypes, or how exactly evolutionary forces shape any given genome." (page 420)
Second, the field of epigenetics has introduced previously unsuspected constraints, whereby environmental factors influence the phenotype without affecting the genotype.
"For example, epigenetic molecular alterations to DNA, such as the addition of a methyl group, can affect the activity of genes without altering their nucleotide sequences." (page 420)
Third, positional information is not revealed by the documenting of amino acid sequences within the DNS molecule, but this information, when recognised, is significant for development.
"Genes can also be regulated by the spatial organization of the chromosomes, in turn affected by epigenetic markers. Although such effects have long been known, their prevalence may be much greater than previously thought." (page 420)
And there are more evidences to throw into the melting pot. Ball refers to the way gene networks are structured: the genes are the same, but differences in organisation of these networks can result in differences in phenotype. Similarly, changes in regulation could be more significant than changes in the genes themselves. There are big questions about the role of natural selection at the molecular level and it is by no means agreed that natural selection is the dominant driver.
"In short, the current picture of how and where evolution operates, and how this shapes genomes, is something of a mess. That should not be a criticism, but rather a vote of confidence in the healthy, dynamic state of molecular and evolutionary biology." (page 420)
Whilst saying this is not a criticism, there are nevertheless aspects of these developments that should be criticised. Notably, it is necessary to vigorously critique the evolutionary consensus that dominates education and the media. Take education first - and recall how vigorously evolutionists have opposed all attempts to introduce critical, evidence-based thinking about evolutionary theory. They have portrayed this as religiously motivated anti-science lobbying, and have ensured that the consensus positions have prevailed. In this they have betrayed a whole generation of biology students.
"A student referring to textbook discussions of genetics and evolution could be forgiven for thinking that the 'central dogma' devised by Crick and others in the 1960s - in which information flows in a linear, traceable fashion from DNA sequence to messenger RNA to protein, to manifest finally as phenotype - remains the solid foundation of the genomic revolution. In fact, it is beginning to look more like a casualty of it." (page 419)
Furthermore, it is a scandal that the whole spectrum of contemporary thinking in genetics is largely hidden from the broader scientific community. The media provides a welcoming stage for celebrity scientists to pronounce on their outdated views, but dissenters find it hard to present on a science platform. When reading the following quotation, it is worth noting that Prospect magazine has honoured Richard Dawkins as the "world's top thinker" as a result of a recent poll of its readers.
"Barely a whisper of this vibrant debate reaches the public. Take evolutionary biologist Richard Dawkins' description in Prospect magazine last year of the gene as a replicator with "its own unique status as a unit of Darwinian selection". It conjures up the decades-old picture of a little, autonomous stretch of DNA intent on getting itself copied, with no hint that selection operates at all levels of the biological hierarchy, including at the supraorganismal level, or that the very idea of 'gene' has become problematic." (page 420)
Philip Ball does suggest some reasons why there has been a reluctance to acknowledge biological complexity. Whilst not disputing the various points he makes, the analysis is not deep enough. The closest he gets is in the last paragraph:
"When the structure of DNA was first deduced, it seemed to supply the final part of a beautiful puzzle, the solution for which began with Charles Darwin and Gregor Mendel. The simplicity of that picture has proved too alluring." (page 420)
It is not just that simplicity is too alluring; it is that the worldview of the scientists demands simplicity. They are predisposed to look for simplicity and they fall into a trap of confirmation bias. It happened in Darwin's day, when the cell was conceived as a simple building block, and organisms were portrayed as assemblages with varying degrees of complexity (see here). This worldview derives from Deism or Atheism, where everything has to assemble itself: from the cosmos to organisms. The only way that people can imagine this happening is incrementally, deriving complexity from simple building blocks. This is Richard Dawkins explaining the point.
"Darwinian evolution is the only process we know that is ultimately capable of generating anything as complicated as creative intelligences. Once it has done so, of course, those intelligences can create other complex things: works of art and music, advanced technology, computers, the Internet and who knows what in the future? Darwinian evolution may not be the only such generative process in the universe. There may be other "cranes" (Daniel Dennett's term, which he opposes to "skyhooks") that we have not yet discovered or imagined. But, however wonderful and however different from Darwinian evolution those putative cranes may be, they cannot be magic. They will share with Darwinian evolution the facility to raise up complexity, as an emergent property, out of simplicity, while never violating natural law."
Ultimately, then, we have worldview issues to evaluate. Those with a naturalistic mindset interpret all complexity as emergent from natural law with a sprinkling of chance. However, their approach is testable - they require ultimate simplicity and blind (tinkering) processes. Arguably, this approach has been falsified in innumerable areas of science. What we find is ultimate complexity and an extraordinary richness of information. This finding is consistent with, and predicted by, advocates of intelligent design. To move the debate in science forward in a meaningful way, both these avenues of inquiry need to be fully and fairly evaluated.
DNA: Celebrate the unknowns
Nature, 496, 419-420 (25 April 2013) | doi:10.1038/496419a
On the 60th anniversary of the double helix, we should admit that we don't fully understand how evolution works at the molecular level
Watson J.D. and Crick F.H.C. Molecular structure of nucleic acids: A structure for deoxyribose nucleic acid. Nature, 1953, 171, 737-738. (also here)
This year marks the centenary of the death of Alfred Russel Wallace, sometimes portrayed as "Darwin's goad". However, as Andrew Berry argues, Wallace should be remembered as a "visionary scientist in his own right, a daring explorer and a passionate socialist". He was awarded the Order of Merit, the highest honour that could be given by the British monarch to a civilian. He has left a -
"- huge scientific legacy, which ranged from discovering natural selection to defining the term species, and from founding the field of evolutionary biogeography to pioneering the study of comparative natural history." (page 162)
The portrait of Wallace is unveiled at the launch of Wallace100 (Source here)
Wallace's first exhibition (four years in the Amazon rainforests) ended in disaster and he narrowly escaped death. As he sailed home in 1852, the ship caught fire and all the specimens he had so carefully collected, including numerous living animals, were lost. Wallace watched the burning wreck from a lifeboat, and it was 10 days before rescuers arrived on the scene. Ever the scientist, he wrote:
"During the night I saw several meteors, and in fact could not be in a better position for observing them, than lying on my back in a small boat in the middle of the Atlantic." (page 163)
Two years later, he was off to the Far East for an 8-year trek. During this time, he established himself as an academic writer and an extremely successful collector, with over 1000 specimens new to science. A landmark paper pointed out that related species tend to be found in the same geographical area.
"Wallace had a prodigious ability to spot patterns in the apparently chaotic (and largely uncatalogued) world of tropical diversity. This is the skill of the true naturalist: to generate a mental database of observed plants and animals that can be referenced when similar forms are encountered elsewhere. It led to his first attempt at biological generalization, a paper he wrote in 1855 while in Sarawak, Borneo: 'On the Law which has Regulated the Introduction of New Species' (often called the Sarawak Law)." (page 163)
Ten years later, Wallace proposed a remarkably modern definition of the species concept:
"In his brilliant 1865 paper on the papilionid butterflies of southeast Asia, he parses variations within and among populations, among subspecies and species, and arrives at this definition: "Species are merely those strongly marked races or local forms which, when in contact, do not intermix, and when inhabiting distinct areas are generally believed to have had a separate origin, and to be incapable of producing a fertile hybrid offspring."
It is emblematic of history's neglect of Wallace that most undergraduates today are taught that the biological species concept was introduced in 1942 by Ernst Mayr." (page 163)
Many students have been introduced to the role played by Wallace in 1858 in triggering a joint presentation alongside Darwin of evolution by natural selection. Suffice to say here that the last word on this has not been written.
However, although Darwin's name is now dominant in evolutionary theory, Wallace is perceived as the Father of historical biogeography. The groundwork was laid in 1857, in a paper about the Aru Islands (off New Guinea). Textbooks today record his discovery of the distinction between Australian fauna and Asian fauna, separated by Wallace's Line.
"It is tempting to see echoes between Wallace's serendipitous path through life and his contingent interpretation of natural systems: his most famous biogeographical discovery also had a dose of luck. In 1856, having missed a connection as he tried to make his way to Sulawesi, he spent a couple of months on the islands of Bali and Lombok, and noted drastic differences in the wildlife even though the islands are only some 35 kilometres apart. To the south and east, the Australian fauna dominated; to the north and west, the Asian one. He had identified an ancient biogeographic split across southeast Asia that biologist Thomas Henry Huxley later dubbed 'Wallace's Line'." (page 163)
Wallace the scientist is often contrasted with the "other Wallace" who dabbled in "suffrage and socialism", "spiritualism and phrenology". But Berry cautions against thinking like this. "But Wallace's worldview was far more coherent than is often claimed." (page 164) Differences with Darwin came to the fore regarding human evolution. Whereas Darwin expected evolution by natural selection to transform an ape-like animal into a human, Wallace rejected this scenario. He argued for "some kind of non-material intervention in the genesis of humans". His religious views allowed him to be open to this hypothesis, although his arguments were drawn from scientific observations of different races of humanity.
"The more I see of uncivilized people, the better I think of human nature on the whole, and the essential differences between so-called civilized and savage man seem to disappear." (page 164)
"[Wallace realised that] many humans have abilities that they never have the opportunity to use. Such a situation, Wallace reasoned, cannot evolve through natural selection alone, which promotes only those traits that are useful. Wallace concluded that human evolution required some divine intervention. This argument shows an excellent appreciation of the mechanics of natural selection [. . . ]" (page 164)
Darwin's reaction reveals his own worldview, which was sometimes deistic and sometimes atheistic - but which never allowed any active role for God in the history of life. Berry puts it this way:
"Darwin was horrified, writing to his friend in 1869: "I hope you have not murdered too completely your own and my child."" (page 164)
Whilst Berry is willing to respect Wallace's integrity in departing from Darwin in this key issue, he does not elaborate on the broader implications of worldview thinking. No mention is made of Wallace's Man's Place in the Universe (1903), which discusses the teleological anthropic principle, or his World of Life (1910), which is devoted to intelligent evolution. Wallace saw himself as a theistic scientist who recognised design and purpose in the natural world. Thus, he is a powerful witness against those who portray intelligent design per se as antiscience. People are free to reach different conclusions, but Wallace should not be dismissed as someone who sacrificed reason and science to satisfy religious scruples. This is a worldview issue and, at this level, both theists and atheists are equally religious in their thinking. We can echo Berry's closing words, with the proviso that in the "etc., etc., etc." are found Wallace's advocacy of intelligent design in the natural world.
"As we remember Wallace 100 years after his death, let us celebrate his remarkable scientific achievements and his willingness to take risks and to advocate passionately for what he believed in. He was, after all, both a scientist, and, in his own assessment, a "Red-hot Radical, Land Nationaliser, Socialist, Anti-Militarist, etc., etc., etc." In short, a whole lot more than Darwin's goad." (page 164)
Alfred Russel Wallace: Evolution's red-hot radical
Nature, 496, 162-164 (11 April 2013) | doi:10.1038/496162a
Sidekick status does Alfred Russel Wallace an injustice. He was a visionary scientist in his own right, a daring explorer and a passionate socialist, argues Andrew Berry.
Flannery, M. Why Darwin Is Remembered More than Wallace, Evolution News& Views (5 March 2013)
Flannery, M. Hijacking Alfred Russel Wallace, Evolution News& Views (24 January 2013)
Tyler, D., Why Alfred Russel Wallace deserves to be remembered, ARN Literature Blog (11 March 2008)
Website: Alfred Russel Wallace
Soft-bodied worms from the Burgess Shale fossil beds in Yoho National Park, British Columbia, Canada have been known form over 100 years. They are known by the name Spartobranchus tenuis and are considered one of the most abundant species in the Walcott Quarry community. However, only recently has a detailed examination of their characteristics been made, leading to the conclusion that they are ancient examples of acorn worms. One member of the research team was Christopher Cameron from the University of Montreal, who studies modern-day acorn worms. Identifying the fossils was not problematic: "Spartobranchus is clearly an acorn worm," he said in an interview. "It's almost like someone took a picture of a modern-day animal - it's absolutely astonishing." These animals are not true worms but belong to a very different phylum: the Hemichordates. The name means "half chordate" indicating that hemichordates share some of the characters associated with chordates. This is relevant to some of the discussion below. Hemichordates comprise three classes: the Enteropneusta or acorn worms; the Pterobranchia - minute colonial tube-dwelling organisms; and the Graptolithina or graptolites. Pterobranchs were already known to be part of the Cambrian Explosion, so the inclusion of acorn worms in this flowering of animals is a significant addition to knowledge. According to Henry Gee in Nature:
"Before this report, the earliest-known fossil enteropneusts were Triassic, between 250 million years and 200 million years old. That Caron et al. extend the fossil record of enteropneusts back to the Cambrian period makes their findings notable, even with no other contribution."
Modern acorn worms live underwater in mud and fine sand (source here)
The find is notable because it reinforces the evidences for stasis in the fossil record. This deserves highlighting because so many think that the fossil record documents Darwinian gradualism - which it stubbornly fails to do. It is notable because it reinforces the phenomenon of the Cambrian Explosion, showing that those who try to fit the evidence into a Darwinian framework are shoehorning data and resistant to the testing of their cherished theory. From the abstract:
"The presence of both enteropneusts and pterobranchs in Middle Cambrian strata, suggests that hemichordates originated at the onset of the Cambrian explosion."
Notwithstanding all this, the commentary on the research has a very strong evolutionary emphasis. Firstly, the fossil acorn worm is presented as an important transitional form.
"According to Dr Cameron and colleagues, Spartobranchus tenuis reveals a crucial evolutionary link between two distinct living groups of animals: enteropneusts and pterobranchs."
"Enteropneusts look very different from pterobranchs in as much as the former are worms, whereas the latter are tiny animals, live in tubes, are colonial and have feeding tentacles," explained Professor Simon Conway Morris from the University of Cambridge, UK, who also worked on the study. [. . .] "By finding enteropneusts in tubes we begin to bridge this evolutionary gap," Dr Morris told BBC Nature. Dr Cameron commented: "It's astonishing how similar Spartobranchus tenuis fossils are to modern acorn worms, except that they also formed fibrous tubes." In many of the fossils, remains of the worms were encased in these tubes, and the team believe they lived in the structures and may have even sealed themselves in a doughnut shape within the tubes. (Source here)
The nature of these tubes is clearly important. Gee refers to "pterobranch-like tubes" and considers this an unambiguous witness to transformation. However, the research paper gives more insight into just how "pterobranch-like" the tubes are. It says that approximately one-quarter of specimens are associated with tubes that have a fibrous composition, and that only one individual is ever associated with a tube. There is no evidence that the worms were attached to the tubes, so they were able to leave them to feed or in response to stress. Apart from the use of the word "fibrous", the only other information on the construction of the tubes is that they are sometimes branched and sometimes show tearing. Whilst the researchers have made a case for an evolutionary link, there seems to be scope for weighing these evidences and considering alternatives.
"Two lines of evidence suggest that the collagenous coenecium of pterobranchs had origins in the organic tubes of S. tenuis. First, the tubes of S. tenuis have a fibrous structure that sometimes shows evidence of tearing. We have no evidence of characteristic growth bands (fuselli), a pterobranch innovation that probably appeared with a reduction in size and the evolution of a shield-shaped secretory organ. Second, the secretory proboscis and cephalic shield are homologous in enteropneust and pterobranchs (both protosoma), and thus the transition from inferred involvement of the proboscis in tube construction by S. tenuis to the secretory role of the cephalic shield is unproblematic. We suggest that in the lineage leading to the Enteropneusta, the tube lining was lost, whereas in pterobranchs it provided a substrate for an astonishing radiation, not least in Palaeozoic planktonic ecosystems."
The scenario these researchers favour is that the common ancestor had a capability for tube construction that was present in the early enteropneusts like S. tenuis but then lost. This means that, if there was a common ancestor, the biological information for tube construction was already present. Descendants either exploited this information (the pterobranchs) or lost it (the enteropneusts). It is worth considering what form of evolutionary change this implies. We have novel biological information in the inferred ancestor, modified information in the pterobranchs, and lost information in the enteropneusts. This does not fit the Neo-Darwinian theoretical model because the relevant biological information already existed in the common ancestor. A much better match to this situation is phenotypic plasticity: where radiations of animals and plants utilize existing biological information in varying combinations and permutations. For more on phenotypic plasticity, go here.
The other evolutionary theme concerns the origin of vertebrates. Henry Gee makes this the headline for his News & Views essay: "The discovery, in 500-million-year-old rocks, of fossil acorn worms that lived in tubes illuminates the debate about whether the ancestor of vertebrates was a mobile worm-like animal or a sessile colony dweller." In this debate, the hemichordates are deemed to be of considerable importance.
"Understanding the origin of vertebrates is fascinating not just because it appeases our self-interest, but because it is inherently difficult. Vertebrates seem to have a qualitatively more complex construction than other animals. This means not only that the origin of distinctive features of vertebrate anatomy, such as the head or the neural crest, are difficult to trace among invertebrates, but also that the evolutionary roots of vertebrates as a whole are hard to fathom. In a paper published on Nature's website today, Caron et al. address a fundamental issue in this regard: whether the ancestor of the deuterostomes (the larger assemblage to which vertebrates belong) was a free-living, worm-like creature or a sessile, perhaps colonial, animal. Their answer, for now, is that it was solitary, worm-like and motile."
Since all the major players in this debate (hemichordates, echinoderms and vertebrates) are all found among the Cambrian Explosion fauna, the fossil record cannot be mapped against the Darwinian gradualist branching model. Instead, we have the primacy of a theoretical paradigm about universal common ancestry that presupposes that ancestral relationships must exist and that uses evolutionary cladism as the tool for interpreting evidences (as in Gee's essay. Also, go here for additional comments). Of course, this debate will continue, but it deserves to be pointed out that Meyer et al. (2006), on the contribution made by intelligent design theory to these important issues, continues to be relevant. One is tempted to add that as fossil discoveries accumulate, the case of intelligent design becomes more and more compelling.
Tubicolous enteropneusts from the Cambrian period
Jean-Bernard Caron, Simon Conway Morris and Christopher B. Cameron
Nature, (Online March 2013) | doi:10.1038/nature12017
Hemichordates are a marine group that, apart from one monospecific pelagic larval form, are represented by the vermiform enteropneusts and minute colonial tube-dwelling pterobranchs. Together with echinoderms, they comprise the clade Ambulacraria. Despite their restricted diversity, hemichordates provide important insights into early deuterostome evolution, notably because of their pharyngeal gill slits. Hemichordate phylogeny has long remained problematic, not least because the nature of any transitional form that might serve to link the anatomically disparate enteropneusts and pterobranchs is conjectural. Hence, inter-relationships have also remained controversial. For example, pterobranchs have sometimes been compared to ancestral echinoderms. Molecular data identify enteropneusts as paraphyletic, and harrimaniids as the sister group of pterobranchs. Recent molecular phylogenies suggest that enteropneusts are probably basal within hemichordates, contrary to previous views, but otherwise provide little guidance as to the nature of the primitive hemichordate. In addition, the hemichordate fossil record is almost entirely restricted to peridermal skeletons of pterobranchs, notably graptolites. Owing to their low preservational potentials, fossil enteropneusts are exceedingly rare, and throw no light on either hemichordate phylogeny or the proposed harrimaniid-pterobranch transition. Here we describe an enteropneust, Spartobranchus tenuis (Walcott, 1911), from the Middle Cambrian-period (Series 3, Stage 5) Burgess Shale. It is remarkably similar to the extant harrimaniids, but differs from all known enteropneusts in that it is associated with a fibrous tube that is sometimes branched. We suggest that this is the precursor of the pterobranch periderm, and supports the hypothesis that pterobranchs are miniaturized and derived from an enteropneust-like worm. It also shows that the periderm was acquired before size reduction and acquisition of feeding tentacles, and that coloniality emerged through aggregation of individuals, perhaps similar to the Cambrian rhabdopleurid Fasciculitubus. The presence of both enteropneusts and pterobranchs in Middle Cambrian strata, suggests that hemichordates originated at the onset of the Cambrian explosion.
Gee, H. Tubular worms from the Burgess Shale, Nature, (Online March 2013) | doi:10.1038/nature11963
Over recent years, researchers have developed the scenario of fleas feasting on pterosaurs and feathered dinosaurs during the Jurassic Period of Earth history. Fossils of strashilid insects have been suggested to have piercing and sucking mouthparts and hind pincers suitable for attaching to a host's hairs or feathers. Further reading on this interpretation is to be found in Rasnitsyn (1992) and Gao et al. (2012). Other putative flea species have also been found and Poinar's (2012) perspective paper has the title: "the 165-million-year itch" (see also here).
A new interpretation of the strashilids has now been proposed after examining spectacular recent finds from the Daohugou beds, Inner Mongolia. The researchers have concluded that the fossils are the remains of flies, not fleas. They were not ectoparasites living on animals, but highly specialized flies adapted to aquatic environments.
"Although definitive Middle Jurassic ectoparasites (fleas) on vertebrates were reported recently from the Daohugou outcrops, earlier speculation regarding strashilids as terrestrial ectoparasites can be rejected owing to an alternative hypothesis stemming from the discovery of hitherto unknown large membranous wings and females of Strashila, in two cases preserved in copula. Males and females have identical head morphologies but differ strongly in the absence of the hind leg pincers in females, which excludes ectoparasitism on terrestrial vertebrates as these are reinterpreted as sex-related structures for grasping the female rather than a host's integument. In addition, unlike ectoparasitic insect lineages, the body is cylindrical in strashilids, rather than dorsoventrally or laterally flattened." (page 94, Huang et al. 2013)
From Poinar (2012): "(A) Reconstruction of the 150 million year old Jurassic flea-like Strashila incredibilis. Note the incredibly long and powerful hind legs clasping the base of two feathers on a feathered dinosaur and a well-developed proboscis. Strashila may have fed on pterosaurs or feathered dinosaurs. Drawing by the author. (B ) Reconstruction of the Chinese Jurassic pseudoflea, Pseudopulex jurassicus, imagined parasitizing a feathered dinosaur." (Source here)
It is worth noting that our understanding of strashilids has changed as a result of finding well preserved specimens. Previous work was based on meagre fossil evidence and was inherently speculative. It is possible to generalise the lessons that should be learned from this: when fossil evidence is sparse, it is unwise to speculate. Unfortunately, the pressures to publicise finds are substantial and are unlikely to diminish. The media is always looking for stories that create interest, and speculation appears to be preferred above caution.
It is also worth noting that the new interpretation of strashilids locates them in a more familiar context. The researchers note characters that are "virtually identical with those of the recent nematoceran flies", are "comparable in critical details with those of nymphomyiids", and "similar to those of nymphomyiids". "We conclude that the Strashilidae were a highly specialized dipteran clade related to Nymphomyiidae, with an aquatic or amphibious life history." This paragraph summarises the evidence:
"These structures provide evidence that strashilids share several potential apomorphies with modern nymphomyiid flies, including the finer details of the antennae, ocelli, wings, terminalia and legs. Their reduced mouthparts and wings are inefficient for feeding and active flight, respectively, and indicate an ephemeral life history, akin to modern nymphomyiid taxa. Similar to modern nymphomyiids, adult Strashilidae probably mated soon after emergence, shed their wings, crawled beneath the water, mated, and in some cases died in copula, with the superposing male grasping the female below, thereby explaining the discoveries of females grasped by males, and both without their wings." (page 96)
It is not without significance that the initial interpretation of the fossil strashilids considered them to be primitive flea-like insects. There were hints from some characters that made sense in the perspective provided by evolutionary theory. However, what we can now see is a highly specialized insect related to Nymphomyiidae. It is derived rather than primitive. And this specialised insect, similar to modern nymphomyiids, was part of the Jurassic world. Is it possible that the Darwinian mindset colours the interpretations placed on fossilised species? Before this thought is dismissed out of hand, the case of the strashilids serves as a salutary case study to ponder.
Amphibious flies and paedomorphism in the Jurassic period
Diying Huang, Andre Nel, Chenyang Cai, Qibin Lin & Michael S. Engel
Nature, 495, 94-97 (07 March 2013) | doi:10.1038/nature11898
Abstract: The species of the Strashilidae (strashilids) have been the most perplexing of fossil insects from the Jurassic period of Russia and China. They have been widely considered to be ectoparasites of pterosaurs or feathered dinosaurs, based on the putative presence of piercing and sucking mouthparts and hind tibio-basitarsal pincers purportedly used to fix onto the host's hairs or feathers. Both the supposed host and parasite occur in the Daohugou beds from the Middle Jurassic epoch of China (approximately 165 million years ago). Here we analyse the morphology of strashilids from the Daohugou beds, and reach markedly different conclusions; namely that strashilids are highly specialized flies (Diptera) bearing large membranous wings, with substantial sexual dimorphism of the hind legs and abdominal extensions. The idea that they belong to an extinct order is unsupported, and the lineage can be placed within the true flies. In terms of major morphological and inferred behavioural features, strashilids resemble the recent (extant) and relict members of the aquatic fly family Nymphomyiidae. Their ontogeny are distinguished by the persistence in adult males of larval abdominal respiratory gills, representing a unique case of paedomorphism among endopterygote insects. Adult strashilids were probably aquatic or amphibious, shedding their wings after emergence and mating in the water.
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