Abiogenesis - Metabolism Without Cells.

Creationism - for when you want to pretend to be an expert on
something you don't understand

Spark of life: Metabolism appears in lab without cells - life - 25 April 2014 - New Scientist

"Metabolic processes that underpin life on Earth have arisen spontaneously outside of cells" - words that must strike dread in the minds of any creationist fraud who depends on suckering scientifically illiterate people for a living. But those are to opening words in the above article in New Scientist.

A team from Cambridge University, supervised by Markus Ralser, has stumbled almost by accident on the startling fact that several of the basic metabolic pathways common to all living cells, and on which living things depend, can be produced spontaneously and entirely naturally.

Most models for the origin of living systems include RNA entering the scene very early on, if not right at the start of it, because RNA is the basic information store which passes information on to the next generation. RNA is important in the evolution of living things because it can self-replicate as well as catalyse organic reactions. It is normally accepted that the basic metabolic pathways are too complex to have arisen spontaneously but they are assumed to have evolved early in the history of life on Earth. These models require the earliest living things to be RNA-based so that the enzymes catalysts needed could be produced.

People have said that these pathways look so complex they couldn't form by environmental chemistry alone... If you look at many different organisms from around the world, this network of reactions always looks very similar, suggesting that it must have come into place very early on in evolution, but no one knew precisely when or how.

Markus Ralser, Cambridge University, UK,
Quoted in News Scientist, 25 April 2014

Now it seems these basic metabolic pathways could have simply been co-opted and incorporated by primitive proto-cells and could pre-date the evolution of RNA or even have led to it by producing RNA precursor molecules.

The process was discovered when a student used a mass spectrometer to quality-check unused cell-culture medium and noticed a signal for puruvate - one of the products pf glycolysis, so they tried to replicate the production of it using a water solution believed to be like the oxygen-free oceans on Earth before the evolution of photosynthesis. They have reported their findings in Molecular Systems Biology.

Abstract
The reaction sequences of central metabolism, glycolysis and the pentose phosphate pathway provide essential precursors for nucleic acids, amino acids and lipids. However, their evolutionary origins are not yet understood. Here, we provide evidence that their structure could have been fundamentally shaped by the general chemical environments in earth's earliest oceans. We reconstructed potential scenarios for oceans of the prebiotic Archean based on the composition of early sediments. We report that the resultant reaction milieu catalyses the interconversion of metabolites that in modern organisms constitute glycolysis and the pentose phosphate pathway. The 29 observed reactions include the formation and/or interconversion of glucose, pyruvate, the nucleic acid precursor ribose‐5‐phosphate and the amino acid precursor erythrose‐4‐phosphate, antedating reactions sequences similar to that used by the metabolic pathways. Moreover, the Archean ocean mimetic increased the stability of the phosphorylated intermediates and accelerated the rate of intermediate reactions and pyruvate production. The catalytic capacity of the reconstructed ocean milieu was attributable to its metal content. The reactions were particularly sensitive to ferrous iron Fe(II), which is understood to have had high concentrations in the Archean oceans. These observations reveal that reaction sequences that constitute central carbon metabolism could have been constrained by the iron‐rich oceanic environment of the early Archean. The origin of metabolism could thus date back to the prebiotic world.

Non‐enzymatic glycolysis and pentose phosphate pathway‐like reactions in a plausible Archean ocean
Markus A Keller, Alexandra V Turchyn, Markus Ralser; DOI: 10.1002/msb.20145228 |Published 25.04.2014

One significant finding is that this process can produce ribose 5-phosphate, which is a precursor of RNA so it raises the possibility that RNA evolved later.

This research isn't conclusive, of course - there is still the problem of where the precursor sugars came from, for example. In living things nowadays, since the evolution of photosynthesis probably by cyanobacteria, sugars come from ingested food unless you are fortunate enough to be either a cyanobacterium or a green plant which has incorporated cyanobacteria in their cells as chloroplasts. But, as Ralser points out, every chemical reaction is, in principle, reversible. So, in theory, they should be capable of building sugars as well as reducing them.

Most worryingly for creationists, of course, is that once again science has closed a little gap and found that there was no magic needed and no god making things work.

'via Blog this'

---

Growing Up And Losing Faith

I was asked recently if I could explain the process I went through as I became an Atheist, as this might help others going through the same process. Apart from not being sure I have anything much to offer people in this respect because I was very young at the time, this is actually quite difficult for me for another reason.

Rather like a reverse of the parody version of evolution which creationists are taught to attack, where evolution is absurdly presented as a sudden event so that even a child will think it's silly, instead of the gradual process spread over time where one thing leads inevitably to another and several things can happen concurrently, my deconversion was a sudden event, or so it seemed at the time, not a slow, accumulative process, as it seems to have been with many others. But maybe this is because, being very young at the time, I hadn't really realised some sort of process was going on in my mind. So far as I was concerned, one minute I believed in the traditional Christian god, gentle Jesus, meek and mild, the Virgin Mary, wise men, shepherds, and the souls of dead babies riding up to Heaven on sunbeams, and the next, I didn't believe a word of it.

I have related this before in The Light Of Reason so I'll just briefly run through it again then look at what a few other well-known atheists have said on the subject.

Manny's Hysteria Explained

I've just found out the reason the expelled seminarian and failed wannabee Catholic priest and habitual Internet abuser from Bronx, NY, Manuel de Dios Agosto, has been spamming my blog with almost daily abuse, threats and delusions of grandeur again, after a lull of several months. It's all because someone has set up a tribute account to me on Twitter specifically to tweet links to my blogs. I understand the account is @R0saRub1c0nd10r. Makes me feel quite proud and more than a little humbled that my blogs were so appreciated by so many people.

Of course I was aware that a supporter and Twitter friend was thinking of setting up this account because, out of common courtesy, he/she (I only know them by their Twitter name) had asked my permission to use my name. What I hadn't realised was how much interest there was in this account although I had noticed a 25% or so increase in page hits. I'm extremely touched and flattered that so many people would like to see me back on Twitter and miss my blog links. I don't have any reason to go on Twitter much theses days so I hadn't realised quite how many supporters were still, after more than six month's absence, calling for my account to be reinstated and including me in #FF lists. I was obviously doing something right ☺.

All I can say on the subject of my return to Twitter is that I don't seem to be able to get past the wall of 'customer support' at Twitter and no one there is willing to give me any reason for my account's suspension other than in the most vague, general terms like 'in breach of the rules'. Despite several requests for specific examples of offending tweets and an explanation of which rule they breached, none has been forthcoming. They either go ignored or, on one occasion, the bizarre excuse was that it would be a breach of privacy to tell me the real reason. Read into that what you will, but I've no intention of creating other accounts only to have them suspended, presumably for the same reason Twitter won't admit to. It seems no one at Twitter Support is allowed to give out the name and contact details of anyone who has the authority to reverse a decision, or maybe they just don't want them knowing what's going on below decks.

Anyway, it seems that the success of this tribute account has sent Manuel off on another one so I am daily having to delete comments on various blogs such as the following selection:

I get a good laugh reading these posts. You really have no clue who I am do you? In any case, I am capitalizing off your paranoia because you are promoting my brand "sacerdotus." Thanks! However, I hate to see when you are taken to court for libel by this kid you're defaming and who you think is me. I can definitely prove I am not him, but your hysteria is indeed profitable for my cause. Thanks again Rosie for promoting me with your paranoia and obsessive compulsive disorder. #won! #noliesrequire #oxfam lol! :-)

---

#WON I bet you got many goosebumps when you got suspended by me again. :) #LOL #WON :)

Since 2010, 7000 followers all gone.. #LOL #WON You wanted to be prideful and fell hard from your high horse. Rubicondior is not the end. We will continue shutting your nonsense down, so don't get used to twitter or blogger. :) #WON #TeamSacerdotus

As we can see from the last of these Manuel appears to have developed multiple personality disorder and imagines he's running Twitter too, as though he hadn't got enough problems to cope with. He hasn't yet reached the volume of dozens a day that it reached last September, although they are no less insane.

Apparently he is now spamming Twitter with his @Atheism707 account asking people to file false complaints and spam reports againt @R0saRub1c0nd10r and a list of other accounts. No doubt these will be accounts who have either had the temerity to doubt Manuel's claims or who have already learned that Manny is behind this, as well as the @SCDTVS account. I wonder what view Twitter will take of this encouragement to others to abuse their clients with false reports. They generally take a dim view of those who create yet more accounts to get round their multiple suspensions for obscene, abusive and threatening accounts - a list of which can be seen here.

Should anyone wish to report Manuel's current accounts, Twitter's complaint form can be found here. You will need a specific example to begin with, then you need to reply to the email you'll received from Twitter Support. You can then send them further examples by replying to this email. This allows them to build up a dossier of complaints.

It might take several weeks before you get a final reply but don't be fobbed off if they tell you the account has been deleted or suspended. Check this out, as they often seem to use this as a quick way to avoid actually dealing with the abusive account. They have told me on three different occasions that another of Manuel's abusive accounts no longer exists or has been suspended before it had actually been suspended. And don't be fobbed off with the assurance that they have asked him to stop his abusive behaviour. Even if he stops it for a few days, he will start up again quite soon. Simply reply to the email telling them you are not satisfied with that response. This will keep the ticket open so you can update them with new abuse.

Anyway, many thanks to whoever is behind my tribute account and I hope that sheds some light on Manuels increasing bizarre behaviour. Now, back to the real purpose of this blog - explaining why religion is a malignant superstition which needs to be exposed and opposed (look at what it's done to Manny, for example), how science is continually closing the gaps in which religions try to sit their ever-shrinking little gods, how religion is used and excuse for otherwise unacceptable behaviour and the most grotesque of human atrocities against other human being, and how it exposes Bronze-Age creationism, the frauds who sell it to scientifically illiterate simpletons, and the fraudulent apologists who give credence to the extremists for money and political influence.

---

Income from ads will be donated to charities such as moderate centre-left groups, humanist, humanitarian and wildlife protection and welfare organisations.

Darwin's Wonderful Worms

Darwin's Medow, Down House, Downe, Kent

Own work

Darwin's Meadow, Down House, Downe, Kent, UK

I was stimulated recently by an interesting question from a creationist which a friend passed to me for comments. Even creationists can sometimes pose interesting questions which need several minutes to think about. The question was, why are dinosaur tracks often found on the surface when human artifacts are often several feet below the surface. If dinosaurs are millions of years old why aren't they found at much deeper levels that human artifacts?

Superficially, this looks like a problem for evolution, and if it were true for every location it would indeed be. It would actually be equivalent to providing the evidence which the great J.B.S.Haldane said would falsify evolution - a fossil rabbit in the Cambrian. Of course, it isn't true for dinosaur tracks. All those found have either been in quarries or on the surface of eroded rocks such as the dry bed of Paluxy Creek, Texas, USA. But, old fossils are found on the surface or just a few feet down, so although my friend's creationist friend was wrong about the dinosaur tracks, there is a general question to be answered here.

The answer of course is that the surface of the Earth is dynamic and subject to forces of change, like erosion or human activity like quarrying and animal activity. Additionally, and more importantly, how fossils get exposed and how human artifacts get burried are two different processes entirely. The site of the Paluxy dinosaur tracks (the subject of the famous hoax that still has creationists fooled) is the bed of the Paluxy Creek, which has eroded away the upper layers, exposing the limestone layer with the tracks on. The dinosaur tracks found in Worth Matravers in Dorset, UK were exposed by quarrying for building material.

Spare A Thought For Poor Old Judas

Judas Iscariot. Gabriel von Max. Prague National Gallery

As it's Easter and the time for good-will to all men... now don't start... just because it's not Christmas there's no reason to bear ill will, is there? Anyway, in this season of goodwill to all men, is it not time someone spoke up for poor Judas Iscariot - possibly the most maligned man in all literature.

You may recall that the character of Judas makes his appearance in the stories about Jesus in the Bible but only seems to play any significant part towards the end of the tale, when his role suddenly become absolutely critical to the plot, only to be maligned and vilified for playing his allotted role later on. Although, as we shall see, this maligning of Judas seems to be a much later addition to the story, added moreover by someone who hadn't been following the plot too closely. Not only that but the later addition seems to have become muddled too.

How American Muslims Silenced Ayaan Hirsi Ali

Ayaan Hirsi Ali

Ayaan Hirsi Ali: ‘They Simply Wanted Me to be Silenced’ | TIME.com

Brandeis University, Waltham, Mass., USA has caved in to pressure from Muslim students and rescinded its plan to honour Ayaan Hirsi Ali with a an honorary degree on 8 May.

If there is anyone who can be described a role model for Muslim girls who want to take control of their own lives, then it is Ayaan Hirsi Ali. A former muslim and member of the Dutch parliament from 2003 to 2008, she is an outspoken advocate for women's rights and a critic of Islam. Born in Somalia and raised as a strict Muslim, she survived a civil war, beatings, genital mutilation and a forced marriage before escaping to Holland and finally renouncing her faith in her 30s. She described the moment thus:

I looked in a mirror and said out loud, in Somali, "I don’t believe in God." I felt relief. There was no pain but a real clarity. The long process of seeing the flaws in my belief structure, and carefully tip-toeing around the frayed edges as parts of it were torn out piece by piece—all that was over. The ever-present prospect of Hellfire lifted, and my horizon seemed broader. God, Satan, angels: these were all figments of human imagination, mechanisms to impose the will of the powerful on the weak. From now on I could step firmly on the ground that was under my feet and navigate based on my own reason and self-respect. My moral compass was within myself, not in the pages of a sacred book.

A fuller account can be read here, in one of the most inspiring and powerful arguments for Atheism I have ever read.

Brandeis University was founded as a secular, co-educational establishment in 1948, soon after World War II and the Holocaust, when many US universities were racially, religiously and gender segregated. It had been assumed that Ali epitomised all that the University stood for, hence the honour. However, Muslim students raised a petition, pointing to a 2007 interview with Reason magazine in which she said of Islam:

Once it’s defeated, it can mutate into something peaceful. It’s very difficult to even talk about peace now. They’re not interested in peace. I think that we are at war with Islam. And there’s no middle ground in wars.

Brandeis University claimed to be unaware of this and decided it was not something they wished to be associated with and withdrew the offer of the honorary degree.

Ayaan Hirsi Ali has responded in typically measured and dignified style with:

Yesterday Brandeis University decided to withdraw an honorary degree they were to confer upon me next month during their Commencement exercises. I wish to dissociate myself from the university’s statement, which implies that I was in any way consulted about this decision. On the contrary, I was completely shocked when President Frederick Lawrence called me — just a few hours before issuing a public statement — to say that such a decision had been made.

When Brandeis approached me with the offer of an honorary degree, I accepted partly because of the institution’s distinguished history; it was founded in 1948, in the wake of World War II and the Holocaust, as a co-educational, nonsectarian university at a time when many American universities still imposed rigid admission quotas on Jewish students. I assumed that Brandeis intended to honor me for my work as a defender of the rights of women against abuses that are often religious in origin. For over a decade, I have spoken out against such practices as female genital mutilation, so-called "honor killings," and applications of Sharia Law that justify such forms of domestic abuse as wife beating or child beating. Part of my work has been to question the role of Islam in legitimizing such abhorrent practices. So I was not surprised when my usual critics, notably the Council of American-Islamic Relations (CAIR), protested against my being honored in this way.

What did surprise me was the behavior of Brandeis. Having spent many months planning for me to speak to its students at Commencement, the university yesterday announced that it could not "overlook certain of my past statements," which it had not previously been aware of. Yet my critics have long specialized in selective quotation — lines from interviews taken out of context — designed to misrepresent me and my work. It is scarcely credible that Brandeis did not know this when they initially offered me the degree.

What was initially intended as an honor has now devolved into a moment of shaming. Yet the slur on my reputation is not the worst aspect of this episode. More deplorable is that an institution set up on the basis of religious freedom should today so deeply betray its own founding principles. The "spirit of free expression" referred to in the Brandeis statement has been stifled here, as my critics have achieved their objective of preventing me from addressing the graduating Class of 2014. Neither Brandeis nor my critics knew or even inquired as to what I might say. They simply wanted me to be silenced. I regret that very much.

Not content with a public disavowal, Brandeis has invited me "to join us on campus in the future to engage in a dialogue about these important issues." Sadly, in words and deeds, the university has already spoken its piece. I have no wish to "engage" in such one-sided dialogue. I can only wish the Class of 2014 the best of luck — and hope that they will go forth to be better advocates for free expression and free thought than their alma mater.

I take this opportunity to thank all those who have supported me and my work on behalf of oppressed women and girls everywhere.

And so American Muslim girls in general, and Brandeis students in particular, have been deprived of the opportunity to hear one of the most inspiring advocates of the principles of secular, liberal freedoms and human rights that Brandeis University was founded on. They have been denied this by those to whom everything Ayaan Hirsi Ali stands for and represents is anathema - the right of women to control over their own bodies and their own destinies and the extension of full human rights and the right to respect and dignity to all members of society.

'via Blog this'

---

Income from ads will be donated to charities such as moderate centre-left groups, humanist, humanitarian and wildlife protection and welfare organisations.

The Internet Is Making Theists Think

Top: Internet use. Bottom: Religious affiliation

How the Internet Is Taking Away America’s Religion | MIT Technology Review

Americans are following many European countries in losing their faith. The change hasn't been so spectacular as in many European countries where Atheists/Agnostics are now in a clear majority, but the growth has been a steady 0.5 percent per year over the last 20 years, rising from just 8 percent in 1990 to 18 percent in 2010.

The obvious question is, why is this happening? There are many social and psychological factors involved in relative religiosity, not the least of which is income inequality with those in the lowest income groups and forming the lowest social strata tending to be more religious and more fundamentalist, while those in the higher social strata tend to be less religious and more moderate.

Vatican Backs Code of Silence Over Child Abuse

Pope Francis "We will not take one step back..."

Italy's bishops pass Vatican-backed rule that child molestation does not have to be reported - Europe - World - The Independent

In stark contrast to what Pope Frankie claims to be doing to clean up the Catholic Church, the Vatican has been complicit in a policy adopted by Italian Bishops that states they are no longer required to report child-abusing priests and nuns to the police.

The 'speed' with which Vatican reforms are progressing can be gaged from the fact that only in the last few months has the Vatican seen fit to strengthen its laws on abuse of minors to include sexual abuse of children. Astonishingly, this was not even considered an abuse of minors when the law was first drawn up.

[I] personally ask for forgiveness for the damage [some priests] have done for having sexually abused children. We will not take one step backward with regards to how we will deal with this problem, and the sanctions that must be imposed.

Pope Francis
(Statement made on day of Italian Bishops' Conference statement)

This legalistic excuse comes from a treaty between the Vatican and the Italian state in 1985 which stipulates that priests are not obliged to inform the police of crimes learned of through their ministry. The Italian Bishops' Conference, which published the guidelines last Friday, say they came from a suggestion by the Vatican's office that handles sex abuse allegations.

Last month Pope Francis had complained that, "No-one else has done more [to tackle child sexual abuse]. Yet the Church is the only one to have been attacked."

[the Vatican is systematically placing the] preservation of the reputation of the Church and the alleged offender over the protection of child victims.

UN Committee on the Rights of the Child,
5 February 2014

In 2010, to great publicity and in response to the growing world-wide outrage at these sexual and psychological abuses as more and more victims found the courage to be open about what they had suffered at the hands of predatory paedophile priests and nuns, the Vatican had instructed bishops to report these offences to the authorities - but only where required to do so by the local law. The Vatican has never seen it as the moral duty of Bishops to protect the vulnerable from predatory clerics by adopting a zero tolerance policy and reporting all such cases even when not required to do so by local law.

Now we see the Vatican office supposedly responsible for dealing with the problem, recommending a policy of strict legalism regardless of the fact that this gives a degree of protection to offenders and removes a little protection from the vulnerable. Obviously this offices sees it as dealing with the problem to prevent it being exposed.

The 'problem' is seen as one of embarrassment and damage to the Catholic Church, not damage to the victims of these abuses. The solution is a Mafioso-style code of silence or a 'no snitching' rule.

As reported on the BBC website, the long litany of Catholic Church abuse scandals includes:

• Germany - A priest, named only as Andreas L, admitted in 2012 to 280 counts of sexual abuse involving three boys over a decade.
• United States - Revelations about abuses in the 1990s by two Boston priests, Paul Shanley and John Geoghan, caused public outrage.
• Belgium - The bishop of Bruges, Roger Vangheluwe, resigned in April 2010 after admitting that he had sexually abused a boy for years.
• Italy - The Catholic Church in Italy admitted in 2010 that about 100 cases of paedophile priests had been reported over 10 years
• Ireland - A report in 2009 [The Cloyne Report] found that sexual and psychological abuse was "endemic" in Catholic-run industrial schools and orphanages for most of the 20th century.

BBC News - Pope Francis asks forgiveness for child abuse by clergy

These are the same people who claim to be guardians of our morals and who demand the right to be consulted on all legislation inasmuch as it related to a woman's rights to her own body, the rights men have over them, what consenting adults may or may not do in the privacy of their own bedrooms and who may form a legal relationship with whom.

'via Blog this'

---

Income from ads will be donated to charities such as moderate centre-left groups, humanist, humanitarian and wildlife protection and welfare organisations.

Fundamentalist Threat To EU Freedoms

Mamber states of the European Union

Pro-Life Citizens' Initiative Worries E.U. Scientists | Science/AAAS | News

In an astonishingly arrogant move, a small, highly organised and well-financed group of Christian fundamentalists, posing as a European citizen's initiative, is seeking to exploit and subvert the democratic process. In the EU a petition with over 1 million authentic signatures collected across at least eight member states must be considered by the European Commission (the legislative body of the EU) for possible legislation.

If the Commission agrees with this petition, embryo stem-cell research will be illegal, and something having its origins in primitive superstition will be mandatory on all 28 current, and all future EU member states. This is because Christians believe a magic entity called a 'soul' enters a zygote at conception and thus a cell, or small group of cells, which could not possibly have independent existence in that state, is a fully human individual with full human rights. No evidence of the 'soul' has ever been found.

Discovery Shows Science Changing Its Mind

Australopithecus sediba

Human 'missing link' fossils may be jumble of species - life - 09 April 2014 - New Scientist

News this week that doubt has now been cast on what had been hailed as a new species of Australopithecus showing striking 'transitional' features between these pre-hominid apes and the hominids. A new analysis by Ella Been of Tel Aviv University, Israel suggests what were believed to be the fossils of one adult female and a juvenile male found in the same location at Malapa, South Africa, in 2008 may actually be two adults and two juveniles of different species - one each of australopithecine and hominid.

This emerging dispute interests me especially because it touches on something that many creationists and other scientifically illiterate people purport to find puzzling about science. If science is the best way to discover the truth, why is it full of disputes and disagreements, often resulting in a change of mind and even a 'rewrite of the science books'. Isn't it better to stick with dogma which hasn't been changed for a couple of millennia so you know where you are?

I'll deal with that in a moment. First, the dispute and it's background.

The exciting thing about the supposed new species, named A.sediba by its discoverer, Lee Berger of the University of Witwatersrand, South Africa, was that it appeared to have a hominid lower body, complete with feet which were close to those of Homo sapiens, and the more chimpanzee-like skull and upper body of an australopithecine. As an interesting sequel to this find, the Boston Museum of Science, MA, USA, asked visitors to walk barefoot across a mechanised carpet that analysed their footprints, and found that one in thirteen had differences in foot-bone structure similar to those of A. sediba.

This suggested that modern humans might well trace their ancestry back not to the Ethiopian Highlands as 'Lucy' (A. afarensis) suggested but to much further south. Of course, this is still consistent with the picture of H. sapiens having evolved in Africa from chimpanzee-like apes which had earlier diverged from the other three African primates; the picture merely shifted further south.

So, a few years ago we had to change our minds a little. From it being fairly safe to assume H. sapiens had evolved in Ethiopia we now needed to allow for the possibility that it might have been in South Africa instead. A little less certain and a little more uncertain and a suspension of belief pending some more evidence. Now we may have to shift it back again as the balance of evidence changes.

The doubt raised by Ella Been revolves around her analysis of vertebra and lower jawbones from the supposed two individuals. She sees close similarity between the boy's vertebrae and the vertebrae of the 1.5 million year-old 'Turkana Boy' (H. erectus) while the adult female has undoubtedly australopithecine vertebrae. This suggested two different species. Then her colleague, Yoel Rak, also of Tel Aviv University, noticed a notch on the boy's lower jawbone which looked australopithecine while a similar notch on that of the adult female looked hominid. Conclusion: there are four individuals, not two; one adult female and one juvenile male australopithecine and one adult female and one juvenile male hominid, the bones of which had become intermixed.

At this point, and admittedly not being in possession of all the facts, I think I would be tempted to ask if just one adult or one juvenile bone had been duplicated, because this would be indisputable evidence of two or more partial skeletons. I assume, since none is mentioned, that none have been found. On that basis I'm inclined not to change my mind that much, just yet.

The question remains to be resolved and one thing is sure - it will only be resolved by evidence. Until that evidence is forthcoming, it remains for science an unresolved question. The interesting this is to see how science copes with evidence which seems to refute an idea. The only honest answer to the question of where the Homo genus split off from the Australopithecus genus is one which reflects the current uncertainty and the respective strength of the evidence for and against while allowing that both could be wrong.

A central tenet of evolutionary theory is that variation within taxa becomes variation between taxa as species diverge.

Lee Berger, University of Witwatersrand, South Africa

Of course, those with an interest in one side or the other will champion their particular views. Lee Berger says that the position of the bones as found makes it likely that they were from one individual. He concedes that the juvenile vertebrae do look like H. erectus but suggests that they would lengthen as he grew to become more australopithecine. To which Been points out that other fossil Australopithecus children have long vertebrae.

Berger also argues that Been's and Rak's analysis would also make sense if A. sediba really was transitional between Australopithecus and Homo because a mixture of features is exactly what we would expect as species diverge over time.

All this is mere detail, of course. It actually matters not at all whether humans evolved in South Africa out of A. sediba or in Ethiopia out of A. afarensis, or out of an as yet undiscovered species. There is little doubt that we evolved in Africa. And even if someone were to discover that modern humans evolved in Europe or Southeast Asia after all, then that would be sensational but nothing more. We would not need to change anything other than our minds, the next editions of the textbooks and some museum displays. And our knowledge would move a little closer to the truth, which remains the truth regardless of our beliefs.

So why is this a better way to determine the truth than going with dogma, and what's the use of 'truths' that keep being disputed and changed?

Imagine you're in court, on trial for something you didn't do. One witness produces evidence which suggests you are guilty and another produces evidence which suggests you are innocent. Would you want the defence and prosecution teams to argue and debate the merits of the evidence, pointing out the flaws in it and the other possible interpretations - maybe that footprint did look like yours but thousands of people have those shoes; maybe you did once own that gun once but it had been stolen in a burglary which you had reported to the police, and the DNA at the scene was not your DNA.

Or would you want the jury to listen to someone who said it was an accepted 'fact' that people like you are criminals and there is an old book which says so, so the jury didn't need to bother with the pros and cons of the arguments over the significance of the evidence when even the experts couldn't agree. They could just go with what the old book says and save a lot of time and expense. After all, it's having an opinion that matters, not whether it's right or wrong. In any case, dogma was deemed to be right so whatever agreed with dogma would be right automatically, and the dogma said you were guilty. Why bother with a trial at all even?

Hands up those who would like to be tried by dogma and not have the jury bother with the evidence and what the experts say about it!

The point is that only by constantly reassessing and disputing the evidence can it be fully tested, assessed and appropriately weighted at the bar of informed opinion. This can only be done by people who are prepared to abandon earlier ideas and adopt new ones when the evidence changes and to whom all conclusions and 'beliefs' are conditional and transient and informed by evidence. It takes a special form of arrogance, and more than a little intellectual dishonesty, to insist that there can be knowledge without evidence. Even in the cases of a wrongful convictions, it is evidence which eventually proves the conviction to be unsafe or wrong.

Dogma is the antithesis of intellectual honesty and explains why science progresses and develops but religions remain unchanged until they cease to have any relevance and are swept aside by the tide of evidence which eventually overwhelms them or they are forced to change to avoid extinction.

'via Blog this'

---

Income from ads will be donated to charities such as moderate centre-left groups, humanist, humanitarian and wildlife protection and welfare organisations.

More Blunders By The Unintelligent Designer

I've written several blogs already about the 'design' mistakes in the human make-up and other blunders in design of natural things of which any self-respecting intelligent designer would be thoroughly ashamed (see list following this article). Here I look at a few of the less obvious ones - less obvious that is because they are less visible and often something we take for granted as 'normal'. This list is based on an article written by Claire Ainsworth and Michael Le Page, published in New Scientist, 10 August 2007.

Inefficient Respiratory System

It's considered a real achievement and a feat of endurance for a super-fit human, after prolonged training, to climb Mount Everest without oxygen tanks and breathing masks. It was first done as recently as 1978. Everest is a mere 8,848 Metres high. In 1975, a jet flying at a height of 11,264 Metres sucked a griffon vulture into its jet engine.

Turin Shroud Forgery Shows Changing Fashions in Art.

Shroud of Turin depicts Y-shaped crucifixion - life - 02 April 2014 - New Scientist

The 14th-century medieval forgery known as the Shroud of Turin, which some Christians still insist was the shroud used to wrap the body of Jesus in following his legendary crucifixion, may show how perceptions of crucifixion and how it was depicted in art changed over time.

Carbon dating has shown that the flax used to make the linen cloth grew in the late 13th or early 14th century, not long before the shroud made it's first public appearance in France. This evidence confirms the evidence from the image itself that the shroud is a medieval European forgery. Strangely, the claim that it is the genuine shroud of Jesus never explains how the linen travelled back in time some 1400 years to 1st-century Palestine and then came forward again to 14th-century France, but such details are of little consequence to people who are desperate for evidence or to a church which habitually tries to trick people with fakes and phoney tales of miracles.

The image on it appears to have been a crude attempt to reproduce a body around which the shroud was wrapped and to make the body look like it had been crucified by painting some 'blood' on the arms. The artist appears to have either been unaware that wrapping a cloth around an object does not reproduce a three-dimensional image of the object, or he/she tried to reproduce an image that many people would assume such a process would produce.

If the forger had thought about it at all, it must have been something of a dilemma to either reproduce a realistic image as produced by wrapping it round the body, that no-one would recognise as the figure of a man unless projected onto a cylindrical mirror, or to produce something laughably unrealistic to an unbiased observer but that uncritical people would recognise as a human figure and allow confirmation bias and an eagerness to be fooled to gloss over the errors. The latter psychological process is the one normally used by religions to fool people with similar 'miracles'.

From the Gorleston Psalter, c.1320-30

Now a study has shown that the forger either deliberately or by chance, reproduced a pattern of blood flow on the left forearm which would be expected if the crucified body depicted had been crucified not in the traditional cruciform position, with arms outstretched, but in a 'Y' shaped position with arms raised above the head. This may well reflect the changing perception of how crucifixions were carried out, and might be because the forgery, like many of his contemporary 14th-century artists, depicted it as a 'Y', like Rubens did less than two hundred years later but unlike the more traditional poses depicted by more contemporary artists.

It could be that the artist just decided to draw the rivulets of blood parallel to the arms for artistic reasons.

Matteo Borrini, Liverpool John Moores University, UK

We can see how the forger was influenced by other artistic and cultural traditions and assumptions of his/her time in the depiction of Jesus as a European in the same pose used for the effigies of important people on their tombs. The hands, which are too small for the size of the face - a common mistake in early art - are discretely folded over the genitalia - something that would have been difficult to maintain whilst wrapping a body in a shroud and something that would not have been regarded as important since there was no expectation that anyone would see the body naked again. But obviously, if you're going to put an image of Jesus on display you don't want to show his naughty bits because that would be disrespectful and you can't use the traditional artistic device of a loincloth because bodies aren't normally buried in them.

'via Blog this'

---

Life On Mars? Death For Creationism?

Search for Martian Life Clears Another Hurdle

I wouldn't want to add to the discomfort and general air of despondency which must be pervading creationist pseudoscience circles these days, so any creationist frauds reading this should stop immediately.

Creationist pseudoscientists have recently had to endure (and ignore) the discovery, which is surely beyond any reasonable doubt now, that modern humans interbred with Neanderthals and formed a ring species with them and other species of humans, typical of an evolving and diversifying group of closely related species. Then we had confirmation of the Big Bang inflation and so the virtual certainty of the multiverse theory being correct.

Now they are now getting closer to what must be their nightmare scenario - the evidence is growing that there was formerly life not just on another planet but on Mars, our near neighbour in the solar system, and that it evolved there may millions of years ago when there was flowing water and habitable lakes on Mars.

The Lunar and Planetary Science Conference held in Woodlands, Texas, USA was told that the Curiosity Mars rover team are now reasonably confident that contaminants from Earth can't account for the carbon compounds Curiosity has obtained from martian rocks. In controlled experiments using Curiosity's Sample Analysis at Mars (SAM) equipment the team have eliminated accidental contamination from an organic reagent brought from Earth for future analysis. They report that the findings are persuasive and offer "compelling" evidence that chlorinated methane, ethane and propane found in the rocks are of martian origin.

This is a long way from proving that there was even simple life on Mars but, apart from it raining down from the Cosmos in the cosmic dust, meteorites and other space debris left over from the formation of the solar system, it's hard to account for it any other way.

So, things are looking bleak for creationism these days.

Not only has the DNA evidence of our interbreeding with Neanderthals knocked on the head any idea of us being a special creation and all descendants from a first couple a few thousand years ago, but it also refutes any notion of original sin - one of the main selling points for religions which diagnose the 'problem' and sell the cure like an 'alternative medicine' fraudster. The DNA evidence is entirely consistent with the scientific explanation of human origins in which no magic and no gods are required.

The confirmation of the mechanism of the first few billionths of a second in the Big Bang, together with the virtual certainty that universes are continually popping into existence so that all possible universes will exist. This refutes so many traditional creationist 'arguments' that it's hard to know where to begin. It destroys the Cosmological Argument which depends on the assumption that there must have been something to cause the Big Bang. Not only does there not need to be anything because quantum events don't require a cause but the probable existence of 'inflatons', which give rise to masses of space, means universes are very probably commonplace.

Of course the 'God did it!' conclusion was always circular anyway. "Look! God must exist because I can arbitrarily designate it as the cause of something I don't understand (and I've no intention of doing so because I already know the answer)"! At least creationists who would like to be honest if only they could be, don't need to use that dishonest tactic any more.

That brings us to the 'fine-tuning' argument or, in the form in which it's sold to children, the 'Goldilocks' argument. This argues that the probability of the Universe being exactly right for life is so infinitessimally small that it must have been designed. And this is entirely consistent with insisting that life only exists on this single planet out of the trillions in the entire fine-tuned-for-life Universe. Now we know that all possible universes pop into existence, of which this one is just one. Of course, if life couldn't have evolved here we couldn't be discussing it, so a Universe in which intelligent beings are discussing anything must be one in which intelligent life can evolve. And now we know there must be very many of them with the same conditions as this Universe.

In fact, this refutation of the 'Goldilocks' creationist fairy tale must come as something of a relief to any intelligent theists who will surely have realised that arguing that their god can only create life which needs a very tightly controlled set of conditions, is arguing that it not only isn't omnipotent, because an omnipotent god could create life anywhere it wanted, but that it is itself constrained and needs a fine-tuned environment in which to work. Who fine-tuned the creator's world and set the constraints under which it has to work? And yet another creationist argument disappears up its own infinite regress.

And of course, should their nightmare ever come true and we find evidence of life on another planet, this will remove any vestige of logic from their fond notion that their god created Earth especially for them, its special creation, to live in and that the chances of life arising even in the 'perfect' conditions their god created are so small that it couldn't have happened spontaneously.

If it turns out that life also arose on the only other planet we definitely know about where the conditions could once have been similar to those on an early Earth, that argues strongly that it happens spontaneously and quite readily. The 'Goldilocks zone' will need to be expanded and the definition adjusted accordingly using creationist circular reasoning - life can only exist in a 'Goldilocks zone' so a 'Goldilocks zone' must be wherever life exists!

Creationist frauds must consider themselves very fortunate that their target marks are almost guaranteed not to read any science and if they stumble accidentally on any will simply wave it aside anyway. In any case, when did having an argument refuted mean a creationist fraud wouldn't try to get away with it on someone else?

I wonder what the chances of proudly ignorant science denialism arising spontaneously in an otherwise intelligent ape are? Surely it must have been created by design. It certainly seems to require very careful maintenance.

'via Blog this'

---

If Only Noah Had Known About Evolution!

Noah's ark on the Mount Ararat, Simone de Myle 1570

Tree of bird life could solve Noah's Ark problem - life - 27 March 2014 - New Scientist

One of the many absurdities in the Noah's Ark myth, several more of which can be found in No Way Noah!, is the sheer impossibility of providing an ocean-going sea-worthy wooden boat large enough to house something like 19 million animals of all shapes and sizes, many of which require highly specialised environments, together with enough food, to last something over a year.

Creationist pseudo-scientists who make their living trying to explain away these absurdities have no option but to fall back on an almost equally absurd version of warp-speed evolution so they can reduce the numbers to mere few thousand from which all the species have evolved in the last few thousand years, apparently with no one noticing all the new species popping into existence every generation. We're expected not to notice that they also tell their credulous followers that evolution is impossible but holding two diametrically opposite views simultaneously has never been a problem for creationists.

Now scientists have suggested a way we could, should the need ever arise in the future to take the world's species into protective custody to prevent the extinction of life on Earth, whilst not needing to take a pair of every single species. What we would need to safeguard is the DNA of all different species, not in test-tubes but in living members of those species which are the most evolutionarily distinct. From these, we could, theoretically reconstruct other related species.

You could increase the amount of evolutionary diversity that is currently protected by 25 per cent by expanding the reserve system by 5 per cent.

Laura Pollock, University of Melbourne, Victoria, Australia

For example, we would not need to save a pair of every wild cat but nor would it work to save, say, lions, or tigers because these have close relatives, so most of their DNA would survive their extinction. What we need to do is to preserve the main limbs and major branches of the evolutionary tree of life rather than the terminal twigs. Losing a species which is closely related to several others, such as the lion, would merely remove a twig from the tree. Conserving an evolutionary distinct species with few living relatives however will conserve more of the DNA from further down the branch for the same effort.

The Zoological Society of London (ZSL) has been running the Edge of Existence Project since 2007. This seeks to identify key endangered and evolutionary unique species and to rank them into an order of priority for conservation. At the moment, effort tends to be concentrated on a few high-profile species, often at the expense of a higher priority species according to this ranking.

Now, Walter Jetz of Yale University has ranked the world's birds in terms of evolutionary distinctness using genetic data from 6500 of the 10,000 species combined with data on threats and population size to produce a list of just 100 priority species. He has also shown that concentrating on just 113 sites could conserve 60 percent of the most endangered evolutionary unique species.

Jetz has used the ranking to point to species that should be protected. For example, the highly distinct shore plover (Thinornis novaeseelandiae) lives only on the tiny Chatham Islands, near New Zealand. Just 250 are left. Focusing on plover habitat would preserve 14.46 million years of evolution for each 10,000 square kilometres conserved. In contrast, the ostrich is the 10th most distinct species, but as it has a large range only 0.05 million years would be preserved per unit area.

Andy Coghlan, Tree of bird life could solve Noah's Ark problem, New Scientist, 27 March 2014.

It's a beautiful irony that, had the Bible's authors had the least inkling of evolution or DNA and how it allows species to be arranged in a tree of life, they could have made their absurd tale just a little more plausible by explaining that Noah had reduced the number of species to conserve by doing just what conservationists are now doing. They would have had to explain how Noah had then reconstructed all the other species by careful bioengineering of course but at least their daft notion would have been just slightly less implausible.

Unfortunately, they had to try to force-fit the story into what little they knew and understood, and the prevailing superstition of the orthodoxy they were selling, and so ended up with a story so implausible that only children and scientifically illiterate, gullible adults could believe it.

'via Blog this'

---

Ringing the Changes - Sex in Siberia

Oldest Homo sapiens Genome Pinpoints Neandertal Input

Just another little piece in the jigsaw puzzle of human evolution emerged this week when researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, announced the results of their sequencing of the entire genome from DNA recovered from the 45,000 year-old Homo sapiens male thigh bone, found in 2008 in an exposed banks of the Irtysh River at Ust-Ishim in western Siberia. It had been found by an ivory carver looking for mammoth tusks.

And, as with so often with science, a little piece of information has raised more questions and suggests that some of our earlier assumptions might just have been wrong.

Svante Pääbo's team have a lot more work to do but already a couple of things have been found:

• The DNA contained unmistakable traces of Neanderthal DNA showing that the man was descended from people who had interbred with H. neanderthalensis.
• Interbreeding had been quite recent judging by the fact that the sequences of Neanderthal DNA occurred in longer chunks than normally found in modern humans. As time progresses the chance of any chunk of DNA being chopped in half by crossover during the first stage of meiosis increases. A bit like whole fruit in a smoothy maker.

Genetically we now have a modern human that just barely postdates the Neandertal introgression into modern humans.

Bence Viola. Max Planck Institute for Evolutionary Anthropology

Now, and this might be a small crumb of comfort for those creationists who haven't simply ignored all this evidence of the hybrid origins of modern humans and must be feeling pretty depressed by all the evidence piling up against them, this has produced one of those small areas of disagreement amongst paleoanthropologists. Creationists normally enjoy these small disagreements and wave them around as evidence that, whilst science claims to be the only way to determine truth, it normally involves disagreement and changes of mind.

It's like having a time machine, to go back 45,000 years to see how the genomes of modern humans differed both from our own and also from Neanderthals and Denisovans.

Sarah Tishkoff, University of Pennsylvania, USA

It had been assumed that H. neanderthalensis had evolved in Europe or Asia, probably from H. heidelbergensis or maybe H. habilis or even H. ergaster or H. antecessor and had adapted to the colder northern climate. Later, when H. sapiens came out of Africa they did not move up into the colder north initially but skirted the southern margins into southern Europe and across Asia. The most likely place for the interbreeding with H. neanderthalensis in this scenario would have been the Middle East somewhere around northern Arabia, Asian Minor, Iraq or Iran. And this more or less tied in with the estimated dates of our expansion out of Africa and the period of cohabitation with Neanderthals.

However, this find suggests that modern humans adapted quite quickly to colder climates and were interbreeding with Neanderthals much further north. But, there is still much to be done to determine if this rapid adaptation was actually the result of the DNA we got from Neanderthals, or even to survival techniques and cold climate technologies we got from them.

One other intriguing possibility here is that, given the close proximity between Ust-Ishim and the Denisovan cave where a finger bone which yielded the DNA of a third species of humans was found, there may have been three different human species all capable of interbreeding and living in a relatively small area. All extra-African modern humans have some Neanderthal DNA and several groups of Southeast Asian and Austronesian people also have some Denisovan DNA, so it could be that this area was the point where all three came into contact and behaved very much like a ring species - just as we should expect gradually diverging species spread across a large geographical range to behave.

Researchers still think the Middle East is a likely place for the encounters. Other fossils in Israel, such as a 49,000-year-old Neandertal at Tabun Cave, might belong to people who were alive at the time of the unions or just after, says archaeologist Ofer Bar-Yosef of Harvard University, who was not a member of the team.

Ann Gibbons, Oldest Homo sapiens Genome Pinpoints Neandertal Input,
Science 28 March 2014: Vol. 343 no. 6178 p. 1417 DOI: 10.1126/science.343.6178.1417

Creationists who may be tempted to latch on to this little disagreement should bear in mind that there is no disagreement about human evolution here, or even the now established fact the modern humans coexisted with, and interbred with, related species of humans. The disagreement is simply over where the interbreeding took place.

'via Blog this'

---

Evolution Has More to Crow About

Carrion crow, Corvus corone corone

Carrion crow, Corvus corone corone

A few days ago I mentioned at the end of a blog post about the evolution of crows in the presence of the great spotted cuckoo, the fact that carrion crows and hooded crows are now regarded as different species. This illustrates neatly the problem of defining a species, especially where two closely related species are at a stage in their evolution where they have not fully diverged and retain the capability of interbreeding. I'll discuss this more later, but first, the case of the Eurasian crows.

As you drive north from England across southern Scotland and up towards the Highlands, you might, if you're interested in the birds, notice that the ubiquitous glossy black crows you will have seen almost everywhere from town parks to country fields and woodlands have quite suddenly been replaced by an equally common crow with a black head, tail and wings and a grey back and underparts.

Ancient Stick Insect Shows Evolutionary History

Early Cretaceous stick insect (Cretophasmomima melanogramma)
Image: Olivier Béthoux

The stripy stick insect that walked with dinosaurs - life - 19 March 2014 - New Scientist:

In my previous blog I touched on how what we see today in a species may be the result of ancient evolutionary forces which no longer apply, so it may not be immediately obvious what adaptive advantage there is to something in particular.

It's easy to overlook the fact that everything alive today is carrying the descendents of genes which survived through the Cambrian, the Devonian, the Triassic, Jurassic and the Cretaceous periods and were selected not by today's environment but maybe a very different one with different species and different ecosystems, even in the absence of orders like birds or mammals or in the presence of dinosaurs, pterodactyls, ammonites or giant tree ferns.

None of today's living species has an ancestor which did not live on an Earth where these extinct species once lived.

So, it should be no surprise to find ancient species like this early cretaceous stick insect which had adapted to live alongside early cretaceous plants by protective mimicry. This fossil was found in Inner Mongolia, China, in the Yixian Formation which has been dated between 122-130 million years ago. This rock formation which was laid down probably as volcanic ash from a catastrophic eruption, so capturing and preserving in exquisite detail, delicate structures like this insect with its wings, feathered dinosaurs and proto-avians as well as plant leaves. This is known collectively as the Jehol biota.

The significance of this fossil of Cretophasmomima melanogramma is that it is the earliest known example of stick insect mimicry. Stick insects today are renowned for their evolved mimicry to resemble the plants on which they feed but this example mimics a plant which was common then, but is extinct today. It was a species related to the maidenhair tree or Ginkgo biloba, now the only known representative of the Ginkgophyta division of the plant kingdom. The dark straight veins in the wings seen in this fossil, when the wings were folded over the back, would have closely resembled the leaves of Ginkgophyta, Membranifolia admirabilis also found in the Jehol biota.

Abstract

Background
Fossil species that can be conclusively identified as stem-relatives of stick- and leaf-insects (Phasmatodea) are extremely rare, especially for the Mesozoic era. This dearth in the paleontological record makes assessments on the origin and age of the group problematic and impedes investigations of evolutionary key aspects, such as wing development, sexual size dimorphism and plant mimicry.

Methodology/Principal Findings
A new fossil insect species, Cretophasmomima melanogramma Wang, Béthoux and Ren sp. nov., is described on the basis of one female and two male specimens recovered from the Yixian Formation (Early Cretaceous, ca. 126±4 mya; Inner Mongolia, NE China; known as ‘Jehol biota’). The occurrence of a female abdominal operculum and of a characteristic ‘shoulder pad’ in the forewing allows for the interpretation of a true stem-Phasmatodea. In contrast to the situation in extant forms, sexual size dimorphism is only weakly female-biased in this species. The peculiar wing coloration, viz. dark longitudinal veins, suggests that the leaf-shaped plant organ from the contemporaneous ‘gymnosperm’ Membranifolia admirabilis was used as model for crypsis.

Conclusions/Significance
As early as in the Early Cretaceous, some stem-Phasmatodea achieved effective leaf mimicry, although additional refinements characteristic of recent forms, such as curved fore femora, were still lacking. The diversification of small-sized arboreal insectivore birds and mammals might have triggered the acquisition of such primary defenses.

Wang M, Béthoux O, Bradler S, Jacques FMB, Cui Y, et al. (2014)
Under Cover at Pre-Angiosperm Times: A Cloaked Phasmatodean Insect from the Early Cretaceous Jehol Biota.
PLoS ONE 9(3): e91290. doi:10.1371/journal.pone.009129
Copyright: © 2014 Wang et al. Published under open access permission.

C. melanogramma being hunted amongst Membranifolia admirabilis foliage
Artists impression.

It seems very likely that these stick insects would have been the prey of the same early birds and mammals which are also found in the Jehol biota and evolved mimicry as a defence against them.

Of course, we can't know for sure if any of today's stick insects evolved directly from C. melanogramma but if they had they would carry genes that were once selected by the presence of early birds and late Ginkgophytes and they might well still have wings with dark straight veins having no apparent adaptive purpose today.

Evolution can't even look forward to tomorrow but it harks back to life on Earth hundreds of millions, even billions of years ago. We all carry the results inside us embedded in our genome, some of which was shaped by species and ecosystems of which we are not yet aware.

Dismissing this as magic, as creationist frauds and pseudo-scientists do, denies those who fall for their deceptions the pleasure of finding out how they were shaped by these forces and how they are connected to every other living thing through the process of genetic evolution by descent with modification from a common ancestor. It's like denying people the wonder of looking up into a night sky and being inspired by the awesome majesty of the cosmos.

It is denying people a heritage which is literally their birthright - the right to know who they are and where they came from.

'via Blog this'

---

Evolutionists Have Even More to Crow About

Great spotted cuckoo (Clamator glandarius)

Predation Favors Parasitism

The fascinating results of research into the relationship between a species of parasitic cuckoo, the great spotted cuckoo, Clamator glandarius, and one of it's host species, the carrion crow, Corvus corone corone, was published in Science this week and illustrates an interesting aspect of evolution - how competing evolutionary pressures can produce a dynamic equilibrium.

The study was carried out in northern Spain where 67.7% of carrion crow nests are parasitized by the great spotted cuckoo, which also parasitizes another member of the crow family, the magpie (Pica pica), which has a broadly similar geographical range to the carrion crow. Unlike the magpie, which will often evict alien eggs from it's nest and will mob great spotted cuckoos in the vicinity, carrion crows exhibit neither of these defence mechanisms. It is normally assumed, when this is found in other cases of avian parasitism that the species has only recently begun to be parasitized, so has not yet had time to evolve these defensive behaviors. However, it is also possible that there has been no evolutionary pressure to evolve defences because there may be a degree of mutualism in the relationship. In other words, the parasitized species might be deriving some benefit.

Abstract

Avian brood parasites lay eggs in the nests of other birds, which raise the unrelated chicks and typically suffer partial or complete loss of their own brood. However, carrion crows Corvus corone corone can benefit from parasitism by the great spotted cuckoo Clamator glandarius. Parasitized nests have lower rates of predation-induced failure due to production of a repellent secretion by cuckoo chicks, but among nests that are successful, those with cuckoo chicks fledge fewer crows. The outcome of these counterbalancing effects fluctuates between parasitism and mutualism each season, depending on the intensity of predation pressure.

Canestrari et al., From Parasitism to Mutualism: Unexpected Interactions Between a Cuckoo and Its Host;
Science, 343 (6177): 1350-1352; 21 March 2014:DOI: 10.1126/science.1249008

Carrion crow (Corvus corone corone)

Unlike many other avian parasites, great spotted cuckoo chicks do not evict host eggs and chicks from the nest but simply out-compete them in their demand for food from the adults. This often leads to reduced breeding success for the host species especially if food is scarce.

The difference in nest location and construction between carrion crows and magpies is also significant in explaining the different responses of these two species to cuckoo parasites. Carrion crows nest in the tops of tall trees and construct an open nest, making the brood prone to predation by predators such as falcons and buzzards. Magpies, however, build a nest in a thicker cover and construct a roof over it, making it harder for flying predators to take the chicks.

This difference in nest construction has created a different dynamic because it means the cuckoo chicks in carrion crow nests are also more liable to predation. This has produced evolutionary pressure for them to evolve a defence mechanism - they secrete a substance which repels predators. This in turn protects the host chicks in the same nest.

Magpie (Pica pica)

Magpies, which don't benefit much from the anti-predator strategy of the parasite chicks because their chicks are not so heavily predated, and therefore suffer much more from competition for resources with it, have had evolutionary pressure to evolve avoidance strategies.

Carrion crows, on the other hand, which can, in situations where predation is high, actually benefit from having a parasite chick in the nest, have had little evolutionary pressure to evolve avoidance strategies and might even be expected to evolve strategies to encourage it. However, given that predator numbers can fluctuate and there are years when predator numbers are low and so any potential benefit is not realised and loss due to competition can be the more significant effect, there may also be pressure acting in the reverse direction.

So, there is a dynamic of competing forces at work here which has probably reached an equilibrium at which the carrion crow does little or nothing to avoid parasitism because of the benefits it can get from it, but it has not evolved behaviours to encourage it because it also often suffers from it. Being dynamic of course means that it is relatively easy for a small change in one of the forces to push the dynamic in one direction or another, maybe over just a small part of the range, especially if the species involved is relatively sedentary.

And the evolution of the different strategies between magpies and carrion crows has its origins in the different nesting strategies adopted by the two species, which was itself probably produced by different responses to evolutionary pressures at some point in their evolutionary histories.

The historic forces which shaped evolution in the past may not even be present today so it can be difficult to see why something like different nesting behaviours in birds developed as related species diverged until we understand how natural selection operates. I'll be looking at this in my next blog.

As always, I'd love a creationist to come here to explain how this finding fits in with their currently fashionable 'intelligent design' notion. None have yet managed it with any other blogs on similar topics, but there is always hope that one will one day find the moral courage to defend their idea or to have the integrity to say they can't.

NB: Corvus corone corone is a three-part name to distinguish it from the Eastern subspecies, C. corone orientalis. The species formerly included the hooded crow, previously Corvus corone cornix. However, since 2002, these have been recognised as distinct species, C. corone and C. cornix respectively, and there is disagreement about the exact taxonomic status of C. corone orientalis. The reasons for this classification debate is interesting in itself and illustrates the problem of precise definition of the terms 'species' and 'subspecies' as an original species diverges and speciates, and may well be the subject of another blog here soon.

---

Tweet Link