Personal Updates: My new job

A collection of insects, sorted by Order

Good and bad news

Hi everyone! I have some great news to share. I just started my new career at NIE (National Institute of Education) at Singapore. In other words, I attending a school that trains teachers.

I am delighted to have started, as this grants me a respite from academia, which I longed to have.

That said, my timetable looks pretty packed. As a result, the frequency of posts on this blog will drop. Nevertheless, this blog will still be running, and I will try to post some interesting articles. In fact, I am working on an interesting article on the age of the Earth coming in Feburary.

As for you my readers, have a good life, and always remember, God loves you.

God bless,

defensedefumer

Pop!ular: Thomas Aquinas

Thomas Aquinas

The smartest man in Europe

If you studied Western Thought or Western Philosophy and you failed to hear of Thomas Aquinas, you have either just started, or enrolled in the wrong school. This Italian theologian lived for 49 years (1225-1274), but his contributions to the Western world cannot be understated. If reputation means anything to you, he is considered one of the “Doctors” of the Roman Catholic Church, and is also known as Doctor Angelicus amd Doctor Universalis. His primary work, Summa Theologica is highly regarded among the Roman Catholic Church, and was consulted along side the Bible during the Council of Trent in 1567 (Hannam, 2011).

Why is he here? Isn’t he just a theologian?

In Sociobiology: The New Synthesis (Wilson, 1975),  Harvard biologist E.O Wilson argued that human nature could be understood in evolutionary terms. Yet 700 years ago, this theologian was applying many aspects of evolutionary theory to the understanding of human beings.

In Summa Theologica, Aqunias classified humans as animals in material, something medieval scholars were reluctant to do. Yet he was no materialists, arguing that the conscience was what separated man from beast.

However, what was really evolution-like was in his lesser known work, Summa Contra Gentiles. For instance in his observationof dogs, he noted that “the male and female stay no time together after the performance of the sexual act”. In birds, he noted the contrary, that “male and female dwell together after the sexual act so long as is necessary for the rearing and training of the offspring”.

The reasoning he gave was that the more helpless the offspring at birth, the more likely the parents would stay together. Many evolutionists would recognise this reasoning to be similar to parental investment theory, where male-female pair bonding are most likely to emerge when offsrping are highly dependant.

In addition, he alludes to another evolutionary concept– parental certainity. He argued males have to stay closey to their offspring to protect them, and ensure his legacy. In the same way, evolutionists would state that mongamy benefits males in allowing them to ensure their genetic legacy.

But didn’t he make mistakes too?

Of course he did. Following Aristole, he accepted spontaneous generation (that living organisms arose from non-living things) and insisted that species were unchangeable. He was no evolutionist (considering that the theory only emerged in 1859), yet the ideas he had were revolutionary.

References

Hannam, J. (2011) God’s Philosophers

Wilson, E.O. (1975) Sociobiology: The New Synthesis

Huh what?: How does religion guide science?

Westminster Abbey, August 2011

Wait a minute– what about NOMA?

In his book Rock of Ages, Stephen Jay Gould (1999) argued for the concept of non-overlapping magisteria (NOMA), that science and religion covers different fields of study, and to force one discipline over the other would diminish both. However, there are certain aspects of science that cannot be answered by science alone.

Before I get into some detail, let me define what I mean by science, and what I mean by religion.

Science, in this case, involves explaining natural occurrences by naturalistic methods. Such methods ideally should be falsifiable, repeatable and reliable.

Religion on the other hand, seeks truth by revelation, and explanation of the world by that revelation.

Do note that the although philosophers do debate about the distinction, I will be using the above definitions for this post.

There some areas where they do overlap, but I will use biological and medical ethics as an example.

“Or to put it more simply, science will tell me that if I put cyanide in my grandmother’s tea, it will give her a pretty rough day. But science cannot tell me whether I should do it or not to get my hands on her property.” — John Lennox (2007)

It is not always easy to apply science. As the quote from John Lennox suggests, science is silent on the issues of morality and ethics. Now we may just say we should do the most good for the most people when it comes to medicine, but it isn’t always clear-cut, as I will list some case studies from Wyatt (2009). Please note that ALL these cases are real, and not made up.

Case Study 1: Persistent Vegetative State (PVS)

In 1989, eighteen year-old Liverpool fan Tony Bland was a victim in the Hillsborough disaster. His body had been crushed against the metal perimeter, leading to severe oxygen deprivation. Although Bland survived, he was in a coma state known as PVS. His basic bodily functions were still working– he could still digest food and breathe. The lower part of his brain (the brain stem) was still working. However, his cerebral cortex (the part of the brain essential for conscious activity) was damaged. His life was maintained by an artificial pump that inserted liquid food into his stomach.

After three years of treatment, Bland still showed no signs of recovery. His devoted parents and doctor petitioned to cease life support for Tony. This led to a debate in the House of Lords (one part of the British parliament), and it was decided that Bland was not consciously aware of his surroundings and the continuation of his treatment brought no “therapeutic, medical or other benefit”.  Artificial feeding was withdrawn, and Bland died a few days later.

While some applauded this decision as a common sensical solution, others raised the issue that the British Courts had stopped respecting the traditional principle of the sanctity of human life. For the first time, the courts had knowingly sentenced an innocent man to death.

Case Study 2: The right to refuse treatment

In 1999, Mrs. B suffered a haemorrhage to her spinal cord. She made a ‘living will’ that treatment should be withdrawn is she became severely disabled. However, her health improved, and the 41-year old returned to work.

In 2001, B suffered from progressive weakness, and soon became paralysed from the neck down. She soon became dependant on a mechanical ventilator to breathe. Despite repeatedly asking the doctors to cease treatment, she was refused. The medical staff insisted it was their professional duty to prolong her life.

This case was brought to the British High Court, where the presiding judge, Dame Elizabeth Bulter-Sloss deemed Mrs. B mentally sound enough to decide her fate. Mrs. B was then transferred to another hospital where treatment was withdrawn.

This case was seen as a landmark in English law– the judge had allowed a competent patient the right to refuse life-sustaining treatment. Did this judgement legalise euthanasia in England? Were the doctors who switched off her life support murderers?

Case Study 3: The keeping of conjoint twins

In 2000, Rina Attard gave birth to twins (Mary and Jodie) in a hospital in Manchester. Mary’s condition was poor and her well-being was supported by the shared aorta. The doctors concluded if the twins were separated, Jodie would live, but Mary would die. If they were left conjoint, both twins would weaken and die.

The parents refused to allow the doctors to separate the twins, refusing to ‘play God’ according to their Roman Catholic beliefs. The parents could not bring themselves to kill Mary to save Jodie. In the end, the courts decided to overwrite the parents’ choices and asked the doctors perform the separation.

Did the courts have a right to overrule the sincere convictions of the parents? Did Jodie’s right to life trump Mary’s? Were the doctors ‘playing God’?

Ahhh! They are not easy questions to answer, what do you recommend?

As expressed, any well-meaning answer is controversial. Yet they cannot be avoided. I will list some principles that some ethicists abide by, and as a further note, I will write on how Christians may think about such issues (I will write on only Christianity as I am most familiar with it among all religions).

View 1: The ‘four principles’ approach

Regarded highly among ethicists, Beauchamp’s and Childless’s (2008) Principles of Biomedical Ethics is often cited as the Bible for bioethics. Beauchamp and Childless (2008) argue that in order to have an ethical system in modern societies, we must find the lowest common denominator values (or ‘common morality’) that everyone can agree on. Arguing that we can infer a common set of values in today’s pluralistic age, the duo reduced this common morality to four fundamental principles:

1) Respect a person’s desire for autonomy (principle of individual freedom)

2) Inflict no harm on others (principle of non-maleficence)

3) Act in best interests of others (principle of beneficence)

4) Ensure healthcare is distributed in a fair and equitable way (principle of justice)

Although it may seem perfect and uncontroversial, there are limitations to this approach. For instance, take the case of abortion of a fetus with Down’s Syndrome. For the principle of individual freedom, whose autonomy should we respect? The doctor’s, the mother’s or the fetus’s? Does the fetus’s right to autonomy make any sense? What about the fetus’s future right to autonomy?

The principle of non-maleficene seems to be violated here as the fetus is clearly killed. Some ethicists would argue that allowing one to live a disabled life is a greater evil than having no life. Thus, the best thing would be to allow the fetus to die as quickly and painless as possible.

Finally, what does the principle of justice say about this (Brock and Wyatt, 2006)? In the interest of fairness, should we offer abortion to mothers carrying fetuses with Down’s Syndrome? What about people in our society who already have Down’s Syndrome? Would it be fair to discriminate against them?

View 2: Liberal Individualism

The difficulty in finding a moral consensus has led some philosophers and ethicists to be more radical. One such person is Richard Dworkins (1995), who argued that “Freedom is the cardinal, absolute requirement of self-respect”. In other words, to Dworkins, liberty involves the right to define one’s own existence.

Being a constitutional lawyer, Dworkins appeals to two fundamental concepts of liberal societies. Firstly, the importance of religious tolerance. Dworkins argued that the ethical questions, especially those involving life and death are essentially religious questions (even if one is atheist). He suggested that the atheist might have a set of principles in the place of an “orthodox belief in God”. As such beliefs about ethical questions are down to individual conscience, we should respect and tolerate everyone’s autonomy in this area.

Secondly, he appeals to the constitutional right of privacy. He draws a distinction between the private and public sphere of life. While the state should govern the public arena of human behaviour, the issues of private morality should be withdrawn.

In other words, Dworkins (1995) has reduced the 4 principle-approach by Beauchamp and Childress (2008) to one basic principle– respect everyone’s desire for autonomy, with all its implications. However, many ethicists have argued that this philosophy would lead to a sense of alienation and isolation so prevalent in Western society today (Wyatt, 2010). Such a liberal society would consist of egocentric individuals reconstructing their own values and goals. Although sounding poetically utopian, it portraying that human dependence as dehumanising as it threatens autonomy. In other words, to be seriously ill is to be less human as your lifestyle depends on others.

View 3: The five commandments

The field of bioethics also provides opportunities to challenge the orthodoxy. The controversial Peter Singer (1995) is one of the most enthusiastic activist in his philosophy of bioethics. Insisting that the era of Judeo-Christian dominance has ended, he suggested we must abandon the idea of the sacredness of  human life in order to operate in today’s world.

First, he argues that the worth of human life varies from person to person. In his view, people suffering from dementia and long-term coma are obviously of no value to anyone. A disabled child is far less valuable than an able-bodied one. In other words, a value of a human being is determined on his/her potential contribution to society. People without a fully functional cerebral cortex (including fetuses) are deemed to be less than human.

Second, Singer adds that traditional prohibition of taking an innocent life should be replaced with an acceptance for mercy killing (a.k.a. euthanasia). He argues that it is the responsibility of society to end lives that are ‘not worth living’.It may lead to a colder and less cohesive world, but he accepts it as a price to pay for a modern society.

Third, he advocates for the individual’s desire to live or die. He argues that to kill a fully functioning human being against his/her will is a worse crime than to end a disabled person’s life. However, if the fully functional person wants to die, we should oblige him as painlessly as we can.

Fourth, he argues that children should only be brought forth into the world if wanted (Singer and Kuhse, 1985). He is in favour of contraception and abortion in an overpopulated world, but goes one step further– Singer recommends medical infanticide for deformed and unhealthy fetuses. In Singer’s view, it is more irresponsible to waste medical resources on such infants in a crowded earth.

Fifth, we should not discriminate based on species. Singer states that society should not discriminate based on attributes that lacked moral significance. By his definition, he argued against sexism, ageism and racism. He extents this reasoning to the species level, stating that rats and dogs are more self-aware than fetuses, and should be regarded as more valuable. Although sounding fair, ethicists have pointed out that Singer is discriminating against individuals with less functional cerebral cortexes, and Singer is not as just as he puts himself out to be (Wyatt, 2009).

View 4: Human Enhancement

The last, secular view I want to cover is Professor John Harris’s (2008). Acknowledging that human beings are an accident of evolution, he advocates the use of technology to direct and enhance our capabilities however we choose. He also extends the argument to that it would be a moral duty to enhance children in order to stay competitive in future world. Not enhancing our offering would be the moral equivalent of making our kids disabled. The only legitimate argument against enhancement  is that if it is shown such enhancement would be presently harmful to others (rather than the harm being future and speculative).

This sounds very abstract….

Yes it does. It may sound like complete ivory-tower nonsense that eggheads academics are paid to produce. However, these views are very real, and these views are not only sought after by philosophers and doctors, but also politicians and technologists.

What are some guidelines to think about for the Christian?

Now that I have briefly covered the popular secular views, let’s go on to the religion I am the most familiar with– Christianity. One may ask, what can the Bible, which was written in a pre-scientific and dominantly agricultural age, say about modern ethical issues? However, historical, trinitarian Christianity can only retain its significance by staying close to Scripture. A Christian cannot pretend the Bible says nothing about contemporary about ethical issues, but he/she cannot interepret the Biblical message to make it more platable to today’s ears.

Let’s get one thing clear first– the Bible is NOT a set of moral rules, telling Christians what they should do it a series of quotations. What the Bible reveals is a comprehensive view of the history of the world, and it’s future. For an summary, I will follow Wyatt’s (2009) view on how Christians should view ethical issues. Wyatt (2009) suggested four issues that Christians should think about:

1) Creation

Human beings are made in the “image of God” (Gensis 1:27). This not only affirms sanctity and equality of human life, it also implies that humans were made to be relational. In other words, humans are a reflection of another reality– being an image means that humans are radically dependent. While liberial individualism oftens sees dependence as a handicapp, the Biblical view recognises dependence as a part of being human.

2) Fall

Although made in God’s image, humanity is doomed to suffering, decay and death due to original sin (Genesis 3: 14- 19). Christian health professionals have to recognise that all humans will die despite our best medical efforts. At the same time, death is not just to be seen as a consequnce of original sin, but as a “severe mercy” (Lewis, 1964) to prevent humaity from being trapped in a decaying body.

3) Redemption

Yet God provides a promise of redemption for mankind (Genesis 3:15). God encourages care for the widowed, orphaned and needy (eg: Deuteronomy 10:17-19; Jeremiah 22:16). He came into the world via Jesus Christ as a baby, supporting the idea of dependence. In Christ, the sick were healed. But he also went deeper– he healed  spiritual sickness too. In Christian theology, Jesus also took the sins of mankind and died for them.

This not only challenges the notion that  the sole goal of  medical science of extending human life, but it encourages to care for their emotional and spiritual needs, and sympathy.

4) Future consummation

But the death and resurrection of Jesus Christ is not the end of the story. Humanity is promised a new heaven and a new earth, and will inherit new bodies (Revelations 21:1). Humanity will not lose its dependence, but will be restored to the likeness it was intended to bear. This portrays (if I am allowed to use analogies) humanity as a flawed, artisitc masterpiece that will eventually be restored to show the original image.

For the Christians…

In the light of these statements, Christian medical professions have to wonder what their theology informs them on such issues. For instance, should they reject transhumanism to improve the human condition, in the same way an art restorers do not “improve” a masterpiece, but only restores it?

Conclusion

These questions, although tough and controversial, are extremely important to answer. As shown from the above secular and religious grounds, these questions rely on non-scientific methods to guide scientific actions.

References

Beauchamp, T.L., Childless, J.F. (2008) Principles of Biomedical Ethics (6th edition)

Brock, B., Wyatt,. J. (2006) Studies in Christian Ethics. 19, 153-168

Dworkin, R. (1995) Life’s Dominion

Gould, S.J. (1999) Rock of Ages

Harris, J. (2008) Enhancing Evolution

Lennox, J. (2007) God’s Undertaker: Has Science buried God?

Lewis, C.S. (1964) Mere Christianity

Singer, P., Kuhse, H. (1985) Should The Baby Live?

Singer, P. (1995) Rethinking Life and Death

Wyatt, J. (2009) Matters of Life & Death (2nd edition)

The Confession: What type of Christian and scientist I am

A Crucifix

Recently, I have been questioned about my attitudes towards religion and science. So this is a post to clear some doubts, lest I am accused of misleading my readers.

Am I a liberal or conservative Christian?

You know, I find it hard to understand labels like this– while classifications may aid us to understand a subject, they do not totally account for the whole object itself. So let’s use me for an example, I consider myself as an Evangelical Christian, even though most Evangelical Christians reject evolutionary theory. I consider myself an orthdox Christian, although not Eastern Orthodox. I consider myself conservative, but that does not mean I am politcally Conservative.

At times, describing what type of Christian I am is very difficult. I’m Methodist by tradition, but Zwinglian when it comes to the Holy Communion. I’m Lutheran when it comes to salvation, but Calvinist when it comes to Apostolic Succession. Is your mind boogled yet?

But the safest description is this– I love Jesus.

What type of scientist am I?

I’m a biologist with a particular interest towards evolutionary theory, botany, ants and genetics. With regard to the philsophy of science, I tend to adopt this definition– science is the explanation of natural observances by natural mechanisms. It does not study supernatural occurances nor causes, simply because it is not intended to.

However, I accept that this definition is tentative at best, and no set consensus of the definition of science has been set (Ruse, 2001). If I do reject anything that is remotely related to science, I reject “scientism”, the belief that only science is the only authority that can discover truth. This not only does injustice to other disciplines such literature, philosophy and history, but itself is self-refuting (i.e. “scientism” cannot be tested scientifically) (Ward, 2006).

My attitude towards science and Christianity

One of the advantages of being Christian, is that my faith in Jesus allows me to ask questions, even difficult and uncomfortables ones. After all Jesus was the one who said He was the Truth (John 14:6), thus Christians should not be afraid to follow the Truth, whereever it may lead them.

In fact, the philosophy of science arose out of Christianity (Hannam, 2011) in medieval Europe. To put it simply, belief in a rational God allowed belief in a rational universe that can be studied.

Lastly, I would like to say that I think it is fascinating on how my faith in Jesus is both informed by theology and science. In fact, the English poet GK Chesterton (1908) described understanding via different disciplines as being able to see with two eyes– as the views of one eye seemingly contradict the other, seeing via both eyes enhances our view of the world. I am still being humbled but how much I do not understand God and his ways.

Conclusions

As one of my friends once said, “Even as a Christian, the questions don’t stop coming. We shouldn’t stop asking them, even if the answers may seem unsatisfactory. But Jesus is always there.”

References

Chesterton, G.K. (1908) Orthodoxy

Hannam, J. (2011) God’s Philosophers

Ruse, M. (2001) Can A Darwinian Be A Christian?

Ward, K. (2006) Is Religion Dangerous?

That can’t be true: Is evolution just pure chance?

A game of Texas Hold'em

“Replay the tape a million times … and I doubt that anything like Homo sapiens would ever evolve again”– Stephen Jay Gould

One of the greatest evolution biologists, Stephen Jay Gould (1989) eloquently argued that evolution has no inherent direction. In other words, he adovocated the view that humanity (or any organism) is a cosmic accident, in his words, a “tiny twig on an improbable branch of a contingent limb on a fortunate tree”.

And it does seem so. After all, did mammals not displace millions of years of dinosaur dominance through a lucky meteor strike? Didn’t human beings emerge form ape-like ancestors by chance mutations?

Gould (1980) took his interpretation to fire an intellecutual shot at theists (people who believe in a God who is actively involved in the world), stating that a “sensible God” would not have used such a “odd” and “funny” process to create life.* Life evolved randomly, constrained by historical events, according to Gould.

Is evolution purely chance?

However, it has been suggested that Gould might overstated the chance aspect of evolution. Recent studies have shown that evolution is really more constrained (or more directed) than it really is.

Convergence

Morris (2003) has documented numerous examples of unrelated lineages acquiring similar biological traits. This phenonomen is known as convergent evolution. For instance consider the trait “bipedalism” (the ability to walk upright on two limbs). This ability is found in humans, kangaroos, birds and even dinosaurs, although all of them are distanly related (humans are more related to mice than kangaroos). Convergent evolution can even be seen in plants. Consider the two desert plant genera Euphorbia and Astrophytum. Although being distantly related, theyshare similar body plans.

What this suggests (with respect to Gould’s view) is that there appears to be a limited number of evolutionary solutions to remedy adaptive problems posed by earth’s ecosystems. In short, evolution seems to rely similar design features to fashion adaptive traits.

Epigenetics

Yet another field challenging the randomness of genetic inheritance is epigenetics. Epigenetics is the study of hertiable changes in gene expression due to mechanisms other than changes in DNA sequences. This field is challenging the traditional evolutionary ideas as it implies that environmental effects on the genes of parents can be passed down to the offspring (Francis, 2011).

One example common cited for this was seen in the offspring of the survivors of the Dutch Famine of 1944. Pregnant women who experienced the famine gave birth to children who were more vulnerable to diabetes, obesity and a number of health problems. In addition to that, it was shown that these health problems appeared to be inherited as the survivors’ offspring also had children who suffered the same diseases (Painter et al., 2009)

Conclusion

Although evolution is often portrayed as relying on purely chance events, recent studies have shown that evolution is more constrained that commonly understood. Of course none of what I have discussed showed that humanity was an inevitability– but it does show that the odds of a rational, self-aware being emerging on this earth is much higher than once entertained. This is food for thought for both the atheist, and the theist.

References

Francis, R.C. (2011) Epigenetics: The Ultimate Mystery of Inhertiance

Gould S.J. (1990) The Panda’s Thumb

Gould, S.J. (1989) A Wonderful Life

Hannam, J. (2011) God’s Philosophers

Morris, S.C. (2003) Life’s Solution

Painter, R.C., Osman, C., Gluckman, P., Hanson, M., Phillips, D.I.W., Rosebloom, T.J. (2008) Transgenerational effects of prenatal exposure to the Dutch famine on neonatal adiposity and health in later life. BJOG 115, 1243-1249.

*A short note on theology

Theologians have rarely argued that the existance of chance was a argument against or for God. In fact, they generally agreed human history was filled with chance events; evolution merely extended this theme (Hannam, 2011)

That can’t be true: The vertebrate complement system is irreducibly complex!

An example of a signalling cascade

A common theme in molecular biology is the idea of genetic cascades. Such cascades describe a system of genetic interactions, in which one gene activates another, which triggers another, and so on and so forth. A major claim from the intelliegent design community is that genetic cascades are irreducibly complex as all participating genes and biochemical molecules have to be present or the cascade cannot function. Evolution by natural selection would be unable to achieve such a cascade as it can only create complexity via functional intermediates.

Wait, what does irreducibly complex mean?

According to Behe (1996), a irreducible complex system “is composed of several interacting parts that contribute to the basic function, and where the removal of any one of the parts causes the system to effectively cease functioning. An irreducibly complex system cannot be produced gradually by slight, successive modifications of a precursor system, since any precursor to an irreducibly complex system is by definition nonfunctional.”

Extending this argument to cascades, Behe (1996) argues that “because of the nature of a cascade, a new protein would immediately have to be regulated. From the beginning, a new step in the cascade would require both a proenzyme and also an activating enzyme to switch on the proenzyme at the correct time and place. ” In other words, each step of the cascade requires several participants to be present to function, and thus making the whole cascade irreducibly complex.

He uses two examples genetic cascades which he considers to be irreducibly complex, namely the blood clotting cascade, and the complement system.

For this post, I will be focusing on the claim that the complement system is irreducibly complex.

What is the complement system?

The complement system is part of the immune system, which helps organism clear pathogens within it. Involving many small proteins (mostly synthesised by the liver), the complement systems aids antibodies and phagocytes (cells that engulf and therefore ridding of pathogens) in elimination foreign agents in the body (Janeway et al., 2001).

Immunologists have often described the vertebrate complement system as acting acting in three pathways– the Lectin Pathway, Alternative Pathway and the Classical Pathway (See Figure 1).

The Three Pathways of the Complement System

Figure 1: The three pathways of the Vertebrate Complement System. Note that the letters (eg: B, C3, MBP) represent different proteins. Additional letters behind the proteins indicate a cleavage product (eg: C3a and C3b is formed from the breakdown of the C3 protein).

As shown from Figure 1, each of the three pathways require an enzyme, C3 convertase, to function*. In other words, the C3 convertase is required to activate the complement proteins. For the lectin and classical pathways, C2b functions as the C3 convertase; for the alternative, the proteins complex consisting of C3b and D acts as the C3 convertase.

Why does Behe (1996) say that is system is irreducibly complex?

On the surface, the complement system seems to be irreducibly complex because

a) all the precusor proteins (ie C3, B, D, MBP, MASP1, MASP2, C2 and C1) require C3 convertase to function

b) C3 convertase has no function beyond activating the precursor proteins.

Hence, since these two components (precursor proteins and C3 convertase) are required at the same time to assemble a functional system, the vertebrate complement system would be irreducibly complex.

In addition to that, humans who lacked C3 convertase are more prone to infections from Haemophilus influenzae and Streptococcus pneumonae. So it appears that Behe (1996) is right.

But….

What Behe (1996) failed to realise is that (i) invertebrates have a complement system that lacked some precursors and (ii) there are vertebrates with intermediates of the complement system, suggesting a possible evolutionary pathway.

i) The complement system of invertebrates

In the study of the Japansese sea squirts ( Halocynthia roretzi), Ji et al. (1997) found that the sea squirts have only the lectin pathway, suggesting that the lectin pathway is evolutionarily the oldest pathway among the three of the complement system. Another interesting thing find is that the sea squirts do not produce the C2 protein, and therefore cannot not produce the vertebrate C3 convertase. However, the complement system functions just fine.

Remember Behe’s (1996) definition of irreducible complexity– if “one or more parts” of the irreducible complex system is removed, the system would be non-functional. However, the invertebrate complementary system lacks several parts of the vertebrate one, and it works just fine.

ii) Possible evolutionary pathway

For the sea squirts, it appears that that the MASP itself acts as the C3 convertase (Ji et al., 1997). Mammalian MASP can also act as C3 convertase, although it is not efficient. In other words, it is not hard to hypothesise that some wat along the evolutionary tape, the protein C2 (and thus C2b) took over MASP’s role as C3 convertase, diminishing’s the MASP’s role as one.

The adoption of C2b as C3 convertase is hypothesised to not only allow the retention of the lytic pathway, but also allowed the formation of the classical pathway. This hypothesis is further strengthened by the fact that the proteins involved in the invertebrate and vertebrate systems are homologous (ie loosely speaking, highly similar), so this complexity of the vertebrate complement system could have arisen via gene duplication (Zarkadis et al., 2001).

Conclusion

Since the complement system has been shown to function in other organisms despite lacking some components of the vertebrate complement system, the vertebrate complement system is shown to be NOT irreducibly complex.

References

Behe, M.H. (1996) Darwin’s Black Box

Janeway Jr., C.A., Travers, P., Walport, M., Shlomchick, M., J. (2001) Immunobiology (5th edition)

Ji, X., Azumi, K., Sasaki, M., Nonaka, M. (1997) Ancient origin of the complement lectin pathway revealed by molecular cloning of mannan binding protein-associated serine protease from a urochordate, the Japanese ascidian, Halocynthia roretzi. PNAS USA 94, 6340-6345

Zarkadis, I.K., Mastellos, D., Lambris, J.D. (2001) Phylogenetic aspects of the complement system. Developmental and Comparative Immunology 25, 745-762

*Please note that C4 is cleaved into C4a+ by MASP or C1, rather than C3 convertase.

That can’t be true: Blood in a dinosaur bone proves that the earth is young!

Fossil of an ammonite

More than 10 years ago, Schweitzer et al. (1997) discovered evidence of red blood cells in an unfossilised Tyrannosarus rex (T.rex) bone. This seems to show that T.Rex died recently instead of millions of years ago as commonly accepted as

a) the blood proteins would have broken down

b) the bones found should have been fossilised.

To add more drama, Schweiter et al. (2005) identified found remains of what appears to be soft tissue (blood vessels) in the femur of the T.rex. And of course the young-earth creationists had a field day (eg: AIG).

But wait…

Firstly, let’s get few things clear first. The age of the fossil is dated as millions years ago (via the amino racemization dating technique), so there’s no controversy there.

Secondly, the bone that Schweiter was not unfossilised, but rather not completely fossilised. More specifically, Schweiter had defined being fossilised as permineralisation (a process which open parts of the bones are filled with minerals). Permineralisation had occured, although not throughout the whole bone.

What about the soft tissues?

Although often touted as red blood cells, the oragnic structures found are not red blood cells– they are remanents of red blood cells (probably haem) (Schweiter et al., 2005). Furthermore, the structures found are not soft tissues, as touted, but give that appearance (Figure 1).

Blood vessels obtained from a T.Rex

Figure 1: Blood vessels, or their look-alikes recovered from a cortical bone from a T.rex from Montana, USA (Schweitzer, 2010).

That said, in recent years Schweitzer et al. (2005) has recovered bone cells (called osteocytes) from another T.rex. In addition to that, they (Schweitzer et al., 2009) not only managed to recover osteocytes from the Duckbill dinosaur (Brachylophosaurus canadensis), but they also managed to show this at the molecular level (via antibody reactions). So soft tissue might be long-lasting after all.

Conclusion

Just because soft tissue or cellular sturctures are obtained from partially fossilised material, it does not automatically mean that the fossil was recent. There are many independant methods for dating fossils.

If anything, the soft tissues recovered do challenge the current paradigm that they cannot be preserved over millions of years. These discoveries will shed light how how little we know about the biochemistry of extinct animals (Schweitzer, 2010).

References

Schweitzer, M. H., Marshall, M., Carron K., Bohle, D., Busse, S.C., Arnold, E.V., Barnard, D., Horner, J.R., and Starkey, J.R. (1997). Heme compounds in dinosaur trabecular bone. Proceedings of the National Academy of Science USA 94, 6291-6296

Schweitzer, M.H., Wittmeyer, J.L., Horner, J.R., Toporski, J.K. (2005) Soft-Tissue Vessels and Cellular Preservation in Tyrannosaurus rex. Science 307, 1952-1955

Schweitzer, M.H., Zheng, W., Organ, C.L., Avci, R., Suo, Z., Freimark, L.M., LeBleau, V.S., Duncan, M.B., Vander Heiden, M.G., Neveu, J.M., Lane, W.S., Cottrell, J.S., Horner, J.R., Cantley, L.C., Kalluri, R., Asara, J.M. (2009) Biomolecular Characterization and Protein Sequences of the Campanian Hadrosaur B. canadensis. Science 324, 626-631.

Schweitzer, M.H. (2010) Blood from Stone. Scientific American 303, 62-69.