Abstract

© Dr M D Magee
Contents Updated: Sunday, July 25, 1999

Arguments against Evolution

Christian apologists are fond of saying that evolution was just a theory, showing that they do not understand how people acquire knowledge. All knowledge is just theory. Even something as self evident as the rising of the sun every morning is a theory. Observations of it can be made daily and these are called facts but no amount of facts can predict what will happen tomorrow. The facts have to be linked by a theory. The theory we have is that the globe of the earth rotates once every twenty four hours and so every twenty four hours the sun rises as the place where we are on the globe rotates into sight of the sun. Is that just a theory to Christians?

Evolutionary theory is of the same kind. We all have genes that differ from person to person and species to species, but we know by observation that genes are passed from parents to children—half from each parent. The genes control the appearance and behaviour of the species, and through the perpetuation of certain genes and not others, appearance and behaviour can change with time. That is evolution. It is a theory to explain certain biological facts, just as the theory of the rising of the sun explains certain facts.

Many Christians do not like the theory of evolution because it gets rid of what for them is an important gap for God—the creation of species and people. They call evolution atheistic because it has no role for God, ignoring that most things are therefore atheistic because there is no role for God in them. Less bigotted varieties of Christianity accept evolution as the scientific explanation for biodiversity.

Some Christians try to refute evolution as an unfalsifiable tautology, apparently not realizing that their abstract idea of God is exactly that, but evolution is actually not.

1. What is seen around us must have had a creator, they say, and they call the creator God. They then tell us that Nature exists because it was created by God.
2. Or, they say the bible is God’s word, and proof of God is the bible.

The theory of evolution is a hypothesis based upon observation and tested against observation to verify or refute it. So far it has been overwhelmingly verified. The evidence for historical evolution—genetic, fossil, anatomical—is so overwhelming that there is no doubt about it.

Gaps in the Fossil Record

Christians are also fond of criticising evolution because there are gaps in the fossil record. They are so used to having everything on authority and therefore, to them, certain, that they cannot understand how real knowledge is acquired. In the case of the fossil record, the chances of any creature being fossilized is extremely low. Mostly animals are eaten by other animals, by maggots and worms or they decay by fungal and bacterial activity. The bones of small animals are also eaten or rot, and the bones of large animals are crushed by herds until they are mere sherds.

Fossilization is therefore rare and the most common fossils will be those of animals that lived in high populations and for a long time. Fundamentalist Christians ask, “Where are the transitional fossils?” But transitional species by definition do not exist for a long time and, being in transition, do not exist in large numbers. They are among the least likely species to be fossilized, and so the record looks like a series of jumps.

Despite the rarity of preservation and the likelihood that speciation occurs in small populations during geologically short periods of time, transitions at higher taxonomic levels are found. A good series of horse fossils have been acumulated and show a steady transition. All of the minor points of transition are not represented however, and that is precisely the absurd level that Christians argue at. Now, birds may be beginning to be another good example.

Bird Evolution

Evidence to shed light on the evolution of fight in birds is the discovery of a preserved “alula,” or bastard wing, in a 125 million year old bird from the Lower Cretaceous of Spain. The alula is functionally equivalent to the leading-edge flaps of an aeroplane, which allow flight at low speeds without stalling. The new find confirms that the wing mechanism that allows modern birds to fly and manoeuvre at low speeds must have evolved early in their history.

Consensus developed around 1980 that birds evolved from small carnivorous dinosaurs of the Jurassic, theropods similar to Velociraptor which ran along the ground and seized their prey with outstretched arms. A short jump—literally—from this stage was to the famous Archaeopteryx, which could flap, but not for long distances, and was not much of a glider. The grasping, predatory stroke of the small theropod dinosaurs was similar to the down-and-forward forelimb motion that propels birds in low-speed flight. These features, plus the ecological context of the theropods from which birds evolved, suggest bird ancestors were not arboreal, and do not support gliding as a stage to flapping flight. But the newest discoveries in avian evolution have helped to fill in the next stages.

Cyril Walker of the Natural History Museum in London gave a name to a collection of Cretaceous birds from Argentina which had strange shoulder girdles, warped foot bones, and a humerus with a large hole in it—little did he realize that these Enantiornithes (“opposite birds”) were soon to become the best known and most diverse group of birds in the Cretaceous world. Enantiornithes, in a variety of sizes, have been found on six continents and in a diversity of habitats, filling in a gap of some 50 million years (Myr) in the bird fossil record. Before their discovery, only a handful of remains were known between Archaeopteryx and two early Late Cretaceous birds known since 1880—the flightless, loon-like diver Hesperornis, and the smaller, tern-like Ichthyornis—neither of which said much about the evolution of flight.

A seventh specimen of Archacopteryx has a partial, rectangular sternum, long suspected but never previously noted. It attests to strong flight muscles, but a capacity for long flights remains questionable.

• Its shoulder joint may not have been angled as in later birds,
• it does not seem to have had the reverse-pulley mechanism of the supracoracoideus muscle, which raises the wing in flight,
• its hand and wrist bones were not yet fused.

So, even if it had the equipment and could perform the motions of flight, it was not locked into this function to the exclusion of others. It still retained the long tail, somewhat reduced and heavily plumed, of its dinosaurian ancestors, which probably helped to stabilize it in the air. However, its claws are as similar to those of ground birds as they are to those of climbing or perching birds, and it has no obvious arboreal adaptations.

If Archaeopteryx was a good runner with moderate flapping ability that could take off from level ground as well as from low heights, what happened next in the evolution of flight? Noguernornis, from the lowest Cretaceous of Spain, already has longer forearms and interlocking hand bones to facilitate flight.

Iberomesornis, which comes from the Las Hoyas deposit in Spain and is slightly younger than Noguernornis) has a strut-like coracoid clearly braced to the sternum, a tail reduced to series of free vertebrae and a pygostyle (the fused bony component of the “Parson’s nose”), and a foot with recurved claws an a fully descended hallux (first toe), which indicate its perching abilities. This is important, because, before the recent fossil bird discoveries, there was little convincing evidence that birds had arboreal habits much befor the Early Tertiary (60 Myr ago). Now they can be established at twice that age.

Enantiornithes share with later birds some more derived flight features. There is increased fusion in the hand and foot bones and in the hip, the free tail becomes shorter, and the sternum is deeper, with a more pronounced keel. The Las Hoyas bird shows an alula, a wing slot that breaks up boundary-layer turbulence so that the wing can function at the big angle of attack necessary for low-speed flight (and hence allow increased manoeuvrability). Archaeopteryx, though not a high-speed flier, lacked this, so it must have been less manoeuvrable or used some alternative strategy, such as running landings. Landing on a tree branch would have been much more difficult than it was for more derived birds.

The alula and other flight-related advances will have added to the success of the Enantiornithes, but they did not survive after the penultimate stage of the Cretaceous. By that time, all but the finishing touches on flight evolution seem to have been in place. Birds closer to our living forms, such as the Late Cretaceous Ichthyornis, had a shorter back and tail, more compact hip, and a deeper sternal keel. The flight-related characters of birds, particularly those of the forelimb, were modernized before the hindlimb and other features such as loss of teeth. This correlates with observations that in avian hindlimb evolution, knee flexion replaced hip extension as the primary kinematic mode. This in turn appears to be related to the reduction of the tail in theropod evolution, and the shift from its role as an anchor for the propulsive muscles of the hindlimb to the flight-related functions that it serves in birds.

So it seems that most avian flight advances were in place by the end of the Early Cretaceous, with fine-tuning through the remainder of the period. Ironically, like most technological pioneers, the bird groups that invented these features were victims of the success of their progeny, and were replaced by them before the end of the age of the dinosaurs.

Evolution in Birds

Speciation and Perfect Design

What of direct evidence for speciation? There are some excellent and curious examples that Christians would do better to study before they open their mouths. A species of gull breeds with other gulls all the way round the northern hemisphere, but where the gulls meet again, having bred all the way through 360 degrees of the earth’s longitudes and over thousands of miles, they do not interbreed. They are different species at the point where they meet again having developed sufficient differences for them to be distinguished and for them to distinguish each other.

Horses and donkeys are different species but can breed to form useful and healthy, but infertile offspring—mules and hinneys. Not too long ago back in time the mules and hinneys would not have been infertile and horses and donkeys would have been the same species even though they were obviously two different races of horse. Ernst Mayr adds the important fact that even when individuals of close species can interbreed, it is the species as a whole that is the entity of evolution. Such interbreeding might happen at species boundaries but cannot affect what happens to the bulk of individuals that make up the species.

Obsessed with the idea that they and their God are perfect, Christians claim that Creation is perfect, but that is far from the case, and if it were, evolution would be impossible. Evolution is the method whereby species change to optimise their characteristics in respect of the environment. If all species were perfectly adapted already, there could be no evolution. All changes would be suboptimal and would be selected against. Essentially that is what happens in the long periods of stability that species often experience.

As for individual features, there are many examples that any tenth grade kid would know very well, but Christians do not. An inflamed appendix can apparently be removed with no apparent harm to anyone, and tonsils and adenoids are similar. They might serve some function still but it is nothing that we cannot do without. These then seem pointless organs for a perfect designer to include in his design. A better example is that wonderful organ, the eye, which Christians cannot conceive as having evolved, but, which is an awful example of design because the eyes of octopuses are better than the creationists’ own eyes. The supposed designer has designed their eyes such that the nerves are in the way of the light reaching the receptors. Not too perfect for a perfect being.

I don’t wish to know that!

Thermodynamics and Randomness

“Well, it is impossible for the diversity of life to be a result of chance occurrence—evolution is impossible,” the Christian thumb suckers continue. They are simply not listening again. They really do not wish to know these things. Evolution is not simply random chance. Random mutations cause the changes in the genes that give lifeforms their characteristics, but their survival in that form depends upon whether they can indeed survive in the environment they are in. Certain unfortunate genetic illnesses give some people a very poor chance of living a full life. Huntingdon’s Chorea that afflicted the great folk song writer, Woody Guthrie, is one such. Again it proves the imperfection of creation, if that is what Christians insist on believing.

These illnesses survive because they are recessive. They do not always express themselves and so the selection pressure against them is smaller than it could be. Thus a small proportion of the faulty genes can survive. What is also not known, is whether these genes convey some positive advantage at the same time as they give a disadvantage—creativity perhaps. Sickle cell disease survives apparently because it conveys a resistance to malaria, a disease which has killed half the people who ever have lived.

Clever Christians say that evolution violates the second law of thermodynamics which says that disorder is tending towards a maximum. The point of the law is that it says “tends!” Local order is just as much a law of nature but local order is balanced by wider disorder. Order emerges from disorder all the time. The formation of a crystal from a melt or a solution is a simple example of order coming from disorder, but heat given back to the environment causes a wider disorder. Life is an example of the same sort of idea on a more complicated scale.

The point is that a local source of energy can promote local order, and life would scarcely be possible on earth without the energy of the sun. Ultimately, though, this energy is dissipated and the second law is vindicated. Indeed, the act of life, though it temporarily yields local order, leads to greater cosmic disorder. We call it pollution.

Some Christians spread a story that Darwin renounced evolution on his deathbed, thinking that it must therefore be invalidated because the founding authority rescinded it. Christians only know anything on authority, so their attitude is understandable, but it shows that they are dunces at science. A scientific theory stands or falls according to how well it is supported by the facts, not according to who believes it—even its proponent! In other words, even if Darwin had withdrawn the theory, it was already in the public domain and had been found to explain the biosphere extremely well, so could not be given up, according to scientific criteria. The criteria do not belong to anyone, so Darwin could not withdraw it. He could, if he wished, have tried to find evidence to refute his own theory. That is another matter. In any case the story is false.

Finally, Christians offer the numbers racket as an argument.

The odds against a simple cell coming into being without divine intervention are impossibly small.

This is the source of such fatuous arguments as the monkeys writing Shakespeare and the jumbo jet assembled by an explosion in an aircraft component factory. Living cells did not come into being through random processes like these silly examples, meant only to look what they are—absurd. Evolution goes right back to the molecular level. Molecules do not combine at random. Only certain combinations are possible. The shape and molecular characteristics of many possible combinations rule them out. They cannot combine at all, but those that can, do. And some reactions cannot occur without catalysts—chemicals that help the reaction to work. Sometimes reactions make catalysts that can therefore make a reaction happen that did not before. This is feedback.

A large molecule therefore does not have to be formed simply by a large number of atoms coming together in random combinations to make the molecule in one jump. The molecule is made up by smaller parts, that have already been made, combining. And so on. Having done so another stage becomes possible. Only the units that can be made by the possibilities of the molecules are made, and all other possibilities are automatically discounted. This cuts out millions of worthless combinations that the Christian insists on counting even though they ought to know there is no need to. Their immensely small probabilities are therefore nothing like as small as they imagine.

Are These Small Molecules Alive?

The team, led by Rebek, created a simple synthetic molecule that makes copies of itself—much the way DNA does—in 1990, and two years later the same chemists carried out experiments with two more self-replicating molecules. The molecules are an ester and an amine. When mixed in a chloroform solution, they form a molecule called an amide. Like DNA, the amide guides its own self-replication by serving as a template on which its components can assemble.

They can cooperate, catalysing each other’s formation, and, when one of the molecules is exposed to ultraviolet light and is mutated, it can take over the system. According to Rebek and his colleagues, this is evidence that evolution can be modelled at the molecular level (Science, vol 255, 848).

The reaction was between a complex imide ester (E) and an adenine derivative (A). These condense together to form a condensation product (A—E), eliminating a phenol. In a medium containing free A and E molecules, the condensation product attracts an E molecule to its A end, and an A molecule to its E end. It does this by forming hydrogen bonds, the same weak bonds which DNA uses to attract the components needed for its own replication.

The attracted A and E molecules are now held close enough together for them to react to form a new condensation product of the same kind, and the two completed molecules then separate. The replication process can go on repeating as long as there is a supply of A and E molecules. This is the basis of life, the food is the supply of single molecules E and A, and the molecular organism is the product A—E.

Molecular biologists such as Leslie E Orgel of the Salk Institute were critical, saying life involved more than just self-replication. The process must occasionally allow heritable mistakes, leading to more efficient replicators. Onlv then can natural selection and evolution—the true hallmarks of life—occur. Rebek went back to his laboratory and his team discovered a system that evolves, albeit only a little. Their new brew contains three amines, each of which joins with an ester to form a self-replicating amide. These three, slightly different amides replicate at roughly the same rate, but when irradiated with ultraviolet light, one amide mutates into a variant that reproduces much faster than the others.

Rebek and his colleagues experimented with adenine derivatives to which they attached slightly different side groups. They took the products A₁—E₁ of one set of modified molecules and added it to a reaction vessel containing a different set, A₂ and E₂. Unexpectedly, they found that the added A₁—E₁ catalysed the formation of its counterpart, A₂—E₂. Rebek says this cooperative self-replication is understandable because the added A₁—E₁ is similar to the A₂—E₂ being formed, and can also attract A₂ and E₂ molecules to itself by hydrogen bonding.

Rebek’s team then chose an A molecule with a side group which blocked its hydrogen bonding, causng the A—B product to form more slowly. They also found that this reaction was catalysed by other kinds of A—E. The blocked version of A could be changed to the unhindered version by ultraviolet light. This produced a mutant, which quickly took advantage of its greater reactivity to scavenge all the B and form its own A—E product at the expense of its “parent.”

This type of research could complement other, more traditional investigations into the origin and fundamental nature of life. Rebek envisions an even grander future for “extrabiology,” a term he has coined to describe the simulation of life in nonbiological systems.

Whether they involve synthetic molecules in vitro or computer constructs in silico, these studies are intended to extend, then subsume that which is currently considered molecular biology.

See: Julius Rebek Jr, Scientific American July 1994 34

Evolution, Gaia and Extinction

In evolution, species in competition with others win the right to existence because they have developed characteristics giving them an advantage. They can get the resources of life—oxygen, sunlight, water, food—better than their competitors.

Mass extinctions happen when something cuts down one or more of the necessary resources below a level needed to sustain the previous biomass. Competition for what remains available increases massively and not all species are able to survive the greater level of competition. Those that do, however, in James Lovelock’s “Gaia” hypothesis, adapt in such a way as to maximise the resources available and make a new increase in biodiversity possible through species finding out how to make use of the resources being formed.

Biodiversity is a mechanism that allows life to get the most out of the resources available. No species has any right to exist, even Homo sapiens, and destroying species will temporarily cut down on available resources, since many species provide the necessary resources of other species. Human beings have been pruning biodiversity for over a million years and the rate is now at dangerous levels. Humans are ravaging the geological world unearthing toxic chemicals that have long ago been locked up in relatively safe minerals, and we are unleashing new types of synthetic toxins into the world. We are polluting the land the air and the water of our world, and our leaders like G W Bush and Tony Blair could not care less, as long as they stay prosperous while they are alive.

We are visibly ushering in a new mass extinction, indeed we already have done. We simply do not yet know how big it will get before it ends. When it does, life will flourish once more, but Homo sapiens will not be part of it!

Migration of Birds

God is not only perverse with human beings, He is perverse with birds too. He has made them so that they have to fly for thousands of miles twice a year in the need to change their quarters from winter to summer and back. It is hard to work out why a good God should have had to devise such a system, but the slow movement of land masses in plate tectonics and evolution provide the basis for a rational explanation.

These birds have had to evolve the most remarkable methods of navigation, whereas the hypothesis of a Creator means that God has had to be first perverse, then give His ornithological creatures these navigation methods as an afterthought to get them to and from their destinations. The birds evidently navigate by sensing the magnetic field of the earth, but scientists, those wicked godless, have shown that the earth has periodic reversals in its magnetic field when the north magnetic pole becomes a south pole magnetically. God therefore had to devise a way round this too. Instead of using the polarity of north and south, God realised it would be no good to them and made them able to tell the declination of the magnetic field instead.

Besides that, though, they also use the position of the stars in the sky, just like sailors. That too offers a problem to the birds because the earth is precessing at a rate of one revolution every 26,000 years making the position of the stars in the sky change relative to the point above the earth’s axis. Creationists who believe the earth was made only 6000 years ago, contrary to all the evidence we have, will not be troubled by this, imagining that God’s feathered victims would adjust to a relatively small change in the appearance of the sky. But birds have certainly been migrating for millions of years, their migration widening as continents drifted apart, and they must have a way of adjusting to the constant pulsations of the celestial axis. Scientists have shown that birds actually learn the position of the celestial axis relative to the rest of the stars. Birds are confused by meaningless star patterns in planetaria, but immediately orient themselves when the pattern is allowed to rotate about a celestial north pole.

All of this undoubtedly is peverse for a God to create, but is not too hard to understand when species have to adapt to the practical circumstances they find themselves in.

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