Feature Article - October 2012
by Do-While Jones

How to Teach Evolution

Here’s how we would teach evolution.

Occasionally people accuse us of not wanting evolution taught in schools. (They even falsely accuse us of not wanting “science” taught in public schools.) The truth is that we do want evolution taught in schools—but we want it taught properly. Perhaps we are at fault for not being clear enough about the proper way to teach evolution. So, here is an outline of what we think a proper course on evolution would include. Of course, we don’t have space in our “six-page newsletter” (eight pages this month) to go into detail; but here are the main points.

The Scientific Method

It should go without saying that science is knowledge obtained through the scientific method. Unfortunately, it often does go without saying, so students never hear it. They get the false notion that “science” is anything a “scientist” believes (where “scientist” is defined to be “atheist”). Students should be taught about hypotheses, theories, and experiments to give them a proper science background before even talking about evolution. If they really understood the scientific method, they would know the difference between science and opinion.

Variation

Darwin correctly observed that there are variations among individuals of a particular species. Students should be shown this in some age-appropriate manner. In elementary school, this might be done by asking students to bring their pet dogs or cats in to class. The dogs could be weighed, and the height to their shoulders could be measured, length of hair could be measured, the color of their fur could be recorded, et cetera. In high school, it would be more appropriate to use current sports statistics to compare athletic ability. In college, we would use zoological data to establish the fact that individuals of a species vary.

There is an opportunity here for some cross-disciplinary education by introducing young children to the concept of “average.” Older students could be shown the application of Gaussian distributions, means, standard deviations, and correlations. This would help to answer the perennial question, “Why do I need to learn math?”

The point is that, in some age-appropriate manner, the students need to recognize that variation among individuals exists.

In all the subsequent sections, the concepts should be taught in some age-appropriate way; but we usually won’t illustrate the different ways the topic can be taught to different age groups.

Limits

Students should be taught that there are limits to variation. Human skin color varies from white to black through all shades of brown, but nobody has green or purple skin. There is a limit to how fast a race horse can run. 1 There is a limit to how much milk a cow can produce per day, et cetera.

Darwin mistakenly believed that there is no limit to the variation in species. He thought small variations could gradually accumulate over time to result in such a large difference that new biological categories would evolve.

Extrapolation

Students should be told that there are limits to extrapolation. Extrapolation is the process by which observations over a limited range can be extended to make predictions outside that range.

For example, if one knows the distance between New York and Chicago, and the how long it takes a freight train to get from New York to Chicago, then one can predict roughly how long it will take a freight train to get from New York to Los Angeles (if one knows the distance from New York to Los Angeles).

But the conditions over the entire range must be constant. One cannot predict how long it will take a freight train to get from New York to Hawaii, even knowing the distance, because there aren’t any train tracks across the Pacific Ocean.

Extrapolation only works as long as the underlying assumptions hold. Sooner or later, one always reaches a point where the assumptions break down.

For example, electronic devices keep getting smaller and smaller because technology evolves, allowing more and more electronic components per square inch. But, sooner or later, Moore’s Law 2 will break down because the limit to the number of components per square inch will be reached.

This applies to evolution, too. One cannot extrapolate the small evolutionary changes commonly seen in microevolution to the big changes that would be necessary for macroevolution because (figuratively speaking) there aren’t any train tracks.

Acquired or Inherited

After establishing that there are limits to variations, the students should be taught the difference between acquired and inherited characteristics. A body builder will acquire a different physique than a couch potato. But a baby born to a couple of body builders will not be born with bulging muscles. In certain cultures girls bound their feet to make them smaller, or put stretching collars around their necks to make them longer, because those cultures considered those characteristics to be beautiful. But these painfully acquired characteristics were not inherited by their daughters.

Some characteristics, however, are inherited. The tallest children in class probably have the tallest parents. The children with the darkest skin probably have parents with darker skin.

In Darwin’s day, scientists had not yet learned the difference between acquired and inherited characteristics. Darwin thought that diet, exercise, and climate (which do produce acquired characteristics) would produce changes that would be inherited by future generations. He was wrong about that.

Scientists are just beginning to learn how prenatal influences can affect gene expression. In some cases, environmental conditions determine the sex of an individual. 3 This is one area where the course needs to be constantly updated to include the latest information.

Mutations

Darwinian evolution has been replaced in evolutionary circles by “neo-Darwinian Evolution.” The difference is that neo-Darwinian evolution credits random genetic mutations for inheritable traits, rather than Darwin’s incorrect notion about diet, exercise, and climate.

Random genetic mutations certainly do manifest differences in the individuals suffering them. In the vast majority of cases, the mutations result in characteristics that are either harmful to the individual afflicted with them, or have no effect. Only in rare instances is the mutation beneficial.

There are two problems for neo-Darwinian evolutionists. First, if every characteristic of every living thing, from an albatross to a zebra, is the result of a random mutation, there would have to have been an unreasonably large number of successful mutations.

Second, there is a difference between a beneficial mutation and a creative mutation.

A mutation to an existing characteristic might be beneficial in a particular environment. The classic example is sickle-cell anemia, which provides some protection against malaria. But, in countries where malaria is not a problem, sickle-cell anemia is not a disease one would want to have. So, sickle-cell anemia is beneficial only in certain environments. Sickle-cell anemia is one of a small number of mutations that modify an existing characteristic in a beneficial way in a particular circumstance.

There has never been a case where an entirely new characteristic has originated by a random mutation. That is, no novel biological functions have ever appeared by chance.

For example, it is unscientific to think that mammary glands (and all the chemical processes that occur at childbirth to make them functional at just the right time) happened by chance when an unknown reptile evolved into the first mammal. The notion that mammary glands are just modified sweat glands is ridiculous. 4 For one thing, reptiles are cold-blooded animals that don’t have sweat glands that could be modified. If mammals did evolve from reptiles, then one would expect to find some warm-blooded reptiles that do have sweat glands to help regulate their temperature. Second, sweat glands respond to temperature, not childbirth. If anyone tries to tell you that mammary glands are modified sweat glands, don’t buy milk at the same dairy he does!

Survival

Darwin correctly observed that more species are born than live long enough to reproduce. (Of course, this is as obvious as when the TV newsman reporting on a disaster says, “The death toll is expected to rise!” Does anyone really think that some of the people who drowned in a flood will come back to life, lowering the death toll? ) Of course, the number of individuals surviving to maturity can’t exceed the number born, and some individuals die before they reproduce. Darwin could not possibly have been the first to notice this; but he gets credit for it.

Darwin went on to speculate that individual differences might influence which individuals survive long enough to reproduce, and which don’t. This notion is called, “survival of the fittest.” Biologists certainly agree that individual differences COULD affect survival rates. The disagreement among modern biologists is to what extent the advantage might be. It isn’t necessarily the slowest gazelle that wanders too close to the hidden lion. “Survival of the fittest” might be insignificant compared to “survival of the luckiest”.

Selection

This leads to the concepts of natural selection and artificial selection. Natural selection is the notion that survival of the fittest affects the breeding population in such a way that certain characteristics become predominant.

Artificial selection is like natural selection on steroids. The breeder allows only the strongest sled dogs to breed. There is no luck involved. The breeder has a goal in mind and controls which dogs are allowed to breed based upon reaching that goal.

In natural selection, there is an improved probability that the fittest will survive; but it is not as iron clad as the ruthless survival determined by a breeder. Furthermore, natural selection has no goal in mind, so a round-about path to the goal will not be taken. The variation has to have an immediate, significant survival advantage in natural selection. Artificial selection allows small, indirect steps toward the goal, and luck has no part in the process. That’s what makes artificial selection more efficient than natural selection.

It is well established that artificial selection can produce significant variations. This is evident from the various breeds of dogs and horses that have been bred for specific purposes. It is equally well established that there are limits to how much change can be achieved through breeding. Despite all the breeding experiments using bacteria, fruit flies, pigeons, dogs, horses, roses, and various crops, the bacteria have never evolved into anything other than bacteria, the fruit flies have never evolved into anything other than fruit flies, et cetera. No amount of breeding can cause a fruit fly to evolve into a bumble bee, or any other kind of insect, known or unknown.

The fundamental reason for this is that breeding eliminates undesirable genes. To breed a fast horse, one has to prevent all the slow horses from passing their genes on to future generations. Eventually, only fast horses are left in the breeding pool. Breeding achieves its goal by removing undesirable information from the DNA molecule.

Information From Nothing

To breed a flying horse, like the mythical Pegasus, one would have to add information to the DNA that causes the horse to sprout wings. Breeding doesn’t create genetic information. But, if Pegasus had existed, it would have been possible for a genetic mutation to prevent the wings from forming, so an ordinary horse could have devolved from Pegasus. Genetic information can be lost by accident; but it cannot be created by accident.

Modern genetics has advanced to the point where “gene jockeys” can remove genes from the DNA of one species and artificially insert it into another species. Such things as genetically modified food, and genetically engineered glowing fish, raise some important ethical questions and potential public safety issues that public schools might want explore, in a fair and honest way. Regardless of the ethical implications, it should be noted that the only way to add genetic information to a DNA molecule is to take existing genetic information from another DNA molecule and insert it into the target molecule.

This naturally leads to the question, “Where did the genetic information in the other DNA molecule come from?” If it came from another DNA molecule, where did that molecule get it? The information either came by accident or on purpose. This naturally leads to a cross-disciplinary discussion of computer science, which would show the student that information is not created by accident.

Populations

In one sense, populations do evolve. That is to say, demographics can change. Introduction of a predator can change the relative numbers of individuals in each species (and subspecies) in the environmental area under consideration. The famous peppered moth observations 5 should be thoroughly discussed, with an emphasis upon the fact that both colors were present at the beginning and end of each period, so there was no evolution from one color to another. All that changed was the proportion of each color.

Chicken or Egg

The classic paradox is, “Which came first—the chicken or the egg?” Scientific observation has firmly established that chickens come from eggs laid by chickens. There has never been a documented case of a chicken coming from anything other than a chicken egg, nor has a chicken egg ever been laid by any bird other than a chicken. So, we have a circular dependency with no beginning. Since there is no observable, natural process by which the cycle can begin, it leads to the conclusion that the cycle either began with a supernatural process, or a natural process that is not observable.

If one makes the assumption that there are no supernatural processes, then one must conclude that chickens (and every other species, for that matter) originated through a natural process that is not observable.

The Hopeful Monster assumption is that the process hasn’t been observed because it happens too quickly. A lizard lays an egg and a bird hatches from it, with no intermediate forms. The Hopeful Monster hypothesis is not accepted by most evolutionists, and should not be given too much consideration (but it should be mentioned).

The Darwinian assumption, on the other hand, is that the natural process is not observable because it is too gradual. That is, the first chicken is the mutant offspring of a previously existing bird that was hardly any different from a chicken.

There are problems with the Darwinian assumption, however. If all the intermediate forms survived, then there would be no clear distinctions between species. It would be very difficult to categorize living things into species. If the intermediate forms went extinct, then there should be countless fossilized transitional forms.

In geology, rocks can be any size. The Krumbein Phi Scale 6 arbitrarily defines “boulders” to have a diameter of more than 256 millimeters, “cobbles” to be 64 to 256 mm in diameter, “gravel” to be 2 to 64 mm in diameter, and “sand” to be less than 2 mm, et cetera. These arbitrary distinctions are necessary because the size of rocks don’t have any natural divisions.

Darwinian evolution would result in such gradual distinctions that biologists would have to make similar arbitrary decisions about living things in order to classify them. In fact, the differences between species would be so small that practically every individual could be considered a different species.

But animals either have backbones or they don’t. The either have feathers, or they don’t. They have mammary glands, or they don’t. The presence or absence of diagnostic characteristics makes plants and animals classifiable. Living things don’t occupy a continuous spectrum of diversity—they naturally fall into distinct groups.

Taxonomy

Biological classification (taxonomy) is largely based on decisions historically made by Carl Linnaeus in the 18th century regarding which shared physical characteristics make the most sense when classifying species. He also devised a hierarchy of similarity going from species to kingdom. Students should become familiar with this hierarchy and be given tests to see if they can correctly place living things in the proper genus, family, order, or phylum.

Students should be taught that the classification criteria are arbitrary. One could argue that whales should be classified as fish (as they once were) rather than mammals (as they are now) because (in someone’s opinion) the fact that whales live in the water is more important than the fact that they nurse live young. The modern classification system has been revised from time to time as opinions change.

DNA comparisons sometimes make the decisions simpler—but sometime yield surprising groupings. 7 This has led to controversy in the biological community as to how some species should be classified.

The belief that species arose from the unobservable gradual natural process of descent with modification has become the driving assumption in modern biological classification. That is, living things assumed to have the closest common ancestor are classified together. But, since the classification system is now based on an assumed evolutionary history, it cannot logically be used as proof of evolutionary history. (It is logically invalid because it is circular reasoning. Lions and Tigers have been assigned to the genus Panthera because they are assumed to have evolved from a common ancestor. Therefore, the fact that they are in the same genus is not proof that they evolved from a common ancestor.)

Fossils

Fossils are evidence of forms of life that died some time in the past. Some of these living things still exist, and some are extinct. Fossils of existing species are easy to identify because the fossils can be compared to bones known to exist in that species. But when an isolated bone or tooth unlike any other known bone is discovered, scientists sometimes try to reconstruct the entire creature based on that one bone or tooth. Sometimes, the reconstruction is not nearly correct. Nebraska Man 8 is an excellent example. Eosimias 9 is another. This is an excellent opportunity to warn students not to draw vast conclusions based on half-vast data.

The course should include an honest presentation of how fossils are dated, and the assumptions used by those dating methods.

It should also be pointed out that even if a fossil really is older than another fossil of a different species, it is not proof that the younger fossil was an actual descendant of the older one, even if there are some physical similarities. The classic example of a bogus construction of an ancestral lineage is the now-discredited horse evolution. 10

Origin of Life

The theory of evolution attempts to explain the diversity of life on Earth. The evolutionary explanation is, “descent with modification from an original life form.” For the evolutionary explanation to be complete, one must include the origin and characteristics of that first life form.

The first living thing had to be able to reproduce in some manner before it died. It needed some form of metabolism in order to grow and reproduce.

The countless failed experiments attempting to show how the first living cell could have formed provide a wealth of information about how complex even the most “primitive” cell must have been. (Of course, the term “primitive” is a pejorative term based on the assumption of evolution.) Students should be told all the obstacles preventing the accidental origin of life.

System Engineering

Analysis of the complexity of the simplest living thing naturally leads to a discussion of biological systems. Living things consist of a number of components which operate in concert to form a functional system. That is, a heart and two lungs are of no value without blood. Lungs and blood are of no value without a heart. An incomplete system cannot function.

The primary emphasis of a biology course should be the study of how biological systems operate. This is the foundation of modern medicine. Furthermore, since biological systems must interact with the environment, this leads to a better understanding of ecology.

Conclusions

The practical applications of biology to medicine, ecology, and agriculture are much more important than foolish speculation about how reptiles turned into mammals. This would be true even if reptiles really did evolve into mammals. But, since reptiles did not evolve into mammals, there is no value in speculating about how it happened at all.

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Footnotes:

1 Disclosure, June 1999, “Kentucky Derby Limit”, http://www.scienceagainstevolution.info/v3i9f.htm
2 http://en.wikipedia.org/wiki/Moore%27s_law
3 Disclosure, February 2003, “Birds and Bees”, http://www.scienceagainstevolution.info/v7i5f.htm
4 Disclosure, January 2002, “Sweating Milk”, http://www.scienceagainstevolution.org/v6i4e.htm
5 Disclosure, February 2002, “Horses and Peppered Moths”, http://www.scienceagainstevolution.info/v6i5f.htm
6 http://en.wikipedia.org/wiki/Krumbein_scale
7 Disclosure, July 1999, “The DNA Dilemma”, http://scienceagainstevolution.info/v3i10f.htm; Disclosure, November 2001, “Fuzz, Birds, and DNA”, http://scienceagainstevolution.info/v6i2n.htm
8 Disclosure, April 2004, “Nebraska Man Sues for Re-instatement”, http://scienceagainstevolution.info/v8i7n.htm
9 Disclosure, September 2000, “Eosimias”, http://scienceagainstevolution.info/v4i12n.htm
10 Disclosure, February 2002, “Horses and Peppered Moths”, http://www.scienceagainstevolution.info/v6i5f.htm