Haldane’s Continuing Dilemma
From March 2006 Creation Answers Newsletter
In 1957 a well known geneticist in Britain wrote about a problem affecting evolution theory. He was known as J.B.S. Haldane. He was known for being an excellent popularizer of science and he eventually turned to a Marxist philosophy. At that time, the field of genetics was relatively new and scientists had only recently put together a view of evolution that relied on genetic mutations as a means of change in living organisms. The concept of natural selection had been put forward by Charles Darwin and others years before this. But, in considering how living things could change from one form to another, evolutionary scientists came to rely on the concept of there being beneficial mutations.
All living things have some mutations in the DNA code in their cells. Many mutations turn out to be essentially harmless because of various mechanisms the body has of preventing mutations from being expressed. To say a mutation is not expressed means that it does not change the body of the organism, at least not in a way that it is carried on to other generations. The cell has many mechanisms for preventing mutations and even for correcting mutations. But, some mutations do not get prevented or corrected by the various biochemical machinery in the cell. The great majority of these are either harmful or “neutral” in their effect on the organism. It is believed by many scientists that some mutations can be beneficial. A beneficial mutation is randomly introduced but it gives some advantage for survival or for reproduction. This advantage would mean the beneficial mutation provides the raw new genetic information for evolution.
Whether there is in fact such a thing as a truly beneficial mutation that aids evolution is a significant controversy in itself. But, let us assume for the sake of the argument that beneficial mutations can happen, though they are very rare. When a beneficial mutation occurs in a population of living things (such as a group of wild horses for instance), this means that one change in the DNA has to replace or substitute for whatever the DNA had before the change. Then for that change to become the new “norm” for the population, that genetic beneficial change has to replace the old genetic code in enough individuals (like the horses) so that eventually there are no more individuals with the old code. Haldane’s dilemma has to do with how implausible it is for a beneficial mutation to grow more and more common in a population of organisms till it becomes the new norm. This is the type of process that must occur for living things to evolve from one form or kind to another. Note that for animals to adapt and undergo small scale changes does not require mutations at all. Thus, changes like changes to fur, teeth, or size do not enter into this discussion. The issue is about changes that would not happen without a mutation that makes significant genetic change in the organism.
There are several terms to explain in order to understand this issue. The generation time is the time from birth until the average adult gives birth to its first young. For ape-hominid supposed human ancestors and for humans the generation time is generally considered to be 20 years. The reproduction rate is the average number of young produced by a given mated couple in a given time. For animals with a long generation time and a low reproduction rate, new traits would take a long time to become common in the population. This is assuming that the new trait, which is from a beneficial mutation, would give a clear advantage to the organism and thus would grow more common over time. It is believed by evolutionists that natural selection tends to “weed-out” traits if a new trait from a mutation gives an advantage that helps the organism produce more offspring.
Creationist Walter Remine has addressed the issue of Haldane’s Dilemma in a well-known book called The Biotic Message, in a recent technical paper (see TJ v19, n.1, 2005), and on the internet. He points out that evolutionists have often misunderstood and confused the issue and failed to clearly explain or understand the problem. Yet the problem does not come from any creationist, but from J.B.S. Haldane, an evolutionist. Over the years some evolutionist biologists have acknowledged the problem. One of the misunderstandings of the issue is over the idea of substitutions.
What exactly is changing in an organism’s DNA in a mutation? There are a number of different types of mutations. But it is important to understand that genes are groups of nucleotides. Nucleotides are the small chemical units that make up the individual “rungs” in the twisted ladder that DNA is made up of. Haldane’s dilemma has to do with point mutations, not genes. Mutations don’t change whole genes, they make particular changes in nucleotides. (There are several billion nucleotides in many mammals.) These changes from mutations can be either beneficial (assume for the sake of the argument), neutral, or harmful to the organism. Mutations also occur randomly. They have nothing to do with the needs of the organism.
Assume for a moment that there is a group of wild horses. There is a mutation that changes the hooves from a split hoof to a single-toed hoof. Assume that this change gives the horse an advantage that helps it in some way (it runs faster, has better circulation, etc.). Thus the horses that have the single-toed hoof have more offspring than the other horses because they live longer or are better able to survive in some way. To understand Haldane’s dilemma we must focus on the horses with the single hooves, which is the new trait from a beneficial mutation. There are various types of “costs” in an old trait being replaced by a new trait, like the single-toed hooves. For the single-toed horses to become the new norm and replace all the individuals who had the split hooves, what must happen? There is a “cost of continuity” as Remine calls it, which is where the horses with the single-toed hooves must have at least one offspring each to keep their numbers from dropping off. Then, for the horses with the single hooves to replace the other older type horses, there is an additional cost, an additional number of offspring they must have so that there will be a net gain in the number of single-toed horses. This cost is known as the reproductive excess, the rate they must reproduce beyond break even to grow in number according to a given scenario.
There are other costs that must be overcome, or “paid” by the animals with the new trait, in order for the new trait to effectively replace the old. For instance, some animals may die at random due to accidents or disease, so that they do not reproduce. Also, harmful mutations may cause some individuals to not be able to reproduce. Remine calls the “cost of evolution” the sum of all these various costs. Each cost is a reproduction rate required for a certain scenario. This can be used to test various evolutionary scenarios to determine if they are plausible. If the organisms cannot pay the cost, that is if they cannot reproduce at a rate that makes it possible, then the evolutionary scenario cannot work.
Haldane’s original work on this issue leads to a certain number that Remine has pointed out to evolutionists. Quoting from Remine’s web site, “Haldane’s Dilemma establishes a limit of 1,667 beneficial substitutions . . . over the past ten million years of the lineage leading to humans. The origin of all the uniquely human adaptations would have to be explained within that limit.” The figure of 1,667 substitutions is a very serious problem for evolution. This number comes from the following assumptions. First, assume it takes 10 million years for humans to evolve from the common ancestor of apes and man. This is actually longer than what evolutionists believe. Second, assume a population size of 100,000. Assume a generation time of 20 years for each individual to become able to reproduce. Now, how long would it take a beneficial mutation to completely replace an old trait? With the rarity of beneficial mutations, this is estimated to be one nucleotide in about 300 generations. These numbers lead to the 1,667 substitutions. 1,667 nucleotides is a very very minute percentage of the ape-hominid’s DNA. This is a generous estimate of how many beneficial substitutions could possibly happen in 10 million years of the evolution of humans. To see how serious a problem this is for evolution, consider this. Assume that only a 1% change in the nucleotides would be necessary for the evolution of man from ape ancestors. How long would it take to evolve a human from an ape-like ancestor, at the rates given in the scenario above? The answer is 500 billion years!
There are many complications to the above that I cannot address here. But this is Haldane’s Dilemma. It continues to be a dilemma for evolutionists. Walter Remine has answered many objections from evolutionists. Remine has gone to some length to clarify and redefine the problem. Remine’s work shows how the problem works out in a wide variety of scenarios. Many proposed solutions to the problem from evolutionists do not actually address the real problem. Remine’s web site is a good source for more explanation on this topic. It is the following: