We have no proof of the doctrine of common descent. The fact that all life uses the same genetic code is not at all proof that all life descended from the same ancestor. If some divine creator or series of extraterrestrial expeditions to Earth had decided to populate our planet with organisms, such a force might well have chosen to introduce organisms with a common genetic code, so that a harmonious ecosystem could develop, without organisms getting poisoned because they fed on some other organism with a different genetic code.
We also have no proof for the doctrine of gradualism. Humans have never observed any species change gradually from one biological form to a very different biological form with a very different structure. We do not have proof that any species gradually changed into some very different species before human civilization started. If you think that things such as fossils of anthropoid organisms are proof of such a thing, you may read this post for a discussion of why they are not.
We also have no proof at all for the claim that any complex visible biological innovation has ever appeared because of random mutations, natural selection, or any combination of these two things. In fact, humans have never even observed the appearance of any complex new biological innovation that was visible to the naked eye. I do not count something such as industrial melanism as such a thing, because such a darkening of moths is not a new complex innovation, and because it has not been proven that there did not previously exist some dark moths before such a change in the gene pool occurred.
Much as some might like to get proof for the claims of Darwinism by examining the past, such a thing is not currently possible. Given two old fossils from different geological eras, there is no way of knowing whether they show one organism descended from another. The half-life of DNA is only 521 years, which means that we do not have anything like complete DNA corresponding to most old fossils. When a very old fossil is found, scientists usually have no more than a tiny fraction of the DNA of the organism that had such bones.
So Darwinism is very much an unproven thing, something that seems more like a belief system than something established by observations. But could there be any observations that might change this situation, and allow us to say that Darwinism was well confirmed? I can imagine a type of experiment that could bolster the empirical credentials of Darwinism. It is an experiment that would be incredibly expensive, and which would need to be carried out for very many generations.
Let us imagine the construction of a special laboratory that would be much bigger than a single building in a university. The laboratory might be as big as a modern zoo. Inside this laboratory-zoo there would live some particular mammal species. That species might be dogs, lions, bears or some other large mammal. A variety of different habitats might be constructed for the animal species to live in. These habitats might be separated, so that there would be a variety of study groups, each living in a different habitat.
The experiment would simply be to monitor the species over very many generations, to find out whether there was any example of visible innovative evolution. The different habitats might have different characteristics designed to increase the likelihood of dramatic evolutionary innovations.
For example, if the species being tested was dogs, we might have habitats such as the following:
- One habitat resembling Hawaii, and with little radiation.
- One habitat resembling northern Canada, and with little radiation.
- One habitat resembling the Amazon forest, and with little radiation.
- One habitat resembling a desert, and with little radiation.
- One habitat resembling the Great Plains of the United States, and with little radiation.
- One habitat resembling a European forest, and with little radiation.
- One habitat resembling Hawaii, and with lots of radiation.
- One habitat resembling northern Canada, and with lots of radiation.
- One habitat resembling the Amazon forest, and with lots of radiation.
- One habitat resembling a desert, and with lots of radiation.
- One habitat resembling the Great Plains of the United States, and with lots of radiation.
- One habitat resembling a European forest, and with lots of radiation.
The idea would be to observe the species in these different habitats, and see whether any complex biological innovations occurred because of random mutations and natural selection. The habitats with higher levels of radiation might have an increased number of random mutations. By having different habitats you could test the Darwinian idea that organisms gradually change their structure to adapt to their habitats.
But it would not be sufficient to merely observe whether any new visible innovations appeared in the biology of this species. You also would have to determine whether such a thing was caused by favorable random mutations that had been promoted by natural selection.
It would therefore be necessary to track changes in the gene pool of the organisms as time progressed. Scientists could do this by taking periodic blood samples. It is easy to imagine a scheme that would work. One scheme would be to simply have a system whereby animals were periodically checked for a collar. If the collar was not found, the animal would be captured, collared, and a blood sample would be taken. By making periodic checks for animals that were not collared, and gaining DNA samples from such animals, the scientists would have up-to-date information on the current gene pool of the animal study groups in each of the different habitats.
It would also be necessary to keep track of the number of offspring of each of the mammals under scrutiny. This would be to test the Darwinian idea that novel improvements spread in a population because they improve the survival rate or reproduction rate of particular organisms. We can imagine a great number of video cameras in our very large laboratory-zoo that might track the reproduction rate of particular mammals, perhaps using numbers printed on their collars. But an easier technique might be to deduce reproduction rates of particular organisms by analyzing blood samples. If you have blood samples of all of the animal population, then it might be possible to figure out who the parents were, using the same type of techniques used to establish human paternity through blood tests. Either way, keeping track of the number of offspring of each of the mammals under scrutiny would probably be quite a headache and hassle.
As long as no new visible biological innovation appeared in any of the animal study groups, the experiment would be considered a failure. But if a new visible biological innovation appeared in one of the animal study groups, it would then be necessary to study how the gene pool of that animal study group had changed. This could theoretically be done by a computer program that would crunch massive amounts of genome data accumulated from all the periodic blood samples. The computer program might be able to pinpoint exactly the DNA mutations that had led to some biological innovation, and how such DNA mutations had spread in the population. So, for example, we might imagine that one particular mutation might occur in some particular year, and that it had taken 200 generations to spread throughout the study group population; and that some other mutation had occurred in some other year, and that it had taken 400 generations to spread throughout the study group population; and so on and so forth until a complete account was made of how the complex biological innovation had appeared.
Nothing like this project has ever been done. Such a project would require very many thousands of years before it had any chance of success. We know that complex biological innovations require the appearance of multiple new proteins. A typical protein in a mammal is specified by a gene consisting of about 25,000 base pairs. But a single random mutation would add or change only one of these base pairs. So how long would this experiment have to be run before there was even, say, 1 chance in 1000 that random mutations would produce the proteins for a new biological innovation? If you answer “pretty much forever,” you're in the right ballpark.
Suppose that after many thousands or millions of years of running such an experiment, a new complex visible biological innovation somehow appeared in the population of mammals under study. Would this be proof that complex visible biological innovations can appear by Darwinian explanations? Not really, because we have been told many times by scientists that something doesn't really count if it was observed only once, and that science is about replicated observations and replicated experiments. So if you got a good result after running such an experiment for 500,000 years, it would then be necessary to spend another 500,000 years or more trying to replicate the positive result.
There are two reasons for believing that this long-term evolution experiment would never succeed. The first is the enormous unlikelihood that random mutations would every produce the proteins necessary for a new biological innovation. A typical protein consists of hundreds of amino acids that have to be arranged in just the right way to achieve a particular functional effect. The chance of such a thing occurring by chance is roughly comparable to the chance of a typing monkey producing an intelligent page of prose specifying how to accomplish some particular objective.
The second reason for believing that this long-term evolution experiment would never succeed is that even if there were to appear the proteins necessary for the new visible biological innovation, such proteins would not be sufficient to explain the new biological innovation. I can give an example. Let us suppose that dogs placed in a desert-like environment for many thousands of years were to evolve some long tube-like appendage capable of sucking small amounts of water from underground. We could not explain that by simply imagining the addition of some proteins to the genome of the organism. There would have to be a complex change in the body plan of the organism.
Is that body plan specified in DNA? No, it isn't. The claim that DNA is a blueprint for an organism is a myth spread largely to prop up Darwinist claims. The truth is that DNA specifies only low-level chemical information such as the amino acids that make up a protein. For example, nowhere in DNA does it specify that humans have one head, two eyes, two ears, two arms, two legs, and ten fingers. DNA does not specify an overall body plan, does not specify the arrangement of parts in an organ system, does not specify the shape of an organ or its arrangement of parts, and does not even specify the shape of a cell or the arrangement of parts in a cell. Where the body plan of an organism comes from is a great unsolved biological mystery. As an article in The Scientist told us a few days ago, "Genomes are not a blueprint for anatomy."
Since DNA does not specify the phenotype or body plan of an organism, and does not specify the arrangement of parts in any organ or appendage, we cannot plausibly imagine how a change in DNA caused by a random mutation could produce some new visible biological innovation. This is another reason for thinking that the long-term experiment I have imagined would never succeed.
Regardless of whether it would have a chance of succeeding or not, the fact is that an experiment like the one imagined (using mammals) has never been done. Slightly similar experiments (but less complex) have been done with fruit flies, which have the advantage of having very short lifetimes. The experiments never produced any useful visible biological innovations in fruit flies.
Suppose an experiment like the one imagined were run, and suppose that very many thousands or millions of years later a single visible biological innovation appeared. Would that prove that Darwinism was the correct explanation for all for the complex functional innovations we see in the biological world? It would not. It would merely prove that one visible innovation could be produced in such a way, not that most biological innovations had been produced in such a way. Similarly, you might build some big machine that picks up logs from the ground, and then drops them from a height of 10 meters, repeating such a cycle over and over, and stopping only when the fallen logs accidentally form into something like a log cabin. If you ran such a machine for 50 years and finally got the fallen logs to form into something like a log cabin, this would not at all prove that most log cabins are formed from accidentally falling logs.
But there is one glimmer of hope for those hoping that Darwinism may become something well-confirmed. There is a potential technological device that might allow scientists to gather evidence that might confirm claims such as gradualism. There is a potential invention that might allow scientists to take as many complete samples of DNA as they might like, from organisms living in any number of different times in the past. There is a potential device that might allow biologists to make a complete photographic record documenting exactly how the organisms on planet Earth have changed over the eons. This yet-to-be-invented device is what is commonly known as a time travel machine.