In a previous post, I asserted that the evidence that evolution was a guided process seems overwhelming to me. To understand why I think this is the case, you need to know that I was doing graduate level research as a chemical engineer at UCLA. As an engineer, I have been trained to do “back of the envelope” calculations that are extremely conservative in order to establish the boundaries of a problem. I apologize that this post is going to be very technical, but if I am going to share why I believe that evolution is guided I must do some “back of the envelope” calculations. We start by estimating the number of multi-cellular lifeforms that have lived in the history of the earth.
The Maximum Number of Multi-Cellular Individuals
To estimate this number, we make a number of simplifying assumptions:
- Multi-cellular life has been on earth for a billion years.
- Multicellular organisms replicate 100 times a year. (This is high, Even termites have a gestation period of two weeks.)
- 1000 times the number of insects on the planet gives us a reasonable upper limit to the number of multi-cellular organisms.
- There are a billion insects for every human being.
- There are 10 billion human beings.
Multiplying these numbers together gives an estimate of the Maximum Number of Multi-cellular Individuals. We will call this number the MNMI and it is equal to 10^33 or 1.000,000,000,000,000,000,000,000,000,000,000. Now you might be able to squeeze a couple more orders of magnitude out of this calculation if you really stretch it, but it wouldn’t really make much of a difference. For our purposes, 10^33 is close enough.
Now in some contexts, the MNMI is a very large number. If I had that amount of money in any currency, for example, I should be able to buy the United States once a second for billions of years. In the context of information bearing sequences, however, the MNMI is a very small number. Just exactly how small is it? This paragraph is not very long, but if you had one permutation of the sequence of words in it for every organism counted by the MNMI, you would have a much better chance of winning the lottery six times in a row then coming up with this exact paragraph.**
The Largest Saltation Allowed by the MNMI
DNA consists of a series of nucleotides (guanine, adenine, thymine and cytosine). Given that the genome of every known multi-cellular organism consists of DNA, we can use the MNMI to calculate that the largest gap between functional sequences in multicellular life is about 55 base pairs of DNA. (4^55 ~ 10^33). Since every three nucleotides in a DNA sequence correspond to a single amino acid in a protein, this corresponds to a protein sequence of about 19 amino acids. What does this number have to tell us about whether or not evolution is unguided?
Conserved Genetic Sequences
When protein sequences are compared between different species, the sequences are aligned and point by point comparisons are made of the amino acids. A protein is considered to have a “conserved sequence” if the amino acids at multiple different points in the sequence are identical. The more amino acids match, the more “conserved” the sequence is said to be.
The most striking example that I have seen of a conserved genetic sequence is found in the protein Ubiquitin. When one compares the amino acids that constitute the ubiquitin used by yeast to the amino acids that constitute the ubiquitin used by human beings, one finds that 73 of the 76 amino acids that make up the sequence are the same in both species. This is an astonishing level of conservation.
Ubiquitin is, of course, a bad example for us to consider because it is common to eukaryotes that are not found within the lifeforms that make up the MNMI. Nevertheless, comparisons of different proteins between different multi-cellular species indicate a very similar phenomena. As a random example I found by doing a quick Google search, consider the Surf1 protein. It is 300 amino acids long and comparison of the human version of the protein to the protein found in various other multi-cellular organisms (from plants to worms) indicates that 28 of the 300 amino acids are identical in all the sequences while another 48 are “conservatively substituted”. (Conservatively substituted means that a different amino acid was found at that point in the sequence, but that amino acid has similar chemical properties to the one in the original sequence.) Since the evolutionary explanation for conserved sequences is that selection filters out mutations to these areas because they are selectively unfit, this seems to suggest that the ancestral multi-cellular Surf1 protein had 76 amino acids in the sequence that are identical or similar to the sequence found in modern multi-cellular organisms.
Let us be clear that we are NOT SAYING that because this level of similarity is beyond the maximum jump size available to the MNMI that unguided evolution could not have created a functional Surf1 protein. Given the unknowns, it is impossible to do the calculations and no such assertion can be made. Rather, we are using the maximum jump size as a metric to demonstrate the degree of guidance that is demonstrated by the evolution that actually occurred. In other words, I am not arguing that guidance was essential, I am arguing that guidance is implied by the observational data. To illustrate what I am talking about, let us consider a simple thought experiment.
A Simple Thought Experiment
Let us say that there was an unmanned car that had a very small gas tank. The car can only drive 5 miles before it needs to be refueled at a gas station. Given that the car made the drive from Los Angeles to New York, we are trying to find out something about its guidance system using GPS data from its journey. As we analyze the data, we are looking to see if the car stretched its gas mileage by using hypermiling techniques. Because these techniques involve slowing the car without brakes, drafting behind larger vehicles, coasting down hill and so forth, we know that if it used such techniques then the guidance system must be extremely sophisticated. If, on the other hand, the furthest the vehicle ever went between refills was 5 miles, then we know the guidance system was not very sophisticated.
So the question is looking at the GPS data that we have from the process of evolution which comes to us from genetic sequence studies, what does it look like? Did the evolutionary car only go 5 miles at a time or did it use hypermiling techniques to get the most out of the gas? The answer from looking at the conserved genetic sequences that are very common in biology is that the system looks like it had a very sophisticated guidance system. The data that we have from the GPS demonstrates no respect for the 5 mile per trip limit that we have calculated. According to the data, the car routinely went 10, 15 or even 20 miles before being refueled. This is powerful evidence for a sophisticated guidance system.
A Different Argument
Now it is to be stressed that this argument is very different from the argument that creationists typically make concerning probability and evolution. From what I have seen, a creation scientist would typically take the MNMI and attempt to prove that unguided evolution could never have produced life as we know it given the maximum jump size of 19 amino acids. In the thought experiment above, this is similar to attempting to prove that it is not possible to drive from Los Angeles to New York with a 5 mile per tank limit. Even with the data available from the Internet, this would be a very tough argument to make. How often did the car coast downhill? How often did the car draft? Are there any gas stations that are not available in the internet data? Can the car use anything else as fuel? Given the unknowns, the calculation is impossible.
Fortunately, I am not trying to prove that unguided evolution could not have produced the conserved elements in the Surf1 protein and many others like it, I am arguing that the degree of conservation that we see in many different protein sequences is powerful observational evidence that the process of evolution was guided. Concerning this argument, proponents of unguided evolution seem to have only two choices:
- They can argue that the observed degree of sequence conservation was essential for minimal function and thereby is not observational evidence of guidance.
- They can argue that the observed sequence conservation is an example of “convergent” evolution for sequences that were not functionally constrained to be the same.
Argument 1 would make strange bedfellows of proponents of unguided evolution and proponents of fiat creation since they would essentially be arguing the same thing. This argument is against the evidence, however, because “knock out” studies have shown no deleterious effects for some highly conserved regions in some multi-cellular organisms.
Though I have seen some hand-waving attempts to explain sequence convergence by arguing that there could be “strange attractors” in gene space that require different organisms to converge on similar sequences, argument 2 is really just saying that, “it happened by chance”. Given the fantastic probabilities involved, you will pardon me for taking option 3 and saying that conserved sequences are conclusive evidence of divine guidance in the evolutionary process.
**For those who are curious, the probability of creating the above paragraph is related to the factorial of the number of words in the paragraph. According to a simple text analysis tool, the total word count of the paragraph is 109 total words with 72 different words being used. There was 1 word repeated 7 times, 1 at 6 times, 2 at 5 times, 1 at 4 times, 3 at 3 times and 9 at 2 times. This makes the probability of coming up with the paragraph, 1 / 72! ignoring the repeated words which make the calculation much more difficult and the probability lower. This is about ~ 1 chance in 10^103. The probability of getting the sequence of the paragraph with 1 try for each organism in the MNMI? 10^33 / 10^103 or ~ 1 in 10^70. The probability of winning the lottery six times in a row? ~ 1 chance in 10^43 attempts if the chance of winning the lottery once is one in 1.5 * 10^7.