Dr Robert DiSilvestro holds a Ph.D. in biochemistry from Texas
A&M University. He is currently professor of human nutrition at Ohio State University.
Dr. DiSilvestro has published nearly 60 peer reviewed, life science-related
Undergraduate biology classes often make statements about origins of life, species or even the universe. In many cases, these statements seem to remove the need for any involvement of a creator God. However, the credibility of many of these statements can be called into question. Below, I provide some short pieces of information that can be used to pose such questions.
I do not recommend using this information to obnoxiously challenge professor's authority during class. However, this information can be useful for conversations with other students, polite private conversations with a professor, or in some cases, a respectfully worded question during class. The information given is not exhaustive, nor does it provide rebuttals to every criticism that could be made to the ideas presented. However, the information does provide some ideas basic to some origins issues.
This work is commonly covered in classes despite the major criticisms it has received. In this experiment, a primitive atmosphere (sometimes called a primordial soup) was set up, and then exposed to an electric spark. This produced a few simple amino acids (the building blocks of proteins). This was touted as demonstrating that life could originate by natural causes. However, this statement has many problems. Some are outlined as follows:
1. The atmosphere conditions were not those of the primordial earth (Discover, Nov, 1996, pp. 76-82).
2. These experiments don't explain the origin of a basic characteristic of life, namely the ability to self replicate. Despite some claims to the contrary, this is still a big problem for all naturalistic origin of life scenarios (Miller's own comments, Discover, November, 1996, pp. 76-82).
3. There is no explanation for stereospecificity. In other words, in real life, proteins are made only of left handed amino acids. On the other hand, a system like Urey and Miller's would give a mixture of left and right handed molecules. This problem of stereospecificity still baffles scientists (Science 267:1265-1266, March 3, 1995).
4. The experiments don't deal with the huge issue that life has informational complexity. For example, amino acids must be in certain orders to create functional proteins. By analogy, in sentences, letters must be in certain orders or they don't convey meaning. If a young child bangs on a word processor, most of the letter arrangements are not sentences, but nonsense. Similarly, most arrangements of amino acids don't give functional proteins, but give nonsense. It has been estimated that only 1 out of every 1064 sequences of amino acids gives functional proteins. That last number is a 1 with 64 zeroes (a million is only 6 zeroes). This ratio has been derived three different ways including an experiment using recombinant DNA technology (Proteins: Structure, Function, and Genetics 7:306-316, 1990).
By oldest estimates, the universe is only about 1018 seconds old. Even if somehow all the right amino acids were present in one place (a big problem in itself), even if somehow they could combine properly (another problem), and even if they combined one time per second for 1018 seconds, the chances of assembling one functional protein is essentially zero. This is because 1018 is still very small compared to 1064.
5. Alternatives to the Urey and Miller explanations for life's origins (i.e., RNA as the original material, life from outer space, amino acids combining on clay crystals in the ocean) all have worse problems than the Urey and Miller ideas (Discover, November, 1996, pp. 76-82).
The journal Nature (377:99, September 14, 1995) calls the Big Bang the only theory in the field of origins of the universe. Some people assume that this means God isn't necessary to explain the origin of the universe. In actuality, as recognized by many astronomers, the best explanation for the Big Bang is a personal God. Upon some reflection, it can also be stated that the type of God who gives the best explanation would have the following traits:
A. Exists outside of one dimension of time (this also solves the issue of: who made God? A God who exists in more than one dimension of time did not have to be made);
B. Exists outside of the normal 3 dimensions of space;
C. Must be capable of deciding to create a universe from nothing at one moment.
The Bible is the only ancient holy book that speaks of such a God (see The Creator and the Cosmos, Navpress, 1995).
The anthropic principle states that the physical constants, the physical laws, and the astronomical make up of the universe (i.e., the mass of the universe) have to be within narrow limits for life to exist (Nature 384:107, November 19, 1996; The Creator and the Cosmos, Navpress, 1995). How did the universe develop within these narrow limits? An article in Nature (384:107, November 19, 1996) says the simplest explanation is that an intelligent creator was responsible. However, the article says that this "interpretation lies outside science." Thus, the article rejects this idea because it is not allowed to be right.
The article goes on to discuss the so called strong anthropic principle. This says that the universe seems so fine tuned that life just had to happen. This idea is called unlikely, but not for scientific reasons. Rather, it's termed unlikely because it would make some research on evolution seem trivial. In other words, some scientists don't want this idea to be right, so it's not.
Most biology courses teach evolution. It is hard to dispute that some evolution occurs. For example, bacteria develop drug resistance and moths change color proportions depending on what best hides them from predators. This is often called microevolution. However, this is just changing proportions for the identity of traits that are already there. For example, color can already exist in moths, but a change is made in what percent of a population has a particular attribute for that trait (ie green color or white color). Ask someone to give evidence that these same processes also work to create color in the first place, or whole species (so called macroevolution). The answers vary, but the answers usually are based on so called "just so stories" (I'll tell you a story, but not give reasons why it was likely to happen). These stories require many jumps in complexity for which there is no rationale for how natural selection could make it happen.
Sometimes, "just so stories" are backed up by looking at interspecies variations in protein amino acid contents. Using this data, an evolutionary scenario is constructed for how these changes evolved. However, these scenarios do not provide actual evidence as to why these scenarios were likely to occur. They just say that based on the amino acid data, this is what must have happened.
Sometimes, the "just so stories" are backed by computer models using random combinations and selection advantages. However, the computer models are always too simplistic compared to biological systems. Also, many of these programs rely on intelligent input that natural selection could not duplicate. with evidence that it actually happens.
I had an interesting exchange few years ago. A faculty member asked me why I didn't think macroevolution is just the sum of many microevolutions. I asked him what made him think it was. Another professor, a firm believer in macroevolution, said he'd take the question. He said there is no reason to think that macroevolution is just the sum of many microevolutions. He added that he is surprised more people don't challenge that idea publicly.
Sometimes, an isolated fossil is held up as evidence of macroevolution. In many cases, there are problems with using the fossil (e.g., a seeming link between birds and dinosaurs is in the wrong time frame to really be a link. Or, a link between whales and land animals requires some imagination to call this a whale predecessor). Regardless of the problems with individual fossils, the real issue here is the following question: does the fossil record as a whole support Darwin? According the journal Science (267:1421-1422), the answer is no. This journal ran an article called "Did Darwin Get It All Right?" The article says that the most thorough study yet of the fossil record finds that new species appear suddenly. That observation, the article says, points away from classical Darwinian ideas.
To explain the lack of transition between major animal groups in the fossil record, the theory of punctuated equilibrium has arisen. This theory says that small, isolated groups of animals face difficult environmental conditions, which then makes them evolve relatively quickly (at least compared to the whole history of life). Since this only happens to a few animals at a time, the fossil record doesn't capture the event. This idea leaves me wondering why the event is never captured when it is supposed to have happened so many times.
In some ways, punctuated equilibrium is more of an excuse for lack of supporting data, rather than actual evidence for what happened. The above mentioned article in the journal Science (267:1421-1422) somewhat supports this idea by saying that punctuated equilibrium is a topic about which "there are a lot of hypotheses and not many facts." This is a little like a prosecuting attorney saying: "We have no evidence that this person committed this crime, but I can give reasons why the evidence disappeared. Now, find this person guilty." However, the case for punctuated equilibrium is worse than that. There are theoretical reasons why it shouldn't work. Some of these are outlined in an article in Nature (394:329) called "Rarity as Double Jeopardy." The basic idea is that the smaller the population, the greater the chance of extinction. One reason is the amount of inbreeding that occurs (Science 280:35).
A while back, Ernst Haeckel presented the idea that all vertebrate embryos go through the same stages of development. For example, a human embryo can look like a fish at some point. This contention was backed up by pictures of embryos at various stages. Recently, the journal Science (277:1435, September 5, 1997) addressed the resurgence of interest in this concept. The article stated: "It looks like it's turning out to be one of the most famous fakes in biology." The article also noted an opinion that reviving interest in this work "does a great disservice to developmental biology."
Dr. DiSilvestro holds a Ph.D in Biochemistry and is currently Associate Professor of Human Nutrition at The Ohio State University