The Rna World
The biggest problem in all origin-of-life scenarios remains explaining in a detailed way the origin of the first DNA replication system found in modern cells. Trying to explain how the DNA replication system arose directly from molecular subunits has proved so difficult that scientists have given up trying. They have concluded that there must have been simpler precursors to the DNA system. Today, many scientists are concentrating their efforts on a replication system based on RNA, which plays a subordinate role in today’s cellular reproduction processes. They imagine in the earth’s early history an “RNA world” that existed before the DNA world. RNA is a nucleic acid, and it has the ability, under certain circumstances, to replicate itself. Proteins cannot replicate themselves without the help of enzymes that catalyze the replication process. So RNA offers a possible solution to this problem. Perhaps a system of replicating RNA molecules could eventually start catalyzing the replication of proteins, the building blocks of an organism.
The main problem with the RNA world is that scientists have not given a satisfactory explanation of how RNA could spontaneously form. Gerald Joyce and Leslie Orgel, two prominent RNA researchers, have admitted that it is difficult to see how RNA could have self-organized in the earth’s early environment. The two primary subunits of RNA—nucleic acids and sugars—tend to repel each other. Joyce and Orgel (1993, p. 13) called the idea that RNA could self-organize “unrealistic in light of our current understanding of prebiotic chemistry” and spoke of “the myth of a self-replicating RNA molecule that arose de novo from a soup of random polynucleotides.” They also called attention to the primary paradox of origin-of-life theories: “Without evolution it appears unlikely that a self-replicating ribozyme [RNA] could arise, but without some form of self-replication there is no way to conduct an evolutionary search for the first, primitive self-replicating ribozyme.” It should also be kept in mind that RNA can self-replicate only under carefully controlled laboratory conditions not easily duplicated in the early history of the earth. Another problem is that there are many kinds of RNA molecules, and not all of them catalyze their own self-replication. Behe (1996, p. 172) observes: “The miracle that produced chemically intact RNA would not be enough. Since the vast majority of RNAs do not have useful catalytic properties, a second miraculous coincidence would be needed to get just the right chemically intact RNA.”
Some researchers have expanded their search for a first nucleotide molecule capable of reproducing itself without the help of enzymes beyond RNA. But thus far all such attempts have been unsuccessful. For example, Stanley Miller and others have proposed peptide nucleic acid (PNA) as an alternative to RNA as the first self-replicating molecule. According to Miller, PNA is a more stable molecule than RNA. But in his experiments Miller has only been able to produce some components of PNA and not the molecule itself (Travis 2000b). In a study published in Science, Eschenmoser (1999, p. 2118) says: “. . . it has not been demonstrated that any oligonucleotide system possesses the capacity for efficient and reliable nonenyzmatic replication under potentially natural conditions.” Eschenmoser, speaking of RNA or any other oligonucleotide molecule, said that “its chances for formation in an abiotic natural environment remain open to question.” He admitted that although most scientists think that the formation of some kind of RNA-like oligonucleotide is a key step in the formation of life, “convincing experimental evidence that such a process can in fact occur under potentially natural conditions is still lacking.”
Developmental Biology
Even if we grant the evolutionists the existence of some first simple living thing, then we have to consider how that first living thing gradually differentiated into other living things, including human beings. One source of evidence about the history of such gradual development is the fossil record. When we looked carefully into the human fossil record, we found evidence that humans have existed since the very beginnings of life. Another type of evidence can be found in developmental biology. Most animals begin life as fertilized eggs, which then become embryos, which then become infant organisms, which then become adult organisms. How this happens is the subject matter of developmental biology. Darwinists say they can find evidence for evolution in developmental biology.
Darwinists often point out that at a certain stage of its development the human embryo resembles that of a fish, and they take this as a proof of evolution. Actually, at a certain stage all vertebrate embryos resemble a fish, and thus resemble each other. Darwin himself said “the embryos of mammals, birds, fishes, and reptiles” are “closely similar.” He thought the best explanation was that the adults of these species are all “the modified descendants of some ancient progenitor.” He also proposed that “the embryonic or larval stages show us, more or less completely, the condition of the progenitor of the whole group in its adult state” (Darwin 1859, pp. 338, 345). In other words, the early fishlike state of the embryo in vertebrates resembles the original adult vertebrate from which all today’s vertebrates supposedly came—we were all once fish. But the logic is flawed by a false estimation of the similarity of the embryos.
The process by which an embryo develops into an adult is called ontogeny, and the process of evolution by which a common ancestor supposedly develops into various descendants is called phylogeny. Many Darwinists, to greater and lesser degrees, have believed that the embryonic development of any vertebrate mirrors the evolutionary process that gave rise to it. As the German Darwinist Ernst Haeckel put it: “Ontogeny recapitulates phylogeny.” To illustrate his point, Haeckel published a series of images of the embryonic development of several vertebrates, each one looking at first like a fish and then developing into its characteristic form. It was later discovered that Haeckel had doctored the images to make the early fishlike stages look more similar in his illustration than they actually were in nature. Haeckel was formally found guilty of this offense by an academic court at the University of Jena. Nevertheless, his illustration of the vertebrate embryos is still widely printed in textbooks of evolution even today.
Apart from the doctoring of the images in the classic illustration of the vertebrate embryos, there is another deception. The first images of the embryo in the illustration, the ones sharing an impressive similarity, are actually from a middle stage of embryonic development. If the illustration included the earlier stages of embryonic development, including the eggs, an entirely different impression would emerge.