Dates calculated from "molecular evolution" do not match those in the fossil record

Fossil evidence indicates that ancient bacteria, Archea (Archaebacteria) have existed on the earth for at least 3.5 billion years (1). A study published in January, 1996 examined the origin of life through molecular evolution of "protein clocks" (2). A total of 531 sequences of the genes of 57 metabolic enzymes from 15 phylogenetic groups were plotted based upon the known divergence dates in the fossil record. The seven divergence points of these phyla were plotted verses the time of divergence, resulting in a straight line (r = 0.94, where r = 1.0 is a perfect fit).

The line indicated the origin of life occurred ~1.5 billion years ago, even though there is definitive evidence for life at 3.5 billion years ago. Drs. Mooers and Redfield attempted to explain the discrepancy with various alternatives (3). They suggested that the molecular evidence may be misleading. However, to reconcile the data, much of molecular biology would have to be discarded. They also suggested that the fossils chosen for use in the Doolittle et al. study may have been misdated. They discounted this possibility, since the fossil record of these creatures has been confirmed by numerous investigators in numerous studies. They suggested that there might have been a slower rate of amino acid substitution in early life forms. However, these creatures, being bacteria, have generation times of minutes, compared to later creatures, which have generation times of days to years. They concluded, "This idea has no basis in theory."

Mooers and Redfield then suggested that the results might be explained by multiple substitutions at the same site, thus underestimating divergence times. However, Doolittle et al. tested departure from the standard model and found that this had little effect upon divergence times. The model, in fact, predicts a divergence between the plants and the animals/fungi at one billion years ago, which many scientists would think was too long ago. The only conclusion Mooers and Redfield could come up with was that present day Archea are examples of convergent evolution and are not directly descended from the ancient Archea. They propose the original Archea arose, diversified, died and arose again two billion years later. The alternative theory, that God, the Creator, does not necessarily work through a protein clock, was not discussed.

References

1. Schopf, J.W. 1993. Science 260: 640-646.
2. Doolittle, R.F., D.-F. Feng, S. Tsang, G. Cho, and E. Little. 1996. Determining divergence times of the major kingdoms of living organisms with a protein clock. Science 271: 470-477.
3. Mooers, A.O. and R.J. Redfield. 1996. Digging up the roots of life. Science 379: 587-588.