Book Review: Science and Human Origins
by Rich Deem

Introduction

Science and Human Origins is the recent book by the Discovery Institute on human origins. Although the Discovery Institute tends to stick to intelligent design without defining the Designer, this offering seems to be aimed specifically at Christians. In fact, the final chapter is entitled, "The Science of Adam and Eve." Is Discovery siding with the creationists or just attempting to market to a larger audience?

John G. West, Associate Director of the Center for Science and Culture introduces the topic by defining terms and the general theory behind common descent and natural selection, along with an introduction of the topics in the book.

Science and human origins

Ann Gauger takes the first chapter, which looks at common descent from the perspective of human origins. Gauger discusses the things that make humanity unique among all other species of life, asking whether such changes were possible in the six million years posited as the timeframe in which humans diverged from apes.

Darwin's little engine that couldn't

Douglas Axe discusses the plausibility of mutation and natural selection accounting for all evolutionary change. Axe and Gauger had performed mutation experiments in order to determine whether mutation could change structurally similar (but functionally different) enzymes into one another. The publication of these experiments cause a lot of controversy, with evolutionists claiming that the results didn't discredit mutation and natural selection as the driving force of evolution. Axe and Gauger attempted to take structurally-related enzymes and produce the function of one from the other through mutation. In the past, creationists have been blasted for showing calculations about how unlikely it would be to produce a given protein from scratch. Since evolutionists don't believe that proteins evolved from scratch (other than the first, putatively simple ones), the calculation is said to be bogus. In theory, similarly functioning proteins could arise, even though the actual amino acid sequences of those proteins could be quite different (although, in practice, this is usually not the case). Axe and Gauger found that even though the two proteins looked the same, the second protein's function could not be coaxed from the first through mutation. Calculations showed that a minimum of seven discrete mutations were required to change the function, something that mutation seemed unable to accomplish. Hence, Axe and Gauger concluded that the putative driving force of evolution (mutation and natural selection) was "Darwin's little engine that couldn't."

Brain Capacities

Human origins and the fossil record

Casey Luskin wrote chapter 3 on human origins and the fossil record. This chapter examines the fossil record of hominins. Luskin reports that the fossil record is, for the most part, sporadic and fragmented, with many early species classified on the basis of a handful of bones. Some of the skeletons required extensive reconstruction from having been crushed, which makes the claims of bipedalism questionable. Luskin also reports on the brain capacities of hominin species, showing that there were definite discontinuities in sizes across the spectrum of hominin species. The figure right (not from the book) shows more recent data from a meta-analysis of all hominin fossils discovered to date. The data shows three distinct groups of species—the Australopithecines, early Homo, and later Homo species. In fact, all four later Homo species have significantly larger brain capacities compared to their nearest "relative," with p values ranging from <0.05 to <0.001 (data from Supplementary Material, Shultz, Nelson, and Dunbar, 2012).¹

Luskin concludes that all hominin species before Homo erectus were apes and not part of the human line. In essence, Luskin concludes that Adam was a Homo erectus and that Neanderthals were all part of modern humanity. However, what Luskin didn't mention was that no Neanderthal mtDNA has survived in modern humans (implying that human males never mated with Neanderthal females or that the offspring of such matings never survived to reproduce) and that evidence of Neanderthal/human mating contributed almost nothing to the modern human genome, and, in fact, did not occur at all in some human populations (such as Africans). Since we don't have any surviving DNA from Homo erectus we cannot determine the genetic relationship between that species and modern Homo sapiens sapiens. However, since there is no evidence of religious artifacts among Homo erectus remains, I would suggest that Adam and Eve were not Homo erectus.

Junk DNA

Luskin examines the evolutionists' claim that "junk DNA" conclusively shows that life evolved through trial and error, with most of eukaryotic DNA consisting of the DNA that has no function. Recent studies show that a large percentage of "junk" or "non-coding" DNA actually codes for a plethora of RNA transcripts (although many of these transcripts do not get encoded into proteins). Most of this RNA is involved in regulation of gene expression, a role vital for the proper functioning of protein-encoding genes. In addition, the structural integrity of chromosomes require the existence of large amounts of repeating sequences that bind to the histone proteins that hold the chromosomes together. However, in bacteria, whose DNA is not contained within chromosomes, have very little "junk DNA," demonstrating that evolution does not produce non-coding DNA for no reason. Luskin ends the chapter with an examination of the putative chromosome 2 fusion event that supposedly took place during the evolution of humanity's ancestors. This section has caused a huge amount of controversy with the evolutionists claiming foul in online blogs about the reporting of the data. The chromosome 2 fusion claim has been an evolutionary mainstay for years, although recent evidence shows that it is not quite as neat and tidy as the evolutionists had originally claimed. It was interesting following the online banter as evolutionary biologists originally attempted to refute the claims, but later just tried to explain how the messy details actually fit with what would have been expected to have been produced through evolutionary mechanisms (maybe not originally, but now that the data is more clear).

The science of Adam and Eve

In a rather shocking deviation from their usual strategy of sticking solely to "intelligent design," Ann Gauger's final chapter deals directly with the Bible's claim that humanity arose from two original parents, Adam and Eve. Studies by population biologist Francisco Ayala and others had originally shown that genes of the human major histocompatibility complex (MHC) had arisen from at least 32 different alleles, requiring an effective population size of 100,000 and a minimum size of 4,000. The problem with the analysis is that the assumptions required by the population model were not met by the MHC genes studied. In order for the mathematical model to work, the genetic sequences in question must not be susceptible to natural selection and have a constant background mutation rate. However, the MHC genes are involved in host defense, so that the more diversity the genes express, the better likelihood individuals will be able to respond to infectious disease. So, the reason why the genes exhibit such a large diversity of alleles is because it is beneficial for populations to express maximal diversity of response to disease. However, what Gauger does not mention is that since Ayala's first analysis of human population sizes in the 1990's, many other studies have been done, most of which have not used MHC genes.² Even so, from the original data suggesting an effective population size of 100,000, the numbers have fallen considerably, and now stand between 3,000 and 10,000. However, the number has never been as low as 2.

Conclusions

Science and Human Origins is a lay-level examination of what science has to say about human origins. A significant amount of the book is also devoted to critiquing the basis for Darwinian evolution. Although the book does not go into the details of the science behind evolutionary theory, it does contain extensive citations of the scientific literature for those who are interested in those details. The book is short and easy to read, even for those who have minimal background in biology. The one thing I didn't like about the book was the overly-zealous attacks on fellow Christian Francis Collins (who believes in theistic evolution), mostly by Casey Luskin.

In a surprise move, the Discovery Institute now seems to be headed toward creationism, which they had previously said was not part of their intelligent design focus. In fact, the book has minimal information on the intelligent design of humans, which makes them unique among all other hominids, although there is much that could have been written on this topic. Still, the book contains a good critique of Darwinian evolution.