Creationists like Todd Wood of Bryan College have admitted that viewing humans and chimps as completely different “kinds” is a “problem” because humans and chimps are nearer to one another genetically than species that creationists view as a single “kind,” like “cats” for instance. Woodʼs technical paper discusses a number of specific “problems” for creationism. Below are edited portions, along with portions of articles by others on the topic, and a suggested reading list.
“The Chimpanzee Genome and the Problem of Biological Similarity” by Todd Charles Wood, creationist [Center for Origins Research, Bryan College, Dayton, TN, USA], 2006
“Abstract. Evidence for the great similarity between chimpanzees and humans was recently reinforced with the publication of a rough draft of the chimpanzee genome…
“If the entire chimpanzee genome had been sequenced, it would probably reveal 40-45 million nucleotides unique to each species. That difference… may sound profound, but remember that the majority of nucleotides are contained in simple repeats, either of satellites or transposable elements. Further, even a length variation of 90 million nucleotides constitutes only 3% of the entire genome.”…
“When comparing the chimpanzee and human genomes, we find a near identity of gene sequences but important differences in transpositional features (including differences in chromosome number, chromosomal inversions, and transposable element content). As noted above, this implies that the important biological differences are not so much in the genes themselves but in how the genes are expressed, which may be related to the substantive differences between the genetic context that arise from transposable or repetitive elements. [See for instance the “60-second science” video, “What is Evo-Devo,” in which Christopher Mims, an editor of Scientific American magazine, explains the role that differing “gene expression” plays in evolution.]
“The high degree of genetic similarity between apes and humans has been repeatedly confirmed since King and Wilsonʼs (1975) summary. Chromosomal banding patterns revealed a high degree of correspondence between human and chimpanzee chromosomes (Miller 1977, Yunis et al. 1980, Yunis and Prakash 1982). Major chromosomal differences detected were a putative fusion of chimpanzee chromosomes 12 and 13 to form human chromosome 2, and pericentromeric inversions on human chromosomes 4, 5, 9, 12, 15, and 16 (Yunis and Prakash 1982).”…“Human chromosome 2 corresponds to two separate chromosomes in chimpanzee. These findings have subsequently been confirmed in studies using fluorescence in situ hybridization (Müller and Wienberg 2001).
“The evolutionary explanation for human chromosome 2 corresponding to two separate chromosomes in the great apes is that two chromosomes in a human ancestor fused at their ends (telomeres), with one of the centromeres becoming inactive. By examining the putative ‘fusion’ point, researchers have discovered an inverted array of telomeric repeats (TTAGGG)n (Ijdo et al. 1991) and other sequences found in subtelomeric chromosomal regions (Fan et al. 2002). Centromeric alpha satellite sequences have been detected on the long arm of chromosome 2, which seem to correspond to an inactive centromere (Alexandrov et al. 2001).…”
“…it is difficult to imagine a scenario other than chromosomal fusion to explain the inverted array of telomere and subtelomere repeats at the putative fusion site on chromosome 2 (Ijdo et al. 1991).”
“Previous Creationist Responses — Since the Bible clearly teaches the special creation of human beings (Gen. 1:26-27; 2:7, 21-22), what does the similarity of humans and chimpanzees mean for creationists? Creationists have responded to these studies in a variety of ways. A very popular argument is that similarity does not necessarily indicate common ancestry but could also imply common design (e.g. Batten 1996; Thompson and Harrub 2005; DeWitt 2005). While this is true, the mere fact of similarity is only a small part of the evolutionary argument.
“Far more important than the mere occurrence of similarity is the kind of similarity observed. Similarity is not random. Rather, it forms a detectable pattern with some groups of species more similar than others. As an example consider a 200,000 nucleotide region from human chromosome 1 (Figure 2). When compared to the chimpanzee, the two species differ by as little as 1-2%, but when compared to the mouse, the differences are much greater. Comparison to chicken reveals even greater differences. This is exactly the expected pattern of similarity that would result if humans and chimpanzees shared a recent common ancestor and mice and chickens were more distantly related. The question is not how similarity arose but why this particular pattern of similarity arose. To say that God could have created the pattern is merely ad hoc. The specific similarity we observe between humans and chimpanzees is not therefore evidence merely of their common ancestry but of their close relationship.
“Evolutionary biologists also appeal to specific similarities that would be predicted by evolutionary descent. Maxʼs (1986) argument for shared errors in the human and chimpanzee genomes would be an example of a specific similarity expected if evolution were true. [Maxʼs article was updated in 2003, including responses to creationists.]
“This argument could be significantly amplified from recent findings of genomic studies. For example, Gilad et al. (2003) surveyed 50 olfactory receptor genes in humans and apes. They found that the open reading frame of 33 of the human genes were interrupted by nonsense codons or deletions, rendering them pseudogenes. Sixteen of these human pseudogenes were also pseudogenes in chimpanzee, and they all shared the exact same substitution or deletion as the human sequence. Eleven of the human pseudogenes were shared by chimpanzee, gorilla, and human and had the exact same substitution or deletion. While common design could be a reasonable first step to explain similarity of functional genes, it is difficult to explain why pseudogenes with the exact same substitutions or deletions would be shared between species that did not share a common ancestor.
“Creationists have addressed these more specific arguments in a variety of ways. Batten (1996) makes three arguments:
- similarity is necessary to reveal a single Creator, since dissimilarity implies multiple creators (also in ReMine 1993, p. 23),
- biochemical similarity is functionally necessary in order for humans (and other organisms) to obtain food (also in Wise 1992),
- the anatomical similarity of humans and chimpanzees should imply a molecular similarity as well (also in Wise 1992; Rana 2001; Wieland 2002).
The first two arguments are good reasons to create some degree of biological or biochemical similarity but they do not explain degrees of similarity. If there were no nonhuman primates, humans would still be recognizably mammalian and therefore revealed as part of the design of a single Creator, but humans would also stand out as special mammals not closely similar to any other particular group of mammals. The necessity for a common biochemistry for nutrient cycles does not explain why chimpanzees exist. They neither form a major source of dietary nutrients for most humans nor share a significant fraction of the diet of most humans. Further, common biochemistry would not explain shared pseudogenes. The third argument merely shifts the problem to the anatomical level. The question remains as to why God created an animal that is so similar to humans.
“More recently, creationists have begun to argue that the similarity between chimpanzees and humans is less - sometimes much less - than claimed by evolutionary biologists (DeWitt 2003, 2005; Criswell 2005; Thompson and Harrub 2005)… Differences are certainly important, and there are many differences between the human and chimpanzee genomes, as detailed above. However, emphasizing these differences does not resolve the problem of similarity. Even if the chimpanzee genome were more than 5% or 10% different from the human genome, the differences are still vastly outnumbered by the similarities (at least 9 to 1). The major pattern that requires explanation is the surprising degree of genomic similarity, as King and Wilson (1975) noted thirty years ago. Listing differences between the genomes does not alter the overall pattern. If anything, the differences are more striking because of the overwhelming similarity.
“An Alternative Creationist Response — Having found most popular arguments about the human/chimpanzee genome similarity insufficent, I find myself in the unenviable position of devising my own explanation. Since I have none, I will attempt instead to develop some principles that could guide research into this problem… As mentioned already, the common creationist response… is to appeal to a designer as the source of the similarity. Although this is undoubtedly true, it is trivial. The point Darwin makes is not that similarity alone indicates common ancestry but that the particular pattern or scheme of similarities across all organisms is the same pattern we would expect from common descent. As Darwin noted in the quote above, appealing to the will of the Creator does not explain the particular pattern of similarity that we observe, except in an ad hoc fashion. Creation biology needs an explanation of the pattern of similarities, not merely an ad hoc appeal to a common designer…
“…Robinson and Cavanaugh (1998b) concluded that all extant felids [cats] belong to the same baramin and presumably descended from a single pair of cats on the Ark, but Slattery and O’Brien (1998) found distances greater than 5% among felid Zfy genes and greater than 3% among felid Zfx genes. Certainly if felid sequences can vary by that amount, what is to preclude the conclusion that the much lower differences observed between human and chimpanzees genomes indicates their cobaraminic status? [“co-baramic” means “belonging to the same ‘baramin’ or ‘kind’”] … As with the genetic diversity of cats, what is to preclude application of this same argument to chimpanzees and humans with the conclusion that we share a common ancestor with an animal? To put this question another way, how can we maintain that felids share a common ancestor with their genomic differences, and deny that the smaller differences between humans and chimpanzees could not also arise from a common ancestor? The only way to do this is to favor other data in baraminology, and to deny the primacy of the genome in determining true phylogenetic or baraminic relationships.
“The Future Of Creationist Genomics — The genome revolution, exciting though it is, is not an obvious victory for creationism. Although more data allows for better testing of ideas, the data that we have present significant challenges to creationist theory, particularly in the realm of biological similarity… If we wish to be good stewards of our very limited resources, we should avoid projects that are unlikely to be productive (e.g. overemphasizing potentially insignificant differences or trivializing the striking similarities) and focus instead on one of the most pressing problems in biology, biological similarity.”
Evidence Of Similarity That The Creationist Above Is Speaking About
2003 — New genetic evidence demonstrates that lineages of chimps (currently Pan troglodytes) and humans (Homo sapiens) diverged so recently [i.e., so closely resemble one another] that chimps should be [reclassified] as Homo troglodytes [i.e., members of the same genus, which is exactly how other species are classified whose genomes resemble one another so closely]. The move would make chimps full members of our genus Homo, along with Neandertals, and all other human-like fossil species. ‘We humans appear as only slightly remodeled chimpanzee-like apes,’ says the study… Within important sequence stretches of these functionally significant genes, humans and chimps share 99.4 percent identity. (Some previous DNA work remains controversial. It concentrated on genetic sequences that are not parts of genes and are less functionally important, said Goodman.) [“Chimps Belong on Human Branch of Family Tree, Study Says” John Pickrell in England for National Geographic News May 20, 2003]
2005 — The first comprehensive comparison of the genetic blueprints of humans and chimpanzees was reported. The DNA sequence that can be directly compared between the two genomes is almost 99 percent identical. When DNA insertions and deletions are taken into account, humans and chimps still share 96 percent of their sequence [with perfect identity].
The typical human protein has accumulated just one unique change since chimps and humans diverged from a common ancestor about 6 million years ago. To put this into perspective, the number of genetic differences between humans and chimps is approximately 10 times LESS than between the mouse and rat. [And just think of how similar a mouse and a rat appear to be, such that some creationists probably are willing to guess that mice and rats arose from the same “kind” via “micro-evolution.” Yet humans are 10 times nearer to chimps than rats are to mice, genetically speaking]
On the other hand, the number of genetic differences between a human and a chimp is about 10 times more than between any two humans.
The researchers discovered that a few classes of genes are changing unusually quickly in both humans and chimpanzees compared with other mammals.
These classes include genes involved in perception of sound, transmission of nerve signals, production of sperm and cellular transport of electrically charged molecules called ions. Researchers suspect the rapid evolution of these genes may have contributed to the special characteristics of primates, but further studies are needed to explore the possibilities.
The genomic analyses also showed that humans and chimps appear to have accumulated more potentially deleterious mutations in their genomes over the course of evolution than have mice, rats and other rodents. While such mutations can cause diseases that may erode a speciesʼ overall fitness, they may have also made primates more adaptable to rapid environmental changes and enabled them to achieve unique evolutionary adaptations, researchers said.
Despite the many similarities found between human and chimp genomes, the researchers emphasized that important differences exist between the two species… Most of these differences lie in what is believed to be DNA of little or no function. However, as many as 3 million of the differences may lie in crucial protein-coding genes or other functional areas of the genome.
“As the sequences of other mammals and primates emerge in the next couple of years, we will be able to determine what DNA sequence changes are specific to the human lineage. The genetic changes that distinguish humans from chimps will likely be a very small fraction of this set,” said the studyʼs lead author, Tarjei S. Mikkelsen of the Broad Institute of MIT and Harvard. [“New Genome Comparison Finds Chimps, Humans Very Similar at the DNA Level,” The National Human Genome Research Institute, 2005]
The human genome is nearly 99% chimp, which also means that the chimp genome is nearly 99% human. And if you changed base pairs in each — one base pair at a time —making both human and chimp draw even nearer to one another genetically, you would eventually reach a point where changing just a single base pair in the genome would make that human a chimp or make that chimp a human. Of course by that time the line between human and chimp would have grown very fuzzy indeed.
Ed (Edward T. Babinski, author of Leaving the Fold: Testimonies of Former Fundamentalists, paperback 2003, Prometheus Books)
Genetic Evidence Exists That Suggests That Soon After The Species That Were To Become “Chimpanzees” And “Humans” Diverged From A Common Ancestor, They Continued To Interbreed For A While
December 10, 2006
Human-Chimp Hybrids
By Stephen Mihm
“On hearing of Darwinʼs theories, the wife of the bishop of Worcester supposedly exclaimed: “Descended from apes? My dear, let us hope that it is not true.” Now the geneticist David Reich of the Broad Institute at Harvard and M.I.T. has advanced a theory that the bishopʼs wife would have found even more disturbing: human and chimp ancestors, after diverging into separate species millions of years ago, came back together and interbred.
“Reich came up with the idea after comparing the genes of humans and chimps. When two species split from a common ancestor, their genes will continue to diverge, or mutate, at a regular clip over time. Reich and his team of researchers, after comparing some 20 million base pairs (the “rungs” of DNA) from humans and chimps, found that different genes began diverging at different times — with genes located on the X chromosome of humans and chimps parting ways most recently.
“Reichʼs explanation is that the two populations interbred on repeated occasions over hundreds of thousands, if not millions, of years, producing hybrids of protohumans and protochimps. The male hybrids were likely to be sterile, but Reich posits that the female hybrids (with their two X chromosomes) were able to mate with males of one of the original species. This would explain why genes on the X chromosome of humans and chimps diverged more recently.
“Itʼs a radical concept. Conventional wisdom holds that the development of separate species happens quickly, most often when populations become separated by a geographical barrier. Even if these groups meet again and manage to mate before diverging too far from one another, their offspring will be unfit and die out. Or so the thinking goes.
“By contrast, Reich argues that hybrids could play an important and positive role in speciation, introducing advantageous traits into a gene pool — including ours. If Reich is correct, the customary image of the human family tree, with its neat and discrete divisions, should be replaced by another metaphor: a dense and impenetrable thicket of branches concealing countless acts of interspecies sex. Itʼs enough to make a bishopʼs wife blush.”
NATURE magazine, 2006
Genetic evidence for complex speciation of humans and chimpanzees
Nick Patterson 1, Daniel J. Richter 1, Sante Gnerre1, Eric S. Lander1, 2 & David Reich 1,3
“The genetic divergence time between two species varies substantially across the genome, conveying important information about the timing and process of speciation. Here we develop a framework for studying this variation and apply it to about 20 million base pairs of aligned sequence from humans, chimpanzees, gorillas and more distantly related primates. Human–chimpanzee genetic divergence varies from less than 84% to more than 147% of the average, a range of more than 4 million years. Our analysis also shows that human-chimpanzee speciation occurred less than 6.3 million years ago and probably more recently, conflicting with some interpretations of ancient fossils. Most strikingly, chromosome X shows an extremely young genetic divergence time, close to the genome minimum along nearly its entire length. These unexpected features would be explained if the human and chimpanzee lineages initially diverged, then later exchanged genes before separating permanently.”
Reading List
Relics of Eden: The Powerful Evidence of Evolution in Human DNA (Published Dec. 2007)
Darwinian Detectives: Revealing the Natural History of Genes and Genomes (Oxford U. Press, July 2007)
The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution (W.W. Norton, Sept. 2007)
Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body
And On The Fossil Front… More Creationist Admissions
“I was surprised to find that instead of enough fossils barely to fit into a coffin, as one evolutionist once stated [in 1982], there were over 4,000 hominid fossils as of 1976. Over 200 specimens have been classified as Neandertal and about one hundred as Homo erectus. More of these fossils have been found since 1976.”
—Michael J. Oard, Creation Research Society Quarterly, Vol. 30, March 1994, p. 222
“The current figures [circa 1994] are even more impressive: over 220 Homo erectus fossil individuals discovered to date, possibly as many as 80 archaic Homo sapiens fossil individuals discovered to date, and well over 300 Neandertal fossil individuals discovered to date.”
—Marvin L. Lubenow, author of Bones of Contention—A Creationist Assessment of Human Fossils, in a letter to the editor of the Creation Research Society Quarterly, Vol. 31, Sept. 1994, p. 70
Ape-Hominid Species In Relative Geological Order Along With Their Cranial Capacities
Sahelanthropus tchadensis
Cranium size, 350 cubic centimeters
Australopithecus [= “Southern Ape” in Latin] afarensis
Cranial capacity varied from about 375 to 550 cc.
Australopithecus africanus Brain size may also have been slightly larger, ranging between 420 and 500 cc. This is a little larger than chimp brains (despite a similar body size)
Australopithecus aethiopicus
The brain size is 410 cc
Australopithecus robustus
The average brain size is about 530 cc.
Australopithecus boisei (was Zinjanthropus boisei)
The brain size is about 530 cc.
Homo habilis
500-800 cc
H. habilis, “handy man”, was so called because of evidence of tools found with its remains. The face is still primitive, but it projects less than in A. africanus. The back teeth are smaller, but still considerably larger than in modern humans. The average brain size, at 650 cc, is considerably larger than in australopithecines. Brain size varies between 500 and 800 cc, overlapping the australopithecines at the low end and H. erectus at the high end. The brain shape is also more humanlike. The bulge of Brocaʼs area, essential for speech, is visible in one habilis brain cast, and indicates it was possibly capable of rudimentary speech. Habilis is thought to have been about 127 cm (5'0") tall, and about 45 kg (100 lb) in weight, although females may have been smaller.
Habilis has been a controversial species. Originally, some scientists did not accept its validity, believing that all habilis specimens should be assigned to either the australopithecines or Homo erectus. H. habilis is now fully accepted as a species, but it is widely thought that the ‘habilis’ specimens have too wide a range of variation for a single species, and that some of the specimens should be placed in one or more other species. One suggested species which is accepted by many scientists is Homo rudolfensis, which would contain fossils such as ER 1470.
Homo georgicus
600-780 cc
This species was named in 2002 to contain fossils found in Dmanisi, Georgia, which seem intermediate between H. habilis and H. erectus. The fossils are about 1.8 million years old, consisting of three partial skulls and three lower jaws. The brain sizes of the skulls vary from 600 to 780 cc. The height, as estimated from a foot bone, would have been about 1.5 m (4'11"). A partial skeleton was also discovered in 2001 but no details are available on it yet. (Vekua et al. 2002, Gabunia et al. 2002)
Homo erectus
750-1225 cc
H. erectus existed between 1.8 million and 300,000 years ago. Like habilis, the face has protruding jaws with large molars, no chin, thick brow ridges, and a long low skull, with a brain size varying between 750 and 1225 cc. Early erectus specimens average about 900 cc, while late ones have an average of about 1100 cc (Leakey 1994). Study of the Turkana Boy skeleton (from Africa) indicates that erectus may have been more efficient at walking than modern humans, whose skeletons have had to adapt to allow for the birth of larger-brained infants (Willis 1989). Homo habilis and all the australopithecines are found only in Africa, but erectus was wide-ranging, and has been found in Africa, Asia, and Europe. There is evidence that erectus probably used fire, and their stone tools are more sophisticated than those of habilis.
Archaic Homo sapiens (also Homo heidelbergensis)
1200 cc on average
Archaic forms of Homo sapiens first appear about 500,000 years ago. The term covers a diverse group of skulls which have features of both Homo erectus and modern humans. The brain size is larger than erectus and smaller than most modern humans, averaging about 1200 cc, and the skull is more rounded than in erectus. The skeleton and teeth are usually less robust than erectus, but more robust than modern humans. Many still have large brow ridges and receding foreheads and chins. There is no clear dividing line between late erectus and archaic sapiens, and many fossils between 500,000 and 200,000 years ago are difficult to classify as one or the other.
Homo sapiens neanderthalensis (also Homo neanderthalensis)
1450 cc on average
Neandertal (or Neanderthal) man existed between 230,000 and 30,000 years ago. The average brain size is slightly larger than that of modern humans, about 1450 cc, but this is probably correlated with their greater bulk. The brain case however is longer and lower than that of modern humans, with a marked bulge at the back of the skull. Like erectus, they had a protruding jaw and receding forehead. The chin was usually weak. The midfacial area also protrudes, a feature that is not found in erectus or sapiens and may be an adaptation to cold. There are other minor anatomical differences from modern humans, the most unusual being some peculiarities of the shoulder blade, and of the pubic bone in the pelvis. Neandertals mostly lived in cold climates, and their body proportions are similar to those of modern cold-adapted peoples: short and solid, with short limbs. Men averaged about 168 cm (5'6") in height. Their bones are thick and heavy, and show signs of powerful muscle attachments. Neandertals would have been extraordinarily strong by modern standards, and their skeletons show that they endured brutally hard lives. A large number of tools and weapons have been found, more advanced than those of Homo erectus. Neandertals were formidable hunters, and are the first people known to have buried their dead, with the oldest known burial site being about 100,000 years old. They are found throughout Europe and the Middle East. Western European Neandertals usually have a more robust form, and are sometimes called “classic Neandertals”. Neandertals found elsewhere tend to be less excessively robust. (Trinkaus and Shipman 1992; Trinkaus and Howells 1979; Gore 1996)
Homo floresiensis
Ancient extinct dwarf human species
Homo floresiensis was discovered on the Indonesian island of Flores in 2003. Fossils have been discovered from a number of individuals. The most complete fossil is of an adult female about 1 meter tall with a brain size of 417cc. Other fossils indicate that this was a normal size for floresiensis. It is thought that floresiensis is a dwarf form of Homo erectus - it is not uncommon for dwarf forms of large mammals to evolve on islands. H. floresiensis was fully bipedal, used stone tools and fire, and hunted dwarf elephants also found on the island. (Brown et al. 2004, Morwood et al. 2004, Lahr and Foley 2004)
Modern Homo sapiens sapiens
1350 cc on average
Modern forms of Homo sapiens first appear about 195,000 years ago. Modern humans have an average brain size of about 1350 cc. The forehead rises sharply, eyebrow ridges are very small or more usually absent, the chin is prominent, and the skeleton is very gracile. About 40,000 years ago, with the appearance of the Cro-Magnon culture, tool kits started becoming markedly more sophisticated, using a wider variety of raw materials such as bone and antler, and containing new implements for making clothing, engraving and sculpting. Fine artwork, in the form of decorated tools, beads, ivory carvings of humans and animals, clay figurines, musical instruments, and spectacular cave paintings appeared over the next 20,000 years. (Leakey 1994)
Human Evolution During The Last 100,000 Years
Even within the last 100,000 years, the long-term trends towards smaller molars and decreased robustness can be discerned. About 30,000 years ago in the Upper Paleolithic the face, jaw and teeth of humans were 20 to 30% more robust than the modern condition in Europe and Asia. About 10,000 years ago in the Mesolithic the face, jaw and teeth of humans were about 10% more robust than ours. Today the smallest tooth sizes of modern day homo sapiens are found in those areas where food-processing techniques have been used for the longest time. This is a probable example of natural selection which has occurred within the last 10,000 years (Brace 1983). Interestingly, some modern humans (aboriginal Australians) have tooth sizes that are larger and more typical of archaic species of homo sapiens.
