afdave
Posts: 1621
Joined: April 2006
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DIFFICULT QUESTIONS REMAIN FOR APE/HUMAN ORIGINS
I appreciate the good information that was exchanged on my "Chimp Chromosome Thread." I have learned some important information regarding the similarity of the genomes of apes and humans. I agree that the similarities are quite striking indeed and cannot be dismissed as some Creationists attempt to do.
However, I believe there are a number of major issues which would have to be solved before a scientist could logically adopt the firm position that humans and apes DO IN FACT share a common ancestor. Of course, I am becoming quite proficient at searching the "Index to Creationist Claims" and the Article DB at Talk Origins now BEFORE posting my questions here, so as not to waste your time. I will summarize the points of agreement that I share with Neo-Darwinists, then pose my questions. I have surveyed the various Creationist refutations of common descent for apes and humans and have found most of them to be inadequate. These inadequacies are spelled out rather nicely by Todd Charles Wood (2006) of the Center for Origins Research at Bryan College in Dayton, Tennessee, who appears from this paper to be a fair-minded creationist.
Wood Article (2006)
Points of Agreement between myself (Wood also) and Common Descent Advocates
(1) Nucleotide mismatches appear to be very small ~1.5%
(2) Alignment gaps are also very small ~3-4%
(3) Human Chromosome 2 does in fact appear to be a result of the fusion of 2 chimp chromosomes
(4) The pseudogene for Vitamin C production does in fact appear to support common descent theory
(5) Body similarities are indeed very striking and pose interesting questions
(6) Many creationist arguments are inadequate.
Summary of Inadequacies of Creationist Responses (Wood)
(1) Similarity pointing to Common Design is inadequate.| Quote | | 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.(p.7) |
(2) Possibility of higher % differences proves nothing.| Quote | | 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). These arguments are inspired in part by a study by Britten (2002) that concluded that the overall similarity of human and chimpanzee genomes is ~95%. Britten arrived at this greater dissimilarity by including in his calculations not only nucleotide mismatches but also alignment gaps. Creationists also tend to emphasize other important differences between the human and chimpanzee genomes, including the differing chromosome numbers (DeWitt 2003, 2005) and the differences in gene expression in the humans and chimpanzees (Rana 2001).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. (p.9) |
(3) There may be NO "Haldane's Dillema" at all.| Quote | | Based on a 10% dissimilarity between the human and chimpanzee genomes, Criswell argued that humans and chimpanzees could not have evolved from a common ancestor. Criswell reasoned that if evolution were true, a 10% difference would mean that 300 million mutations had been fixed in the human and chimpanzee genomes, or roughly 150 million mutations in each species. Assuming that the human/chimpanzee last common ancestor lived 5 million years ago (Ma), he calculated that an average of 600 “beneficial mutations” must have been fixed in each generation. He concluded that Haldane’s dilemma prohibits such a large number of mutations fixed by selection.Even conceding his assertion of <90% identity between human and chimpanzee genomes, his argument suffers from some errors. (p.10) |
Wood then goes on to propose an intriguing alternative ...| Quote | Despite these shortcomings[of the ReMine Message Theory], it is possible that ReMine’s message theory could be modified to explain biological similarity. Although ReMine (1993, p. 368) claimed that his message theory would be invalidated if the unique, nested hierarchy of organisms was falsified, other interpretations of the biotic message could be consistent with non-nested or non-hierarchical patterns. For example, a network pattern of similarity can also serve as a message because a network pattern has the attributes of language. In written language, a very limited number of letters can be rearranged to form a great number of words, which in turn can be rearranged (following rules of grammar and syntax) to express a virtually unlimited number of ideas. If organisms and their genomes are conveying a message (or messages) from the Creator, we should expect a high degree of repetition, both within and between genomes, because of the nature of language. It is therefore intriguing that the human and chimpanzee genomes contain a high fraction of repetitive DNA and that some of the more significant differences between the genomes are in their repetitive DNA (segmental duplication and transposable element) content. If correct, this line of reasoning would imply that a proper understanding of the similarity of humans and primates would depend on detecting rules of “syntax” and “grammar” in the biotic message and applying them.
Furthermore, a network pattern of similarity resulting from transposition could serve a non-naturalistic function since a network pattern is not expected from tree-like inheritance. ReMine (1993, pp. 342-343) argued that evolution “does not predict a nested hierarchy,” but that is only true if evolution is understood in the broadest possible way to include many different (and potentially contradictory) theories. Specific theories of evolution (like Darwin’s) do predict nested hierarchies. Other theories (e.g. Woese 1998) could be constructed to accommodate widespread transposition, but these arguments are not arguments for common descent. As a result, a network pattern of similarity resist simple explanation by naturalistic theories (although complicated theories of transposition might explain it), thus reinforcing its origin by design.(p.12) |
and he asks an important question which serves as an excellent prelude to my own questions ... | Quote | | What is a Genome? This might seem like a trivial and self-evident question, but its simplicity hides a deep challenge (Wood 2001). The Bible teaches that God created adult organisms and presumably even complete ecosystems by covering the land with plants. Thus, the Bible favors a holistic perspective of organisms. Modern molecular biology has favored the opposite perspective: that life is the complicated interaction of molecules and that DNA is the “code of life.” If the molecular viewpoint is correct, then the differences between organisms that really matter are indeed the differences in the DNA. If a holistic perspective is correct, then perhaps differences in the DNA are not paramount to understanding organismal differences.Complicating this reasoning is the fact that differences in DNA do indeed cause differences at the organismal level. There is a definite relationship between phenotype and genotype, even though the relationship is not as simple as Mendel might have imagined it. We could understand the genome as a repository of some of the information necessary for the physical composition of the organism (Wood 2001). In that case, far more important than the genome may be its cellular context, which interprets and applies the information stored in the genome. Since some of the cellular context is coded by the genome, we have something of a chicken/egg problem, which can only be resolved by a creation event.The similarity of the human and chimpanzee genomes offers evidence that the genome could primarily be a repository. If the fixed nucleotide mismatches between the chimpanzee and human genomes are 1.06%, then the original nucleotide identity could be as high as 99%. At that high level of similarity, perhaps it is not impossible to believe that God created humans and chimpanzees with identical genomes. The known differences between human and chimpanzee biochemistry (see Varki 2000; Varki and Atheide 2005) may well rule this out, but it is an intriguing possibility. Even at 99% identity, however, the biological and behavioral differences between chimpanzees and humans indicate that the source of these differences is not likely to be found entirely in the genome sequences. Theologically, the high similarity of humans and chimpanzees reinforces our spiritual – not physical (Ecc. 3:18-21) – distinctiveness from the animals. It is the image of God that makes us human not some intrinsically valuable genetic element.(p.12) |
This paper by Wood is quite interesting to me and serves well as a prelude to my own questions which I shall now present to you ...
(1) How do we explain the complete lack of 'Hominid Civilizations' (for lack of a better term) today? It seems to me that if Common Descent Theory is correct, that we would expect to see numerous 'civilizations' of 'less evolved' humans. I suppose a hopeful candidate for this type of civilization has been the remote tribes of jungle natives found throughout the world. However, I have firsthand experience with one such tribe, the Wai-Wai indians of Southern Guyana/Northern Brazil (My father is a Bible Translator for this tribe), and we have observed no evidence of anything 'primitive' about their human characteristics. To be sure, their civilization and technology was quite primitive (they were basically hunter/gatherers), but their language is every bit as complex as English or Spanish or many other languages (I speak the language some and have a copy of their grammar, which my dad produced). Their behaviour is in no way 'primitive' for the purpose of determining if they are 'less evolved.' They laugh, cry, make jokes, tell stories, get mad at one another, read, write, learn foreign languages, play guitars and keyboards, have political battles, and in short do everything that any human society also does. The main difference is in technology, which of course is not advanced. As far as I know, there are Apes and there are Humans. And there are no existing 'in-betweens.' How do you explain this?
(2) The fossil record of human evolution is unconvincing to me. Here is the supposed evidence from Talk Origins ... | Quote | Intermediate fossils include
Australopithecus afarensis, from 3.9 to 3.0 million years ago (Mya). Its skull is similar to a chimpanzee's, but with more humanlike teeth. Most (possibly all) creationists would call this an ape, but it was bipedal.
Australopithecus africanus (3 to 2 Mya); its brain size, 420-500 cc, was slightly larger than A. afarensis, and its teeth yet more humanlike.
Homo habilis (2.4 to 1.5 Mya), which is similar to australopithecines, but which used tools and had a larger brain (650-cc average) and less projecting face.
Homo erectus (1.8 to 0.3 Mya); brain size averaged about 900 cc in early H. erectus and 1,100 cc in later ones. (Modern human brains average 1,350 cc.)
A Pleistocene Homo sapiens which was "morphologically and chronologically intermediate between archaic African fossils and later anatomically modern Late Pleistocene humans" (White et al. 2003, 742).
A hominid combining features of, and possibly ancestral to, Neanderthals and modern humans (Bermudez de Castro et al. 1997).
And there are fossils intermediate between these (Foley 1996-2004). |
Do we not have plenty of LIVING HUMANS which could correlate very nicely with some of these fossil finds, but which we now know are completely human? i.e. Pygmies and 'Aborigines' ?
(3) Some have claimed that for all practical purposes, we are apes and biologically speaking, I see what they are saying. But does this not minimize the ENORMOUS non-biological differences? Humans have highly complex symbolic languages. Apes probably communicate some, but do they communicate in DIFFERENT LANGUAGES in different parts of the world? Are there any apes that have learned how to write? Do apes organize themselves into 'governments' and seek to conquer other ape groups? Is there any indication of abstract thinking among the apes? Is there any evidence of any 'technology' developed by apes? Even primitive technology? And this is only the tip of the iceberg with such questions.
(4) Has anyone thought about the implications of an assertion by a government entity that "Apes are 98.5% human and therefore should be afforded certain 'human rights.'" This would be a silly idea to me of course, but it appears to be a logical conclusion of some evolutionist thinking.
(5) Was not Adolf Hitler affected by current evolutionary thinking when he came up with his "Aryan Master Race" theory? I believe he was, and why shouldn't he have been? Isn't it logical to assume that some races might be 'less evolved' than others if human evolution is true? How about slavery? Did not many whites view themselves as 'more evolved' than blacks, thus justifying their ownership and ill treatment of slaves? And if human evolution is true, why would Hitler and slave owners be wrong in their actions? After all, we 'enslave' chimps in zoos and we do medical experiments resulting in the death of lab rats. Why should we not do the same with 'less evolved' humans?
My conclusion then is that in spite of striking genome similarities, humans and the apes are VERY DIFFERENT in many important ways. All the evidence that I have seen so far is explained in a much better way by the Biblical assertion that mankind was made "in the image of God." It appears to me also that Neo-Darwininsts are not even close to being able to answer ANY of the above questions in a satisfactory manner. But maybe you will prove me wrong.
OK. That should do it for starters. I welcome your comments.
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A DILEMMA FOR THE COMMITTED NATURALIST
A Hi-tech alien spaceship lands on earth ... DESIGNED.
A Hi-tech alien rotary motor found in a cell ... NOT DESIGNED.
http://afdave.wordpress.com/....ess.com
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