Today’s New Reason To Believe

Posted on February 14th, 2007 by Virgil L. Robertson, DC, QME, FAFICC

Bio: Dr. Robertson received his Chiropractic doctorate from Southern California University of Health Sciences in 1985, and currently serves as Clinical Director at Brea Canyon Pain Relief and Rehabilitation Center in Brea, California.

The arch in the small of your lower back is known as the “lumbar lordosis” and it plays an important role in allowing humans to stand upright and walk on two feet. If you’ve ever seen a pregnant woman negotiating her way down the aisle of a supermarket, you’ve surely noticed that the bigger the belly, the more the mother-to-be has to arch backward to keep her balance. Recently, researchers from Harvard University and the University of Texas examined this biomechanical phenomenon and made some fascinating discoveries, which were reported in the December 2007 edition of Nature.

As it turns out, the spines of men and women are not created equal. In fact, it now appears that women have been designed with specific anatomical features that enable them to safely carry the large asymmetric loads associated with pregnancy. Specifically, the research team headed by anthropologist Dr. Katherine Whitcome found that the lumbar spine of human females differs significantly from that of males. The female spine possesses an additional wedge-shaped vertebra, which substantially increases lordotic curvature in women (three wedge-shaped lumbar vertebrae in women vs. two wedge-shaped lumbar vertebrae in men). This feature allows expectant mothers to comfortably assume more extended (lordotic) postures during pregnancy. Additionally, the researchers found that the lumbar zygoapophyseal joint surfaces of women are proportionally larger and more coronally oriented than corresponding posterior joint structures in men. This distinctively female spinal configuration provides a more stable base for posterior weight bearing (hyperlordosis) and helps prevent anterolisthesis (fracture and forward slipping) of the lumbar vertebrae in pregnant women. As pregnancy proceeds and the fetus grows larger, mom simply leans back a little further (up to 28°) to balance the center of gravity over her hips—it’s a simple yet ingenious biomechanical system!

These new research findings indicate that women are particularly well equipped to safely bear the heavy anterior loads that come with pregnancy. Without these anatomical design features, pregnant women would have great difficulty balancing their unborn bundles of joy, and would be much more susceptible to myoligamentous (muscular) injuries and vertebral fractures during the third trimester of gestation.

The research team also reports that the spines of extinct hominid species (australopithecines) possessed the same kind of anatomical features and dimorphic disparities found in humans. The identification of anatomic features and biomechanical systems uniquely common to bipedal primates is not surprising. Previous authors have identified numerous anatomical and physiological characteristics in bipeds that differ from those found in quadrupeds. While the authors of this new study interpret their findings in terms of an evolutionary framework, it should be noted that these findings are, likewise, fully consistent with the predictions of RTB’s Testable Creation Model. In fact, explaining why the unique features of bipedalism appear suddenly in the hominid fossil record some seven million years ago (in the absence of transitional intermediate forms), has proven to be a substantial challenge for evolutionary biologists.

When considering the abundance of elegantly engineered biomechanical systems found in the human body, it’s hard not to be impressed by the obvious hallmarks of design. To quote British physicist Paul Davies, “The impression of design is overwhelming.”

These latest research findings fall into a long line of evidences that provide support for the existence of an Intelligent Designer. The generation of such exquisitely engineered biosystems is simply beyond the scope and capability of random mutation and natural selection.

For more on the emergence of bipedalism see Who Was Adam?

Posted by Fazale ‘Fuz’ Rana, Ph.D.

The 1% Myth

In 1891 Harley Procter commissioned a laboratory to conduct a chemical analysis that would have far-reaching impact. The laboratory determined that only 0.56% of the measured ingredients in a bar of soap failed to fit into the category of “pure soap.” This result led to one of the best-known advertising slogans of all time: Ivory Soap™ “99 44/100% Pure.”

In 1975 Mary-Claire King performed an analysis that also had far-reaching impact. She determined that several human and chimpanzee proteins display a 99% agreement in amino acid sequence. King’s work showed that humans and chimpanzees possess a closer genetic relatedness than anyone at that time had thought. This result has led to one of the best-known cultural icons of our time: “Humans are 99% chimpanzee.”

For many, this genetic similarity represents one of the most compelling arguments for humanity’s evolutionary origin. Presumably, the 99% sequence overlap observed for proteins and DNA indicates that humans and chimpanzees arose from a common ancestor some time in the relatively recent past. Accordingly, the small genetic differences arose after the human and chimpanzee lineages split as a consequence of mutational changes to each species’ genetic material.

(By the way, a high degree of genetic similarity between humans and chimpanzees does not controvert a biblical view of human origins. In fact, Scripture seems to imply that biological similarity exists between humans and other animals, including the Great Apes. (See a recent article I wrote in Connections for a full explanation.)

Even though many evolutionary biologists consider the 99% genetic similarity between humans and chimps as a profound truth, it turns out to be largely useless information. The genetic similarity between humans and chimps doesn’t explain why there is such a fundamental biological and behavioral difference between us and these creatures.

Anthropologist Jonathan Marks addresses this point in his book, What It Means To Be 98% Chimpanzee. Marks maintains that comparisons based on the percent similarity (or difference) of DNA sequences is largely meaningless. As a case in point, he highlights the fact that humans and daffodils possess a 35% genetic similarity. According to Marks,

In the context of a 35% similarity to a daffodil, the 99.44% of the DNA of human to chimp doesn’t seem so remarkable. After all, humans are obviously a heck of a lot more similar to chimpanzees than to daffodils. More than that, to say that humans are over one-third daffodil is more ludicrous than profound. There are hardly any comparisons you can make to a daffodil in which humans are 33% similar.

A recent news focus piece written by John Cohen for Science makes the same point as Marks. The 99% genetic similarity provides limited biological insight, at best. University of California, San Diego zoologist Pascal Gagneux states in the article that

Now it’s totally clear that it’s (the 99% genetic similarity) more a hindrance for understanding than a help.

It turns out that there are numerous features of the human and chimpanzee genomes that differ significantly. And these genetic differences have the potential to account for the biological and cognitive disparities between our species and chimpanzees.

Cohen identifies several key differences between human and chimp genomes that went unnoticed until recently because of the fixation on the 1% genetic difference. For example:

1. The true genetic similarity between humans and chimps is not 99% (which is based on substitution mutations). Instead it’s about 90% when indels (insertions and deletions in the DNA sequences) are considered.
2. Researchers have also discovered that the gene copy number differs for human and chimp genomes. In fact, preliminary data suggests that gene copy number may differ by 6.4% between the two genomes.

Both indels and gene copy number are biologically significant, affecting gene expression.

Thus, the research reveals that humans and chimpanzees are not as genetically similar as popular myth would have us believe. If a 99% genetic similarity implies a close evolutionary relationship, what does a 90% similarity mean?

Nobody would have bought Ivory Soap if it was only 90% pure. Nobody should buy that humans are 99% chimpanzee.

Next week I will discuss another important genetic difference between humans and chimpanzees.

For a detailed discussion of the genetic similarities and differences between humans and chimpanzees and what it means for a human evolutionary and for RTB’s creation model see Who Was Adam?

Chimps Live in Caves, Hunt with Spears, and Make Tools

Who doesn’t like visiting the chimpanzee exhibit at the zoo? These primates are fascinating creatures. New field work indicates that these apes are even more remarkable than anyone could have known. Several recently published reports describe previously unobserved behavior for chimpanzees in the wild. These newly recognized activities bear significantly on evolutionary models and on RTB’s creation model for humanity’s origin.

Chimps Use Caves for Shelter

A study reported by a team of anthropologists from Iowa State University describes cave use by chimpanzees. Jill Pruetz and her team collected chimpanzee feces and hair samples from caves in Senegal and uncovered evidence of feeding in these locales. Occasionally, the researchers observed chimps entering and leaving caves. Correlating temperature measurements and cave usage suggests that chimps temporarily dwell in caves to avoid extreme heat.

Chimps Hunt with Spears

Another study, published in Current Biology by Jill Pruetz’s team, reports that chimpanzees hunt bushbabies with wooden spears that they deliberately manufactured from tree branches. The spear-production process involves several steps, including:

1. Selecting an appropriate branch
2. Stripping away smaller side branches and leaves
3. Removing bark from the branch
4. Using incisors to sharpen the ends to a point

The chimps were observed in the wild jabbing spears into tree openings to kill the bushbabies for food. This behavior was observed for males, females, and juvenile chimps.

Chimps Make Stone Tools

Anthropologists have known for some time that chimpanzees in the wild make use of a wide range of tools produced from leaves, twigs, sticks, and branches. A recent studypublished in the Journal of Human Evolution documents the range of chimp tool usage observed between 1999 and 2006 in the Republic of Congo. Chimps from this locale typically use tools to puncture, pound, and extract ants and termites from their nests. These primates usually manufacture tools from materials in their immediate vicinity. Manufacturing processes include anywhere from 1 to 4 steps that include removing extraneous parts from the raw material, shaping it, and cutting it with their hands and mouths. This study demonstrates that chimpanzee tool usage is much more diverse than previously conceived by primatologists.

Chimpanzees also manufacture stone tools. These implements are used to crack open nuts. Recently, a team of paleontologists uncovered stone tools produced by chimpanzees that date to 4300 years in age. Analysis of these stone tools seem to indicate that chimps transport stones some distance for later use and seek out raw materials with optimal properties.

Implications of Chimpanzee Behavior

These recently recognized behaviors are reminiscent of the types of activities attributed to hominids, like Homo habilis and Homo erectus.

Many think that H. habilis was the first hominid to use “tools.” Paleoanthropologists refer to the “technology” used by this creature as Mode I (or Oldowan) technology. Mode I tools appeared about 2.5 million years ago and consisted of rock flakes chipped away from a stone core using a rock called a hammer stone. Mode I technology persisted for at least 1 million years in the archeological record with no perceptible change.

H. erectus used a more sophisticated “technology,” called Mode II or the Acheulean, than H. habilis. Still, this technology, which appeared about 1.5 million years ago, was quite crude. Mode II technology involved shaping stones, called bifaces, into a variety of forms: (1) teardrop-shaped rocks (hand axes); (2) rocks with a flat, sharp edge (cleaver); and (3) triangular-shaped rocks (pick). Once this technology appears in the archeological record it remains static for nearly 1 million years. Presumably, the bifaces were used to butcher animal remains. Much debate, however, centers on whether H. erectus was a hunter or scavenger.

It appears as if chimps behave in ways that are similar to the first Homo hominids.

Julio Mercader et al., note that:

“The full implications of this line of work require a reevaluation of the terms under which we can make meaningful comparisons of Oldowan and Chimpanzee cultures. The behavioral variables documented at Noulo indicate that chimpanzees and hominins share cultural attributes, including the transport of stones across the landscape for a projected use elsewhere; the optimal combination of raw material, size, and weight criteria to perform a predicted activity; the re-occupation of focal points (the accumulation and concentration of both stone and botanical debris is artificially created by behavior); creation of activity areas; the use of locally available resources; and the curation and selection of specific types of stones that are most optimal for specific technological activities.”

Additionally, the use of caves and the production of spears for hunting by chimpanzees render these same behaviors by Neanderthals much less impressive.

For many, tool use is considered a uniquely human quality. Often, hominid tool use is taken as evidence that these creatures were gradually acquiring human characteristics as they evolved from an ape-like creature. Presumably, this ancestral species had limited, if any, tool-making capabilities. The newly recognized behavior of chimpanzees-which supposedly descended from the same ancestral creature as humans, and hence the hominids-suggests that this interpretation of the archeological record may not be correct. The behavior of H. habilis and H. erectus does not seem to have been that big of a departure from creatures that preceded them in the fossil record, and may represent not much more than microevolutionary advances.

This natural history stands in sharp contrast to the dramatic difference in behavior that takes place when modern humans appear. As paleoanthropologist Christopher Stringer points out in his book African Exodus:

“Certainly, something very special was happening to human society around this time. Before then, Homo sapiens (the hominids) was simply marking time culturally. For millennia upon millennia, we had been churning out the same forms of stone utensils, for example. But about 40,000 years ago, a perceptible shift in our handiwork took place. Throughout the Old World, tool kits leapt in sophistication with the appearance of Upper Paleolithic style implements. Signs of use of ropes, bone spear points, fishhooks and harpoons emerge, along with sudden manifestations of sculptures, paintings, and musical instruments…We also find evidence of the first long-distance exchange of stones and beads. Objects made of mammal bones and ivory, antlers, marine and freshwater shells, fossil coral, limestone, schist, steatite, jet, lignite, hematite and pyrite were manufactured. Materials were chosen with extraordinary care: some originated hundreds of miles from their point of manufacture…It is an extraordinary catalogue of achievements that seem to have come about virtually from nowhere-though obviously they did have a source. The question is: What was it?”

Could it be that the source for this behavior is the image of God?

Clearly, the behavior of the hominids is quite distinct from modern humans.

The new insights into chimpanzee behavior further distance the hominids from modern humans. Chimpanzees use caves, hunt with spears, and make tools from a variety of materials, including stones. Still, these primates unquestionably and profoundly differ from humans in terms of cognitive abilities, capacity for rational and symbolic thought, language use, and musical and artistic expression. Likewise, just because the habiline and erectine hominids made and used tools and engaged in hunting and scavenging activity doesn’t necessarily mean that they were becoming “human.” Instead, their behavior appears to be increasingly animal-like, particularly when compared to chimpanzee activities.

Who Were the Hominds?

RTB’s biblical creation model views the hominids found in the fossil record as animals that were created by God’s direct intervention, and that existed for a time and then went extinct. RTB’s model considers the hominids to be remarkable creatures that walked erect and possessed some level of limited intelligence and emotional capacity. This allowed these animals to employ crude tools and even adopt some level of “culture” much like baboons, gorillas, and chimpanzees. While the RTB model posits that the hominids were created by God’s divine fiat, they were not spiritual beings made in His image. The RTB model reserves this status exclusively for modern humans.

RTB’s model treats the hominids as analogous to, but distinct from, the great apes. Because of this, the RTB model predicts that anatomical, physiological, biochemical, and genetic similarities will exist among the hominids and modern humans to varying degrees. But since the hominids were not made in God’s image, they are expected to be clearly distinct from modern humans, particularly in their cognitive capacity, behavior, “technology” and “culture.” While the RTB model maintains that modern humans reflect God’s image in their activities, hominids should not. The model asserts that modern humans are uniquely spiritual and that the hominids lacked this capacity. The archeological record associated with modern humans and hominid fossils substantiates this prediction. And the close similarity in behavior between chimpanzees and the hominids further corroborates this claim.