Human Body Hair is Useless, Right? WRONG!

Many evolutionists think that body hair in humans is useless. The data say otherwise. (Click for credit)

One of the many reasons scientists are rejecting the hypothesis of evolution (see here and here, for example) is that many of its predictions have been falsified (see here, here, here, and here for even more examples). The more we learn about the world around us, the more clear it is that the predictions of the evolutionary hypothesis just don’t work. This is probably most apparent when it comes to “vestigial organs,” biological structures that are supposed to serve no real purpose; they are simply leftover vestiges of the evolutionary process. As Darwin himself said, they are like the silent letters of a word. They don’t serve a purpose in the word, but they do tell us about the word’s origin.


I have written about vestigial structures many times before (here, here, here, here, here, here, and here) because they are so popular among evolutionists. However, as the data clearly show, the evolutionists are simply wrong about them, and the more research that is done, the more clear it becomes. The latest example is human body hair. This has always been a favorite among evolutionists. Here are two evolutionary descriptions of human body hair. The first comes from a book specifically designed to help the struggling evolutionist in his attempt to convince people that his hypothesis has scientific merit.1

Humans, like all other organisms, are living museums, full of useless parts that are remnants of and lessons about our evolutionary histories (Chapter 6). Humans have more than 100 non-molecular vestigial structures. For example, our body hair has no known function.

The second comes from a textbook2

Body hair is another functionless human trait. It seems to be an evolutionary relic of the fur that kept our distant ancestors warm (and that still warms our closest evolutionary relatives, the great apes).

As is the case with most evolutionary ideas, serious scientific research has shown that such statements are simply wrong.

Many people are surprised to learn that they are actually a walking ecosystem. Your body is home to roughly ten times as many bacterial cells as human cells. There are also fungal cells, but they have not been nearly as well characterized as the bacterial cells. While this might sound gross, it is actually a good thing. These bacteria are so “thankful” for the food and housing you are providing for them that they “pay you back” by doing all sorts of important tasks for you. Some make chemicals that you cannot make for yourself, some help you to digest your food, and some help you fight off infection. Without them, you would not be nearly as healthy as you are today.

As time has gone on, this community of microorganisms (collectively called the human microbiome) has become an object of intense scrutiny. In 2011, a review paper was published in Nature Reviews Microbiology about the human skin microbiome, surveying what was known at the time. One thing it noted was that the different parts of the skin provide different habitats for different microorganisms. For example, the microorganism population that resides in a hair follicle is different from the population that resides in a sebaceous gland.3 As a web review of the article says:

The folds, follicles and tiny oil-producing glands on the skin’s surface create a multitude of diverse habitats, each with its own community of microbes.

In other words, for a person to have a complete microbiome, he or she must have all the habitats that the skin microorganisms need, including hair follicles.

Why is it important to have a complete microbiome? A paper was recently published in the journal Science that gives a partial answer. The authors studied mice that had been raised in germ-free conditions. They looked at how these mice (which had no microbiome) and normal mice (which had a complete microbiome) reacted to a specific skin infection. When the infecting agent (Leishmania major) was introduced to both groups of mice, they all produced a specific kind of cell (called a T-cell) to fight the infection. However, the activity of the T-cells in the germ-free mice was not nearly as effective as that of the T-cells in the normal mice.

To make sure that it was the actual skin microbiome that caused the difference in the response between the two groups, the authors did two things. First, they gave the normal mice oral antibiotics to kill all the microorganisms in their intestines. Since the intestinal microbiome is known to aid the immune response, it was possible that the intestinal microbiome was the reason the normal mice produced more effective T-cells. However, they found that the normal mice still produced effective T-cells against the infection, even without intestinal microorganisms.

Second, they added a single species of bacterium that is found on human skin (Staphylococcus epidermidis) to the “germ-free” mice. When they did that, the germ-free mice started producing effective T-cells. Here is what the authors conclude:4

Altogether, our work proposes that resident [microorganiams] are necessary for optimal skin immune fitness…Understanding the role of the skin microbiota in maintaining tissue function is not only of primary importance for human health, but will also lead to the development of more rational tissue specific adjuvants and vaccine approaches.

Note that, according to these researchers, understanding how the microorganisms (microbiota) maintain tissue function is of primary importance to human health. So in order to be healthy, you need to have a good microbiome. However, to have a good microbiome, you must have all the habitats that the microorganisms need in order to maintain strong populations. This includes hair follicles. Rather than being useless, then, hair is critically important to maintaining skin health, as its follicles provide a necessary environment for certain members of the skin microbiome.

Now the importance of this research goes beyond demonstrating that yet another evolutionary prediction has been falsified. It even goes beyond the author’s suggestion of producing better products to promote skin health and fight off infection. To me, it provides possible insight into the pre-Fall role of certain microorganisms. Creationists have proposed that microorganisms (and even viruses) were initially created as a link between macroorganisms and the environment. They were designed to allow the macroorganisms access to the chemical richness of their surroundings. It makes sense that in a post-Fall world, the skin microbiome, which was likely associated with drawing beneficial chemicals from the environment, would change to becoming a support system against infection.

As we learn more about the specific interactions that take place between an organism’s microbiome and its own cells, we might be able to better understand how the microbiome was (and probably still is) able to perform its pre-Fall role.

REFERENCES

1. Sehoya Cotner and Randy Moore, Arguing for Evolution: An Encyclopedia for Understanding Science, Greenwood 2011, p. 193.
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2. Gerald Audesirk, Teresa Audesirk and Bruce E. Byers, Biology: Life on Earth with Physiology (8th Edition), Benjamin Cummings 2007, p. 292.
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3. Elizabeth A. Grice and Julia A. Segre, “The skin microbiome”, Nature Reviews Microbiology 9:244-253, 2011.
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4. Shruti Naik et. al, “Compartmentalized Control of Skin Immunity by Resident Commensals”, Science DOI: 10.1126/science.1225152, 2012.
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64 Comments

  1. Jason July 30, 2012 10:36 am

    I must say, once again I am blown away by the fine tuning, design and complexity of our bodies.

  2. Student M July 30, 2012 2:10 pm

    Thanks for a great blog, Dr. Wile! So is it a bad idea to shave your legs or get laser hair-removal? Are we more likely to get skin infections that way, since the skin-protecting bacteria’s habitat is destroyed?

    • jlwile July 30, 2012 3:53 pm

      Thanks for your question, Student M. Shaving the hair doesn’t affect the follicle, so I wouldn’t expect any negative consequences when it comes to shaving. Obviously, if you shave with too dull a blade, you can cause inflammation, and if you cut yourself shaving, that could lead to infection. However, just cutting the hair back should not have any negative effects.

      http://www.drwile.com

  3. Raphael Verelst July 31, 2012 7:53 pm

    Even if this were true and well (which it most certainly is not), who says that the answer is by default the christian god?

    Take a look at this fascinating article showing how bacterial life could spring up on another planet through -coughs- abiogenesis and -coughs- the “hypothesis” of evolution:

    http://www.guardian.co.uk/science/2012/jul/29/alien-life-enceladus-saturn-moon

    • jlwile July 31, 2012 8:29 pm

      Thanks for your comment Raphael. I wonder why you indicate that what I have written is “most certainly” not true. Do you disagree with the findings of the studies? If so, can you tell us the flaws that you see in them? Also, could you please indicate to me where I say that because body hair is not useless, the Christian God must exist? I don’t even imply that in this article.

      You might want to be a bit careful when it comes to linking evolution and abiogenesis. Most evolutionists are very careful to separate the two, since abiogenesis has so many scientific problems that even its supporters recognize that the data are stacked heavily against it.

      In terms of the article, I note that it doesn’t even make an attempt to explain how life might have originated on Enceladus. Instead, it simply talks about scientists’ hopes that it might have. Hopes are very good, but they are not a part of science. Once you come up with a reasonable explanation for how life might have formed on Enceladus (or on earth for that matter), then it becomes a scientific discussion.

      http://www.drwile.com

  4. Raphael Verelst July 31, 2012 7:59 pm

    We have several other useless apparatus that require “refutation”, Jay:

    VOMERONASAL ORGAN
    A tiny pit on each side of the septum is lined with nonfunctioning chemoreceptors. They may be all that remains of a once extensive pheromone-detecting ability.

    EXTRINSIC EAR MUSCLES
    This trio of muscles most likely made it possible for prehominids to move their ears independently of their heads, as rabbits and dogs do. We still have them, which is why most people can learn to wiggle their ears.

    WISDOM TEETH
    Early humans had to chew a lot of plants to get enough calories to survive, making another row of molars helpful. Only about 5 percent of the population has a healthy set of these third molars.

    NECK RIB
    A set of cervical ribs—possibly leftovers from the age of reptiles—still appear in less than 1 percent of the population. They often cause nerve and artery problems.

    THIRD EYELID
    A common ancestor of birds and mammals may have had a membrane for protecting the eye and sweeping out debris. Humans retain only a tiny fold in the inner corner of the eye.

    DARWIN’S POINT
    A small folded point of skin toward the top of each ear is occasionally found in modern humans. It may be a remnant of a larger shape that helped focus distant sounds.

    SUBCLAVIUS MUSCLE
    This small muscle stretching under the shoulder from the first rib to the collarbone would be useful if humans still walked on all fours. Some people have one, some have none, and a few have two.

    PALMARIS MUSCLE
    This long, narrow muscle runs from the elbow to the wrist and is missing in 11 percent of modern humans. It may once have been important for hanging and climbing. Surgeons harvest it for reconstructive surgery.

    MALE NIPPLES
    Lactiferous ducts form well before testosterone causes sex differentiation in a fetus. Men have mammary tissue that can be stimulated to produce milk.

    ERECTOR PILI
    Bundles of smooth muscle fibers allow animals to puff up their fur for insulation or to intimidate others. Humans retain this ability (goose bumps are the indicator) but have obviously lost most of the fur.

    APPENDIX
    This narrow, muscular tube attached to the large intestine served as a special area to digest cellulose when the human diet consisted more of plant matter than animal protein. It also produces some white blood cells. Annually, more than 300,000 Americans have an appendectomy.

    BODY HAIR
    Brows help keep sweat from the eyes, and male facial hair may play a role in sexual selection, but apparently most of the hair left on the human body serves no function.

    PLANTARIS MUSCLE
    Often mistaken for a nerve by freshman medical students, the muscle was useful to other primates for grasping with their feet. It has disappeared altogether in 9 percent of the population.

    THIRTEENTH RIB
    Our closest cousins, chimpanzees and gorillas, have an extra set of ribs. Most of us have 12, but 8 percent of adults have the extras.

    MALE UTERUS
    A remnant of an undeveloped female reproductive organ hangs off the male prostate gland.

    FIFTH TOE
    Lesser apes use all their toes for grasping or clinging to branches. Humans need mainly the big toe for balance while walking upright.

    FEMALE VAS DEFERENS
    What might become sperm ducts in males become the epoophoron in females, a cluster of useless dead-end tubules near the ovaries.

    PYRAMIDALIS MUSCLE
    More than 20 percent of us lack this tiny, triangular pouchlike muscle that attaches to the pubic bone. It may be a relic from pouched marsupials.

    COCCYX
    These fused vertebrae are all that’s left of the tail that most mammals still use for balance and communication. Our hominid ancestors lost the need for a tail before they began walking upright.

    PARANASAL SINUSES
    The nasal sinuses of our early ancestors may have been lined with odor receptors that gave a heightened sense of smell, which aided survival. No one knows why we retain these perhaps troublesome mucus-lined cavities, except to make the head lighter and to warm and moisten the air we breathe.

    • jlwile July 31, 2012 8:32 pm

      Thanks for copying from a website, Raphael. I am sure the author of that article would appreciate it if you actually give her credit next time you plagiarize her work.

      The supposedly “useless” nature of each of these has already been addressed, and as you can see, they are either not useless or are actually pathological conditions that have nothing to do with the hypothesis of evolution.

      http://www.drwile.com

  5. Raphael Verelst July 31, 2012 8:16 pm

    Logical proof Adam and Eve had AIDS:

    Premise 1: AIDS is transmitted via sexual intercourse
    Premise 2: AIDS was created by God
    Premise 3: Adam and Eve were “created” by God

    Conclusion 1: To spread AIDS to the human race, Adam and Eve must have had aids

    Conclusion 2: God must have been a real [deleted because of foul language] if he made it.

    Plus, why would an all-benevolent father deliberately place an evil tree in “paradise” which he knew (due to his omniscience (don’t go spouting about free will. Omniscience directly contradicts free will)) they would find.

    If God did execute the Genesis story, he must have been an enormous [deleted because of foul language]?

    • jlwile July 31, 2012 8:46 pm

      There is a big problem with the argument in your third comment, Raphael. Premise 2 is quite incorrect. As Romans 8:18-22 tells us, things like AIDS are the result of man’s rebellion in the Fall. Thus, God did not create AIDS. Man’s rebellion created AIDS. I also find your Conclusion 1 rather odd. I assume you are an evolutionist, yet you don’t seem to entertain the idea that AIDS could have evolved, as all other evolutionists do. Could you explain that a bit for me?

      You ask, “Plus, why would an all-benevolent father deliberately place an evil tree in “paradise” which he knew (due to his omniscience (don’t go spouting about free will. Omniscience directly contradicts free will)) they would find.” The tree was not evil. Man’s rebellion was evil. The tree was all good. However, God told man not to eat from the tree. The fact that man disobeyed God is the evil in the account. Also, omniscience has no conflict at all with Free Will.

      I also find it odd that you say that the God who created this incredible planet in this amazing universe is somehow a bad guy because man couldn’t live within the boundaries that God established. Do you have children? When they go beyond the boundaries that you have established, do you say that YOU are the bad guy for establishing those boundaries?

      http://www.drwile.com

  6. Raphael Verelst July 31, 2012 9:09 pm

    Doc, why did God, an omniscient being who knows EVERYTHING THAT EVER HAPPENED AND HAS HAPPENED, deliberately place a mortal danger in front of his loving creation? Really? You’re in paradise, but there’s one danger you can’t abide. The article you cited says that “he knows what we will choose ahead of time”. So he KNEW that Eve would pluck the tree of knowledge?

    Most theologians agree that this is a symbolic story referring to innocence while leaving childhood (created = pregnancy).

    I presume you’re a YEC, but how come 1 Peter 3:15 says “A day can be any time with God?”

    Good suggestion: look up the BioLogos foundation, founded by Francis Collins to promote theistic evolution.

    Also explain to me why coincidentally the genetics fit the fossil record, and the fossil record fits, according to the time calculation via various forms (not just radiometric dating), and look identical via morphology?

    Also, my Conclusion 1 is based firmly on the fact that “viruses adapt only because of there host”. The virus, considering the host was always the same (humans). has always been virulent

    Doctor, if Eve was created from Adam’s rib, they had identical DNA.

    If they had identical DNA, their children must have been identical, because the 23 chromosomes would be identical.

    So, if the Genesis were true, why are we not all identical?

    Our ear lobes are useless, by the way, so is our appendix, that only filters low calory items.

    • jlwile August 1, 2012 7:04 am

      Thanks for your follow-up comments, Raphael. You seem to have a lot of misconceptions, so let me try to clear them up for you. First, you ask why a God who knew everything would put a mortal danger in paradise. As I told you before, the tree was not a mortal danger. It was most likely an incredibly beautiful tree. The danger was in Adam and Eve disobeying God. Now…if you are wondering why God would make Creation the way He did knowing that Adam and Eve would sin, your focus is in the wrong place. You are focusing on the fact that Adam and Eve lost Paradise. What you don’t seem to understand is that God also knows that Paradise isn’t lost forever. God had also planned redemption through Jesus Christ. Since God knows everything, He knows that Paradise is not really lost. It is regained through Christ.

      Second, you say that “most theologians” agree that this is a symbolic story referring to innocence while leaving childhood. Could you please cite some statistics to back up that claim? I have a very broad reading list, and I see some theologians who believe that the story is symbolic (not necessarily about leaving childhood) and some who believe it is history. I have seen no trend to indicate that the majority see it as symbolic. In addition, I don’t know many who believe it relates to leaving childhood.

      Third, you need to check your Bible. 1 Peter 3:15 says, “But in your hearts revere Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect.” I think you are referring to 2 Peter 3:8, which says, “But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day.” That is most certainly correct, but that passage is talking about when the Day of the Lord will come. It isn’t referencing creation.

      Fourth, you seem to think that I don’t know about the Biologos foundation. If you took the time to peruse this blog, you would find that I reference it frequently. Thus, I am very well aware of it. If you read some of those articles, you will understand why I find their work far from convincing.

      Fifth, you seem to think that genetics fit the fossil record when it comes to evolution. That is certainly not the case. In fact, genetic studies contradict the fossil record, which is why there is a big controversy in the evolutionary community about how to track evolution. It’s actually worse than that, though. Genetic studies contradict other genetic studies. If you look at one suite of genes, you get one evolutionary story, if you look at another suite of genes, you get a different evolutionary story. In addition, the timelines don’t work, either. For example, there is strong evidence for the existence of birds long before birds were supposed to have evolved, and there is strong evidence for amphibians long before amphibians evolved. Those are just two examples.

      Sixth, you seem to think that humans have never changed. That is, of course, not at all true. Humans have changed remarkably over the years. In fact, one genetic study shows that there have been more than 2,000 genetic adaptations in humans throughout archaeological history. There is no reason to think that the AIDS virus has always been around and has always been virulent. In fact, there are great reasons to think otherwise.

      Seventh, you seem to think that Eve was a clone of Adam. That’s certainly not the case. If it were, she would be male, not female! The rib was the starting point for Eve. It wasn’t the sole contributor to Eve’s genetic makeup. Please note that even if Even and Adam were genetically identical, they would not have identical offspring. Sexual reproduction has been designed by God to produce variation. Because of the dominant/recessive nature of genetic alleles, there would be a lot of variation in the sexual reproduction of identical genomes. Consider a simple trait like being able to roll your tongue. That is determined by a singe gene in humans. If Adam was heterozygous in that gene and Eve was as well, they would both be able to roll their tongues. However, 25% of their offspring would not be able to roll their tongues. You might want to learn a bit more about the genetics of sexual and asexual reproduction.

      Eighth, you still seem to think there are a lot of useless organs out there, which the data tell us just isn’t correct. We’ve known for nearly eight years now that the appendix is very important in maintaining healthy intestinal flora. As far as earlobes go, they are part of what makes each of us different. This allows for different levels of sexual selection in the population, which is crucial to allow for a lot of genetic diversity.

      I appreciate your link to the article about Gerald Schroeder’s work, but once again, I have already addressed that (here and here)

      Finally, you ask whether or not the article I wrote and the article I gave you were peer reviewed. No, they were not. Of course, the article that you copied and pasted wasn’t peer reviewed, either. Neither was the link about Gerald Schroeder. What we find in the peer-reviewed literature is a constant refutation of supposedly vestigial organs, as shown here, here, here, here, here, here, and here.

      http://www.drwile.com

  7. Raphael Verelst July 31, 2012 9:11 pm
  8. Raphael Verelst July 31, 2012 9:20 pm

    Dr Wile, was that article you wrote peer-reviewed? Was the article you sent me peer-reviewed? Because evolutionary biologists usually smack them down after careful reading.

  9. gracekalman August 1, 2012 7:55 am

    Excuse me if I cheer. It has been much too long. At least Raphael appears to be a tad more respectful than L.W.

    • jlwile August 1, 2012 8:10 am

      I am glad that you feel entertained, Grace! I agree that while I did have to edit out some vulgar comments in his first posts, Raphael is a better commenter than L.W.

      http://www.drwile.com

  10. Raphael Verelst August 1, 2012 10:32 am

    But Doc, the problem is: we can live without an appendix! I had mine removed at an early age. Also, my mother wanted my leg hair laser removed, and I don’t really notice the dfference.

    Can you cite me peer-reviewed sources where genetic history contradicts the fossil record? Because last time I was in my evolutionary biology class, we analyzed the entire mammalian gene, and genetics coincides perfectly with the fossils

    • jlwile August 1, 2012 2:46 pm

      Yes, Raphael, we can live without our appendix. We can also live without our gall bladder. Does that mean the gall bladder is useless, too? One reason we in the U.S. (and other developed countries) can live well without our appendix is because we aren’t at risk for cholera, Clostridium difficile, and other intestinal parasites. However, in regions where such infections are a problem, the appendix makes a huge difference. For example one study looked at people who had a Clostridium difficile infection. They followed them for some time, and they found that 11% of the patients who had an intact appendix ended up having at least one recurrence of the infection, but 48% of those who did not have an appendix had at least one recurrence of the infection. [Gene Y. Im, et. al., “The Appendix May Protect Against Clostridium difficile Recurrence,” J Clinical Gastroenterology and Hepatology, 9(12):1072-1077, 2011]. Thus, those without an appendix were more than four times more likely to have trouble recovering from the infection! This, of course, is supported by other studies, such as Randal Bollinger R, Barbas AS, Bush EL, Lin SS, and Parker W., “Biofilms in the large bowel suggest an apparent function of the human vermiform appendix,” Journal of Theoretical Biology, 249(4):826-831, 2007. So the appendix is far from useless. In the same way, you might be fine with your leg hair removed, but if you went to a country that had significantly worse sanitation, you would probably be significantly more likely to develop a skin infection.

      I am happy to give you several peer-reviewed references that explicitly show that genetics and fossils disagree:

      Judith C. Masters and Denis J. Brothers, “Lack of congruence between morphological and molecular data in reconstructing the phylogeny of the galagonidae,” American Journal of Physical Anthropology, 117(1):79–93, 2002

      Patterson et al., “Congruence between Molecular and Morphological Phylogenies,” Annual Review of Ecology and Systematics, 24:179, 1993.

      Trisha Gura, “Bones, Molecules or Both?,” Nature 406:230-233, 2000.

      W. W. De Jong, “Molecules remodel the mammalian tree,” Trends in Ecology and Evolution, 13(7):270-274, 1998

      Matthew A. Wills, “The tree of life and the rock of ages: are we getting better at estimating phylogeny,” BioEssays, 24:203-207, 2002.

      I am not sure exactly what you mean by your statement, “Because last time I was in my evolutionary biology class, we analyzed the entire mammalian gene, and genetics coincides perfectly with the fossils.” Most mammalian genomes have not been sequenced, so there is no way you could have analyzed the entire mammalian genome. As far as I know, only 25 mammalian genomes have been fully sequenced, and some of them were sequenced quite recently. Even with all 25, you could not test the fossil tree in any serious way. If you mean that you looked at a single gene in many different mammals, it is not surprising that a single gene was found that matched the evolutionary stories made up using fossils. However, as many other peer-reviewed publications tell us, the evolutionary story you get from different genes contradict one another significantly:

      Carl Woese, “The Universal Ancestor,” Proceedings of the National Academy of Sciences USA, 95:6854-9859, 1998

      Lynn Margulis, “The Phylogenetic Tree Topples,” American Scientist, 94(3):194, 2006.

      Antonis Rokas & Sean B. Carroll, “Bushes in the Tree of Life,” PLOS Biology, 4(11):1899-1904, 2006

      This is one reason serious scientists are realizing that evolution simply doesn’t work in a flagellate to philosopher sense. Genetics contradict fossils, and one suite of genes contradict another suite of genes. There is simply no coherent picture of evolution emerging from the data.

      http://www.drwile.com

  11. Jason August 1, 2012 6:48 pm

    Dr Wile, thank you for clearing up some of the many misconceptions currently floating about. In answering Raphael you answered some questions I had too, thank you.

    As always your blog entries are well presented, well researched and well referenced.

    I also respect and appreciate your patience, professionalism and gentle attitude toward comments clearly contentious in nature.

    I for one am thankful for your time and effort in maintaining your blog and answering our questions.

  12. Raphael Verelst August 1, 2012 9:01 pm

    Doc Wile, I admire and thank you for your clarity and sincerity, and I have read those articles, except I have presented them to my evolutionary biologist dad whom is a Ph D, who has basically slapped them down the moment he saw it.

    When I mean “useless”, I mean superfluous. I have a very good intestinal flora, except I don’t have an appendix. The appendix was mostly used to digest very low-calorical aliments, like grass, or leaves, when we were, wait for it, apes!

    The parasinuses are also useless, as they just serve as auxilliaries to the main sinuses. The article you sent me forgot to mention that :)

    Here is a fine lecture by one of my heroes. Hope you enjoy it!:

    http://www.youtube.com/watch?v=JVRsWAjvQSg&feature=player_embedded

    • jlwile August 2, 2012 6:14 am

      Raphael, I am really impressed that you were able to find and read a total of eight very technical scientific papers on genetics and morphology in under seven hours! However, I am even more impressed that your father was able to “smack them down” the moment he saw them. I am impressed by this because those studies have been a major headache in the evolutionary biology community for years! Could you please tell me exactly how your father was able to “smack down” each of those papers? Please note that I have answered each one of your questions, but you have yet to answer a single one of my questions. I kindly ask you to answer this question, because I think we all would benefit from learning how your father was able to refute papers that the evolutionary biology community hasn’t been able to refute for more than a decade!

      You still seem to be confused about the appendix. It most certainly isn’t superfluous. If it were superfluous, its presence in the body would not strongly affect the ability of people to recover from disease. You might have very good intestinal flora, but you have never had cholera or a Clostridium difficile infection. Those who have had such infections do not have good intestinal flora if they don’t have an appendix! Also, there is no evidence that the human appendix ever had any digestive function. If it once had a digestive function, it would have digestive tissues (or at least some remnants of them) in it. However, it does not. As the peer-reviewed literature clearly shows, it has all the tissues one would expect if it always performed the function that we see it performing now – being a safe harbor for intestinal flora.

      I am not sure why you think the paranasal sinuses (you called them “parasinuses”) are useless. You need to learn more about them, as they perform several functions. They increase the resonance of the voice, warm and moisten inhaled air, decrease the weight of the facial bones, help to reduce the damage of blows to the face, and they are lined with lymphatic tissues to aid in the defense of airborne pathogens.

      Likewise, you need to learn more about the recurrent laryngeal nerve. Creationists do not say that the nerve is designed the way it is because “God works in mysterious ways.” Instead, creationists show that the recurrent laryngeal nerve is designed the way it is for two very important reasons. First, it is a necessary consequence of the nerve’s job during embryonic development. When you consider how a human embryo develops, you see that the design of the nerve is the best possible way to get all of the functions that are necessary. Second, it is necessary because the nerve serves all the tissues through which it passes. Thus, it takes its circuitous route because it has lots of tissues to service.

      Please also note that it is very, very odd that you would say the recurrent laryngeal nerve is not designed because it takes a circuitous route through the body. There are many, many well-designed human machines that have what seem to be needless circuitous routes in them. As John Woodmorappe says in his article, “Why evolution need not be true,” (Journal of Creation 24(1):24–29, 2010):

      Now let us consider situations in which a circuitous route is actually harmful to its bearer. The automobile with its engine in front requires a long, tortuous exhaust system perched underneath the car. This clearly makes it more vulnerable to injury from obstructions than the short exhaust system of engine-in-back cars (I speak from personal experience). Following Coyne’s logic, should we suppose that engine-in-front cars are not the products of intelligent design? No. We realize that there is an engineering trade-off between the advantages of the car with its front-situated engine and the concomitant disadvantage of its more easily-damaged long, circuitous exhaust system

      In regard to the video you posted. I watched it back in 2006, shortly after he gave the talk, and unfortunately, your hero was not very accurate. For example, he praised the Judge’s decision in Dover, but he failed to mention that the judge essentially copied that decision from a brief filed by the ACLU. He also claims that there are great transitional forms in the whale evolution series. However, as this article shows, nothing could be further from the truth. In addition, he claims that we silly creationists have stopped discussing whale evolution since these supposedly great transitional forms have been found. Once again, that is simply not true. This creationist article has continued to discuss whale evolution for more than a decade, with its last update just this year.

      Not only was Miller inaccurate when it comes to the Dover decision and whale evolution, he was very wrong about chromosome fusion. This article points out how wrong he was. He also claimed that the only creationist response is to shrug our shoulders and say that’s the way the designer made it. Of course that’s not true at all. The creationist response is that the fusion took place in humans prior to the worldwide Flood and the genetic bottleneck caused by the Flood ended up making the fused chromosome the only version in all future generations.

      Finally, Dr. Miller was completely wrong about the bacterial flagellum. He claims that he can show how the bacterial flagellum could have evolved by co-opting proteins from the Type III Secretory System. The big problem there is that evolutionists think that the Type III Secretory System came after the flagellum, not before. It’s odd that he left that inconvenient fact out of his talk! This, of course, makes total sense. Since the Type III Secretory System has fewer proteins than the flagellum, it is very easy to understand how the bacterium could develop it from a degenerated flagellum system. On the other hand, like most of the evolutionary hypothesis, there hasn’t even been a serious mechanism proposed for how the flagellum could have evolved from the Type III Secretory System.

      http://www.drwile.com

  13. Raphael Verelst August 1, 2012 9:02 pm

    Also, the laryngal nerve, if God would have designed us, would have gone straight from head-neck-heart. Except it goes a long long way around the arteries.

    Creationist explanation: God works in mysterious ways

    Evolutionary explanation: Back when we were fish, this was useful.

  14. Jonathan August 1, 2012 9:27 pm

    Dr. Wile,

    Thank you for sharing this information. For some reason, I feel like I already knew that hair was important to the human microbiome. However, it is nice to know that a thorough scientific study has been conducted.

    On another note, I am very glad that God gave me leg and arm hairs. I have been working at a camp for children this summer. There are a lot of mosquitoes here. A staff member and I were marveling at the sensitivity of our leg hairs: many times we are able to feel and kill the mosquitoes that land on our legs. I think that the sensitivity provided by human hair is amazing as well!

    • jlwile August 2, 2012 6:21 am

      Jonathan, that is an excellent point. Many of our body hairs serve as very sensitive motion detectors.

      http://www.drwile.com

  15. Josiah August 3, 2012 6:39 am

    Jonathan, I’m terribly envious. I don’t think I ever managed to catch a mosquito landing on me from the sense of touch, and it would probably have saved me some quite painful bites if I had.

    As a random point of trivia, if you ever have some time and a few hundred mosquitoes to kill soap suds work remarkably well. The large number of very small bubbles confuses their compound vision in a similar way to a fly swatter or rolled up newspaper (The second choice weapon), but unlike the fly swatter a handful of soap suds only needs to hit the creature and not a hard surface behind it. I failed to ask the mosquitoes how they feel about this discovery.

    A more serious comment to Dr. Wile, why is it that certain parts of your body have so much more hair than others? I’m thinking particularly of under the arms, where it certainly can’t be related to the sense of touch.
    My own theory has always been that it’s related to sweat and the body’s cooling mechanism; as though the extra hair acted as some sort of heat sink drawing warm sweat away from the skin and giving a greater surface area from which it could evaporate. However, I have no idea whether that’s plausible or backed up by any sort of studies.

    • jlwile August 3, 2012 8:19 am

      Josiah, I don’t think we know the precise reason underarm hair is thicker than other body hair. Our head hair is thicker for insulation purposes, and our eyebrow hair is thicker to catch sweat. There are those who think that underarm hair is thicker to reduce skin chafing as the arm moves. I suppose that’s possible, but I am not sure that’s testable. I am not sure that your idea is plausible. I would think that thicker hair would reduce evaporation, as it would tend to hold on to the sweat. Even if it encouraged evaporation, that would cool the underarm hair, not the skin. Evaporation of sweat cools because the sweat must absorb energy from the surface on which it is found to evaporate. If it’s on the hair, it would absorb energy from the hair, not the skin.

      I wouldn’t be surprised if there is an immunity reason. After all, bacteria love it when it is dark, moist, and warm. Where the conditions for bacteria growth are good, you would expect to find more of the “good guys” to fight off the “bad guys.” So perhaps there is more hair there so that there is a greater defense against pathogens.

      http://www.drwile.com

  16. gracekalman August 3, 2012 5:23 pm

    Random bug killing trivia… to kill hornets, put out a bowl of cornstarch and one of water. The hornets eat the cornmeal, drink the water, and explode. I’ve actually seen it, so I don’t know why some people say it’s a myth. It’s pretty hilarious.

    • jlwile August 4, 2012 7:00 am

      Grace, I am not an entomologist, but I always thought that adult hornets couldn’t eat solids. The larvae do, but I thought adults could only eat liquids. So you actually saw the hornets eating the cornmeal?

      http://www.drwile.com

  17. gracekalman August 4, 2012 12:57 pm

    Sorry, I meant ants. I don’t know where the hornets came from.

  18. Eric H. August 5, 2012 7:08 pm

    Your reply to Raphael was excellent and could not have been more thoroughly documented. Thanks for taking the time to compile all that information into one place, for his sake and ours as well. While we have some, what are now, minor disagreements about Theology and how important its link is to the method of creation, the science discussed, as usual, is right on, and put in very clear terminology. I’ve learned a huge amount from this blog, especially the comments sections, and have learned things from Scientific study that I would have never known about at all, and from a Godly perspective that I simply couldn’t find from other sources. Once again, thanks for the time you put in. You are making a huge impact for the kingdom of heaven through your diligent pursuit of showing complete scientific honesty and integrity.

  19. Mia August 5, 2012 11:21 pm

    “What you don’t seem to understand is that God also knows that Paradise isn’t lost forever. God had also planned redemption through Jesus Christ. Since God knows everything, He knows that Paradise is not really lost. It is regained through Christ.”

    I get that, but what about all the people who lived from Able to 0 AD? That’s 4,000 to 8,000 years, right? And for that matter, everybody since 0 AD that never heard the Gospel? Thanks.

    • jlwile August 6, 2012 5:31 am

      Thanks for your questions, Mia. The Bible answers both of them. Romans 4 tells us that even those who lived before Christ are saved through their faith. Prior to Christ, their faith was in the promises of God, and it was credited to them as righteousness. Remember, God is not bound by time. Thus, the sacrifice of Christ can apply to everyone, even those who lived before Him. So those who had faith in God’s promises before Christ were justified through Christ’s later death, and those who have faith in God’s promise fulfilled (Christ) are also justified by Christ’s death.

      Romans 1:20 and Romans 2:15 tell us that God has revealed Himself to all people. They know Him because of His Creation (Romans 1:20) and the fact that His Law is written on their hearts (Romans 2:15). Once again, these people are saved by their faith. If they don’t know of Christ but they have faith in what God has revealed to them through Creation and by His Law being written on their hearts, then they are justified as well. Once again, Christ died for all people, even those who haven’t heard of Him.

      http://www.drwile.com

  20. MBI August 7, 2012 1:34 pm

    It has been past time that evolutionists take a good hard look at themselves and examine their beliefs. I’ll make this short. Evolutionists should retire themselves from the profession of science stoppers themselves! All because they presuppose evolution is true they continue to look for vestigial biological systems that look flawed to add weight to their own flawed doctrine. This in turn also means they in some ways have become puffed up to the ‘know it all’ d(e)-grade. Stop looking for flaws outside of yourselves and realize just maybe you are in need of an upgrade which is coming soon for all those who believe in the truth.

    Thanks for allowing me to vent Dr. Wile.

  21. Jason August 7, 2012 6:14 pm

    Great comment MBI, lets hope the ‘upgrade’ happens sooner rather than later.

  22. Mia August 8, 2012 12:28 am

    Thanks for replying. Does God mean just the God of the Trinity? If so, does that mean that Muslims will not be saved, even if they are righteous in the eyes of Allah?

    • jlwile August 8, 2012 6:53 am

      Mia, it is not my place to judge who gets into heaven and who doesn’t. However, Christ Himself is very specific, saying:

      I am the way and the truth and the life. No one comes to the Father except through me. (John 14:6)

      Now if people have only God’s revelation in nature (1:20) or His laws written on their hearts (Romans 2:15), it is possible they might confuse the God of the Trinity with the god of some other religion. I doubt Christ would hold that against them. Nevertheless, it’s not my place to judge such things.

      http://www.drwile.com

  23. Jason August 8, 2012 10:37 am

    Dr Wile,

    Isn’t the God of Adam, Moses, Noah etc the same God the Muslims, Jews, Christians, Mormons, JW’s, 7th day advent. etc all worship?

    I understand there are theological differences (some more extreme than others) concerning the nature of God, the Trinity, who Jesus Christ was / wasn’t but at the core, don’t we all worship the same God?

    Just asking, don’t mean to offend anyone :)

    • jlwile August 8, 2012 11:25 am

      I certainly am not offended, Jason. However, I will have to disagree with you. I don’t think the God of the Christians is the same as the gods of the Muslims, Mormons, JW’s, etc. After all, the God of the Christians is a Trinity, and Jesus is a part of that Trinity. Thus, Christians worship God the Father, God the Son (Jesus), and God the Holy Spirit. Muslims view Jesus as a human prophet that got some things wrong. The JW’s don’t view Jesus as a human being, but they do view Him as not a part of God. Instead, they think Jesus was the first created being, and He acted as an agent through which God worked. Mormons think that God lives on a planet with His spirit wives making spirit children who inhabit physical bodies once they become available. According to them, Jesus was just the first of these spirit children. Obviously, the Jews don’t even think of Jesus as a prophet, so in their mind, Jesus has nothing to do with God.

      This isn’t a minor theological point. It is an important distinction regarding the very nature of God, which means the God that Christians worship is different from the gods that other religions worship. As I mentioned to Mia earlier, Jesus was rather clear on this point:

      I am the way and the truth and the life. No one comes to the Father except through me. (John 14:6)

      http://www.drwile.com

  24. Mia August 8, 2012 9:40 pm
    • jlwile August 9, 2012 7:13 am

      Thanks for the link, Mia. There are several problems with the article, which is typical for Dr. Coyne. Let’s start with the most obvious problem. He admits that sloths still need balance (“Well, sloths still have to hang in trees and maintain balance when they defecate…”), but he suggests that “maybe they don’t need a perfectly-formed inner ear to do that.” I would think just the opposite. It seems to me that if you are going to defecate in trees, you need a really good sense of balance.

      The second problem is that he assumes variation in the ratios of inner-ear features indicates that an organ is under less selective pressure. Once again, I don’t see that as reasonable, either. The fact that sloth inner ear features are more variable than the inner-ear features of other animals could just as well indicate that the sloth sense of balance is more individualized than the sense of balance of other animals. After all, a squirrel doesn’t use its sense of balance to defecate in the trees. It uses its sense of balance to run quickly in the trees and do amazing feats of acrobatics. That kind of balance could easily be less variable simply because it isn’t affected strongly by an animals individual traits. So sloth inner ears could easily be more variable simply because they need to “fine tune” their balance to their individual characteristics more than do other animals. Until we know the details of the sloth’s sense of balance, it seems rather silly to suggest that it is under less selective pressure than the sense of balance for other animals.

      Also, he says that creationists often don’t understand that vestigial organs can be useful. That’s not at all true. We understand that evolutionists try to explain away the function of organs that they want to interpret as vestigial by claiming the current functions came about later. The problem with that desire is obvious, however. If an organ serves an important purpose, how do we know that it was once useless and then became useful later on? There is no way to know that. Consider the body hair discussed in this article. Evolutionists want to believe that it was originally used for insulation in our ancestors. As modern humans evolved, it then became less and less useful. Maybe, even for a time, it was useless. However, as time went on, it adapted to serve the purpose we see today. Either that, or our ancestors used hair for both purposes, and now we use it only for one purpose. That’s a nice bedtime story, but there is no evidence to support it. What we see is human body hair performing an incredibly important function, and we see no evidence that it ever performed any other function. It is therefore much more reasonable to assume it has always been used for that purpose rather than making up some circuitous story by which it became less and less useful and then slowly became useful again.

      http://www.drwile.com

  25. Mia August 9, 2012 10:23 am

    You misread on the first point. Sloths come down to the only to defecate (once a week!), so they need to balance while they do their business. Hanging in trees requires minimal balance because orientation to a horizon is barely needed.

    • jlwile August 9, 2012 11:43 am

      Mia, I did miss that they end up climbing down the tree. Thanks for pointing that out. However, that doesn’t affect my point. They obviously need good balance to climb down and then back up the tree, even if they don’t do it all that often.

      http://www.drwile.com

  26. Mia August 9, 2012 10:29 am

    Forgot the word “ground” in the second sentence.

  27. Mia August 9, 2012 11:02 pm

    “So sloth inner ears could easily be more variable simply because they need to “fine tune” their balance to their individual characteristics more than do other animals.”

    That’s special pleading, isn’t it? As for human hair, how do you explain goose flesh other than we used to have more hair?

    • jlwile August 10, 2012 5:55 am

      No, Mia, it’s not special pleading. We know that some characteristics, like the thickness of a person’s bones, vary considerably between individuals so as to meet the specific needs of the individual. Since we know sloths actually do use their sense of balance, it is simply a case of applying what we know from science to produce a better explanation than the one offered by Coyne.

      Goose flesh is caused by the erector pili muscles pulling on the hair. The erector pili muscles are very important, because as they pull on the hair, it causes protective oil from the sebaceous glands to flow onto the skin. When they pull on the hair enough to make “goose flesh,” it accomplishes two things. First, it warms the skin. The constant contraction of the muscle expends energy, which causes heat to radiate into the skin. This is why you get goose flesh when you are cold. Second, body hair is connected to very sensitive nerves, making it an excellent motion detector. That’s why you get goose flesh when you are scared. The erect body hairs allow you to sense even the finest motion around you, allowing you to know where the danger is coming from. Thus, far from being a useless remnant of when we had more hair, goose flesh and the mechanism that causes it perform very important functions in people.

      http://www.drwile.com

  28. Jason August 10, 2012 1:13 pm

    Goose Flesh?, haven’t heard that expression before. I assume its what those of us on the other side of the pond call Goose Bumps?

    Seems to me Goose flesh is yet another example of our bodies being “fine tuned”.

    Thanks for further clarification Dr Wile.

    • jlwile August 10, 2012 1:14 pm

      You’re right, Jason. We are talking about goose pimples, and they are an excellent example of how finely-tuned the body is.

      http://www.drwile.com

  29. Mia August 10, 2012 11:54 pm

    Not the other side of the pond, Jason. There are quite a bit of names for them: http://en.wikipedia.org/wiki/Goose_bumps.

    Did you watch the video showing sloth movement? They are really slow! I don’t think they do need a finely developed sense of balance. (no one claims sloths don’t use balance, but that worsening balance isn’t very deleterious in sloths) Since they are hanging on to trees at all times, it really doesn’t matter at what orientation their head is. As for #2, again the key is they move very slow. Visual cues are all they need to remain upright.

    It is not Dr. Coyne claiming these things, but the authors of the paper. Unfortunately it doesn’t seem to be free as Coyne said in his post.

    • jlwile August 11, 2012 6:39 am

      Mia, you seem to think that because something moves slowly, it doesn’t need balance. That is just incorrect. Have you ever been on a jetski? Once it is moving quickly, balance is easy to maintain. The tricky part is keeping the jetski upright when it is moving slowly. The vast majority of jetski turnovers occur when the jetski is moving very slowly, because slow movement is when balance on a jetski is most important. In the same way, a sloth might need MORE balance because it moves so slowly. After all, a fast-moving animal can make quick adjustments to recover if its balance is thrown off. A slow-moving animal cannot. Thus, the high degree of variation could also be due to the fact that balance is so important and thus must be fine-tuned to each individual.

      I understand that the authors of the paper are claiming these things, but Coyne is giving credence to their view, which simply isn’t justified based on what we know about science.

      http://www.drwile.com

  30. Jacob August 11, 2012 2:37 pm

    Sloths don’t always move slowly. They’ll move quickly in times of a predatory attack. The reason for why they don’t move as fast is because it’ll burn up their calories, a substance that their diet of leaves doesn’t provide a lot of.

    http://www.greatchristiandebate.wordpress.com

    • jlwile August 11, 2012 4:50 pm

      Excellent point, Jacob. Thanks for bringing it up.

      http://www.drwile.com

  31. Mia August 11, 2012 9:49 pm

    Jay, your jet ski analogy is ridiculous. Jacob, sloths are easy prey when they go to ground for pooping, which might be a reason they only do it once a week. They do not scamper up a tree to get away. Their natural defenses are living high in trees, moving slowly, and algae that grows on their hair that serves as camouflage when they sleep. All adaptations to avoid predators, not escape them. They are slow. Period.

    • jlwile August 12, 2012 5:36 am

      Mia, could you please explain how my jetski analogy is “ridiculous?” It is a real-life demonstration of the fact that when things move slowly, they often require more balance than when they move quickly. In addition, your statement that sloths are “slow. Period.” is simply false. Here’s a first-hand account from a sloth biologist:

      One female took a dislike to me. I’m one of the only sloth biologists who’s been bitten,” he said. “They can use their big claws and slash out. But what she did was run at me, upside down along a vine, as fast as a cat would run along the floor. She grabbed me and pulled my hand to her mouth and then bit. It all happened very quickly. (emphasis mine)

      Also, according to this website, “Sloths eat, sleep, mate, and give birth all while hanging upside down!” That would take a LOT of balance!

      http://www.drwile.com

  32. Jason August 12, 2012 6:59 am

    Anyone that rides a bike etc will be able to relate to Dr Wile’s analogy. Once in motion, the bike is easy to balance requiring little effort from the cyclist. On slowing down however, the situation changes.

    https://www.youtube.com/watch?v=DvxsM4QaFAA&feature=related

    What I find particularly interesting is that sloths have to climb down, from their “safe” places, to defecate. Seems this “inconvenience” is kind of “counter” to the creatures evolutionary fitness.

  33. Mia August 13, 2012 2:51 pm

    Jay, the analogy fails just because it is a non-animate vs. primate comparison. But, even ignoring the category error, jet skis are heavy, float in water, are basically flat bottomed without a keel, and have uni-directional thrust. Bikes balance on a two thin strips of rubber. Are those remotely like a primate that can hang on to a tree with hands and feet? No.

    So one sloth had a burst of house cat like speed over a couple of feet. And something like this is rare. How about finding some video of a sloth moving quickly? (btw, using your variation argument, it could be that this just happened to be the fastest sloth in the world.)

    But the main point here is you misunderstand balance. Balance means keeping track of the 3D orientation of the head. When you are hanging on to ropes or tree branches, it makes no difference how your head is oriented in space to whether you fall or not. It is simply a matter of grip. As long as the sloth is hanging on to something, it doesn’t take any balance to do anything.

    Jason, the adaptation is to poop and pee once a week, rather than much more frequently, like hourly or daily. The selective pressure would be to extend the period between bathroom stops.

    • jlwile August 13, 2012 4:04 pm

      Mia, the analogy does not fail. First, it is not a category error. The person on the jetski is doing the balancing. Thus, I am comparing a living organism to another living organism. One is moving slowly on the water; the other is moving slowly on a tree. Both need good balance to get the job done, and many times, slow movement requires more balance.

      The point about the fast sloth is that you claimed sloths are slow, period. This example shows that such a statement is simply false. Sloths can move quickly, if they want to. You are right that this could be the fastest sloth in the world. However, since it moved as quickly as a cat, even slower sloths can still move pretty quickly if they need to. After all, I am pretty fast, but not nearly as fast as a cat. Thanks for pointing out how variable species can be, which is probably all that this study really demonstrates.

      I think you need to learn a bit more about balance, because you seem to be confused. I will try to clear things up for you. Balance is not just about knowing the orientation of the head. It is a result of the eyes, the vestibular system, the cerebellum, and proprioception working together. Since all the systems work together, variety in one system will cause variety in another. So, for example, variety in the vestibular system might be the result of variety in sloths’ muscular systems.

      Balance tells the body how to operate the muscles to preserve the position that it wants. If a sloth is hanging upside down in a tree, it needs good balance so that it knows which muscles to contract and relax to move its body in the way that it needs to be moved, especially if it is mating upside down! You might want to learn more about balance by going here.

      http://www.drwile.com

  34. Mia August 13, 2012 4:35 pm

    When a sloth gets on a jet ski, let me know, I’d like to see that. Species inter vary. So? The question the study addressed is the fact that sloth inner ears vary more than the controls included. Why is that? Do you have a better explanation than that there is less selective pressure on sloth balance than the control species?

    No, balance in this case is a simple way of saying the vestibular system, because the study examined the inner ear. The paper didn’t address the visual or proprioception systems. Sloths have bad eyesight anyway.

    “Since all the systems work together, variety in one system will cause variety in another. So, for example, variety in the vestibular system might be the result of variety in sloths’ muscular systems.”

    You don’t know what you’re talking about, do you? How would you test that hypothesis?

    Again, balance on your link means all three systems. The paper just considered vestibular. “Balance is the ability to maintain an upright position.” But even there it fails, because this quote only applies to something that walks on the ground. The sloth can be upright, downright, sideright or just right and it doesn’t affect his ability to stay in the tree.

    • jlwile August 13, 2012 5:10 pm

      Mia, I didn’t imply that sloths ride jetskis. I was just using the jetski to make a perfectly valid analogy that demonstrates quite clearly that many times, slow movement requires more balance.

      I have already given you a better explanation for the results of the study. Let me remind you of what it was:

      The fact that sloth inner ear features are more variable than the inner-ear features of other animals could just as well indicate that the sloth sense of balance is more individualized than the sense of balance of other animals. After all, a squirrel…uses its sense of balance to run quickly in the trees and do amazing feats of acrobatics. That kind of balance could easily be less variable simply because it isn’t affected strongly by an animal’s individual traits. So sloth inner ears could easily be more variable simply because they need to “fine tune” their balance to their individual characteristics more than do other animals. Until we know the details of the sloth’s sense of balance, it seems rather silly to suggest that it is under less selective pressure than the sense of balance for other animals.

      Also, you still seem to be confused about balance. Once again, I will try to help clear things up for you. Yes, the study focused on the vestibular system, but the vestibular system does not act alone. It acts in concert with three other systems. Thus, any changes that are observed in that one system could be the result of changes in the systems with which it interacts. Thus, you can’t make accurate conclusions by just looking at the vestibular system. You ask how I would test this “hypothesis,” but it is not a hypothesis. It is a known fact. For example, we know that the skeletal system works in concert with the muscular system. If you study athletes, you will find that their bones are significantly different from the bones of non-athletes, because their muscular systems are different from those of non-athletes. Anyone with a basic knowledge of physiology understands that variations in one system will affect the characteristics of the other systems with which it interacts.

      You are quite incorrect when you say that a “sloth can be upright, downright, sideright or just right and it doesn’t affect his ability to stay in the tree.” If a sloth is upright in the tree, he will have to use one set of muscles to stay in the tree. If he is downright, another. If he is sideright, he needs another set of muscles. Each set of muscles must be controlled by the cerebellum, which relies on the vestibular system to get the information it needs to know in order to control the relevant muscles. Thus, the vestibular system is vitally important in each possible orientation of the sloth. As a result, it is not surprising that slot vestibular systems are highly variable. They are more variable than the controls because for the sloths, balance has to be much more individualized.

      http://www.drwile.com

  35. Jacob August 13, 2012 4:51 pm

    Just to give an example of a primate climbing a tree, I’ll give a human climbing a tree.

    If you climb a tree, moving slowly requires a lot of focus on your hands and legs. Moving quickly also requires a lot of focus as well, but moving slowly normally requires more focus and balance because of the time it takes from moving yourself from point A to point B.

    I would assume that it would be even harder hanging upside-down, because now you have vision that doesn’t see right-side up.

    http://www.greatchristiandebate.wordpress.com

  36. Mia August 13, 2012 9:33 pm

    Yes, and your explanation is special pleading. I was trying to be nice but you keep on insisting. For example, are athletes’ tendons and ligaments significantly different from non athletes? They are not, and yet they are more closely related to muscle operation than bones.

    Another point is that athletes have different bones and muscles than non athletes for the same reason: the high stress placed on both systems and the ability of those systems to physiologically change as a result. This example is also off point because non humans do not have the great variability that humans do in activities such as working out. The variability in human muscles and bones is a result of human activity. Sloths do not cause the variability in the sloth population of inner ear components.

    • jlwile August 14, 2012 6:22 am

      Mia, you tried the “special pleading” angle before, and it doesn’t work. My explanation simply takes what we know from science and applies it to sloths in a way that explains the data better than Coyne and the authors of the study.

      I think you need to learn a bit more about tendons, because the tendons of athletes are, indeed, different from those of nonathletes. In general, the tendons of athletes are thicker and stronger than the tendons in non athletes. As this sports medicine site says about one particular tendon, “In the non athletic population, the Achilles tendon becomes weak and thin from disuse …” The same is true of ligaments. For example, this study of rabbits showed, “…that changes in stress and motion significantly altered the tissue properties as well as mass in the case of ligaments and digital extensor tendons.”

      You say that “non humans do not have the great variability that humans do in activities such as working out. The variability in human muscles and bones is a result of human activity. Sloths do not cause the variability in the sloth population of inner ear components.” However, that simply isn’t true. Sure, sloths don’t “work out,” but they definitely have different levels of activity depending on the situation. As this article points out, sloths in captivity sleep a lot more than sloths in the wild. The article speculates, “Wild sloths might be wakeful because they need to find food or avoid predators, Rattenborg suggests. Or there might be INDIVIDUAL DIFFERENCES: the 16-hour figure comes from a study published in 1983, which looked at an unspecified mixture of adult animals and juveniles. Young animals tend to sleep more.” If the article’s first explanation is correct, then slots that are in safer environments will sleep more than sloths in environments with more predators or less food. As a result, there will be substantial variation. Of course, his second explanation is more likely – that there is a lot of individual variation in sloths.

      I agree that comparing muscles and bones is just as reasonable as comparing muscles and tendons or muscles and ligaments. In each case, the use of one affects the other. Once again, my explanation simply takes what we know from science and applies it to this study to come up with a more reasonable conclusion than Coyne and the study’s authors.

      http://www.drwile.com

  37. Mia August 13, 2012 9:36 pm

    Oh, to explain special pleading. You chose muscles and bones because it strengthened your position (or you thought it did). You avoided muscles and ligaments because it didn’t. Neither choice can be shown to any more reasonable comparison than the other.