Wednesday, July 25, 2007

A creationism vs. evolution discussion,. Part 6

Question 10:
The hair stands up on the back of our necks when we are afraid. What does this have to do with evolution?
Possible answers
Only humans have evolved this gesture
Our ancestors looked bigger when they were frightened if their hair stood up
It shows our muscular structure is similar to that of apes
Correct answer: Our ancestors looked bigger when they were frightened if their hair stood up
To get an example of this physiological phenomenon, one need look no further than the family cat when it's scared by a dog, puffing up and hissing. This 'piloerection' is nearly universal among mammals- chimpanzees do it too. However, in modern-day short-haired humans, the gesture has lost its original significance. If it is not an evolved response, why should we have it at all?

Question 11:
What do goosebumps have to do with evolution?
Possible answers:
Our ancestors were warmer when they fluffed up their hair
They prove we are related to birds
They are unique to humans
Correct answer: Our ancestors were warmer when they fluffed up their hair
Again, this is easily observable in modern-day birds and mammals. Also, again, it's easily explainable by evolution, but not by creation. As one scientist put it, 'Goosebumps were obviously 'created' to erect and 'fluff up' the hair or fur on a hairy or furry mammal ancestor, thereby improving its insulation value against the cold. Since most of us nowadays have so little body hair as to render it useless for insulation purposes, goosebumps are another vestigial reaction whose tool (fur) is no longer with us.'

Marcsana’s response (to both questions)
You say that the hair standing on our necks is evidence of our ancestors. This is preposterous. Before making such a bold claim, one must first PROVE evolution, which can't happen. This question assumes evolution to be true and is, therefore, argumentative. Before stating evolution as fact, you should show a mechanism that ADDS information to an organism. Not one has been found. You also need to show some transitional fossils in the record, and yet there are none. You could probably also make a reasonable case how life can from nothing. But there's not. There is also that huge information hurdle to jump over. Nothing in nature adds or gives information. An intelligent source must add information and since our DNA is packed with untold libraries of information, we need a source. But non-living things do not give rise to information. Just a few problems. Having hair stand up is not good evidence of millions of years of man's evolution.

My response:
Firstly- I am going to do two things here. So far, both in this conversation and in email correspondence, Marcsana has been less than attentive to answering direct questions. I’ve tried to address all of his. So I have a few such questions to start with. I’d appreciate direct answers to these questions in your own words, Marcsana. I’ll also happily answer any direct questions you ask of me in return.
  1. Why do we have piloerection at all?
  2. Why does the hair stand up on our necks when we are frightened or otherwise experiencing extreme emotion?
  3. Why do we have goosebumps at all?
  4. Why do we have goosebumps only when we are cold or experiencing extreme emotion?

Secondly- as to the information argument (which has absolutely nothing at all to do with goosebumps or piloerection) I have been preparing a post about creationist language, and I’ll discuss it there.

Transitional fossils also have exactly squat to do with our prickly neck hairs. In the interest of not taking up vast megabytes of Internet space on topics that simply aren’t relevant to this discussion (but are immensely important aside from it) , I refer anyone interested in this topic to my quiz Evidence for Evolution- Transitional Fossils.


Marcsana said...

'We have no acceptable theory of evolution at the present time. There is none; and I cannot accept the theory that I teach to my
students each year. Let me explain. I teach the synthetic theory known as the neo-Darwinian one, for one reason only; not because
it's good, we know it is bad, but because there isn't any other. Whilst waiting to find something better you are taught something
which is known to be inexact, which is a first approximation...'
Professor Jerome Lejeune
From a French recording of internationally recognized geneticist, Professor Jerome Lejeune, at a lecture given in Paris on March
17, 1985. Translated by Peter Wilders of Monaco.
The meaning of this quote is pretty clear, I think. But before I get accused of being off topic, I'm using it to supplement the
part of my response that didn't deal with goosebumps. Where this fits in is written about below. Your direct questions are also
answered. So in this installment, I would like to address the point of piloerection, and then I would like to address the rest of
my comment from the FunTrivia website.
Before I do, I would like to reiterate that when I wrote my response to the quiz, I wasn't sure if I would get a response.
Now, the point of goosebumps. An important function is that they intensify the sense of touch. So when we're scared or under
duress, our hair stands up and greatly increases our sensitivity to outside stimuli. This can work (but doesn't have to) hand in
hand with our fight or flight response. We get them when we are cold because they trap warmth. The goosebumps here are caused by
muscle contractions (shivering) and this forces oil into a follicle and, then, onto the skin. This provides insulation by trapping
the air around the skin. You don't need a lot of hair for this to be effective. This answers questions 1-4. My source on this is
"Vestigial Organs Are Fully Functional" Jerry Bergman Ph.D. and George Howe Ph.D. (pg. 65)
Enough said here. Next, I want to tackle something that is very relevant to this topic. I will expand and say that it is important
to ANY discussion of evolution vs. creation. We need to discuss the fossil record (upcoming), information theory and the fact that
science knows of no information-adding mechanism to an organism. Why? Because if first life didn't evolve, no life evolved (there
is A LOT to come on that thermal vent story, by the way!). You wrote the following: "If it is not an evolved response, why should
we have it at all?" This is a huge jump in logic. That's like saying, "Oh hey! I found the lead pipe! It was Professor Plum in the
Conservatory with the lead pipe!" Only it's even worse because evolutionists don't even have the "lead pipe," so to speak.
Moreover, there are a lot more components to this mystery than those three mentioned pieces of information from "Clue." Evolution
is FAR from proven. Since evolution didn't happen, you need another framework to interpret the data. I wrote these things here
because if evolution didn't begin in the first place, then goosebumps are not an evolutionary throwback. As such the evidence must
be interpreted differently. When correctly analyzed, everything looks like it had a Common Designer.

Cris Waller said...

I asked that you specifically address the comments I made. Your first quote is totally irrelevant and really adds nothing to the discussion.

Your explanation of goosebumps is physiologically incorrect. Your citation is a creationist book; unfortunately, I do not have a copy of that book so cannot check its citations. But your statements fly in the face of basic biology as well as common sense.

Goosebumps are not caused by shivering. There is indeed a correlation between shivering and goosebumps- they can occur at the same time- but it is not a causative correlation. Your explanation for the physiology of goosebumps is also totally incorrect. Shivering and goosebumps are controlled by completely different neural pathways. Here's an abridged explanation
The smooth muscle that is responsible for "goose bumps" is called arrector
pili or pilimotor muscles. The are attached to the hair follicle and when
contacted, raise the hair and pull the skin down in an "attempt" to
insulate us from cold via trapping air between the hair. The "bumps" are
really the indentions due to the muscle pulling the epidermis down and we
notice the difference in height along the skin. Since these muscles are
smooth, they are innervated by the Autonomic Nervous System (ANS). The
sympathetic branch of the ANS is the only branch that is connected to these
muscles. When activated by the ANS, contraction occurs.
The cold receptors, sometimes called
Bulbs of Krause, reach threshold between 12 and 35 degrees C whereas the
hot receptors (Ruffini organs) are activated between 25 & 47 degrees C.
Below 12 and above 47, pain receptors reach threshold. Both the cold and
hot receptors use the same sensory pathway to the brain called the lateral
spinothalamic tract. This tract goes through the thalamus and terminates
in the appropriate location of the post central gyrus of the cerebrum.
This helps us to locate the area of the body that is being stimulated.
Temperature changes are mediated by nuclei in the hypothalamus which
has connections to the thalamus and which then sends messages to the
medulla. From there, impulses go down the spinal cord and out spinal
nerves, which make up the sympathetic division or thoracolumbar outflow.
These send a nerve impulse to the arrector pili muscles and they contract.

Shivering on the other hand, is independent of goosebumps:
The primary motor center for shivering is located in the posterior hypothalamus. When activated by cold signals from both the skin and spinal cord receptors, this center then transmits impulses down the lateral columns of the spinal cord to the anterior motor neurons, increasing muscle tone and thereby inducing shivering.

As for goosebumps serving to spread oils to keep us warm or increase our sense of touch- there is absolutely no scientific evidence to support any such assertions, and even a bit of common sense shows they are not tenable. Do you feel any warmer when you have goosebumps? And does your skin feel any oilier afterwards?

Hair follicles do not secrete liquid oils. Hair follicles do indeed have sebum-secreting glands at their bases- the sebaceous glands. The secretions from these glands don't serve to keep us warm; they serve primarily to lubricate our hair and skin. When excess sebum is secreted, we don't get warmer- we get acne! Sebum secretion is, not produced by lipid-filled cells breaking down by "squeezing." Sebum is also not a liquid "oil" that could spread over the skin rapidly; it is a fairly thick, waxy substance. There exists an instrument called a "sebumeter" that quickly and accurately checks sebum secretion, not a single journal article indexed on Medline tells of any increase in sebum production associated with goosebumps.

As for erected hairs trapping heat- that works great on a long-furred mammal. Our hairs are much too short to trap heat. Indeed, because they are so short, erecting them would probably cause a slight loss in heat, if anything! But again, any possible benefits by heat retention are too minor to be of significance. And, if our body hair is important to warmth, why are the Inuit people the least hairy
in the world, while the hairiest people are found in warm climates?
And as for touch- I found a portion of the work you cited online, which stated ("Vestigial Organs are fully functional" pg 65) refer to a work by Harris in which it was found that "the cluster of nerve fibers at the base of each human hair enables it to serve as a nerve amplifier or nerve extender. When the hair is moved, it physically transmits that information to the nerve. There's no clue as to who "Harris" is, and the quite is an extremely general one that doesn't even mention goosebumps. That hair is sensitive to movement is indisputably true. But there is no explanation here that would show that goosebumps amplify this.
Then, back to something that again, doesn't address what I have asked. We are discussing evolution here, and I truly hope your response doesn't mean "Can't happen, so no need to discuss it any further."

You have asked why I post things that seem to you to be "rude." I am afraid this post is an example of why. You spend 90% of the post on topics that have nothing to do with my original post, and only 10% on the actual topic. And, rather than being a carefully-researched response, your response is a quick rendition of a biologically-incorrect source,.

Marcsana said...

I have a correction to make. There is no oil secretion anything which relates to goosebumps and cold. Also, it's very true that goosebumps are not caused by shivering although they can occur simultaneously. I was wrong and misread my information. (The blog host made a mistake regarding rib regrowth. I guess we're even! :) :) joke!) I'm going to now quote from the experts and the referenced sources will be directly below the quote. The issue more or less deals with human body hair.

(And I rather like the quote I posted in my original response. And I did address what you said.)

"For protection against the cold, man has thick hair on his head (where 40% of body heat is lost) and fine hairs all over his body. These fine hairs extend the boundary layer (a layer of still air next to any surface) and reduce the air flow over the skin somewhat. The effect is not the same as fur, of course, and when the cold wind blows, we certainly feel it. But there is a definite benefit. (Have you ever noticed on a cool night you feel slightly warmer when you get goosebumps? Look closely and you'll see those tiny hairs standing erect, increasing the resistance to air flow.) All those little hairs may not seem like much, but it is a fact that many competitive swimmers shave off their body hair to reduce their resistance through the water."


"But man's small hairs are of even more benefit for body cooling than body heating. Their function here is to hold the body's perspiration in an even layer, so that it will not just drip off. (The armpits have thick hair because that's the area of heaviest perspiration.) Take a close look at your skin next time you are perspiring freely and you'll see how well the hair shafts utilize the surface tension of water. I think the importance of this function is further evidenced by the fact that, who with equal exertion perspire much more heavily than women, also generally have much hairier bodies than women. A man produces more heat and requires more cooling."

God would also make features in us which serve aesthetically as well. "Only the evolutionists think everything must have survival or reproductive value." (R. Harris)

I apologize for the "secreted oil" comment. It was carelessly placed and certainly doesn't represent the creationist side at all. That was MY mistake only.


"Vestigial Organs" Are Fully Functional
by Jerry Bergman, Ph.D. and George Howe, Ph.D.

(This will answer who "Harris" is.)

Robert Harris. 1982. In: "How Can Creationists Explain Human Hair?" Edited by G. Howe. Origins Research 5(2):10.

Regarding goosebumps. They DO serve as nerve amplifiers and nerve extenders. I cite the same sources above and:

B.R. Landau. 1981. "Essential Human Anatomy and Physiology. Scott Foresman, Glenview, IL.

Lastly, I'll be more careful in the future. I was rushing entries before and now I made a few mistakes.

Just to give you a heads up, my next post will be another response to the Second Law stuff or the thermal vents.

Cris Waller said...

"The blog host made a mistake regarding rib regrowth. I guess we're even!"
I think you misread my initial posting. There was no mistake. I never said there was no rib regrowth; the study I cited and then you re-cited found optimal growth with a scaffolding and suboptimal without one. It seemed we agreed on that point.

"B.R. Landau. 1981. "Essential Human Anatomy and Physiology. Scott Foresman, Glenview, IL."
I presume, since you're citing this, that you have read the original and not just copied a cite from a creationist journal. Would you mind please quoting, in the original, the text that specifies that goosebumps are touch amplifiers?

The argument about swimmers shaving off hair to reduce drag also won't wash. Water is approximately 1000 times denser than air
, and the reduction in drag swimmers gain from shaving is small- significant in an Olympic event but not huge- on the order of 1 second per 100 meters
or about a 5% increase in distance per stroke
So the reduction in drag caused by skin hairs in air would be 1/1000 of the very small reduction in drag swimmers experience. How about some scientific studies showing that there is any significant effect? It would be very easy, if goosebumps actually reduce drag by any amount significant enough to affect temperature, to prove it. After all, there are dozens of studies about the swimmers and drag!

There actually has been an enormous amount of research on the effects of animal hairs on thermal conductivity and insulation. Most of this research is extremely technical. However, - some points are obvious

-the thermal insulation of animals increases with thickness of their hair
- one inch of fur has approximately the same insulation as .6 inch of still air

A comprehensive review
of the skin’s role in human regulation and comfort failed to find any significant warmth advantage from goosebumps: “In cold weather, the skin develops bumps (gooseflesh) around hair follicles,
and the hair itself ‘stands on end’ – pilo-erection. For fur-bearing animals,
this serves to insulate the skin. For humans, the hair density on most of the
skin has become thin, and both the hair and the muscular apparatus that
erects it have evolved to be insignificant for thermoregulatory purposes.”

As for "Have you ever noticed on a cool night you feel slightly warmer when you get goosebumps?"- this is purely anecdotal. I could just as easily state "Have you ever noticed on a cool night you feel slightly colder when you get goosebumps?"
The sweat/cooling passage also has nothing to do with goosebumps.