Evolution of the appendix: A biological 'remnant' no more

Aug 20, 2009
appendix
Image: Wikimedia Commons

The lowly appendix, long-regarded as a useless evolutionary artifact, won newfound respect two years ago when researchers at Duke University Medical Center proposed that it actually serves a critical function. The appendix, they said, is a safe haven where good bacteria could hang out until they were needed to repopulate the gut after a nasty case of diarrhea, for example.

Now, some of those same researchers are back, reporting on the first-ever study of the through the ages. Writing in the , Duke scientists and collaborators from the University of Arizona and Arizona State University conclude that was wrong: The appendix is a whole lot more than an evolutionary remnant. Not only does it appear in nature much more frequently than previously acknowledged, but it has been around much longer than anyone had suspected.

"Maybe it's time to correct the textbooks," says William Parker, Ph.D., assistant professor of surgical sciences at Duke and the senior author of the study. "Many biology texts today still refer to the appendix as a 'vestigial organ.'"

Using a modern approach to evolutionary biology called cladistics, which utilizes genetic information in combination with a variety of other data to evaluate biological relationships that emerge over the ages, Parker and colleagues found that the appendix has evolved at least twice, once among Australian marsupials and another time among rats, lemmings and other rodents, selected primates and humans. "We also figure that the appendix has been around for at least 80 million years, much longer than we would estimate if Darwin's ideas about the appendix were correct."

Darwin theorized that the appendix in humans and other primates was the evolutionary remains of a larger structure, called a cecum, which was used by now- extinct ancestors for digesting food. The latest study demonstrates two major problems with that idea. First, several living species, including certain lemurs, several rodents and a type of flying squirrel, still have an appendix attached to a large cecum which is used in digestion. Second, Parker says the appendix is actually quite widespread in nature. "For example, when species are divided into groups called 'families', we find that more than 70 percent of all primate and rodent groups contain species with an appendix." Darwin had thought that appendices appeared in only a small handful of animals.

"Darwin simply didn't have access to the information we have," explains Parker. "If Darwin had been aware of the species that have an appendix attached to a large cecum, and if he had known about the widespread nature of the appendix, he probably would not have thought of the appendix as a vestige of evolution."

He also was not aware that appendicitis, or inflammation of the appendix, is not due to a faulty appendix, but rather due to cultural changes associated with industrialized society and improved sanitation. "Those changes left our immune systems with too little work and too much time their hands - a recipe for trouble," says Parker.

That notion wasn't proposed until the early 1900's, and "we didn't really have a good understanding of that principle until the mid 1980's," Parker said. "Even more importantly, Darwin had no way of knowing that the function of the appendix could be rendered obsolete by cultural changes that included widespread use of sewer systems and clean drinking water."

Parker says now that we understand the normal function of the appendix, a critical question to ask is whether we can do anything to prevent appendicitis. He thinks the answer may lie in devising ways to challenge our immune systems today in much the same manner that they were challenged back in the Stone Age. "If modern medicine could figure out a way to do that, we would see far fewer cases of allergies, autoimmune disease, and appendicitis."

Source: Duke University Medical Center (news : web)

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otto1923
4.3 / 5 (3) Aug 20, 2009
Darwin had no way of knowing that the function of the appendix could be rendered obsolete by cultural changes that included widespread use of sewer systems and clean drinking water."
-Just in case though, shouldnt it be wise for people without one to be taking probiotics? Especially after being sick?
vika_Tae
2.8 / 5 (6) Aug 20, 2009
Would it not be wise for all people to take probiotics?
M_N
3.7 / 5 (9) Aug 20, 2009
So much for a useless "evolutionary remnant".

Similarly, every year scientists are discovering that more and more of the so-called "junk DNA" actually performs vital roles. Just because we don't understand the function of something, it's pretty presumptuous to assume it has no useful role.
Birthmark
5 / 5 (4) Aug 20, 2009
Just because we don't understand the function of something, it's pretty presumptuous to assume it has no useful role.

Very true, but I think it's ridiculous to call any part of DNA "junk" because it's everything we are, it's what makes us, us. On the other hand an organ can be useless, there's many useless things less debatable than the appendix, for example male nipples (due to the fact we all start out as female in the womb-then change to male), wings of some flightless birds, the coccyx, eyes of a mole, hind leg bones in whales, sex organs of dandelions, etc. and yes some of them may have uses but I doubt a lot of them really do, they're due to evolution.
Soylent
5 / 5 (7) Aug 21, 2009
Nature is the master of spaghetti programming; writting the by far most intractable, action at a distance, undeclared global variable, unstructured control flow, inelegant junk programs that have ever successfully run.

It would not surprise me if the hundreds of ancient inactivated retrovirii and other crap that is strewn higgledy-piggledy into human DNA have been coopted to serve some very indirect and completely unintuitive function.
bugmenot23
5 / 5 (4) Aug 21, 2009
I good way to challenge the immune system is to eat soil.
nilbud
not rated yet Aug 21, 2009
Raising Arizona
mabarker
3.2 / 5 (9) Aug 21, 2009
Yup - the appendix has a function - along with the tonsils, *tailbone*, etc. etc.
When I was in university grad school (zoology) in the mid-80s I took an advanced histology course. My prof told us (all 6 of us!) to write a paper on the ultrastructure of a tissue of our choice. As a non-darwinist, I told him I would do my paper on the appendix. As an evolutionist, what do you suppose he said? Right!! He said *NO* because it was *a useless vestige*. Now secular science has validated what creationists have been saying for decades: God doen't make junk. For every structure there is a function. My grad prof was being anti-science, not allowing me to do research because of his *belief* in a corrupt philosophy.
laserdaveb
2.6 / 5 (5) Aug 21, 2009
a few rough edges doth not make a "corrupt philosophy"
one god's junk is another god's treasure!
damnfuct
2.4 / 5 (5) Aug 21, 2009
Now secular science has validated what creationists have been saying for decades: God doen't make junk. For every structure there is a function.


What about that little nub in your eye that is the remant of a nictitating membrane?
Is a non-functioning nub less "junk" than a functioning nictitiating membrane? No.
damnfuct
5 / 5 (1) Aug 21, 2009
Just because we don't understand the function of something, it's pretty presumptuous to assume it has no useful role.


I'd say that assuming it has no role is better than assuming it's a "gathering place for evil spirits, so it must be removed immediately."
Soylent
3.9 / 5 (11) Aug 21, 2009
Why would god reuse the same body plan for all mammals, just like you'd expect to if they evolved?

Why would god place fossils in sedimentary rocks, giving the appearance of a fossil record ordered as you would expect if creatures evolved(e.g. no rabbits in the precambrian)?

Why would god preserve intricate similarity between human and simian DNA down to where genes are located on chromosomes, making it appear as if they are closely related?

Why would god make it appear as if new functions were derived from old ones as ugly hacks and kludges rather than making new, perfect designs from scratch?

Why would god distribute species of animals on isolated continents or islands to make it appear as if they evolved in isolation?

Why does every example of irreducible complexity trotted out by creationists invariably turn out to be a beautiful example of evolution with tens or hundreds of intermediary stages? (e.g. the eye, bacterial flagellum)

Creationists still have not got past the "magic man did it!" stage. The best they can do to support their unfounded hypothesis is to launch various weak attacks on evolution chiefly composed of straw, lies and scientific illiteracy. Pathetic.
Omega_Pluto
1.8 / 5 (5) Aug 21, 2009
Answer: Because it works. Why would any intelligent being "re-invent the wheel" when a working on is already established.

The modern evolutionary theory, as presented, is biologically unfounded as the fundamental theory of life states that life is made of cells which come from preexisting cells, hence life is NOT SPONTANEOUS! Darwinistic belief has yet to present a plausible theory to explain how it started. Hydrocarbons spontaneously assembling into organelles which then spontaneously formed cells is just like saying "the magic man did it," just leaving the man out.
John_balls
3.4 / 5 (5) Aug 21, 2009
Yup - the appendix has a function - along with the tonsils, *tailbone*, etc. etc.

When I was in university grad school (zoology) in the mid-80s I took an advanced histology course. My prof told us (all 6 of us!) to write a paper on the ultrastructure of a tissue of our choice. As a non-darwinist, I told him I would do my paper on the appendix. As an evolutionist, what do you suppose he said? Right!! He said *NO* because it was *a useless vestige*. Now secular science has validated what creationists have been saying for decades: God doen't make junk. For every structure there is a function. My grad prof was being anti-science, not allowing me to do research because of his *belief* in a corrupt philosophy.

Creationism is a brain washed philosophy. Do brain washed people even know that they are brain washed, I guess they wouldn't be brain washed then.
Ethelred
5 / 5 (2) Aug 22, 2009
Why would god reuse the same body plan for all mammals, just like you'd expect to if they evolved?


You don't really expect Mabarker to answer do you? He ignores all questions that he doesn't like thinking about.

Ethelred

Sorry for the new signature. But It Needed Killun.

From QubitTamer's fake profile

Quantum Physicist, torturer of AGW religious zealots like Ethelred because i laugh at his hysterics.


Qubitwit gets the rest of August in my signature for aiming his idiocy at me. Again.
Ethelred
4 / 5 (4) Aug 22, 2009
The modern evolutionary theory, as presented, is biologically unfounded as the fundamental theory of life states that life is made of cells which come from preexisting cells, hence life is NOT SPONTANEOUS!


Like making things up don't you? Would you like to show any book on evolution, that didn't come from a Creationist, that defined evolutionary theory that way? Even one?

First, evolution has nothing to do with biogenesis. That is inherent, as natural selection only occurs AFTER reproduction gets going. How it gets going is irrelevant to evolution. However life got started, evolution is an inherent process that will occur in ANY system that has imperfect reproduction. It cannot not happen under those circumstances.

Darwinistic belief has yet to present a plausible theory to explain how it started.


Nor will it ever since it a matter of chemistry and not evolution. Nor has Creationism ever presented a plausible explanation for fossils. Only in that case there really should be such since Creationism is indeed a 'theory of everything'.

Hydrocarbons spontaneously assembling into organelles which then spontaneously formed cells is just like saying "the magic man did it," just leaving the man out.


I don't think that anyone, other than Creationists, has made such a claim. Especially that hydrocarbon part. Reminds me of the various cranks that signs of hydrocarbons on Venus was evidence for life mistaking it for carbo-hydrates.

Organelles evolved AFTER the development of self-reproducing molecules. None of which are hydro-carbons or even carbo-hydrates. This is clear with just a modicum of thought.

Ethelred

Sorry for the new signature. But It Needed Killun.

From QubitTamer's fake profile

Quantum Physicist, torturer of AGW religious zealots like Ethelred because i laugh at his hysterics.


Qubitwit gets the rest of August in my signature for aiming his idiocy at me. Again.
Ethelred
4 / 5 (4) Aug 22, 2009
As an evolutionist, what do you suppose he said? Right!! He said *NO* because it was *a useless vestige*.


I think it had more to do with being a pompous twit. I strongly suspect that if the apendix really was purely vesitgal it would have been lost completly long ago. Maybe not though as some whales still have a bones left from there now non-existent legs. Would you care to comment on what you think THOSE vesital orgins are doing and why you think Jehovah put them there since you think there is no junk in life on earth.

I still say mosquitos are uneeded and a clear indication that if there is a creator that creator is either EXCEEDINGLY whimiscal or psychotic. Both is not contraindicated either.

Now secular science has validated what creationists have been saying for decades:


Even a stopped clock is right twice a day. Once if it is a 24 hour clock.

God doen't make junk.


I totally agree. God didn't make anything, at least if that god is Jehovah, which is clearly your god. Or Allah for that matter. As neither exists. There may be some god out there but those two don't fit the known evidence.

Now evolution doesn't make junk either. It can produce fairly crappy results. Such as having blood vessels in front of the retina. No competent god would do such a thing yet that is where we humans have blood vessels. Unlike, say, octopuses which their supporting blood vessels where they should be, behind the retina.


Ethelred

Sorry for the new signature. But It Needed Killun.

From QubitTamer's fake profile

Quantum Physicist, torturer of AGW religious zealots like Ethelred because i laugh at his hysterics.


Qubitwit gets the rest of August in my signature for aiming his idiocy at me. Again.
Mr_Frontier
3 / 5 (2) Aug 22, 2009
I think I'm in love with how the human imagination has pitted within itself; a war. I hope God doesn't win, that would be unimpressive of the human story.
gideon
4 / 5 (2) Aug 22, 2009
"On the other hand an organ can be useless, there's many useless things less debatable than the appendix, for example male nipples (due to the fact we all start out as female in the womb-then change to male),..."

Anytime i see that thrown in an argument i keep thinking "uh sexual pleasure, duh...". Besides what the male experiences, it gives him an understanding of what a woman feels which for him is an evolutionary advantage.

So the supposed uselessness of male nipples is more debatable than maybe you've personally sought to consider.
Yes
1 / 5 (1) Aug 23, 2009
Now evolution doesn't make junk either.

Huh. The evolution process produces an incredible amount of junk and then disposes of it. If some junk is useful, then it remains. Isn't that the evolution process resumed?
Now what drives the process? That is another story.
We don't know if it is God or Dices?
Until we truly understand we will know. (probably never) I like it when JC says: Ye according to the flesh do judge; I do not judge any one.

This last expression is rather scientific.
Therefore I find it very unscientific to say:
God didn't make anything, at least if that god is Jehovah, which is clearly your god.

While there may be evidence pointing to dices, the evidences objectively looked at are clear as mud.
Ethelred
3.7 / 5 (3) Aug 24, 2009
This last expression is rather scientific.
Therefore I find it very unscientific to say:

"God didn't make anything, at least if that god is Jehovah, which is clearly your god."


Sorry but the Jehovah of Creationists simply does not fit the world we live in so it simply doesn't exist. If you can see some wiggle room in reality to show that Genesis could possibly be right about creation then please post it. In the meantime I have a LOT of science on my side and there is none on the side of the Creationists.

Please keep in mind that Creationists are not the same as the Intelligent Design crowd. Dr. Behe understands that evolution is real but such people are quite rare in the Creationism movement. Most of them, including nearly everyone besides Dr. Behe, at the Discovery Institute are Young Earth Creationists. Same for most of them on this forum. For some reason Old Earth Creationist are fairly rare. Pretty clearly the reason is religion.

While there may be evidence pointing to dices,


That depends on just where you think the dice are involved. It is quite clear that much in particle physics involves probabilities and not certainties. Einstein was wrong about dice.

the evidences objectively looked at are clear as mud.


What 'evidences', a word favored by Creationists and no one else, are unclear to you? What ever are you talking about there?

Now what drives the process? That is another story.
We don't know if it is God or Dices?


Actually we do know what drives evolution. We KNOW that much at the level of electrons is Uncertain. We KNOW that there are mutations. We KNOW the environment will select out bad mutations. The mutations are random but the selection is not.

Now if you want to claim a god is directing the mutations it will take some seriously intensive research to prove that. First you would have to establish just what a random process of mutation should produce and then you would have to show that mutations don't fit the expected results by a very significant degree. Even then it would have to be shown that there isn't something we don't yet understand involved in the results.

Ethelred

Sorry for the new signature. But It Needed Killun.

From QubitTamer's fake profile

Quantum Physicist, torturer of AGW religious zealots like Ethelred because i laugh at his hysterics.


Qubitwit gets the rest of August in my signature for aiming his idiocy at me. Again.
jimbo92107
4.5 / 5 (2) Aug 24, 2009
If you don't have your appendix anymore, you might consider taking probiotics to replenish your gut flora, particularly if you've had diarrhea.

That's what I deduced from this article, not an argument for or against evolution.

Oh, and the "Creation Museum" is missing about 29 thousand species of dinosaurs whose fossils have been confirmed, and more are being discovered every day. That's a lot to sweep under the rug...
donavanbadboy
2.7 / 5 (3) Aug 24, 2009
I have always believed that "a bit of dirt does you good", to the guy suggesting we all eat "Pro-biotics", errrr, hello? Why not just let a bit more filth into your lives, much cheaper than buying bacteria cultures from supermarkets. If I ever have kids they're going to eat mud and worms and lick snails.
Shaffer
3.5 / 5 (2) Aug 24, 2009
God created Evolution....There, you happy?
Or maybe Satan planted the fossils?
I'm all for believing in the teachings of religion, but you gotta take it all with a grain of salt...
I don't have my appendix, and I'm fine....I eat plenty of bacteria in my over-processed diet to keep me overweight at my desk job...I assume switching to an all organic diet would yield the same result since natural plants and animal meat and my boogers all still have plenty of bacteria in them...eat a can of yogurt for cryin out loud!
vika_Tae
not rated yet Aug 24, 2009
The 'guy' suggesting everyone drinks probiotics, isn't a guy. I suggest that you actually check profiles before you label people.
donavanbadboy
not rated yet Aug 25, 2009
Some people use the word "guy" as non-gender specific. Stop being so pedantic.
vika_Tae
1 / 5 (1) Aug 25, 2009
The word 'guy' means a male. You cannot repurpose a word as you feel like, else I could decide from now on that 'retard' means 'honourable person' and walk up to you, shake your hand and say "I've always felt you were a true retard", then smile, and move onto the next.
Velanarris
3.5 / 5 (2) Aug 25, 2009
The modern evolutionary theory, as presented, is biologically unfounded as the fundamental theory of life states that life is made of cells which come from preexisting cells, hence life is NOT SPONTANEOUS! Darwinistic belief has yet to present a plausible theory to explain how it started. Hydrocarbons spontaneously assembling into organelles which then spontaneously formed cells is just like saying "the magic man did it," just leaving the man out.


You do realize Darwin didn't talk about the Origin of life. He spoke only of Evolution, not spontaneous generation.

You need to study something to disagree with it. That being said any argument you have for creationism can be empirically disproven very very easily. Feel free to give it a go.
Ethelred
5 / 5 (1) Aug 25, 2009
The word 'guy' means a male.


While that is true for guy singular it is no longer true for guys plural. As in 'hey guys, to a group including both sexes. English needs a gender neutral pronoun. Guys is now being used that way even if the pedants haven't noticed it yet.

And I just reading a book on such pedantry but the author hadn't notice the use of 'guys' and I didn't think of it while I was reading it. I just noticed it now while reading your remark.

From Merriam-Webster

3 a : man, fellow b : person %u2014used in plural to refer to the members of a group regardless of sex

So someone agrees with me on this. Same at Dictionary.com. But its only for the plural.

Ethelred

Sorry for the new signature. But It Needed Killun.

From QubitTamer's fake profile

Quantum Physicist, torturer of AGW religious zealots like Ethelred because i laugh at his hysterics.


Qubitwit gets the rest of August in my signature for aiming his idiocy at me. Again.
Omega_Pluto
1 / 5 (2) Aug 27, 2009

You need to study something to disagree with it. That being said any argument you have for creationism can be empirically disproven very very easily. Feel free to give it a go.



It does not matter what I say, you will believe you have proven me wrong, and I will disagree.

To appease you, the Book of Genesis is not by any means a complete record - only what was pertinent to the Israelites of the time. The Book does not, for example, tell how long after man was created Adam and Eve ate the forbidden fruit and were cast out of the Garden. Also, because there was somewhere to be cast out to, there was more to the Earth than the Garden. No account is given for the span of time after the creation of man and the fall thereof for what was happening in the region outside Eden.

As far as the 'young earth' concept, the Bible only records AFTER man was cast out, and thus dates relating to this do not apply to the relative or absolute ages of anything else.



p.s. It would be 'disproved' not the grammatically incorrect 'disproven' and there would be a comma in your 'very very' - thought you should know before you go around making yourself look uneducated
Velanarris
3 / 5 (2) Aug 27, 2009
p.s. It would be 'disproved' not the grammatically incorrect 'disproven' and there would be a comma in your 'very very' - thought you should know before you go around making yourself look uneducated
You're incorrect in regard to both.

Interesting tactic. Unfortunately Webster's Rules of American English Grammar are not in play on the internet outside of e-mail format.
vika_Tae
2.7 / 5 (3) Aug 27, 2009
Well, we can see you took that rule to heart, Velanarris. I wonder if your last budget request also could not be asked to bother with grammar?
Ethelred
5 / 5 (1) Aug 27, 2009
. The Book does not, for example, tell how long after man was created Adam and Eve ate the forbidden fruit and were cast out of the Garden.


True. But it does give some strong hints and after that the time frame is pretty much definite and not relative. Then again there is the problem that there was no Adam and Eve in the real world. No Great Flood either.

Ethelred

Sorry for the new signature. But It Needed Killun.

From QubitTamer's fake profile

Quantum Physicist, torturer of AGW religious zealots like Ethelred because i laugh at his hysterics.


Qubitwit gets the rest of August in my signature for aiming his idiocy at me. Again.
Velanarris
5 / 5 (2) Aug 27, 2009
Well, we can see you took that rule to heart, Velanarris. I wonder if your last budget request also could not be asked to bother with grammar?

My last budget request wasn't supposed to be intepreted using the rules of dialogue as internet converse is. It was within the confines of the grammar set.

Thanks though, guy.
vika_Tae
Aug 27, 2009
This comment has been removed by a moderator.
Shaffer
not rated yet Sep 02, 2009
I'm not a guy, you piece of shit.

Maybe not, but you are THE MAN!