VESTIGIAL: Learn what it means!

Aren't swim bladders vestiges of lungs, rather than the other way around?

John: Darwin did in fact not have the relationship of air bags in fish right, lacking the needed information.

I think the whole vestigial question vis-a-vis Darwin could be reconsidered in a way that makes Darwin's point more clear and makes it easier to not mess up an understanding of the modern term "vestigial organ."

People are confused by the idea of a "vestigial organ" because there are organs that function (for something) that are also called vestigial. The cited case with whales is an example. One might ask if there are organs that do absolutely nothing ever of any kind no matter what vs. those that actually do some things but not the original function and maybe even ask if we should have two terms. But that misses the point, and in fact, most discussions of vestigial I've seen miss the larger point Darwin was making.

Lots of organs do not have the function for which they evolved. Consider wings. Darwin notes that the Ostrich wing is "vestigial" (he does not use that word but that is what we would interpret his comments to mean) and "act merely as sails." But wings on regular birds probably do not serve their original function either. Originally, wings probably acted as something else, possibly sails in a glider, possibly something for cooling before that. The point is, wings for powered flight in birds are vestigial in the Ostrich because they are now used for a different function AND they are reduced in size. Could bird wings in Hawks also be said to be vestigial because they no longer act as cooling mechanisms (assume for a sec that this is true) and are now merely for powered flight? Darwin would not say that because 1) they are not reduced in size and 2) the newer function is major in the bird's life. We might imagine Ostriches giving rise to a species that does not even have the wings as sails, and still be an Ostrich. We could not imagine a Hawk giving rise to a species that does not have powered flight and still be a Hawk. It would be a tiny Ostrich!

So, there are two things Darwin said about what we now call vestigial organs. 1) They are smaller than their ancestral form and 2) they represent a function having gone away for that species.

The size bit matters in thinking about the history of this idea; Darwin refers again and again to size, about as much as he refers to function. These organs are always described as reduced, and Darwin talks about a general mechanism for organs reducing in part as a response to conservation of materials. Today we would expand that to include more reference to energy (he may have said that somewhere, not sure) and we would talk about loss of gene function. But he does refer to gene function to the extent he could have, in that he talks about an organ becoming vestigial because (proximately) of a change in developmental mechanism.

But step back a bit and really look at what Darwin said. He did not talk about vestigial organs per se; he uses related terms and clearly addresses the concept. But if we were to pay more attention to his words and tried to apply the concept today it is really a bit more interesting and complex.

To Darwin there were three kinds of organs. Regular (not sure what word he would use there), Nascent, and Reduced. A Nascent organ is an organ that will someday be a regular organ. It is a lump or bump or normal organ with a normal function but nothing spectacular, then it evolves to have new and more important function. For example, most (all?) secondary sexual traits would have a nascent form. Consider the regular feathers on the bird's head and an evolved form that is bigger and has a new function, the brightly colored crest on the bird's head that now is an element of sexual selection. If you see this process starting, so the bird has enlarged feathers, a small not-quite-crest and it is not of a novel color, you may be looking at a nascent organ. Darwin notes that nascent organs are rare because to identify them we have to see a process that he argues would be dynamic. Nascent organs are literally organs in the process of novel directional selection. Most such organs, by chance, that we happen to see, would be farther along than nascent.

Reduced organs are organs that have reduced selection, or directional selection against (conservation of materials, etc.) with respect to a certain function. PZ's example is exactly described this way by Darwin in more than one place in the Origin.

Darwin saw the whole thing as a larger process that integrates speciation, diversification, function, and selection. He talked about all of this as evidence for evolution and selection as opposed to the alternative view of divine symmetry in nature (or some other thing having to do with proper expression of the mind of god etc. etc.) Today we focus on the "vestigial organ" as a special unique thing separate and different from all of the other organs. Darwin, rather, described a larger process that, if true, would produce the rarely visible nascent organ, the somewhat more commonly seen reduced organ, and a lot of regular organs, and he put these classes of organs in a dynamic model.

We can refer to Darwin's concept and keep his excellent idea intact by remembering that dynamic model.

We can modernize the concept by being more tinbergian about it, and more genetic; all these organs are related to developmental/genetic systems. A set of genes that produces a regular organ (simplifying here) may lose function or effect and that is not selected against, so developmental controlled reduction occurs and there is no selection against that (that accords perfectly with what Darwin said and modern genetics). Ultimately the genetic system only barely does anything, and you have a reduced organ. If the organ becomes totally invisible the genes may still be there; we might call them vestigial genes.

We can clarify the entire discussion of vestigial organs by not calling them that. If we call them what Darwin called them, "Reduced", and refer to the function as vestigial, things would be more clear.

(Note: Darwin may have used the term "vestigial" somewhere. I did not find it in the later editions of the Origin, looking there because I'm more interested in what he ultimately said than what he originally said. He uses the term "vestige" in his discussion of reduced organs.)

For reference, large parts of Darwin's discussion of Rudimentary Organs, including reference to Nascent organs, function (or lack of) and process, nicely linking his selection theory to observation s in nature (though I hacked out many of the examples for quasi-brevity):

From Chapter 14, Orign, 6th edition, 1876:

Rudimentary, Atrophied, and Aborted Organs.

Organs or parts in this strange condition, bearing the plain stamp of inutility, are extremely common, or even general, throughout nature. It would be impossible to name one of the higher animals in which some part or other is not in a rudimentary condition. ...

Rudimentary organs plainly declare their origin and meaning in various ways. There are beetles belonging to closely allied species, or even to the same identical species, which have either full-sized and perfect wings, or mere rudiments of membrane, which not rarely lie under wing-covers firmly soldered together;...

An organ, serving for two purposes, may become rudimentary or utterly aborted for one, even the more important purpose, and remain perfectly efficient for the other. ...

Useful organs, however little they may be developed, unless we have reason to suppose that they were formerly more highly developed, ought not to be considered as rudimentary. They may be in a nascent condition, and in progress towards further development. Rudimentary organs, on the other hand, are either quite useless, such as teeth which never cut through the gums, or almost useless, such as the wings of an ostrich, which serve merely as sails. As organs in this condition would formerly, when still less developed, have been of even less use than at present, they cannot formerly have been produced through variation and natural selection, which acts solely by the preservation of useful modifications. They have been partially retained by the power of inheritance, and relate to a former state of things. It is, however, often difficult to distinguish between rudimentary and nascent organs; for we can judge only by analogy whether a part is capable of further development, in which case alone it deserves to be called nascent. Organs in this condition will always be somewhat rare; for beings thus provided will commonly have been supplanted by their successors with the same organ in a more perfect state, and consequently will have become long ago extinct. The wing of the penguin is of high service, acting as a fin; it may, therefore, represent the nascent state of the wing: not that I believe this to be the case; it is more probably a reduced organ, modified for a new function: the wing of the Apteryx, on the other hand, is quite useless, and is truly rudimentary. Owen considers the simple filamentary limbs of the Lepidosiren as the "beginnings of organs which attain full functional development in higher vertebrates;" but, according to the view lately advocated by Dr. Günther, they are probably remnants, consisting of the persistent axis of a fin, with the lateral rays or branches aborted. ...

Rudimentary organs in the individuals of the same species are very liable to vary in the degree of their development and in other respects. In closely allied species, also, the extent to which the same organ has been reduced occasionally differs much. This latter fact is well exemplified in the state of the wings of female moths belonging to the same family. Rudimentary organs may be utterly aborted; and this implies, that in certain animals or plants, parts are entirely absent which analogy would lead us to expect to find in them, and which are occasionally found in monstrous individuals. Thus in most of the Scrophulariaceæ the fifth stamen is utterly aborted; yet we may conclude that a fifth stamen once existed, for a rudiment of it is found in many species of the family, and this rudiment occasionally becomes perfectly developed, as may sometimes be seen in the common snap-dragon. In tracing the homologies of any part in different members of the same class, nothing is more common, or, in order fully to understand the relations of the parts, more useful than the discovery of rudiments. This is well shown in the drawings given by Owen of the leg-bones of the horse, ox, and rhinoceros.

It is an important fact that rudimentary organs, such as teeth in the upper jaws of whales and ruminants, can often be detected in the embryo, but afterwards wholly disappear. It is also, I believe, a universal rule, that a rudimentary part is of greater size in the embryo relatively to the adjoining parts, than in the adult; so that the organ at this early age is less rudimentary, or even cannot be said to be in any degree rudimentary. Hence rudimentary organs in the adult are often said to have retained their embryonic condition.

I have now given the leading facts with respect to rudimentary organs. In reflecting on them, every one must be struck with astonishment; for the same reasoning power which tells us that most parts and organs are exquisitely adapted for certain purposes, tells us with equal plainness that these rudimentary or atrophied organs are imperfect and useless. ...

On the view of descent with modification, the origin of rudimentary organs is comparatively simple; and we can understand to a large extent the laws governing their imperfect development. ...

It appears probable that disuse has been the main agent in rendering organs rudimentary. It would at first lead by slow steps to the more and more complete reduction of a part, until at last it became rudimentary,—as in the case of the eyes of animals inhabiting dark caverns, and of the wings of birds inhabiting oceanic islands, which have seldom been forced by beasts of prey to take flight, and have ultimately lost the power of flying. Again, an organ, useful under certain conditions, might become injurious under others, as with the wings of beetles living on small and exposed islands; and in this case natural selection will have aided in reducing the organ, until it was rendered harmless and rudimentary.

Any change in structure and function, which can be effected by small stages, is within the power of natural selection; so that an organ rendered, through changed habits of life, useless or injurious for one purpose, might be modified and used for another purpose. An organ might, also, be retained for one alone of its former functions. Organs, originally formed by the aid of natural selection, when rendered useless may well be variable, for their variations can no longer be checked by natural selection. All this agrees well with what we see under nature. Moreover, at whatever period of life either disuse or selection reduces an organ, and this will generally be when the being has come to maturity and has to exert its full powers of action, the principle of inheritance at corresponding ages will tend to reproduce the organ in its reduced state at the same mature age, but will seldom affect it in the embryo. Thus we can understand the greater size of rudimentary organs in the embryo relatively to the adjoining parts, and their lesser relative size in the adult. If, for instance, the digit of an adult animal was used less and less during many generations, owing to some change of habits, or if an organ or gland was less and less functionally exercised, we may infer that it would become reduced in size in the adult descendants of this animal, but would retain nearly its original standard of development in the embryo.

There remains, however, this difficulty. After an organ has ceased being used, and has become in consequence much reduced, how can it be still further reduced in size until the merest vestige is left; and how can it be finally quite obliterated? It is scarcely possible that disuse can go on producing any further effect after the organ has once been rendered functionless. Some additional explanation is here requisite which I cannot give. If, for instance, it could be proved that every part of the organisation tends to vary in a greater degree towards diminution than towards augmentation of size, then we should be able to understand how an organ which has become useless would be rendered, independently of the effects of disuse, rudimentary and would at last be wholly suppressed; for the variations towards diminished size would no longer be checked by natural selection. The principle of the economy of growth, explained in a former chapter, by which the materials forming any part, if not useful to the possessor, are saved as far as is possible, will perhaps come into play in rendering a useless part rudimentary. But this principle will almost necessarily be confined to the earlier stages of the process of reduction; for we cannot suppose that a minute papilla, for instance, representing in a male flower the pistil of the female flower, and formed merely of cellular tissue, could be further reduced or absorbed for the sake of economising nutriment.

Finally, as rudimentary organs, by whatever steps they may have been degraded into their present useless condition, are the record of a former state of things, and have been retained solely through the power of inheritance,—we can understand, on the genealogical view of classification, how it is that systematists, in placing organisms in their proper places in the natural system, have often found rudimentary parts as useful as, or even sometimes more useful than, parts of high physiological importance. Rudimentary organs may be compared with the letters in a word, still retained in the spelling, but become useless in the pronunciation, but which serve as a clue for its derivation. On the view of descent with modification, we may conclude that the existence of organs in a rudimentary, imperfect, and useless condition, or quite aborted, far from presenting a strange difficulty, as they assuredly do on the old doctrine of creation, might even have been anticipated in accordance with the views here explained.

Aren’t swim bladders vestiges of lungs, rather than the other way around?

Yes. That's one of the things Darwin was wrong about, because not that much was known about the anatomy of obscure subtropical and tropical fishes in his lifetime. Science Marches On.

Vestigials are a risible hoax.

What. People go around planting bones in whales? Bones attached to muscles and stuff? :-)

For one evolution violates the Law of the Fixity of Species.

There is no such law. No, not even if you write it with Three Capital Letters.

This is exactly why we biologists can't agree on which entities best to call "species" – they're all so fuzzy; they overlap widely, they aren't congruent. There are about 150 different species concepts out there. If you apply one of the more widely used ones, you'll find that there are 101 endemic bird species in Mexico today; apply another one of the more widely used ones, and you'll find 249.

"Richard Dawkins", I've noticed a pattern too: in some cases a brain may lose its primary function, leaving it only capable of the vestigial repetition of childhood nonsense.

"Any change in structure and function, which can be effected by small stages, is within the power of natural selection; so that an organ rendered, through changed habits of life, useless or injurious for one purpose, might be modified and used for another purpose."

So What PZ is really saying is in a Darwinian evolutionary context all organs are vestigial. But here I must protest! Because if all are vestigial then in reality none is because vestigial literally means!

"Relating to a body part that has become small and lost its use because of evolutionary change. Whales, for example, have small bones located in the muscles of their body walls that are vestigial bones of hips and hind limbs."

http://www.thefreedictionary.com/vestigial

Of course this definition came right out of the mouths of the Darwinists, but now has to change because their neat little theory was proven to be wrong! Fortunately for us science just like Darwinian processes evolve all the time!

Better get the sceptic police or Nick Matzke to bully the guys at the freedictionary to change their definition or else face the full might of the Darwin Dogma police!

Hi, troll! My, are you good with copypasta! :-)

Now be a good trollboy, learn some highschool genetics and then come back.

because vestigial literally means

You seem to believe that languages are invented by dictionary authors, so dictionary authors get to, uh, dictate what words mean.

In reality, dictionaries of languages other than Klingon are descriptive. They describe current usage, as far as the authors actually understand it; they are neither concerned with the historical origins of that usage*, nor do they necessarily get technical terms right – very often they don't.

Scientific terms sometimes slowly change their meanings, too. Case in point: evolution. Literally it means "unwrapping", so it was first applied to embryonic development, which was 200 years ago mistakenly believed to be some kind of unwrapping of already existing structures. Later that was metaphorically extended to descent with heritable modification; Darwin preferred to write "transformation" and used the word "evolution" only once, late in his life. Don't bother trying to step into the same river twice.

* The exception are historical dictionaries like the Oxford English Dictionary: they try to give all meanings a word has ever had.

Better get the sceptic police or Nick Matzke to bully the guys at the freedictionary to change their definition or else face the full might of the Darwin Dogma police!

Don't you think scientists have more urgent things to do? Exhibit A: the fact that no dictionary or printed encyclopedia I've ever seen has remotely managed to correctly explain what is and what is not a dinosaur.

David if you're willing to play this game lets go!

A staple website that has been used for years to sell your pseudo -science has this page on the matter

http://www.talkorigins.org/features/whales/

This page is refrenced in countless other web pages for the proof and facts of evolution Darwinian style.... What exactly does it say about vestigial organs?

I quote!

"A few species of whales still possess a vestigial pelvis, and some have greatly reduced and non-functional hind limbs"

Non-functional now also means functional according to PZ? WTF?

Another site making the case for these non-functional limbs

http://www.livescience.com/11317-top-10-useless-limbs-vestigial-organs…

Here is self esteemed cat lover Jerry Coyne's take on the matters!

http://whyevolutionistrue.wordpress.com/2011/02/10/the-hind-legs-of-wha…

All useless non-functional stuff that proves Darwinian evolution as fact!

What fact? These organs serve a purpose and dismantles the average Darwinian's claim that it is useless remnants from an evolutionary past......

But I tell you what lets stray off topic have you ever seen Dr Phil Gingerich admitting that he speculated some things on Rodocetus and added the stuff in himself?

https://www.youtube.com/watch?v=R7e6C6yUqck

Yes whale evolution aka Darwinian story telling is absolutely true! It is a fact, as certain as physics! I mean if you tell it long enough people will start believing it! Look how many zombies are here already mindlessly believing this nonsense!

As for scientists having better things to do Nick Matzke is known for his bulling tactics…. Would you like me to point out some examples or will you defend the indefensible?

Huh? I barely know Matzke exists. I have no idea what he's done, and I have no idea if I'd defend it. :-|

Scientists for the most part are obviously not really doing science because most of them are blogging

:-D :-D :-D :-D :-D

How could you even tell? I'm not blogging, and neither are the two colleagues in this room, and neither is my coauthor who's right now working on a manuscript I sent him on Sunday...

about how some god would not have done it in this, or that way….. What is scientific about that?

The hypothesis that things were made by a creator leads, inevitably, to certain predictions. To test whether predictions derived from hypotheses agree with what can be observed in the real world – that's science. It's what we do all day.

Storytelling? Each story leads to predictions that can be tested. Testing them is science.

Oops, I used my museum address instead of my private one for comment 14, that's why the picture is different.

Evolution is a dogmatic religious belief unbacked by science and supported only by radical atheism.

1) If it were dogmatic, why has it changed since Darwin? Does "modern synthesis" ring any bells? Or "punctuated equilibrium" on a smaller scale?

2) Atheism? Most scientists aren't atheists, and I don't think most biologists are.

3) You keep claiming there is no evidence. Tell me, then, why the similarities between organisms form a tree – not a circle, not a line, not a cross, not a star, but a tree. Tell me why DNA falls apart when kept in water – a large part of our metabolism goes into constantly repairing it. Tell me why vertebrate eyes are inside-out (the light first needs to pass a layer of blood vessels and nerves, then needs to pass the whole length of the light-sensitive cells to hit them on the far end) when cephalopods show it doesn't have to be that way. Tell me why we're born through a ring of bone when that ring is just a wide-open parenthesis in birds. Tell me why biodiversity is so large. I could go on for hours.

They point to museum plaster statues of so-called early man and this is their dogma.

I have no idea what you're talking about. Plaster statues? How about bones?

They cannot defeat the science that rejects evolution.

You haven't even tried to show us any such science.

Their so-called peer review system, as we have seen with Climategate, is scandalously false and dishonest to its very core.

Ooh, crank magnetism. :-) On "Climategate", start to inform yourself for the first time here before progressing to the real scandal, Climategategate.

Tell me how you think peer review works. I review a manuscript every few weeks, and have had a few of my own published, so I'll compare with my experience.

For them evolution is a dogma. All they have is weeping, wailing, and gnashing of teeth, screaming insults.

You're projecting.

The eight-hundred-pound gorilla in the room is the fossil record’s support of a Creation paradigm.

LOL. Creationism can't explain a single champsosaur.

Tell me about all those bird fossils that are as old as the oldest "fish" (whatever a "fish" is) and older than the oldest land animals!

The evolution scientists can no longer contain the lie that the fossil record supports evolution.

And you really believe repeating this will eventually make it true? Say, have you successfully turned the moon into cheese yet?

Now they are even saying that no change is still evolution.

Evolution doesn't automatically result in phenotypic change; look up that word, and then look up stabilizing selection. Change on the genetic level, however, is inevitable – and is indeed observed everywhere. Coelacanths have lots of molecular evolution behind them.

They fabricate the theory of transitional fossils, but cannot prove a single one to be transitional.

Colorless green ideas sleep furiously, don't they?

We have whole transitional series. Let me give a brief overview of the transitions to Tyrannosaurus and to Phoenicopterus (the flamingos) from their last common ancestor:

To Tyrannosaurus: Coelurus, Tanycolagreus; Proceratosaurus, Guanlong, Kileskus, Stokesosaurus, Sinotyrannus, Juratyrant; Dilong; Eotyrannus; Bagaraatan; Dryptosaurus; Alectrosaurus, Xiongguanlong; Appalachiosaurus; Alioramus; Gorgosaurus, Albertosaurus; Daspletosaurus; Teratophoneus; Bistahieversor; Lythronax; Tarbosaurus, Zhuchengtyrannus; Tyrannosaurus. From each semicolon to the next, the animals become a bit more similar to Tyrannosaurus. If you think anything is wrong with that picture, show me what and why!

To Phoenicopterus: Compsognathidae (too many to list individually); Ornithomimosauria, Ornitholestes, Therizinosauria; Alvarezsauroidea; Oviraptorosauria; Eosinopteryx; Dromaeosauridae, Troodontidae in a narrow sense, Jinfengopteryx, Aurornis, Anchiornis, Archaeopteryx, Xiaotingia, Epidendrosaurus/Scansoriopteryx/Epidexipteryx; Jeholornis/Shenzhouraptor; Sapeornis; Confuciusornis, Changchengornis; Enantiornithes; Archaeorhynchus; Yanornis; Yixianornis, Songlingornis; Ambiortus; Apsaravis, Hesperornithes, Ichthyornis; Iaceornis; Palaeognathae; Gallanseres; most other birds; Juncitarsus; Podicipedidae; Palaelodus; Phoenicopterus.

Questions? :-)

As for scientists having better things to do Nick Matzke is known for his bulling tactics…. Would you like me to point out some examples or will you defend the indefensible?

Huh? I barely know Matzke exists. I have no idea what he’s done, and I have no idea if I’d defend it.

As I recall, Matzke actually usually comes down on the side of moderation, or even accommodationism. Don't insult religious allies by criticising religion or suggesting that religious beliefs conflict with science! That sort of thing.

I suspect that Matzke's "bulling" [sic] probably involves moderating comment threads at the PT. Oh noes! Censorship!

I suspect that Matzke’s “bulling” [sic] probably involves moderating comment threads at the PT.

Ah, that makes sense. :-)

BTW, here's a fresh new open-access paper on a transitional lungfish – transitional between the Devonian marine ones which munched on reef-builders and the modern freshwater ones which are more generalistic. And here's one on the origin of bird wrists, featuring some of the other dinosaurs I've mentioned above.

"That you can artificially reduce the size of an appendix by literally cutting it out, with no effect on the individual (other than that they survive a potentially acute and dangerous inflammation) tells us that these are vestigial."

I recently heard about a guy getting his arm surgically removed for no apparent medical reason. Therefore the guy's arm must be vestigial.

What a brilliant evolutionary explanation.

John, you quoted "with no effect on the individual". Why are you now acting as if you hadn't seen it?!?