Sperm whale breathing anatomy?

[stephanurus]

A creationist has made this statement in a private message to me:

"Take a sperm whale fir instance. That creature could not have evolved naturally. They breathe thru a tube that is in no way linked to their mouth. Had they evolved that way, evolution would have ended with the seperated windpipe long before eons of furher evolution provided a whale."

Is this a new creationist claim about sperm whales? What is the answer to it?

stephanurus

[Arete]

It's completely false. Blowholes in whales are anatomically analogous to nasal passages in terrestrial mammals.

 

In mysticetes the nasal passages are separate tubes all the way to the external nares, whereas in odontocetes, the two nasal passages branch into a complex series of nasal sacs that eventually coalesce into a single blowhole. The sperm whale is however intermediate as it exhibits a sigmoidally-shaped blowhole formed by two nasal tubes that remain distinct from the bony nares to the top of the head: the anterior and posterior curves of the sigmoid blowhole represent the apertures of the right and left nares, respectively (rare examples of adult sperm whales with two distinct blowholes have even been reported). In the pygmy sperm whales (Kogiidae), the situation is only slightly different since the nasal passages remain discrete tubes until just proximal to the single blowhole.

http://tolweb.org/Cetacea/15977

http://rebeccamackay...le-got-its-name

http://www.spermwhale.org/

Edited February 8, 2012 by Arete

[Phi for All]

A creationist has made this statement in a private message to me:

A private message here at SFN? This is your first post, and someone here is targeting you with creationist PMs? I'd like to know who the member is, since preaching and abuse of the PM system are against the rules.

[questionposter]

A private message here at SFN? This is your first post, and someone here is targeting you with creationist PMs? I'd like to know who the member is, since preaching and abuse of the PM system are against the rules.

 

It could be from something in real life. You do know there's life outside of these forums right?

[Phi for All]

You do know there's life outside of these forums right?

Do you have any evidence to support this assertion?

 

I've seen some new members with questionable posting habits using the PM system lately. I just wanted to know if it was one of them.

[stephanurus]

Sheesh! Questionposer is right: there IS life outside these forums. The message to me had nothing to do with this forum and was not from a person on it. I came here to find an answer to the question because I myself did not know the answer and I assumed that somebody here might know.

 

stephanurus

[Moontanman]

Sheesh! Questionposer is right: there IS life outside these forums. The message to me had nothing to do with this forum and was not from a person on it. I came here to find an answer to the question because I myself did not know the answer and I assumed that somebody here might know.

 

stephanurus

 

 

And someone did, arete's post was very informative...

[Arete]

arete's post was very informative...

 

*cue hat tipping and a firm handshake, good sir*

 

In answer to the creationist argument:

 

1) The "fact" is simply not true. The nasal passages of cetaceans meet the trachea at the back of the throat - just like the rest of mammalia.

 

2) Even if it were true, displacement of a extant organ is rather unpersuasive as an anti evolution argument. Consider what a frog or a flounder can achieve over a single lifespan by relatively simple modification of expression and regulatory pathways. Take selection pressure over several thousand generations and the anatomical displacement of a individual, already present organ is well within the plausible range of evolutionary outcomes.

Edited February 9, 2012 by Arete

[stephanurus]

At the site http://www.enchantedlearning.com/subjects/whales/anatomy/blowhole.shtml the following statement is made: "Whales cannot breathe through through their mouths (like people can). Their trachea (the tube to the lungs) and esophagus (the tube to the stomach) are not connected."

I imagine that something like that is where the creationist claim in my first post above comes from. Where is the evidence that this tracheal arrangement in whales is an adaptation of whales to their environment and not something created de novo as a creationist might imagine it? What about anatomical studies of whale embryos/fetuses? Are there any or just crude diagrams?

stephanurus

[questionposter]

At the site http://www.enchanted.../blowhole.shtml the following statement is made: "Whales cannot breathe through through their mouths (like people can). Their trachea (the tube to the lungs) and esophagus (the tube to the stomach) are not connected."

I imagine that something like that is where the creationist claim in my first post above comes from. Where is the evidence that this tracheal arrangement in whales is an adaptation of whales to their environment and not something created de novo as a creationist might imagine it? What about anatomical studies of whale embryos/fetuses? Are there any or just crude diagrams?

stephanurus

I don't know about blow-holes, but there's a lot of evidence supporting that whales evolved from wolf-like creatures on land. Most whales even have a vestigial pelvis bone.

[stephanurus]

Yes, they deny that too but at least one creationist has fallen back on this breathing anatomy in whales as evidence against evolution.

 

stephanurus

[questionposter]

Isn't proof of evolution the mere fact that life doesn't actually do the "most" efficient thing? Life doesn't automatically evolve to do the most efficient thing, it just evolves to whatever the hell survives, that could be anything. If there really was intelligent design, we wouldn't eat and breath out of the same hole.

[Halucigenia]

A creationist has made this statement in a private message to me:

You should invite them to participate on a forum such as this or Ratskep.

 

 

"Take a sperm whale fir instance. That creature could not have evolved naturally.

That’s a bold statement not backed up by the following assertions.

They breathe thru a tube that is in no way linked to their mouth.

This statement is false, but I don’t think it has been fully explained why yet. As far as I can find out the whale’s blowhole is connected to the trachaea which as in all mammals does connect to the esophagus. The explanation is that mammalian anatomy having the upper part of the trachaea above the esophagus and the lower part of the trachaea below the esophagus which are connected rather than bypassing each other, which is why it is possible for most mammals to choke on food, is still the arrangement in whale anatomy. However, in whales, the intersection is bridged by a structure known as the laryngeal spout or “goose beak” possibly a novel evolutionary modification of the epiglottis or other parts of the larynx in the whale lineage. In effect this extends the trachea through the gap that other mammals have between the lower and upper opening of the trachaea through the esophagus. Imagine a pipe passing through the walls of another pipe from one side to the other. This can still cause problems in whales, as if this extension tube gets displaced or constricted by food or foreign objects in the esophagus the animal can suffocate or be unable to get food past the blockage and thus starve. It’s not as if it’s a prefect “design” more of a kludge as most evolutionary innovations are.

dolphins.org has a good basic explanation of dolphin evolution and also mentions the “goose beak” under the section respiratory system.

 

Had they evolved that way, evolution would have ended with the seperated windpipe long before eons of furher evolution provided a whale."

That’s just a non sequitor – it does not follow from the preceding assertion even if that were true. Simply because something has evolved in one specific lineage, that of whales in this example, does not mean that this trait would have to have evolved in an earlier lineage. That is simply nonsense and would contradict evolutionary theory if it were true. Taken to its absurd conclusion every evolutionary innovation should have been effected early in evolutionary history just as soon as it was possible to do so (reductio ad absurdum is not necessarily a fallacy, it can be effectively used to make a point). Obviously if this were the case all organisms would have evolved the same adaptations therefore no divergence – no biodiversity etc. would have been possible.

Evolution obviously does not proceed this way as it is a process contingent on random modifications being promoted due to their effectiveness under specific environmental conditions. The argument therefore, as usual with creationist arguments, depends on a misunderstanding or deliberate misrepresentation of evolutionary theory therefore it is a straw-man argument.

 

 

Is this a new creationist claim about sperm whales?

Well after years of arguing against creationism on the internet myself I have never heard of it before.

What is the answer to it?

As with all creationist assertions it is nonsense – see above.

 

Where is the evidence that this tracheal arrangement in whales is an adaptation of whales to their environment and not something created de novo as a creationist might imagine it? What about anatomical studies of whale embryos/fetuses? Are there any or just crude diagrams?

I am sure that if you wanted to follow up on your suggestion that this should be evidenced by whale embryology that it would be, as the developing embryo would, no doubt, show that development of this “goose beak” extension tube from the larynx follows on from normal mammalian developmental processes. However, I just don’t think that the research would be worth the effort as the original claim is so easily demonstrated to be false.

Also the creationist would no doubt still just claim that embryology is not “proof” that the “goose beak” evolved either.

[Arete]

At the site http://www.enchanted.../blowhole.shtml the following statement is made: "Whales cannot breathe through through their mouths (like people can). Their trachea (the tube to the lungs) and esophagus (the tube to the stomach) are not connected."

I imagine that something like that is where the creationist claim in my first post above comes from. Where is the evidence that this tracheal arrangement in whales is an adaptation of whales to their environment and not something created de novo as a creationist might imagine it? What about anatomical studies of whale embryos/fetuses? Are there any or just crude diagrams?

stephanurus

 

Here's a peer reviewed paper that has a demonstrative diagram and extensive explanatory notes specific to sperm whales:

My link

 

Figure 1A clearly shows a common nasopalatine cavity with an epiglottis - the sperm whale simply doesn't have a tracheal bypass of the mouth as the PM you quoted suggests.

 

and a book chapter specifically on the evolution of cetacean nasal anatomy:

http://books.google....20nasal&f=false

 

Here's a couple more relevant papers:

http://onlinelibrary...0882.x/abstract

http://onlinelibrary...0086.x/abstract

http://scitation.aip...s_2/1143_1.html

 

What is interesting from an evolutionary perspective is that 1/3 of a sperm whale's body is essentially its nose - the spermaceti organ. We don't have a great handle on exactly what it's for or how it evolved. The first paper I quoted is older (hence details more extensive basic anatomy) and the author speculates that the organ is related to a buoyancy function. A quick literature search shows it is most likely an organ associated with the production of sound - and thus potentially an echolocation organ (see last link) or a sexual display organ (see the third paper I listed). So if you really wanted to use the sperm whale as an example of what eolutionary biologists don't know, you wouldn't be making up falsehood about their respiratory anatomy, you'd be pointing out that we still don't really know what an organ that makes up a third of a whale's body weight is for, or how it evolved...

 

edit link fixed.

Edited February 10, 2012 by Arete

[Halucigenia]

Actually you could turn this argument around on the creationist.

If what they are asserting is that if the arrangement found in whales is not also in other mammals then it could not have evolved because it is a superior arrangement and therefore all mammals should have evolved it, all you have to counter with is; If it is such a superior arrangement and was designed for whales, why did the creator not also endow other mammals like humans with this superior arrangement.

[Arete]

Actually you could turn this argument around on the creationist.

 

Given that a) the initial assertion is patently false and b) even if it were true, it poses no conceptual challenge to evolutionary theory (i.e. a mammal exploits a novel niche and develops a novel respiratory trait - perfectly feasible under an adaptive radiation model) I'm not sure if it's worth the effort. It'd be like arguing with someone insisting that because flamingos are blue they can't fly.

[Halucigenia]

Actually, it's more like arguing with them that since you think that flamingos were created blue so they can fly why weren’t all organisms created blue so that they can fly too.