Zimmer on whales

| 41 Comments

There's an excellent summary of whale evolution on The Loom, with a lovely logic puzzle to illustrate the pattern of evolutionary transformations.

41 Comments

And one of Carl’s readers has kindly linked to a couple of illustrated charts.

The reconstructions of the transitional fossilized critturs nicely complement Carl’s lucid article.

(breathing hard)

Sheesh! That Lenny’s faster than I would’ve thought, given all that pizza he’s chowed down over the years!

But he’ll never think of looking between pakicetes and ambulocetes. This is the old “purloined letter” technique, heh heh. I know that Lenny’s so familiar with the transitional whale fossils (after all, Lenny’s the one who told Blast From The Past all about them), that this is probably the last place he’ll look!

Yeah, and like he actually tips with nickels! Here’s a tip for you, Lenny: the little brown ones with the profile of Lincoln are NOT nickels! And half the time, I don’t even get the Lincolns, I get the similar-sized ones with the Queen of England on them!

(takes another deep breath, and ducks into the next doorway)

This is sort of funny (I’m bored at work, so I’m pathetically actually following this um, chase). But you guys need a special effects budget.

(sotto voce, from behind door:)

Hey, don’t knock the hall of doors! Didn’t you ever notice that the cat and mouse never come out the door they went in? Behind this comparatively-inexpensive loooking facade is a whole system of wormholes, I’ll have you know! (Or have you never wondered how we get those pizzas delivered as quickly as we do?)

Special effects budget, indeed!

(Receding footsteps, then sound of more-distant door slamming)

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Umm, no. The relationships are based on very specific, unique details of the skeleton. For instance, whales have unusual otic capsules…and the skulls of these animals show a remarkable similar organization of those bones, distinct from that of other animals.

Saurian and giraffe skulls are clearly very, very different in structure. This isn’t vague handwaving about superficial similarities – we leave that to the intelligent design creationists.

Is it just me? Or does the pick of the “walking whale” http://carlzimmer.com/water_4.html>; not look anything like a walking whale? They may as well have used a picture of a T-Rex or a Giraffe.

It’s you.

Copied:

In the same area that Pakicetus was found, but in sediments about 120 meters higher, Thewissen and colleagues (1994) discovered Ambulocetus natans, “the walking whale that swims”, in 1992. Dating from the early to middle Eocene, about 50 million years ago, Ambulocetus is a truly amazing fossil. It was clearly a cetacean, but it also had functional legs and a skeleton that still allowed some degree of terrestrial walking. The conclusion that Ambulocetus could walk by using the hind limbs is supported by its having a large, stout femur. However, because the femur did not have the requisite large attachment points for walking muscles, it could not have been a very efficient walker. Probably it could walk only in the way that modern sea lions can walk - by rotating the hind feet forward and waddling along the ground with the assistance of their forefeet and spinal flexion. When walking, its huge front feet must have pointed laterally to a fair degree since, if they had pointed forward, they would have interfered with each other.

The forelimbs were also intermediate in both structure and function. The ulna and the radius were strong and capable of carrying the weight of the animal on land. The strong elbow was strong but it was inclined rearward, making possible rearward thrusts of the forearm for swimming. However, the wrists, unlike those of modern whales, were flexible.

It is obvious from the anatomy of the spinal column that Ambulocetus must have swum with its spine swaying up and down, propelled by its back feet, oriented to the rear. As with other aquatic mammals using this method of swimming, the back feet were quite large. Unusually, the toes of the back feet terminated in hooves, thus advertising the ungulate ancestry of the animal. The only tail vertebra found is long, making it likely that the tail was also long. The cervical vertebrae were relatively long, compared to those of modern whales; Ambulocetus must have had a flexible neck.

Ambulocetus’s skull was quite cetacean (Novacek 1994). It had a long muzzle, teeth that were very similar to later archaeocetes, a reduced zygomatic arch, and a tympanic bulla (which supports the eardrum) that was poorly attached to the skull. Although Ambulocetus apparently lacked a blowhole, the other skull features qualify Ambulocetus as a cetacean. The post-cranial features are clearly in transitional adaptation to the aquatic environment. Thus Ambulocetus is best described as an amphibious, sea-lion-sized fish-eater that was not yet totally disconnected from the terrestrial life of its ancestors.

And if you want to read about all kinds of transitional whale fossiles, you can do it here

My front teeth are “similar” to a felines front teeth. And my fingernails are “similar” to a cats claws. Did I evolve from a cat?

Lots of neat pictures and theories about “transitional whale fossils.” More artist’s conceptions. Do you have any photographs of these “transitional” fossils. Or any more cool sites with pictures of ape men walking around in hula dresses with clubs? Oh wait, I’m sure the fossils are locked up in some museum where 5 people a year get to actually see them.

If you want to read about FACTS and EVIDENCE which support the historicity of the BIBLE, you can do it here: http://www.harkarkom.com/SinaiDiscoveries.php

HuckFinn: “Lots of neat pictures and theories about ‘transitional whale fossils.’ More artist’s conceptions. Do you have any photographs of these ‘transitional’ fossils.”

photograph: http://www.bringyou.to/apologetics/[…]ulocetus.jpg

Q: Where was Ambulocetus found? A: Ambulocetus has been found in Pakistan, which would have been on the shores of the Tethys sea separating the European archipelago from Africa and Asia.

Q: How big was Ambulocetus? A: Ambulocetus was 3m long, which is bigger than many crocodiles.

Q: How do we know that Ambulocetus is an early form of whale? A: Ambulocetus’ teeth and skull structure shows that it is a whale. Many other fossils have been found showing early whales with varying sizes of leg and tail (e.g. Pakicetus, Rodhocetus, Dorudon, and the already well known Basilosaurus). The teeth of all of them, including those which were fully aquatic, are very similar, as are their ear structures. Whales separate their ears from the skull – they “float” in a region of fat. To get sound to the ear, modern whales have a partially hollow jaw that is filled with a special type of fat. When sound waves hit the jaw they are conducted through the fat to a thin bone connection to the ear from the back of the jaw. This thin bone connection has a characteristic “S” shape that is totally unique to the whales, and has proved to be so remarkable to paleontologists over the last two decades. Ambulocetus already had the S-shaped ear bone and had jaws that would have been packed with sound-conducting fat, despite the fact that they seemed to live mostly on land. This implies that the strange way of hearing had initially evolved not for hearing underwater, but for some other purpose (e.g. sensing prey on land).

Q: How do we know that Ambulocetus lived in water as well as on land? A: Its long body is shaped rather like an otter, with a broad flattened tail and paddle-like hands and feet. The back legs are very short and strong and would have been powerful in the water, but clumsy on land. All these features suggest that it was a good swimmer, and easily capable of moving on land as well.

Q: How do we know how Ambulocetus swam? A: The long body, powerful hind legs, and flattened tail all suggest that Ambulocetus swam a bit like a modern otter. Certainly (like all mammals) its spine would have flexed up and down, not side to side like a fish or a crocodile. Its tail and paddle-like back feet would have helped push it through the water.

Q: How do we know that Ambulocetus lived in fresh as well as salt water? A: The fossils so far have all been found in marine sediments, initially suggesting that these were seashore animals. However, there is another clue from an unlikely-sounding source – their teeth. Paleontologists have made a chemical analysis of Ambulocetus’ teeth, and this tells a different story. The teeth were formed early on in the animals’ lives, and their chemical composition shows that at that time the animals were in rivers or estuaries, rather than the sea. There are two possible explanations for this strange result. Maybe Ambulocetus went upstream to give birth in fresh water, and then spent its adult life around the seashore. Another alternative is that, rather like modern sea cows, they move freely between fresh water and seawater. Only a few fossils have so far been found, so perhaps we will find some in river deposits soon.

Sources: see both P.D. Gingerich and J.G.M. Thewissen on the evolution of whales

Comment #49244

Posted by Huckleberry Finn on September 22, 2005 08:04 PM (e) (s)

My front teeth are “similar” to a felines front teeth. And my fingernails are “similar” to a cats claws. Did I evolve from a cat?

And are also similar to the horny laminae, which means you’re as likely evolved from a jackass…

My front teeth are “similar” to a felines front teeth. And my fingernails are “similar” to a cats claws. Did I evolve from a cat?

Impossible. Cats are way too smart and my neighbor’s tabby is deeply offended at the suggestion!

WRT Huckleberry Finn on Bible evidence: I haven’t seen any discussion in this thread that denies the historical veracity of the Bible. I have never heard a lecture in any science course that challenged the Bible directly or even addressed the subject. I have never seen a direct refutation of Biblical claims or principles in any physical or natural science textbook. The natural sciences generally don’t care. While individual scientists may have and express opinions that span the entire spectrum of spiritual belief, the professional conduct of science is generally unconcerned with religion.

y front teeth are “similar” to a felines front teeth. And my fingernails are “similar” to a cats claws. Did I evolve from a cat?

Nah. But I have a friend who’s in CSI who’s ready to arrest you for impersonating a higher form of animal…

Huckster: “If you want to read about FACTS and EVIDENCE which support the historicity of the BIBLE, you can do it here: http://www.harkarkom.com/SinaiDiscoveries.php

Maybe I’m missing something really obvious, but this is from the front page of Huck’s link: “Travelling through the harsh land of the Sinai Peninsula and the Negev Desert, hominids arrived in Asia from Africa over one million years ago. In the following ages, the Sinai and the northern Negev became an enduring passageway between Africa and Asia for clans and tribes of migrating peoples. Groups of homo sapiens crossed this region from Africa to the Near East for over 40,000 years, and various prehistoric, proto-historic, and historic peoples followed in the ensuing millennia.”

Histo-what-now?

Huckelberry Finn Wrote:

They may as well have used a picture of a T-Rex or a Giraffe. “Hey, look, Bill. I just found a skeleton of a creature with huge legs and it’s about the size of a whale.”

The fact is is that this animal was about 12 feet long–including the tail. That’s obviously not the size of a whale.

In looking at the hypothesized reconstruction of the skeleton, the hind feet don’t make any sense to me at all. It really looks like they have the feet turned the wrong way. But, of course, that would certainly make it a “land animal”, and probably not even a likely relative to the cetaceans.

There’s also the problem of very small processes in the spinal column–except in front of the pelvis. This is not very whale-like at all. What it looks like to me is an animal that spent a lot of time paddling in the water using its hind limbs. And, yes, the “otic area” has similarities with the cetaceans, but from what I could read, it’s not the same as in whales.

So, where does that leave things exactly?

So-called Huckleberry Finn said - And my fingernails are “similar” to a cats claws. So they have muscles that retract them into your hands - cool!

Why bother replying to such an obvious troll? It couldn’t be the real Huck Finn: he had a conscience. And he wasn’t a benighted asshole, either.

HuckFinn: If you want to read about FACTS and EVIDENCE which support the historicity of the BIBLE, you can do it here: http://www.harkarkom.com/SinaiDiscoveries.php

Well, if Huck’s quoting that as evidence for his case he obviously can’t be a YEC, unless he’s a really, really bad one. If he is a YEC, he should read Genesis Chapters I and II and try and decide how to reconcile the differing Creation Stories that they describe.

The historicity of the Bible is fairly irrelevant: yes, the Bible mentions plenty of peoples and places that existed. So what? Does the fact that Harry Potter mentions London Paddington train station mean that I should start applying to Hogwarts?

The fact is is that this animal was about 12 feet long—including the tail. That’s obviously not the size of a whale.

Neither is a dolphin. (shrug)

Displaying your ignorance publicly again, Blast?

In looking at the hypothesized reconstruction of the skeleton, the hind feet don’t make any sense to me at all.

Well, Blast, since you never even HEARD of any of these fossils until someone here pointed them out to you just a few weeks ago, I am a little puzzled why on earth you think anyone should care in the slightest about your uneducated uninformed opinion on the matter?

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Comment #49261

Posted by BlastfromthePast on September 23, 2005 12:51 AM (e) (s)

The fact is is that this animal was about 12 feet long—including the tail. That’s obviously not the size of a whale.

The smallest whale is the dwarf sperm whale which is 8.5’ in length.

In looking at the hypothesized reconstruction of the skeleton, the hind feet don’t make any sense to me at all. It really looks like they have the feet turned the wrong way. But, of course, that would certainly make it a “land animal”, and probably not even a likely relative to the cetaceans.

Ironically, hippos and whales are close cousins. Here is a little article from Berkeley: http://ib.berkeley.edu/courses/ib16[…]l-hippo.html

There’s also the problem of very small processes in the spinal column—except in front of the pelvis. This is not very whale-like at all. What it looks like to me is an animal that spent a lot of time paddling in the water using its hind limbs. And, yes, the “otic area” has similarities with the cetaceans, but from what I could read, it’s not the same as in whales.

Right… Right… I forget, creationists can’t deal with TRANSITIONAL FOSSILES… Oh well. You have your answer.

So, where does that leave things exactly?

Let me just quote the Berkeley article: “Despite disagreements over methods, molecular evolutionists are now at one on the whale’s family tree. The story goes like this. First there was an ancestral even-toed ungulate. Then the family tree split between camels and all the rest. Next the pigs and peccaries split off, followed by giraffes and deer, leaving just the ancestor of all hippos. Romping in the water, some hippos ventured into the ocean. These seafaring hippos then branched into the two superfamilies of the baleen whales (finbacks, blue whales) and the toothed whales (dolphins, porpoises).

Hey Blast:

Perhaps you’d also like to tell your electrician how to wire your house.

Why don’t you learn something about whales before spouting your stupidity?

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Huck,

You need to learn the difference between historical truth and what Plato calls “true truth.” Take a look at the second half of Book II in the Republic. Parts of the Bible can be historically false, and nevertheless, they convey truth.

tytlal Wrote:

Time for a Dover stickie?:

http://www.newscientist.com/article.ns?id=dn8042

From that New Scientist article:

One expert witness for the defence will be Michael Behe, a scientist at Lehigh University in Bethlehem, Pennsylvania, and an outspoken ID proponent. He declined to comment when contacted by New Scientist because of his involvement in the trial, but he promotes ID as a scientific theory.

Strange, his upcoming (Sept 30, 2005) talk in Minnesota is entitled Toward an Intelligent Understanding of the Intelligent Design Hypothesis

Italics added to both lines.

I too would like to see some stickies about Dover. The trial starts soon. I think we know roughly how it’s going to end. So I think we should follow it closely, in order to savor every moment.

My favorite part so far is how Of Pandas and People was a creationist textbook global search and replaced with ID:

Rothschild also brought forth several other examples of the foundation’s possible religious ties, including an early draft of the book, which in its infant stages was titled “Biology of Origins.”

The draft mentioned “creationism” frequently. But in the final copy of the book, after the title was changed, the word creationism was replaced with the phrase “intelligent design.”

Yeah, Dover’s going to be fun.

In looking at the hypothesized reconstruction of the skeleton, the hind feet don’t make any sense to me at all. It really looks like they have the feet turned the wrong way. But, of course, that would certainly make it a “land animal”, and probably not even a likely relative to the cetaceans.

Well that’s enough for me. Blast from the Past, with his remarkable paleontological acumen, has me convinced. Gawd musta dunnit.

There’s a section at the York Daily Record about the trial:

http://ydr.com/news/doverbiology/full/

“The trial starts soon. I think we know roughly how it’s going to end. So I think we should follow it closely, in order to savor every moment.”

We should be optimistic but cautious; trials can take strange twists and it is possible that the Judge will rule in favor of the defendants. Not likely, but possible.

Not likely enough for me to worry. The creationists in Dover have botched things so badly, I’m not worried. For instance, all those statements in the beginning about taking a stand for Jesus, and board members being asked if they were christian, etc.

If it was a jury trial, I would be worried. Might wind up with a bunch of Paul Nelsons, who side with religion over reality.

Thanks to steve for the link to the recent articles in the York Daily Record. I sent the following email to the newsroom regarding one of the recent articles, which quoted a home-schooling mother’s impressions:

As you folks well know by now, this “Intelligent Design” affair has attracted nationwide attention, and your own reporters are now embroiled in the resulting court case.

It’s a little discouraging, therefore, for an outside observer with pro-reality, pro-science proclivities to read this kind of comment (from Brent Burkey’s 9/23/05 story) from a home-schooling mother:

“Bowen said she taught Kelci on Thursday about how the structure of eagles’ wings allow them to soar so high. She said that design is not an accident.

“ ‘It’s too intricate,’ Bowen said.”

My problem, of course, is not with the notion of interviewing a lay person like Ms. Bowen–who is entitled to her beliefs and opinions–or giving space to her views on the matter, but on your reporter’s failure to then go on and place Ms. Bowen’s remarks in anything like a fair, overall context.

Any evolutionary biologist–and I would sure hope your reporters would know how to find at least one or two of those by this stage in this matter!–would have informed your readers that, yes, the eagle’s wings have been “designed” to do what they do and, yes, that “design” is no “accident,” but the result of the very well-understood process called natural selection, which filters the variation displayed by all organisms (even very closely-related people vary in important ways amongst themselves, as any family member will testify), insuring that–on average and over time–those variations displayed by the individuals who best meet the environment’s challenges are the most likely to survive and spread.

Ms. Bowen may or may not be persuaded by this view. Your editors may or may not be persuaded by this view. But surely your readership at least deserves to hear it explained, as part of the “whole story.” You do everyone whose attention is focused on this important issue a disservice whenever you leave an observation like Ms. Bowen’s “hanging,” as if there was not a solid and well-evidenced scientific explanation for it.

If it was a jury trial, I would be worried. Might wind up with a bunch of Paul Nelsons, who side with religion over reality.

So long as it doesn’t end up with a Judge Roy Moore or Antonin Scalia.

My front teeth are “similar” to a felines front teeth. And my fingernails are “similar” to a cats claws. Did I evolve from a cat?

Try looking up the DNA similarities between whales, camels, and cows some time. You’d be amazed how similar they are. The DNA evidence for humans and cats, on the other hand, speaks against that. You see, there are ways we can check and double-check this stuff. It all speaks in favor of evolution.

“My front teeth are “similar” to a felines front teeth. And my fingernails are “similar” to a cats claws. Did I evolve from a cat?”

No, but humans and cats did evolve from a common ancestor. Incisors and nailed/clawed toes are just two similarities evidencing our descent from a common ancestor.

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This page contains a single entry by PZ Myers published on September 22, 2005 4:41 PM.

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