[_ Old Earth _] Article of Whale and Dolphin Evolution

[lordkalvan]

Circular reasoning? Every land dwelling mammal drinks fresh water. Every ocean dwelling mammal is saturated with saltwater.

You have no idea what I'm talking about, do you?....

Hence my 'Huh?'

 

[Crying Rock]

Circular reasoning? Every land dwelling mammal drinks fresh water. Every ocean dwelling mammal is saturated with saltwater.

...Paleontologists believe that Pakicetus and other early cetaceans were furry, four-legged creatures that lived mostly on land, venturing into the water to feed on fish. According to current thinking, the earliest whales hunted in rivers and were unable to feed in salt water. Indeed, Pakicetus is found in river sediments, and the mixture of oxygen isotopes in its bones suggests it swam in fresh water.

The Indian fossil, however, came from marine sediments containing oysters and other ocean species, indicating that Himalayacetus swam in salt water. The ratio of oxygen isotopes in its bones supports this interpretation.

"Before, we might have thought that [these early whales] were restricted to fresh water, but here is a record from a marine environment," says Gingerich.

Despite its marine predilection, Himalayacetus apparently lacked key adaptations to aquatic life. Later whales developed enlarged canals in their lower jaws that improved their hearing underwater. Himalayacetus, though, had the small jaw canals of a land mammal, reports Gingerich. It appears that the Indian whale had already gained adaptations for feeding in salt water even though it could not hear well in that environment, he says.
http://www.thefreelibrary.com/Fossil+la ... a021237664

...

Paleontologists believe that Pakicetus and other early cetaceans were furry, four-legged creatures that lived mostly on land, venturing into the water to feed on fish. According to current thinking, the earliest whales hunted in rivers and were unable to feed in salt water. Indeed, Pakicetus is found in river sediments, and the mixture of oxygen isotopes in its bones suggests it swam in fresh water.

"Believe", "current thinking", "suggests"...Sounds pretty loose to me.

"Before, we might have thought that [these early whales] were restricted to fresh water, but here is a record from a marine environment,"

Big deal, right? If a mammal can swim and prey in fresh water, why not in salt water?

...Later whales developed enlarged canals in their lower jaws that improved their hearing underwater. Himalayacetus, though, had the small jaw canals of a land mammal, reports Gingerich. It appears that the Indian whale had already gained adaptations for feeding in salt water even though it could not hear well in that environment, he says...

Did "later whales" evolve from "Himalayacetus"?

How many known specimens of "Himalayacetus" exist?

 

[lordkalvan]

"Believe", "current thinking", "suggests"...Sounds pretty loose to me.

Well, what do you believe the evidence suggests should be current thinking on the origins and development of whales?

"Before, we might have thought that [these early whales] were restricted to fresh water, but here is a record from a marine environment,"

Big deal, right? If a mammal can swim and prey in fresh water, why not in salt water?

The significance lies in the implications for the inferred evolutionary history of whales and the transition of a land-dwelling ancestral species to a marine-dwelling descendant species. Evidence of salt water habitation indicates a change in (or at least a move towards a different) environment in which the animal could successfully survive. Note the present-day differences between riverin otters and sea otters, for example.

Did "later whales" evolve from "Himalayacetus"?

How many known specimens of "Himalayacetus" exist?

You may find this article of interest:

A new Eocene archaeocete (Mammalia, Cetacea) from India and the time of origin of whales

at http://www.pnas.org/content/95/26/15464.full.

 

[Barbarian]

CR mutters:
Circular reasoning? Every land dwelling mammal drinks fresh water. Every ocean dwelling mammal is saturated with saltwater.

...Paleontologists believe that Pakicetus and other early cetaceans were furry, four-legged creatures that lived mostly on land, venturing into the water to feed on fish. According to current thinking, the earliest whales hunted in rivers and were unable to feed in salt water. Indeed, Pakicetus is found in river sediments, and the mixture of oxygen isotopes in its bones suggests it swam in fresh water.

The Indian fossil, however, came from marine sediments containing oysters and other ocean species, indicating that Himalayacetus swam in salt water. The ratio of oxygen isotopes in its bones supports this interpretation.

"Before, we might have thought that [these early whales] were restricted to fresh water, but here is a record from a marine environment," says Gingerich.

Despite its marine predilection, Himalayacetus apparently lacked key adaptations to aquatic life. Later whales developed enlarged canals in their lower jaws that improved their hearing underwater. Himalayacetus, though, had the small jaw canals of a land mammal, reports Gingerich. It appears that the Indian whale had already gained adaptations for feeding in salt water even though it could not hear well in that environment, he says.
http://www.thefreelibrary.com/Fossil+la ... a02123766

"Believe", "current thinking", "suggests"...Sounds pretty loose to me.

If you think so, you're not familiar the scientific literature. That's the language they use when they think they have enough evidence to make it compelling.

"Before, we might have thought that [these early whales] were restricted to fresh water, but here is a record from a marine environment,"

Big deal, right?

Yep. The key to being a marine organism is being able to drink saltwater. That's why land-bound whales had different oxygen isotope ratios.

If a mammal can swim and prey in fresh water, why not in salt water?

As you see, that's not the issue. Manatees, for example, go into salt water, but they have to return to fresh water to get a drink. And oxygen ratios will show that.

...Later whales developed enlarged canals in their lower jaws that improved their hearing underwater. Himalayacetus, though, had the small jaw canals of a land mammal, reports Gingerich. It appears that the Indian whale had already gained adaptations for feeding in salt water even though it could not hear well in that environment, he says...

Did "later whales" evolve from "Himalayacetus"?

Or something very like it. Remember "transitional" doesn't mean we have the very individual that gave rise to new species.

How many known specimens of "Himalayacetus" exist?

Why would it matter?

 

[Crying Rock]

Barb wrote:

Yep. The key to being a marine organism is being able to drink saltwater. That's why land-bound whales had different oxygen isotope ratios.

CR:

As far as I know whales get their fresh water from their food. They can't survive on saltwater. However they do have kidneys capable of excreting the salt from the minimal amounts of saltwater they ingest. That's the way I was taught. Is there new research out?

The reason land-bound mammals have different oxygen isotope ratios is probably from the food they ingest.

 

[Crying Rock]

CR wrote:

How many known specimens of "Himalayacetus" exist?

Barb wrote:

Why would it matter?

CR wrote:

I'm just wondering about the sample we're dealing with.

Any idea of the size of the sample we're dealing with?

Are we dealing with N=1, N=1000 or something significant?

 

[Crying Rock]

CR wrote:

"Believe", "current thinking", "suggests"...Sounds pretty loose to me.

Barb wrote:

If you think so, you're not familiar the scientific literature. That's the language they use when they think they have enough evidence to make it compelling.

CR wrote:

Who is they (not to be confused with "Who Made Who" ;) ):

http://www.youtube.com/watch?v=gQDz1hbNh6A

 

[Crying Rock]

CR wrote:

Did "later whales" evolve from "Himalayacetus"?

Barb wrote:

Or something very like it. Remember "transitional" doesn't mean we have the very individual that gave rise to new species.

CR wrote:

So you can't answer my question?

 

[Barbarian]

Did "later whales" evolve from "Himalayacetus"?

Barbarian observes:
Or something very like it. Remember "transitional" doesn't mean we have the very individual that gave rise to new species.

So you can't answer my question?

If an atheist were to ask me what color cloak Jesus wore to the last supper, I couldn't answer that, either.

But if he suggested my ignorance of that detail cast doubt on His death and resurrection, I'd laugh at him just as much as I'm laughing at you.

For the same reason.

 

[Barbarian]

Barbarian observes:
Yep. The key to being a marine organism is being able to drink saltwater. That's why land-bound whales had different oxygen isotope ratios.

As far as I know whales get their fresh water from their food. They can't survive on saltwater. However they do have kidneys capable of excreting the salt from the minimal amounts of saltwater they ingest. That's the way I was taught. Is there new research out?

Well, not exactly new...

A very nice example of another independent line of evidence which reinforces the paleontological evidence indicates habitat changes associated with early whale evolution. This can be seen in the Osmoregulation Diagram showing the relative percentage of the Oxygen-18 isotope (significantly higher in the teeth and bones of marine cetaceans than in those of freshwater cetaceans). This is due to their incorporation of the particular ratio of oxygen isotopes in fresh vs. salt water ingested. The earliest archaeocetes (e.g. Pakicetus and other Pakicetids) have lower O-18 ratios, associated with a freshwater habitat, while Indocetus (and Rodhocetus), and Zygorhiza (Gaviacetus), very similar to Prozeuglodon and Dorudon, all have higher ratios, indicating a fully marine habitat. Ambulocetus data show a wide range of O-18 levels, suggesting they lived in a wide range of salinities, as one might expect for a clearly transitional form. The original work on this was published by Thewissen, Roe, and others in 1996.
http://www.indiana.edu/~ensiweb/lessons/whale.ev.html

You're probably thinking of carbon and nitrogen ratios, which are indicative of diet.

ICES Journal of Marine Science, 54: 500–503. 1997
Short communication
Differences in stable isotope ratios of carbon and nitrogen
between long-finned pilot whales (Globicephala melas)
and their primary prey in the western north Atlantic
Alan G. Abend and Tim D. Smith

 

[Crying Rock]

Did "later whales" evolve from "Himalayacetus"?

Barbarian observes:
Or something very like it. Remember "transitional" doesn't mean we have the very individual that gave rise to new species.

[quote:1i7m6ksj]So you can't answer my question?

If an atheist were to ask me what color cloak Jesus wore to the last supper, I couldn't answer that, either.

But if he suggested my ignorance of that detail cast doubt on His death and resurrection, I'd laugh at him just as much as I'm laughing at you.

For the same reason.[/quote:1i7m6ksj]

So you can't answer my question.

 

[Crying Rock]

Barbarian observes:
Yep. The key to being a marine organism is being able to drink saltwater. That's why land-bound whales had different oxygen isotope ratios.

As far as I know whales get their fresh water from their food. They can't survive on saltwater. However they do have kidneys capable of excreting the salt from the minimal amounts of saltwater they ingest. That's the way I was taught. Is there new research out?

Well, not exactly new...

A very nice example of another independent line of evidence which reinforces the paleontological evidence indicates habitat changes associated with early whale evolution. This can be seen in the Osmoregulation Diagram showing the relative percentage of the Oxygen-18 isotope (significantly higher in the teeth and bones of marine cetaceans than in those of freshwater cetaceans). This is due to their incorporation of the particular ratio of oxygen isotopes in fresh vs. salt water ingested. The earliest archaeocetes (e.g. Pakicetus and other Pakicetids) have lower O-18 ratios, associated with a freshwater habitat, while Indocetus (and Rodhocetus), and Zygorhiza (Gaviacetus), very similar to Prozeuglodon and Dorudon, all have higher ratios, indicating a fully marine habitat. Ambulocetus data show a wide range of O-18 levels, suggesting they lived in a wide range of salinities, as one might expect for a clearly transitional form. The original work on this was published by Thewissen, Roe, and others in 1996.
http://www.indiana.edu/~ensiweb/lessons/whale.ev.html

You're probably thinking of carbon and nitrogen ratios, which are indicative of diet.

ICES Journal of Marine Science, 54: 500–503. 1997
Short communication
Differences in stable isotope ratios of carbon and nitrogen
between long-finned pilot whales (Globicephala melas)
and their primary prey in the western north Atlantic
Alan G. Abend and Tim D. Smith

http://www.scientificamerican.com/artic ... mals-drink

http://whale.wheelock.edu/archives/ask98/0013.html

http://www.thenakedscientists.com/HTML/ ... tion/1521/

http://animals.howstuffworks.com/mammal ... -info2.htm

http://marinelife.about.com/od/marineli ... neLife.htm

 

[Barbarian]

From your source:

Some species of seals and sea lions apparently do drink seawater at least occasionally, as do common dolphins and sea otters, but the practice is very rare in some other species. When given the choice, manatees and some pinnipeds will drink fresh water.

Which pretty much confirms what the research said.

 

[jasoncran]

manatees mainly like the brackish water off my state the indian river laggon and other like estauries.

 

[jasoncran]

http://pelotes.jea.com/Manatee.htm

according to this one the florida manatee likes fresh water ,but can live in salt water.

the lagoon i speak of is brackish, closer to fresh then salt.

 

[Barbarian]

manatees mainly like the brackish water off my state the indian river laggon and other like estauries.

They prefer fresh water to drink, if they can get it. But like pinnipeds, they are much more recently adapted to the sea, than cetaceans. The point is, oxygen isotopes will be different in those organisms that drink mostly seawater, as opposed to fresh water. CR was confusing oxygen ratios with nitrogen and carbon ratios.

 

[jasoncran]

actually they have to have it. to survive, according to that link.

 

[Barbarian]

actually they have to have it. to survive, according to that link.

Right. That's why the oxygen ratios are different in the later whales. There were entirely marine.

 

[Crying Rock]

actually they have to have it. to survive, according to that link.

Right. That's why the oxygen ratios are different in the later whales. There were entirely marine.

Yes, they were eating entirely marine dependent organisms. What does that have to do with land dwelling mammals? Are they entirely marine? I believe you stated earlier that some "early whales" "oxygen ratios" pointed towards a marine adaptation. What were these cats doing?

 

[Crying Rock]

manatees mainly like the brackish water off my state the indian river laggon and other like estauries.

They prefer fresh water to drink, if they can get it. But like pinnipeds, they are much more recently adapted to the sea, than cetaceans. The point is, oxygen isotopes will be different in those organisms that drink mostly seawater, as opposed to fresh water. CR was confusing oxygen ratios with nitrogen and carbon ratios.

"...CR was confusing oxygen ratios with nitrogen and carbon ratios..."

No I wasn't.