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Author Topic:   Evidence for Evolution: Whale evolution
dan4reason
Junior Member (Idle past 1609 days)
Posts: 25
Joined: 01-03-2010


Message 1 of 443 (646052)
01-02-2012 12:36 PM


Whale evolution

One strange creature that we find is the whale. Surprisingly whales are genetically far more similar to other mammals than to fish even though they look like fish. Whales may look like fish on the outside, but they are far different on the inside, and are actually mammals.

Whales have hair, a trait found in mammals not fish. Whales give birth to live young and don't lay eggs like fish. They feed their young with breast-milk which is a mammal trait not seen in fish. Whales have smooth skin not fish scales. Whales move their tails up and down when swimming, a mammal trait. Fish move their tails side to side. Whales have pelvises just like mammals, and have a hand structure in their front fins unlike fish.

The below links show the fish and whale skeletons compared.


The most important feature of all is that whales have lungs instead of gills. This would be comparable to making a monkey with gills instead lungs. This monkey would live and eat up in the trees, but from time to time they will have to rush back in the water to breathe. Dolphins are also mammals that look like fish.

Whales also have a four-chambered stomach which is a super-stomach meant to grind up grass and leaves that most other animals can't really use. However whales don't eat grass or leaves but they do eat tiny sea creatures called krill, and zooplankton. They also eat tiny single-celled algae, fish, squid, shrimp, marine mammals and birds. Of course different whales have different specialized diets. Whales do not need four-chambered cattle stomachs to eat sea creatures, so a four-chambered stomach is very unnecessary. Having a four-chambered stomach is like cutting paper with a chain saw.

This makes sense from an evolutionary view because whales are most related to cattle which eat grass and leaves, and so inherited their stomachs. The closest land-mammals relative of the whale, the hippo lived mostly in the water, exhibiting a life-style maybe very near that of the ancestors of whales, and eats grass.

The reason for this is that millions of years ago, some land animals that lived in shallow water began adapting themselves more and more for water with fins and the like, until they could not live in the water any-more. This is why whales look like mammals dressed up like fish. The hippo a close relative of whales hints at the possible lifestyle of these ancestors.

In fact we find transitional fossils of land animals evolving into whales.


The above image shows the evolution of whales with more whale-like creatures in higher geological strata. This evolutionary series starts out in 50 million year old strata and becomes more and more whale-like as we approach 35 million year old strata. We find these fossils in Pakistan.


The above link shows the skeletons of the transitionals.

Notice how the front arms are becoming reduced as we go into higher strata. Also notice how the back legs disappear and the pelvis becomes small and distant from the spine. Indeed Dorudon has a transitional pelvis between that of a normal mammal and that of a whale. Notice also how the transitionals increase in size over time.

Richard Dawkins on whale evolution
This two minute video shows how the nose of the mammal ancestors of the whale starts moving up the forehead to become the blow-hole of the whale as we look at more and more whale-like fossils.

Looking at the whale pelvis, we see that it is vestigial. It is tiny and just sitting separated from the spine in the whale. Lets take a closer look on this pelvis.


As you see, it still has the femur which is a leg bone. This is an astounding piece of evidence for evolution.

It is doubtful if this pelvis has any function at all, although it might have some minor function. It is vestigial because it has lost its former function (holding the legs solidly).

29+ evidences for evolution and dolphin embryos
Indeed in the above link, we find that some dolphin species still develop leg bugs in embryonic development. What evolution did was keep the leg buds from developing further into legs; in the dolphins. The embryonic evidence is screaming out who the ancestors of whales are.

Evolution and atavisms
Edward t Babinski on whales and atavisms
The most astounding thing of all is that sometimes unlucky whales and dolphins will develop atavistic legs on their vestigial pelvises! Atavisms are traits formed from ancestral genes that were turned off, but through some mutation is turned back on in a descendent. Often these genes will allow something which started in embryonic development (leg buds) to continue to develop and not stop.

Everything about the whale screams of its origins. The fossil record shows the ancestry of the whale. Whales are strong evidence for the theory of evolution.

Edited by dan4reason, : No reason given.

Edited by Admin, : Reduce image width.


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Message 2 of 443 (646054)
01-02-2012 2:49 PM


Thread Copied from Proposed New Topics Forum
Thread copied here from the Evidence for Evolution: Whale evolution thread in the Proposed New Topics forum.
    
Dr Adequate
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Joined: 07-20-2006
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(1)
Message 3 of 443 (646059)
01-02-2012 4:53 PM
Reply to: Message 1 by dan4reason
01-02-2012 12:36 PM


Whales also have a four-chambered stomach which is a super-stomach meant to grind up grass and leaves that most other animals can't really use. However whales don't eat grass or leaves but they do eat tiny sea creatures called krill, and zooplankton. They also eat tiny single-celled algae, fish, squid, shrimp, marine mammals and birds. Of course different whales have different specialized diets. Whales do not need four-chambered cattle stomachs to eat sea creatures, so a four-chambered stomach is very unnecessary. Having a four-chambered stomach is like cutting paper with a chain saw.

Looking for references for this, I found the statement "baleen whales have four chambered stomach system", in Tamura, T., Konishi, K., Isoda, T., Okamoto, R. and Bando, T. 2009c. Prey consumption and feeding habits of common minke, sei and Bryde’s whales in the western North Pacific. Paper SC/J09/JR16 presented to the JARPN II review meeting, January 2009. Besides cutting up whales themselves, they reference the following two papers:

* Hosokawa, H. and Kamiya, T. 1971. Some observations on the cetacean stomachs, with special considerations on the feeding habits of whales. Rep. Whales Res. Inst, 23: 91-101.

* Olsen, M. A., Nordøy, E. S., Blix, A. S. and Mathiesen, S. D. 1994. Functional anatomy of the gastrointestinal system of Northeastern Atlantic minke whales (Balaenoptera acutorostrata). Journal of Zoology, London, 234: 55-74.

Now exceptio probat regulam, and the fact that they specified baleen whales suggests that this is not true of toothed whales.

Another problem is your assumption that the four-stomached whales don't need four stomachs. Why not? You haven't really demonstrated it; perhaps they do. Algae might be as tough to digest as grass and leaves.

You could rescue your argument by showing that toothed whales gain and then lose this arrangement in embryo, but this might not be true --- even if the four-chambered stomach is the ancestral form, the T.o.E. only permits this, it does not necessitate it.

---

You have made no mention of molecular phylogeny and little mention of embryology, both of which are useful lines of evidence. For example, IIRC, baleen whales grow and then lose teeth in embryo.


This message is a reply to:
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Replies to this message:
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dan4reason
Junior Member (Idle past 1609 days)
Posts: 25
Joined: 01-03-2010


Message 4 of 443 (646077)
01-02-2012 8:19 PM
Reply to: Message 3 by Dr Adequate
01-02-2012 4:53 PM


quote:
Looking for references for this, I found the statement "baleen whales have four chambered stomach system", in Tamura, T., Konishi, K., Isoda, T., Okamoto, R. and Bando, T. 2009c. Prey consumption and feeding habits of common minke, sei and Bryde’s whales in the western North Pacific. Paper SC/J09/JR16 presented to the JARPN II review meeting, January 2009. Besides cutting up whales themselves, they reference the following two papers:

* Hosokawa, H. and Kamiya, T. 1971. Some observations on the cetacean stomachs, with special considerations on the feeding habits of whales. Rep. Whales Res. Inst, 23: 91-101.

* Olsen, M. A., Nordøy, E. S., Blix, A. S. and Mathiesen, S. D. 1994. Functional anatomy of the gastrointestinal system of Northeastern Atlantic minke whales (Balaenoptera acutorostrata). Journal of Zoology, London, 234: 55-74.

Now exceptio probat regulam, and the fact that they specified baleen whales suggests that this is not true of toothed whales.


Well, dolphins are toothed whales.
Toothed whales.
and... dolphins have three-chambered stomachs. Most ruminants have four chambered stomachs. Others have three.

quote:
Another problem is your assumption that the four-stomached whales don't need four stomachs. Why not? You haven't really demonstrated it; perhaps they do. Algae might be as tough to digest as grass and leaves.

You could rescue your argument by showing that toothed whales gain and then lose this arrangement in embryo, but this might not be true --- even if the four-chambered stomach is the ancestral form, the T.o.E. only permits this, it does not necessitate it.

---


Well, there are many organisms that eat algae and do not have 4-chambered stomachs. For example, some snails eat algae, and some shrimp. Also, some fish eat algae. You don't need a 4-chambered stomach to eat algae.

quote:
You have made no mention of molecular phylogeny and little mention of embryology, both of which are useful lines of evidence. For example, IIRC, baleen whales grow and then lose teeth in embryo.

Well, I can tell that you know more about this than I do. Can you present this evidence with sources? Thanks. I will add it to my collection of evidence.

Thanks for the critique.

Edited by dan4reason, : No reason given.

Edited by dan4reason, : No reason given.


This message is a reply to:
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TheArtist
Junior Member (Idle past 118 days)
Posts: 14
Joined: 01-05-2012


Message 5 of 443 (646631)
01-05-2012 6:59 PM
Reply to: Message 1 by dan4reason
01-02-2012 12:36 PM


Very interesting topic. I have a few thoughts though.

First of all, I do not agree with the evolutionary diagrams depicting the changes happening over several millions of years. The oldest known DNA found according to http://news.nationalgeographic.com/...070705-oldest-dna.html is 400 000 years old. Thus, even getting the ‘youngest’ organism, Odontocetes’s DNA would not be possible. How can a diagram like this be assumed to be true when there are no DNA records that can prove that the transitions are even remotely related? There are so many different species of animals, you could make infinitely many different transitional diagrams to ‘prove’ that one species evolved into another when in fact evolution would totally disagree that the particular animal evolved in such a way. Mesonychids and Pakicetus for example could be two different and unrelated animals, putting them next to each other in such a diagram does not prove that the one evolved into the other. Off coarse I cannot disprove this either, I just believe that it should not be used in ‘proving evolution’ as there is NO evidence! For unproven facts no information is better than fiction.

On one of your responses

Well, there are many organisms that eat algae and do not have 4-chambered stomachs. For example, some snails eat algae, and some shrimp. Also, some fish eat algae. You don't need a 4-chambered stomach to eat algae.

Still, you have not provided Dr Adequate with a satisfactory answer in my opinion. It does not mean that if fish or other organisms eat algae and have only one stomach that whales do not need four. I would be very interested in some reference to evidence that whales do not use their four stomachs.

In closing, if whales have these vestigial stomachs why didn’t they just stay on land where they would have gotten the most nutrition from a fully adapted system for eating grass. Where did this need come from? What was so attractive about the sea?

Edited by TheArtist, : No reason given.


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jar
Member
Posts: 29136
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.7


Message 6 of 443 (646632)
01-05-2012 7:14 PM
Reply to: Message 5 by TheArtist
01-05-2012 6:59 PM


Welcome home, glad you came and look forward to your finally learning the truth.

We determine the same way that we determined that you are descended from earlier primates; by looking at the physical evidence. Remember the evolution of what was to become whales was worked out before DNA was a tool, but it has helped confirm the relationship.


Anyone so limited that they can only spell a word one way is severely handicapped!

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Perdition
Member (Idle past 705 days)
Posts: 1593
From: Wisconsin
Joined: 05-15-2003


Message 7 of 443 (646633)
01-05-2012 7:15 PM
Reply to: Message 5 by TheArtist
01-05-2012 6:59 PM


In closing, if whales have these vestigial stomachs why didn’t they just stay on land where they would have gotten the most nutrition from a fully adapted system for eating grass. Where did this need come from? What was so attractive about the sea?

The same things that are always attractive for a set of creatures to enter a new area: protection from predation & easy access to new food sources.

If a niche is open, something is going to figure out how to capitalize on it.


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Dr Adequate
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Posts: 15946
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Member Rating: 3.5


Message 8 of 443 (646643)
01-05-2012 7:58 PM
Reply to: Message 5 by TheArtist
01-05-2012 6:59 PM


First of all, I do not agree with the evolutionary diagrams depicting the changes happening over several millions of years. The oldest known DNA found according to http://news.nationalgeographic.com/...070705-oldest-dna.html is 400 000 years old. Thus, even getting the ‘youngest’ organism, Odontocetes’s DNA would not be possible. How can a diagram like this be assumed to be true when there are no DNA records that can prove that the transitions are even remotely related?

DNA records are not the only way to detect relatedness, people managed to do that before the invention of DNA sequencing, you know.

For example, even without DNA evidence, wouldn't you conclude that the two animals depicted below were related?

There, how hard was that?

There are so many different species of animals, you could make infinitely many different transitional diagrams to ‘prove’ that one species evolved into another when in fact evolution would totally disagree that the particular animal evolved in such a way. Mesonychids and Pakicetus for example could be two different and unrelated animals, putting them next to each other in such a diagram does not prove that the one evolved into the other. Off coarse I cannot disprove this either, I just believe that it should not be used in ‘proving evolution’ as there is NO evidence! For unproven facts no information is better than fiction.

No-one ever said that drawing the diagram proves the relatedness of the animals.

Rather, it is the evidence of their relatedness that led people to draw the diagram.


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dan4reason
Junior Member (Idle past 1609 days)
Posts: 25
Joined: 01-03-2010


Message 9 of 443 (646655)
01-05-2012 9:36 PM
Reply to: Message 4 by dan4reason
01-02-2012 8:19 PM


RE: TheArtist

quote:
Very interesting topic. I have a few thoughts though.

First of all, I do not agree with the evolutionary diagrams depicting the changes happening over several millions of years. The oldest known DNA found according to http://news.nationalgeographic.com/...070705-oldest-dna.html is 400 000 years old. Thus, even getting the ‘youngest’ organism, Odontocetes’s DNA would not be possible. How can a diagram like this be assumed to be true when there are no DNA records that can prove that the transitions are even remotely related? There are so many different species of animals, you could make infinitely many different transitional diagrams to ‘prove’ that one species evolved into another when in fact evolution would totally disagree that the particular animal evolved in such a way. Mesonychids and Pakicetus for example could be two different and unrelated animals, putting them next to each other in such a diagram does not prove that the one evolved into the other. Off coarse I cannot disprove this either, I just believe that it should not be used in ‘proving evolution’ as there is NO evidence! For unproven facts no information is better than fiction.


There is a strong correlation between anatomy and genetics. In fact the family tree constructed from genetics is very similar to that from morphology.

quote:
Still, you have not provided Dr Adequate with a satisfactory answer in my opinion. It does not mean that if fish or other organisms eat algae and have only one stomach that whales do not need four.

If algae can be digested without a stomach specialised for eating grass and leaves, then why in the world would a ruminant stomach be needed for algae?

quote:
I would be very interested in some reference to evidence that whales do not use their four stomachs.

I never claimed that.

quote:
In closing, if whales have these vestigial stomachs why didn’t they just stay on land where they would have gotten the most nutrition from a fully adapted system for eating grass. Where did this need come from? What was so attractive about the sea?

Maybe the land-resources were getting all eaten by other animals or there was a drought so they took advantage of water resources. Maybe there was too much predation on land, and far less at sea so they adapted to live in the water, and fight in the water.

Hippos are a good example of this kind of lifestyle.


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jar
Member
Posts: 29136
From: Texas!!
Joined: 04-20-2004
Member Rating: 2.7


Message 10 of 443 (646656)
01-05-2012 9:51 PM
Reply to: Message 9 by dan4reason
01-05-2012 9:36 PM


Maybe the land-resources were getting all eaten by other animals or there was a drought so they took advantage of water resources. Maybe there was too much predation on land, and far less at sea so they adapted to live in the water, and fight in the water.

Remember that it is unlikely anything happened quickly and that the critters diverged gradually. The important point is that it is divergence of a population into two populations that we are talking about.


Anyone so limited that they can only spell a word one way is severely handicapped!

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dan4reason
Junior Member (Idle past 1609 days)
Posts: 25
Joined: 01-03-2010


Message 11 of 443 (646659)
01-05-2012 10:50 PM
Reply to: Message 10 by jar
01-05-2012 9:51 PM


RE jar:

quote:
Remember that it is unlikely anything happened quickly and that the critters diverged gradually. The important point is that it is divergence of a population into two populations that we are talking about.

Sure, that seems reasonable.


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Dr Adequate
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Posts: 15946
Joined: 07-20-2006
Member Rating: 3.5


Message 12 of 443 (646660)
01-05-2012 11:04 PM
Reply to: Message 5 by TheArtist
01-05-2012 6:59 PM


In closing, if whales have these vestigial stomachs why didn’t they just stay on land where they would have gotten the most nutrition from a fully adapted system for eating grass. Where did this need come from? What was so attractive about the sea?

Clearly there is an ecological niche for whales, since there are in fact whales.


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Dr Adequate
Member
Posts: 15946
Joined: 07-20-2006
Member Rating: 3.5


Message 13 of 443 (646663)
01-05-2012 11:22 PM
Reply to: Message 4 by dan4reason
01-02-2012 8:19 PM


Well, dolphins are toothed whales.
Toothed whales.
and... dolphins have three-chambered stomachs.

Thank you.

I think saying that these stomachs are "unnecessary" is too strong a statement, for one thing it might be read by the incautious as meaning that they're vestigial. They're not, and if you cut three of them out of a whale and then sewed it back up it might well impair its digestion.

If I were to make the point, I'd put it something like this:

There seems to be no functional reason why whales should have multiple stomachs rather than some simpler arangement. The absence of such a reason is evidenced in two ways.

First, the presence of multiple stomachs exists across the whale clade, even though ceteceans don't all have the same diet. It would be a remarkable coincidence if multiple stomachs just happened to suit sperm whales eating giant squid, dolphins eating fish, and blue whales eating krill.

Second, we can see that in other groups of fauna with similar diets multiple stomachs are not present: for example a shark or a tuna with the same diet as a dolphin does not share its digestive arrangements.

However, this anatomical feature can readily be explained as part of the evolutionary heritage of ceteceans ...

... etc etc.

Edited by Dr Adequate, : No reason given.


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dan4reason
Junior Member (Idle past 1609 days)
Posts: 25
Joined: 01-03-2010


(1)
Message 14 of 443 (646853)
01-06-2012 9:19 PM
Reply to: Message 13 by Dr Adequate
01-05-2012 11:22 PM


quote:
Thank you.

I think saying that these stomachs are "unnecessary" is too strong a statement, for one thing it might be read by the incautious as meaning that they're vestigial. They're not, and if you cut three of them out of a whale and then sewed it back up it might well impair its digestion.

If I were to make the point, I'd put it something like this:

There seems to be no functional reason why whales should have multiple stomachs rather than some simpler arangement. The absence of such a reason is evidenced in two ways.

First, the presence of multiple stomachs exists across the whale clade, even though ceteceans don't all have the same diet. It would be a remarkable coincidence if multiple stomachs just happened to suit sperm whales eating giant squid, dolphins eating fish, and blue whales eating krill.

Second, we can see that in other groups of fauna with similar diets multiple stomachs are not present: for example a shark or a tuna with the same diet as a dolphin does not share its digestive arrangements.

However, this anatomical feature can readily be explained as part of the evolutionary heritage of ceteceans ...

... etc etc.


I do have to agree with you. I will make sure to revise my language if I use this in future posts. Thanks for the critique.


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NoNukes
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Posts: 9721
From: Central NC USA
Joined: 08-13-2010
Member Rating: 2.9


Message 15 of 443 (646878)
01-07-2012 4:17 AM


Recent discussion.
There was a recent thread in here in which a pro-creationist proponent made a commendable effort to debate the idea that whales had evolved from land animals. That thread is worth a peek. It shouldn't be too difficult to find.

Under a government which imprisons any unjustly, the true place for a just man is also in prison. The proper place to-day, the only place which Massachusetts has provided for her freer and less desponding spirits, is in her prisons, to be put out and locked out of the State by her own act, as they have already put themselves out by their principles. Thoreau: Civil Disobedience (1846)

    
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