Whales did (NOT) evolve


(Ashwin S) #1

Hi Mervin,

I am not a young earth creationist. Its interesting you mentioned whales.

Earlier scientists used to think that whales evolved from mammals living in the land 53 million years ago taking a time of 10 to 15 million years to get the first full fledged whale…
All this came crashing down when they found a whale fossils that was 49 million years old.Meaning the time required reduced by a third.

And of course, how do we know there isn’t an older fossil out there? Or that whales existed earlier… say 55 million years ago and the oldest fossils just happen to be 49 Mya?There is a higher chance for evolution to happen rapidly as opposed to slow, because the examples of a slow transition may be due to a result of older fossils not being preserved.


Creating Information Naturally, Part 1: Snowflakes, Chess, and DNA
(Ashwin S) #2

Hi Lynn,

Thanks for the link. If you read the wiki article. You must have noticed the following disclaimer.

Blockquote
Almost all of the transitional forms in this list do not actually represent ancestors of any living group or other transitional forms. Darwin noted that transitional forms could be considered common ancestors, direct ancestors or collateral ancestors of living or extinct groups, but believed that finding actual common or direct ancestors linking different groups was unlikely.
Blockquote
Emphasis in bold is mine.
This leaves me with a weird picture that none(or at least most) of the extinct species really transitioned into anything that exists today… This is probably because there is still a lot of uncertainty with respect to the tree of life.
One example of a tree of life that got seriously messed up recently was that of the whale. It’s evolutionary “story” went something like below:
Pakicetids (fully terrestrial): ~50 mya
Ambulocetids (semi-aquatic): 49 mya
Remingtonocetids (semi-aquatic): 49 mya
Rodhocetus (a Protocetid, semi-aquatic): 47 mya
Basilosaurids (fully aquatic): 40 mya…

Only problem is that, a whale fossil dated 49 Mya was discovered recently… And all those semi-aquatic transitional fossil ancestors became… Cousins. And whales seem to have taken to the waters quite abruptly.


(Mervin Bitikofer) #3

Thanks for clarifying that. And sorry if you had laid out more about your views somewhere and I just didn’t see it.

This Biologos article on whales that I indirectly linked to above might be interesting to you. It was written in December of 2017, so that would probably be more recent than the problems you mention. In any case, the new data seems to be taken well into hand.

image

…though the article doesn’t give much detail about the picture it includes above, the dates shown would seem to confirm your observation about the current fossil dates such as they know. More to the point, though, may be these paragraphs from the same article. If you have a better explanation than the multiple converging lines of evidence (including the fossil record!) that are discussed in the article, please let us know. It is always a given that more fossils are expected to turn up, and hopefully refine the model. I’ll paste the paragraph below.

As we have seen, the strength of evolution as a scientific theory does not rest in any one piece of evidence, but rather in the numerous pieces from multiple disciplines that fit together in a cohesive way, mutually reinforcing one another. One aspect of Christian anti-evolutionary materials that I find frustrating is that the broad sweep of evidence for evolution is avoided in favor of focusing in on specific, isolated details in an attempt to refute them individually. This approach fosters the misleading impression that evolution, as a theory, stands or falls on the interpretation of small experimental details. In reality, evolution as a theory is supported by a vast array of data from many independent fields, and any attempt to refute evolution will fail scientifically unless it addresses that vast array. As such, Christian anti-evolutionary approaches do not offer a significant scientific challenge to evolution. Rather, they merely create an impression of evolution that does not do justice to its true strength.


(Lynn Munter) #4

Of course it is appropriate to use an abundance of caution when talking about transitional forms. For example, let’s say you know some of your ancestors lived in Scotland. You visit a random cemetery and see a tombstone with a name pretty similar to your ancestors’. It would be much more appropriate to say “this person may have been a close relative to my family tree” rather than “I am descended from this person” so long as you have no more information to go on.

Similarly, even if we did find a direct ancestor in the fossil record, it would be indistinguishable from a close relative, so best practice is to not say more than we are confident of and call them all close relatives. In some cases we can tell that a fossil is somewhat diverged from what we would expect from a direct ancestor; in some cases it isn’t at all clear.

Statistically, if we crunch the numbers of all the living things that have ever existed and how many of them have living descendants, we expect finding direct ancestors to be surprisingly rare. But ‘close cousins’ on the tree of life can still tell us an amazing amount about how evolution proceeded; it’s a mistake to dismiss them just because they’re not on a direct line of descent, because they’re probably a lot closer to that direct line of descent than anything else we have to look at.

I see @Mervin_Bitikofer has addressed your whale question already above me, does that answer your concerns about whales?


(Ashwin S) #5

Well Mervin,

The frustrating part is how evidence is ignored.
Many of those organisms mentioned as ancestors or intermediate forms are not… simply because a functional whale fossil has been found that is 49 Mya.
The same kind of interdisciplinary argument could be made that whales and bats share a common ancestor if we look at how the echo location systems of both species work . This is true ESP if we look at genetic similarities. So the question remains why cherry pick and make up stories…?
And why continue with the stories even decades after contradictory evidence turns up. Shouldn’t honest science involve discussing evidence that contradicts ones position as well?


(Ashwin S) #6

Hi Lynn,
this is a very interesting comment. If I remember correctly, rapid evolution in the punctuated equilibrium scenario usually involves bottlenecks and isolation of species… Allowing mutations to take hold and speciation to occur.
For a whale to appear 49mya and intermediate species to still be alive and kicking at say 45mya is a rather unexpected phenomenon.
Besides , if we are speculating. Why not speculate the other way? That whales existed 60mya and just left fossils after 10my?
I think a distant cousin is more feasible.

I agree with you here on the facts. It’s true that it’s very difficult to tell whether features were lost or are even examples of “convergent evolution”. My only complaint is that this kind of situation leaves a lot of room for making up stories and cherry picking facts.
There is so much room not just in family trees, but also in dating methods that “fitting” data to a narrative becomes very easy as well as tempting.


#7

They are transitional forms because they have a mixture of modern whale features and earlier features from terrestrial mammals. Transitional does not mean ancestral, it simply denotes a mixture of characteristics.

“A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group.[1] This is especially important where the descendant group is sharply differentiated by gross anatomy and mode of living from the ancestral group. These fossils serve as a reminder that taxonomic divisions are human constructs that have been imposed in hindsight on a continuum of variation. Because of the incompleteness of the fossil record, there is usually no way to know exactly how close a transitional fossil is to the point of divergence. Therefore, it cannot be assumed that transitional fossils are direct ancestors of more recent groups, though they are frequently used as models for such ancestors.[2]”
Wikipedia

“In looking for the gradations by which an organ in any species has been perfected, we ought to look exclusively to its lineal ancestors; but this is scarcely ever possible, and we are forced in each case to look to species of the same group, that is to the collateral descendants from the same original parent-form, in order to see what gradations are possible, and for the chance of some gradations having been transmitted from the earlier stages of descent, in an unaltered or little altered condition.”–Charles Darwin, “Origin of Species”


(Ashwin S) #8

Hi,
I assumed the derived descendent group were whales and the ancestral group were land living mammals.
These “transitional fossils” must be ancestral to the first whale…unless you believe modern whales are not related to the ancient ones.


(Lynn Munter) #9

Hi, Ashwin!

So long as the starting population of the diverging species is small, there’s really nothing to say one way or another what happens to the bulk of the population or closely related species. At the risk of sounding like I’m making up stories, let’s think about what happens as soon as the transition to a fully aquatic animal happens: all of a sudden they can travel the whole world, but nothing prevents their semi-aquatic brethren from staying put right where they’ve been all along. Or just because a species figures out how to exploit a new ecological niche, and adapts to a different lifestyle in a number of ways, doesn’t mean the old ecological niche that they were well adapted to before isn’t there anymore.

This runs into the old argument, if humans descended from monkeys, why are there still monkeys? The answer is simply that evolution branches like a tree, easily and often.

This might be true to a certain extent, but I don’t think genetically constructed trees assembled by computer programs that map extremely well to morphologically constructed trees are products of bias.


(Lynn Munter) #10

Perhaps I should clarify that I don’t think it’s necessary that all of the proto-whale examples fit into a direct line of descent. However I think the chances that at least a couple of them will prove to have existed as species for a few million years longer than we currently have fossil evidence for are excellent. The “evidence of their existence” you want is all the different whale-related descendants they left.

Related to other comments on this thread, I do think living animals can qualify as transitional species. For example, there are frogs living today and the original amphibians that crawled out of the oceans pretty rapidly became something we would call “frogs,” despite not matching exactly any present-day frog species. Similarly, we would probably look at the original transition to reptilian characteristics and call it a “lizard,” more or less, and the precursor to all of them we would call a “fish.”

If you want to call a chimp an intermediate form between us and baboons, that’s actually fine with me, keeping in mind that chimps do have a few characteristics that our common ancestor didn’t.

The article didn’t at all say you could get practically any result. It was addressing uncertainties much farther back in time than any of the whales or other examples we’re talking about. This is a known issue. We expect DNA trees to start looking fuzzy after enough time elapses that everything is probably mutated, and the solution is to look at things like the genes for mitochondria that can’t change freely while maintaining viable organisms. But this is kingdom/subkingdom levels of uncertainty, not orders like Cetacea. For looking at the recent past, genetic trees are amazingly reliable.


#11

It is a fact that these fossils have a mixture of modern whale features and features from terrestrial mammals. That’s what makes them transitional, and no stories are needed.

That’s not what happens. They use as many genes as possible, and the contradictions are right where we would expect to see them if evolution is true. When you are dealing with deep nodes with little genetic data you would expect contradictory trees for different genes. However, the contradictions are still well within the expected phylogenies. It isn’t as if some mouse genes have them more closely related to squid than to squirrels.


#12

If whales evolved from terrestrial mammals then there should have been species in the past who had a mixture of whale and terrestrial mammal features, correct?


(Mervin Bitikofer) #13

That’s pretty cool! (that bats and dolphins both benefit from what might be some convergent evolution). God’s creation is full of wonderfully complex things! (Wonderful as long as you aren’t a mosquito in some bat’s echolocation cross-hairs, that is!)


(George Brooks) #14

@Ashwin_s,

If I were going into a florist shop to tell the professional florists that they don’t know anything about flowers, I would first make sure I knew A LOT of A LOT about flowers.

How is it that you believe you can present yourself in the midst of many knowledgeable people, including professional biologists and geneticists, and tell them that they don’t know how to do science?

In just this little section I quote from above, you lay down two charges:

  1. That Evolution does not allow predictions; and
  2. the theory of evolution will predict a continuum over time rather than
    vested heirarchies clearly differentiated from each other…

In response to (1), you apparently think you can take any non-predicted part of the discipline of Evolution, and say that if it was real science, these unpredicted things SHOULD have been predicted. This is like Climate Warming Denialists saying climatologist models are useless because they can’t accurately predict average temperatures for the next 12 months. Below is a highly condensed description of a successful prediction of what genetic testing should reveal (in existing whales) regarding those with baleen instead of teeth:

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
"Some of the genes known to be used in all mammals for tooth formation were the obvious candidate genes to start with: the products of the ameloblastin, amelogenin, and enamelin genes are all used in the formation of tooth enamel, the hardest structure in the vertebrate skeleton. Researchers went looking for these genes in several Mysticete (i.e. toothless whale) species. The results showed that all the species studied did indeed have these three genes present as pseudogenes (and more specifically, as unitary pseudogenes, a special class of pseudogene we have discussed in detail previously).

Finding these genes as pseudogenes in toothless whales was exactly what evolution predicted, but there was a catch: none of the mutations that removed the functions of these three genes were shared between different species, suggesting that these genes lost their function independently in the species studied. This finding was at odds with data from the fossil record, which suggested that teeth were lost only once, and early in the lineage leading to all modern toothless whales. So, the researchers seemed to have two lines of evidence that at face value contradicted each other. The fossil record suggested that tooth loss occurred once in the common ancestor of all toothless whales, but these three genes seemed to have been inactivated independently, several times over, suggesting that loss of teeth should be happening later in Mysticete evolution, and more than once.

One proposed explanation for the apparent discrepancy (among several put forward) was to predict that a fourth gene required for enamel formation was lost early in Mysticete evolution. The loss of any one gene necessary for forming enamel would be enough to prevent the process altogether. In this case, the loss of this fourth gene would prevent tooth enamel from forming, even though the genetic sequences of the other three enamel genes would still be intact. Once enamel function was lost, random mutations in the remaining enamel genes could then accumulate later in Mysticete evolution after speciation in this group was already underway. To test this hypothesis, the research group went hunting for other enamel genes in toothless whales.
[END OF SECTION]


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Is the confirmation of “toothless whale genetics” a rare success? No. What else has evolution successfully predicted? Here is a short list:

1] A biochemical way for information to be passed on from generation to generation that can be subject to mutation
2] Shared transposons between closely related species
3] The synteny between genes on chromosomes
4] Shared pseudogenes with shared means of inactivation
5] Incomplete lineage sorting when we encounter three closely related clades.
6] Mechanisms for new genes to be created
7] Feathered dinosaurs
8] The ability of closely related species to interbreed
9] Countless intermediate forms in the fossil record including this startling find of the Tiktaalik. One group estimated the geologic period and conditions where an intermediate “Fish-to-Tetrapod” should have existed on the Earth. The most accessible place for an intersection of these conditions was on Ellesmere Island, in the
far north of Canada. The team went there… the rest is history.

10] One of the successful predictions easiest to explain was the conclusion that one set of human chromosomes must be a fusion of two chromsomes, “… because we have one fewer pair than other great apes do. Long after that prediction the fusion site was found.”

@Ashwin_s, I’ll tackle your other egregious accusation … [re-stated below]

[ (2) the theory of evolution will predict a continuum over time rather
than vested heirarchies clearly differentiated from each other…]

^^… in a separate posting.


(George Brooks) #15

@Ashwin_s, (@pevaquark )

You are kidding right? You are going to lecture fossil experts that they are wrong about anatomical analysis of intermediate forms?

Why should a pakicetid look like a cow?

We aren’t looking for cow shaped bodies… we are looking at the ankles… and proto-whales had them!


.
.
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How do you explain marine reptiles drowning below the KT boundary, while proto whales appear in the middle of the so-called “flood sediments” ? And then when they disappear…suddenly the whales without any feet at all show up … in the so-called “flood sediments”? And then the balleen whales show up above all those other whales… not because they drowned last … but because balleen whales were a later development.

You are focusing on all the wrong information.


(Ashwin S) #16

Let’s start with facts both of us should be able to agree about. I will quote some things from the university of Berkeley site from which you seem to have sourced your info from.

  1. The whale “evolutionary tree” does not make any claims about direct decent.

Blockquote
The first thing to notice on this evogram is that hippos are the closest living relatives of whales, but they are not the ancestors of whales. In fact, none of the individual animals on the evogram is the direct ancestor of any other, as far as we know.
Blockquote
Source:https://evolution.berkeley.edu/evolibrary/article/evograms_03

Asper the above article, Pakicetus was a land based animal that loved 53 million years ago. From the pakicetus we have a line of fossils which are amphibian and said to be more and more aquatic. This is certainly encouraging.
There is a beautiful story of the nostrils shifting from the edge of the nose upwards… let me show the pic…nostril_migration

The only problem is that the fossil of the more aquatic animal with a slightly pushed up nose is only 36 Mya… While the oldest whale fossil is at least 40-46 Mya (more probably 49mya)…
Which means we would have to speculate on/ assume all the “interim species” existed millions of years before their fossils were formed… and actually predated the fully aquatic whale.

Nice pics… pretty story… No fossil evidence.


#17

That is no more a problem than wolves still being around after evolving into the domestic dog.


#18

That is false. It is OBSERVED that these species have a mixture of terrestrial mammal and cetacean features. This not speculation. This is an observation.

That is also false. Wolves still exist even though wolves evolved into domestic dogs. Modern wolves are sister taxa to domestic dogs. In the same way, these species with a mixture of terrestrial mammal and cetacean features are sister taxa to the direct lineage that led to whales. Those sister taxa still have the transitional features that were found in the direct lineage.

How do you determine how many fossils there should be in our collections? How much of the world do you think we have searched for fossils?


(Chris Falter) #19

Hi Ashwin,

So far as I can tell, the problem with whale evolution that seems to puzzle you is that, per the source you consulted, no fossils-- none whatsoever, zilch, nada–have been found in the period from 47 mya to 36 mya.

Am I understanding you correctly?

Yours,
Chris


(Ashwin S) #20

Since you mentioned the platypus… Seems like it’s also got bird features…

In addition to the bill… it’s sex chromosome seems to have both mammalian and bird features…

Blockquote
Two centuries after the duck-billed platypus was discovered, monotreme chromosome systems remain deeply puzzling. Karyotypes of males, or of both sexes, were claimed to contain several unpaired chromosomes (including the X chromosome) that form a multi-chromosomal chain at meiosis. Such meiotic chains exist in plants and insects but are rare in vertebrates. How the platypus chromosome system works to determine sex and produce balanced gametes has been controversial for decades. Here we demonstrate that platypus have five male-specific chromosomes (Y chromosomes) and five chromosomes present in one copy in males and two copies in females (X chromosomes). These ten chromosomes form a multivalent chain at male meiosis, adopting an alternating pattern to segregate into XXXXX-bearing and YYYYY-bearing sperm. Which, if any, of these sex chromosomes bears one or more sex-determining genes remains unknown. The largest X chromosome, with homology to the human X chromosome, lies at one end of the chain, and a chromosome with homology to the bird Z chromosome lies near the other end. This suggests an evolutionary link between mammal and bird sex chromosome systems, which were previously thought to have evolved independently
Blockquote

Do we have a winner for the evolution falsifiability test?
It’s got a beak… but it’s not a bird.
It’s skeletons looks like that of a reptile’s … but it’s not a reptile.
It’s reproductive chromosomes are a mix of mammalian and bird types…

I would bet not.

@Chris_Falter : unless we have intermediate fossils that predate whales and show a clear linkage showing plausible route for how whales evolved, we can’t be sure how it happened. Since evolutionary trees are constructed assuming descent, evidence is interpreted in that way. For example, if there is similarity between organisms which are dissimilar in other features, these similarities are called convergent evolution or parallel evolution and considered not related to lineage. This problem is made worse in the genomic/molecular level.
Since the process assumes common descent and all evidence is interpreted in line with that irrespective of whether there is a direct cause effect link/evidence of the same, common descent cannot be falsified by cladistics.
If an anamoly is found, it will be explained away by the plot armour which is the unknown common ancestor. For example, if the duckbill platypus had features similar to birds in their sex chromosomes, it’s assumed that the common ancestor of mammals and the platypus (which is not known and so cannot be put to any kind of test) had these features.

Hence rendering common descent unfalsifiable. Not identifying direct relationships in lineage makes the process unfalsifiable… and very bad science.