Whale Evolution in the Fossil Record
The evolution of whales and dolphins (cetaceans) is represented in the fossil record by a great series of fossil intermediate (otherwise known as transitional forms/fossils) including Pakicetus, Ambulocetus, Remingtonocetus, etc.
The definition of transitional form:
A transitional form is a life form that has traits characteristic of one taxa, traits characteristic of another taxa and/or traits intermediate between two said taxa. A transitional form does not have to be a directly ancestor (equivalent to a mother or grandmother) to the hypothetical descendant group, but can be a collateral ancestor (equivalent to an uncle or cousin):
"...Transitional forms do not have to be on the direct line of descent from an ancestor to a living descendant - they could be evolutionary cousins that went extinct." - Prof. Jerry Coyne, Why Evolution is True, 2009.
Furthermore, most fossils are not interpreted as direct ancestors, but collateral ancestors because genealogies always have more collateral ancestors, especially when you go further back in time. For instance, going back one generation I have two direct ancestors (mother and father) and one collateral ancestor (brother). One more generation back I have increased my direct ancestors to 6 (four grandparents and two parents) but have greatly increased my collateral ancestors to 16 (4 uncles, 1 aunt and 11 cousins). Going back even further, counting all my great uncles and second cousins and third cousins and so on, the exponentially-increasing number of collateral ancestors eclipses my direct ancestors. Similarly, the tree of life, according to the theory of evolution, includes an infinitely larger number of collateral ancestors. This is why transitional fossils are rarely considered direct ancestors to living groups, because the odds of finding one is very small.
"It is theoretically conceivable that a particular fossil really is the direct ancestor of some modern animal. But it is statistically unlikely, because the tree of evolution is not a Christmas tree or a Lombardy poplar, but a densely branched thicket or bush... Fossils as well as living creatures are usually best treated as cousins, not ancestors."
The fossil whales series is not a direct line of descent. Pakicetus is not the direct ancestor of Ambulocetus and Ambulocetusis not the direct ancestor of Basilosaurus and so on. They are interpreted as cousins.
The Fossil Whales Series:
Pakicetids have a great mixture of traits found only in living cetaceans and traits found in artiodactyles (even-toed ungulates). Firstly, they have four limbs with the 'double-pulley' astragalus (ankle bone) which is a feature unique to artiodactyles. But they also have features found in cetaceans such as the thickening of the medial lip of the auditory bulla (called the involucrum) as well as the presence of a sigmoid process (both traits are only found in whales). The bones of Pakicetids were also osteosclerotic (heavy and thick) which is common for bottom walkers in rivers and oceans because it ways them down so they can forage on the floor.
Remingtoncetids, just like Pakicetids, also has the involucrom and sigmoid process (as well as four limbs). But they also have another feature: the reduction of the semi-circular canals. Cetaceans are unique in that their semi-circular canals are three-times smaller compared with other mammals relative to body size. So remingtonicetids have three unique whale features: the involucrom, sigmoid process and a three-fold reduction in the semi-circular canals.
Remingtonocetids also had another trait found (but is not unique) in cetaceans. This trait is the ability to osmoregulate in saltwater (a trait not found in land mammals) Because I am getting tired I will use this wonderful explanation by 'The Virus and the Whale: How Scientists Study Evolution':
"Living whales and dolphins can drink seawater, while land mammals can drink only freshwater. The two kinds of water are different in several ways, and not just because seawater is salty and freshwater is not. Both kinds of water contain oxygen atoms, but the oxygen atoms are slightly different.
Like other elements, oxygen atoms are made up of a combination of negatively charged electrons, positively charged protons, and neutral neutrons. All oxygen atoms have 8 protons, and most have 8 neutrons. But a fraction of oxygen atoms on the Earth have extra neutrons, making them heavier. Scientists have observed that seawater has more oxygen atoms with 10 neutrons than does freshwater. And animals that live on land and at sea reflect this difference in the oxygen atoms incorporated in their bones. Living whales and dolphins have a larger percentage of heavy oxygen in their bones than do mammals that live on land.
Thewissen wondered if the oxygen atoms in ancient whale fossils might indicate where they lived. So he and his colleagues ground up tiny samples of ancient whale teeth and measured the ratio of light and heavy oxygen. They discovered that Pakicetus still drank freshwater. Ambulocetus, which belongs to a younger branch of the whale tree, had an intermediate ratio, suggesting that it was drinking brackish water near the shore, or a mix of freshwater and seawater. More recent fossil whales had the ratios you would expect in animals that drank seawater alone."
Remingtonocetids has a oxygen isotope ratio of marine organisms, indicating that they lived their life in the ocean. You can look up the document by typing the name of it into Google (it's free).
Also note that Ambolucetids had an transitional oxygen isotope value (neither showing that it drank freshwater nor seawater but brackish or a mixture). Ambulocetids also had an involucrum. However, the region that should show the sigmoid process in Ambulocetus was not preserved and I believe the semi-circular canals were also not preserved so we don't know what size they were.
I am getting really tired so I await your response.
Thanks for your opening argument. Usually you state the premise or resolution for the debate so the voters know how to determine a winner. I will state that there is no demonstrable evidence of whale evolution having taken place.
I must point out that it seems your line of reasoning is that these "whale ancestors" or "cousins" are related because of homologous structures which is to me a very weak argument. Homology of any kind is just as much evidence of a common Designer as it is for common ancestry. I realize homology is important for evolution, especially when studying fossil creatures which you wish to "fit" in the tree of evolution, but it is not a very strong argument. Homology can be evidence for either a common Designer or a common ancestor depending on the model of origins being applied. I will make an argument against your position under the following subtitles.
A Mechanism for Evolution
So first off, for your model of origins (in the case of cetaceans) to even be considered viable, you must have a demonstrable mechanism for evolutionary change. Unless you can provide a mechanism which has demonstrably shown to add new genetic information and to form novel structures (such as a blowhole or flipper), then your "interpretation" of the fossils of Pakicetus, Ambulocetus, Remingtonocetus, etc., cannot be taken seriously.
This first example you give as a candidate for a transitional form in the whale evolution series falls far short of your intended aspirations. You point out "transitional" structures which are homologous to cetaceans and artiodactyles, yet you fail to point out that Pakicetus was entirely a land dwelling mammal. "A prominent whale expert, Thewissen, and colleagues unearthed some more bones of Pakicetus, and published their work in the journal Nature. The commentary on this paper in the same issue says, "All the postcranial bones indicate that pakicetids were land mammals, and . . . indicate that the animals were runners, with only their feet touching the ground'" (http://creation.com...).
In a detailed analysis of the semicircular canal systems in both living and fossil cetaceans, it was demonstrated that a sharp gap in relative sizes between whales and non-whales existed, including the pakicetid Ichthyolestes. There were no examples of slow and gradual shrinking of the canals in any of the fossil series, they were either one relative size or the other. In fact, the paper affirms that the alleged change in canal structure happened ‘instantaneously’ and produced a ‘unique’ apparatus (Spoor F., Bajpai S., Hussain S.T., Kumar K. and Thewissen J.G.M., Vestibular evidence for the evolution of aquatic behaviour in early cetaceans, Nature 417(6885):163–166, 9 May 2002).
It is a huge jump to say Pakicetus evolved into modern whales, or to even say it is related as a "cousin." Lets move one.
I'm afraid your evidence here is just to circumstantial. Your assuming whale evolution has taken place, and you are interpreting these homologous structures as evidence. Marsupial moles and placental moles are nearly identical, yet since evolutionists say these evolves separately and are not closely related to each other, the phenomena is categorized as "convergent evolution." So I am supposed to accept you three homologous structures as evidence for Remingtonocetus being ancestrally related to modern whales when marsupial and placental moles share nearly 100% of their morphology yet they are unrelated. Homology is selectively used in the story of evolution and is therefore untrustworthy.
You yourself admitted that two key "evidential bones" of Ambulocetus were missing, so I'm not following your reasoning here. If the sigmoid process and semi-circular canals are supposed to be striking evidence of whale kinship, why bring up Ambulocetus?
As already stated, homology does not provide conclusive evidence of evolution as it is model-dependant evidence. Furthermore, it has been demonstrated that homologous structures are in many cases not derived from homologous genes (http://creation.com...). Genetic research has not shown that homologous structures are produced by homologous genes and follow homologous patterns of embryological development (http://creation.com...). So how do you know that these similarities are based on homologous genes if these are mere fossils with no DNA information to study? And how can you say that these cases of homologous structures are not examples of convergent evolution rather than evidence of ancestral relationship?
So far all you have demonstrated are a few fossil creatures which share a few structures with cetaceans. I can show many more structures shared between Chimpanzees and humans, that doesn't ultimately "prove" we share a common ancestor. Your evidence so far is very weak and very circumstantial. I look forward to your response and I am prepared to defend my statements. On to you...
"...The evidence is absolutely conclusive that they [cetaceans] were not originally aquatic in habit, but are derived from terrestrial mammals of fairly high organisation, belonging to the placental division of the class, - animals in which a hairy covering was developed, and with sense organs, especially that of smell, adapted for living on land; animals, moreover, with four completely developed limbs on the type of the higher vertebrate, and not of that of fishes." - Flower, W. H. 1883. "On whales, past and present and their probable origins II", Nature, vol. 28, pp. 226-30.
"The whales and porpoises together form a great order of animals known as the order Cetacea, all the members of which are most admirably adapted for an exclusively aquatic life. Nevertheless, the details of their anatomy (rudiments of hind-limbs, &c.) conclusively prove that they are the descendants of beasts which were quadrupeds fitted to live upon the earth's surface. But although the fossil remains of countless Cetacea have been entombed, yet the transitional forms are still amongst "missing links" of Nature." - London Quarterly Review 1886, pp. 275-284.
Before any cetacean transitional forms were found (except for Basilosaurids), anatomists concluded that the modern forms must be derived from terrestrial, quadrupedal mammals. The hypothesis meant that transitional forms linking these aquatic mammals with their terrestrial ancestors must have previously lived, died and some should have fossilized. This is a prediction which can be tested. If cetaceans really did descend from terrestrial quadrupeds, than forms intermediate between them should be found in geological strata.
You argue that that what if these forms were merely intermediate not because they are closely genealogically related to modern cetaceans, but merely mimic the transition due to convergent evolution. It is impossible to conclusively determine whether or not this the case, but there is some evidence that indicates that it is not an example of convergent evolution.
Firstly, the first appearance archaeocetes ('archaic whales') precedes modern cetaceans in the fossil record exactly where they should to be if they are ancestral. If modern cetaceans appeared before the first appearance of archaeocetes in the geological strata, then it would definitely be a case of convergent evolution.
Secondly, in some cases, the apparent transition of certain characters is very gradual and continuous. For instance, let's take a look at some transitions that have taken place:
1) Freshwater osmoregulation to seawater osmoregulation (i.e. the ability to drink seawater).
2) The nostrils (external nares) posteriorly migrating from the tip of the snout (rostrum) to the the vertex of the head (forming a blowhole).
3) The reduction of the semicircular canals relative to body size.
I have already brought up the first and third transitions, with the former having an intermediate stage (Ambulocetus) and the latter being discontinuous, but appearing in early semi-aquatic cetaceans. The second transition, however, is actually presented by some fine transitional fossils that form a gradual series. The external nares being located posteriorly from the tip of the rostrum is a very useful aquatic adaptation as it allows the cetaceans to breath without having to lift their face out of the water. Below is a figure showing a gradual series of steps in "nasal drift" which begins at the tip of snout and migrates posteriorly. There are even more fossils which are intermediate with respect to external nare position between some of the fossils shown below (but I will not show due to the size of the image):
Note: All the fossil craniums are the same size for comparison purposes only. There is dramatic variation in size, especially between the first and last cetacean in the series. In addition to this, you can see that I took different photos, drawings and schematic diagrams from different sources. Also, the fossils do not represent a lineal line of descent, but are interpreted as evolutionary "cousins". The external nares are highlighted in red.
It should also be noted that during early embryological development of cetaceans, the nostrils initially form at the tip of the snout and then later migrates posteriorly up towards the vertex of the head.
The characters mentioned are only but a few of the traits which unite archaeocetes with modern whales. I mentioned the sigmoid process and the involucrum because they are simple, distinct and unique features of cetaceans, but there are much more complex and subtle features that are shared between archaeocetes with modern whales. Modern whales are unique in that their mandibular foramen is quite large when compared to non-cetaceans. I will let Thewissen & Bajpai (2001) explain why this is the case:
"In all mammals, including cetaceans, the nerves and blood vessels of the lower teeth travel through a canal called the mandibular foramen on the medial, or inner, side of the lower jaw. In odontocetes, this foramen covers the entire depth of the mandible and is much larger than is necessary for a simple conduit for nerve and vessels. Indeed the foramen has become part of the whale's hearing apparatus: It houses a fat pad, which extends posteriorly to the middle ear. Sounds are received by the lower jaw and are then transmitted by this fat pad to the middle ear. The posterior side of the mandible, with its fat pad, is the most sound-sensitive area of a modern odontocete, more sensitive than the area of the ear itself."
Here are to figures from Thewissen & Bajpai (2001) and Nummela et al. (2007):
This shows that Pakicetids had small mandibular foramens like non-ceataceans while Ambulocetids, Remingtonicetids, Protocetids (includuing Maiacetus inuus) and Basilosaurids have enlarged mandibular foramens like modern cetaceans.
There is a difference between making predictions from a model and later observing those predictions and finding observations that are consistent with the model, but they were never predicted in the first place. The former exercise actually puts your model to the test; you are so confident that the model is valid that you are willing to “put it on the line”, in a manner of speaking. While the latter exercise can be evidence for a model, it’s not as strong because all that is being done is post hoc rationalization.
Once again, these intermediate fossils are evidence for the hypothesis that cetaceans descended from terrestrial mammals because they were predicted to exist in the fossil record a century beforehand. The hypothesis was tested and confirmed because these intermediates have been observed in the fossil record. Your competing hypotheses that you are bringing forth are a post hoc analyses, where you are not predicting anything, but instead coming up with other explanations that are just consistent with the evidence.
I don’t normally like to quote young-earth creationists because I don’t like it when creationists misquote scientists. However, I will quote paleontologist Dr. Kurt Wise because I think his position is quite clear:
“Darwin’s fourth expectation - of stratomorphic series - has been confirmed by such examples as the early bird series, the tetrapod series, the whale series, the various mammal series of the Cenozoic (for example, the horse series, the camel series, the elephant series, the pig series, the titanothere series, etc.), the Cantius and Plesiadapus primate series, and the hominid series. Evidence for not just one but for all three of the species level and above types of stratomorphic intermediates expected by macroevolutionary theory is surely strong evidence for macroevolutionary theory. Creationists therefore need to accept this fact. It certainly cannot be said that traditional creation theory expected (predicted) any of these fossil finds.”
You notice in the summary below that some parts of the intermediates are missing or analyses are yet to be done on them. You can make predictions about these unknown features. If an oxygen isotope analysis is ever done on Maiacetus inuus, I predict that its oxygen isotopic composition will have a high oxygen-18 abundance. If the another Ambulocetid fossil is ever found with the auditory bulla completely preserved, it will have a sigmoid process present.
Below is a summary of the presence/absence of cetacean/marine traits in some archaeocetes:
Pakicetids (e.g. Pakicetus)
Sigmoid process: present
Three-fold reduction in semicircular canal radii: absent
Capacity to osmoregulate in seawater: absent
Enlarged mandibular foramen: absent
Remingtonocetids (e.g. Remingtoncetus)
Sigmoid process: present
Three-fold reduction in semicircular canal radii: present
Capacity to osmoregulate in seawater: present
Enlarged mandibular foramen: present
Sigmoid process: unknown
Three-fold reduction in semicircular canal radii: unknown
Capacity to osmoregulate in seawater: present
Enlarged mandibular foramen: present
Sigmoid process: present
Three-fold reduction in semicircular canal radii: unknown
Capacity to osmoregulate in seawater: unknown
Enlarged mandibular foramen: present
Sigmoid process: present
Three-fold reduction in semicircular canal radii: present
Capacity to osmoregulate in seawater: present
Enlarged mandibular foramen: present
You also did not address my point on the selectivity of homology in evolutionary practice. I share many homologous structures with bonobos, orangutans, etc., but this does not prove that I am their cousin. In order to take such an idea seriously, you would need to explain a possible mechanism(s) for such change to be feasible and then you would need to put it to the test and make observations which demonstrate its veracity. I believe mountain gorillas and silverback gorillas are part of the same created kind despite their being separate species. The mechanism for this type of change-within-a-kind is well known and observable, namely natural selection. Natural selection, though, only works to select from what is already available in the genome, it can add new genetic information. So wolfs can become Chihuahuas with a loss of information but Chihuahuas cannot become wolfs because they would need the introduction of new genetic information. Given these issues, I will address your round 2 argument below.
You begin by sharing two highly biased evolutionary quotes basically affirming the case for whale evolution yet without providing "conclusive" evidence and making unfounded claims (such as whales having vestigial legs).You first state, "Before any cetacean transitional forms were found (except for Basilosaurids), anatomists concluded that the modern forms must be derived from terrestrial, quadrupedal mammals." You mean they assumed evolution to be true before they had any conclusive evidence, which is fine by the way, as long as we recognize that evolution is an axiomatic model which was not initially based on any conclusive evidence (and I would argue that it still has no such evidence).You say, "It is impossible to conclusively determine whether or not this the case, but there is some evidence that indicates that it is not an example of convergent evolution." This highlights the nature of the type of historical science of which we are arguing. We cannot conclusively determine whether your interpretation is true because we cannot observe past history, hence the accurate classification of this forensic-style science as historical science. You will find that creationists never (or should never) argue against observation/operational science because that is something you can observe, test and demonstrate in the here-and-now (e.g. natural selection). The best anyone can do to determine if a certain model of past history is true or not is to see if the observable evidence is consistent with the model, which you are attempting to do. I say all this for the sake of the reader, but I digress.
Your first proposed evidence of ancestral relationship is the geologic column/fossil record. Your second evidence is gradual, continuous "transitional" characteristics. I will address these two evidences you give below.
The Geologic Column / Fossil Record
You cite the geologic column/fossil record as evidence for your position but you do not provide any evidence to support it. The geologic column, as it is taught in textbooks, does not exist in its entirety anywhere on the planet; it is very fragmentary and piecemeal. "It has been claimed that the geological column as a faunal succession is not just a hypothetical concept, but a reality, because all Phanerozoic systems exist superposed at a number of locations on the earth. Close examination reveals, however, that even at locations where all ten systems are superposed, the column, as represented by sedimentary-thickness, is mostly missing. In fact, the thickest local accumulation of rock is only a tiny fraction of the inferred 600-million year"s worth of depositions. The global "stack" of index fossils exists nowhere on earth, and most index fossils do not usually overlie each other at the same locality. So, even in those places where all Phanerozoic systems have been assigned, the column is still hypothetical. Locally, many of the systems have not been assigned by the index fossils contained in the strata but by indirect methods that take the column for granted"clearly circular reasoning" (http://creation.com...).
Since you did not provide any evidence to support your claim of the fossil record, I will simply provide another quote. "When we consider the fact that fossil succession is limited in overall extent, it is another way of stating that there are many fossils which are found at many stratigraphic intervals. In fact, only a minority are confined to rocks attributed to only one geologic period. Since the early days of the acceptance of the standard geologic column, fossils have been turning up in "wrong" places as more and more fossils have been collected, and this process continues to this very day. And even this does not include the numerous instances where fossils are supposed to be reworked from older strata, often with no independent supporting evidence. Furthermore, extension of stratigraphic ranges occurs not only for individual fossils, but also for presumed grade of biologic complexity (that is, so-called stratomorphic intermediates) . . . extension of stratigraphic ranges is the rule and not the exception. This is even more remarkable when we remember that there is the ever-present evolutionary bias which tends to cause overemphasis of minute differences in fossils located in different horizons of strata, and hence the proliferation of questionable taxonomic names for essentially the same organism found at different stratigraphic horizons" (http://creation.com...).
Again, homologous structures do not bring one to the conclusion that they are cousins without having an evolutionary model as one's basis for interpreting these fossils. When you state things such as the "migration" of the nostrils, or the "reduction" of the semi-circular canals, you are already interpreting these fossils as transitional. Otherwise, all the location of the nostrils would tell you is that these creatures had nostrils at different locations. To jump to the conclusion that they are then related requires an interpretation based on a certain model. If I took the fossils of a pigeon, a turkey, and a condor and lined them up in that order, I could loosely make a case that these creatures are a series of evolutionary change, but I would of course be wrong. These creatures also share many homologous structures, yet this does not prove that they share a common ancestor. Using homology as evidence of a shared common ancestors a logical fallacy:
1) If organisms X and Y have a common ancestor, they will have homologous structures;
2) X and Y have homologous structures;
3) X and Y have a common ancestor.
This demonstrates that it is an example of the fallacy of affirming the consequent. The conclusion is not proven"the homologous structures could be due to a shared common Designer rather than a common ancestor. Dr. Jonathan Sarfati highlights the problem with using homology as evidence for evolution:
"Genes are inherited, not structures per se. So one would expect the similarities, if they were the result of evolutionary common ancestry, to be produced by a common genetic program. But in many cases, this is clearly not so. Consider the example of the five digits of both frogs and humans"the human embryo develops a ridge at the limb tip, then material between the digits dissolves; in frogs, the digits grow outward from buds. This argues strongly against the "common ancestry" evolutionary explanation for the similarity . . . assuming the truth of Darwinism as "evidence" for their explanation is begging the question. There is no experimental evidence, since we lack the DNA code of these alleged ancestors. There is also the theoretical problem that if we change the code, then the wrong proteins would be made, and the organism would die"so once a code is settled on, we"re stuck with it" (http://creation.com...).
You state that predictions put your model to the test, which I agree with, but you gave quotes to begin your argument with which were from the 1800s. Did they now about the genome back then? I don't think so. So "post hoc," they rationalized the evidence from genetics. Since you cannot study the DNA information and embryonic development of fossil creatures, you cannot demonstrate that any given homologous structure is evidence for common ancestry as you do not know if such structures are derived from homologous genes and followed homologous patterns of embryonic development.
As for your given quote of Dr. Kurt Wise, it should be noted that he states at the very beginning of his abstract that fossil evidence can be understood to support evolution when INTERPRETED as transitional forms. He also says, "Even at this early stage of development [of creationist paleontology] and with significant challenges as the whale series, the creation model appears to have potential for developing a creationist explanation of stratomorphic intermediates which is superior to that of evolutionary theory" (http://web.archive.org...).
You say that these fossils confirm whale evolution, yet you have not conclusively shown that these are indeed transitional forms.
"You state that predictions put your model to the test, which I agree with, but you gave quotes to begin your argument with which were from the 1800s."
The purpose of the quotes were to demonstrate that the transitional forms were predicted by the by evolutionary theory to exist over a century ago before they were eventually found. This is very important in the scientific method. As the late Dr. Richard Feynman explained, the scientific method goes like this (I am paraphrasing):
Make a guess.
Derive and compute consequences of the guess being true.
Go into nature or the lab and see if you observe those consequences.
If you observe the consequences of the guess being true, then you have yourself a good guess. If you don't, your guess is false. This is not to say that the guess is therefore absolutely "true", but it shows that it can pass tests you put it through and is therefore not currently false. It may be falsified one day, but the guess is still tentatively true for now.
Early proponents of the theory of evolution followed this formula:
They guessed that cetaceans descended from terrestrial, quadrupedal mammals.
They concluded that if this is true, intermediate forms must exist in the fossil record.
They searched the geological strata for these intermediates.
They eventually found these intermediate forms and so therefore the guess is tentatively true.
It's not just enough to merely find the transitional forms and delude yourself into thinking "Of course! This is consistent with my model so it was predicted all along." That's not an actual prediction, but a post-diction, where you only think facts were expected only after they have been discovered. It's a form of confirmation bias. A true prediction is to explicitly assert the consequences of the model being true before the consequences have been observed, otherwise no test is taking place. And a test did take place by paleontologists and anatomists concluding that transitional forms between cetaceans and terrestrial mammals must exist in the fossil record and searched for them. For instance, here is another prediction by evolutionary theory regarding whale evolution:
"Prof. Flower particularly directed the attention of the Members to the skeletons of Cetacea, of which the Museum contains a fine series. After some general remarks upon the characters of the Order, he pointed out that all the known species, both living and extinct, could be arranged under one or other of two primary groups-the Mystacoceti, or Whalebone Whales, and the Odontoceti,or Toothed Whales; and that at present no transitional form between these two have been met with."
That quote is from 1879. Professor Flower is making a very explicit statement that transitional forms between baleen and toothed whaled had not yet been found. That's another prediction. It's a prediction because it shows that a consequence of the theory of evolution had not been observed at that point and potentially could (paleontology was in its infancy at that time). Aetiocetus weltoni was described in 1995 and it is a transitional form between baleen and toothed whales because it is a species of cetacean that had both baleen and teeth, among other traits found in both baleen and toothed whales. It tentatively confirms the hypothesis.
As I stated at the beginning, a transitional form is a life form that has traits characteristic of one taxa, traits characteristic of another taxa and/or traits intermediate between two said taxa. That's it. That's all that is necessary to confirm the predictions regarding transitional forms. Intermediate forms are predicted by the theory of evolution, but the transitional/intermediate status of a particular fossil is in no way dependent on the theory of evolution. You can completely reject the theory of evolution and acknowledge that fossils have been found that meet the definition of a transitional form. Dr. Todd C. Wood, a young earth creationist, completely rejects the theory of evolution and rejects that macroevolutionary transitions took place, but he recognizes that transitional forms have been discovered as predicted by the theory.
Kurt Wise also accepts that transitional forms exist in the fossil record, but is merely rejecting the term "transitional form" and prefers using other terms to describe the same fossils. His definition of "morphological intermediate fossil" is actually nearly identical to the definition I presented at the beginning (except he only focuses on morphology) and understand how they are predicted under the theory of evolution and not predicted under "traditional" creationism.
Let me reiterate this: finding fossils that are morphologically and physiologically intermediate between terrestrial artiodatyles and cetaceans with traits found in both groups and/or traits intermediate between the two groups is not only consistent with the hypothesis that whales descended from terrestrial mammals, but predicted by the hypothesis. The terrestrial artiodactyl traits include the double-pulley astragalus and quadrupedalism (among other traits) and cetacean traits include marine and estuarine osmoregulation, reduced hind-limbs, the external nares positioned intermediately between the tip of the snout and the vertex of the head, with sigmoid processes, involucrums, three-fold reduced semi-circular canals and large mandibular foramens (among other traits). And even more so, these fossils form this highly striking series based on their appearance in the fossil record (which actually both Kurt Wise and T. H. Huxley would agree is very strong evidence for theory of evolution).
"You say that these fossils confirm whale evolution, yet you have not conclusively shown that these are indeed transitional forms."
Once again, I have conclusively shown that these are transitional forms as these fossils meet the standard definition as stated in the beginning of this debate. You can can completely reject the theory of evolution, but you cannot reject that transitional forms (as defined above) exist. These transitional forms were predicted by the theory of evolution and were eventually found. This shows that the hypothesis is tentatively true.
P.S. I also reject the creationist "historical vs observational science" construct. I have literally never heard a non-creationist use the term "observationa science" and every single scientist I have heard discuss the topic, reject it.
Whilst some genetic evidence for whale evolution was not predicted, some predictions were derived from the hypothesis and tested. For instance, geneticists predicted that toothless whales would have psuedogenes for the production of teeth and they were found (also toothless whales develop tooth buds during embryonic development but don't develop teeth).
You did not address the lack of a mechanism for evolution which undermines your whole argument. Second, you did not address my points about using homology as evidence of evolution. In my view, while you provided plenty of interpretations of the fossils, you did not demonstrate the veracity of your interpretations. I agree that finding true transitional forms would be consistent with the predictions of evolution, but you have not shown that these are indeed intermediate creatures on the way to evolving into a new organism.
You say, " a transitional form is a life form that has traits characteristic of one taxa, traits characteristic of another taxa and/or traits intermediate between two said taxa. That's it. That's all that is necessary to confirm the predictions regarding transitional forms." Wow really? No wonder we both disagree. If that's all that was required to satisfy the resolution, I'm a believer! lol! But seriously, if that's all that is required, then all creatures can be seen as evidence for transitional forms. A platypus for instance has a beaver-like body, a duck-lick beak and webbed feet, and it lays eggs. Consider the possibility that God created creatures as basic kinds (i.e. dog kind, cat kind, etc.) with the genetic capability to change and adapt to their environment but with parameters set by its original genome (nothing "new" can be created that is not already coded for, only variations of traits). If this was the case, then God has made many creatures with homologous structures: pentadactyl limbs, two eyes, four limbs, one heart, etc.
The best way to determine if evolution has truly provided these traits is to see whether there truly is a mechanism for evolutionary change to take place between major groups of organism (e.g. fish, amphibians, reptiles, mammals, birds, etc.). If their was such a mechanism that was seemingly built into biochemistry, then the interpretation of such fossils as transitional forms would at least be plausible. It would gain even more points if such a mechanism was immediately observable in real-time (e.g. such as punctuated equilibrium). We of course have tested for such a mechanism with bacteria, but at the end of the day, bacteria always remain bacteria, nothing new, that is not already coded for in their genome, is gained.
I will not repeat what I said about homology, other than that there is no biology to test with true fossils, so you cannot determine whether homologous structures are derived from homologous genes, as opposed to being the result of convergent evolution, and you definitely cannot observe whether such homologous structures follow homologous patterns of embryonic development. So homology alone is poor evidence both for evolution (common ancestry) and also for creation (common designer).
You say, "I also reject the creationist 'historical vs observational science' construct. I have literally never heard a non-creationist use the term 'observationa science' and every single scientist I have heard discuss the topic, reject it." Then you must not be exposed to any honest scientists. It's a very simple concept. Observational science involves the scientific method in real-time where you should be able to observe, test and repeat. You cannot observe, test, or repeat the past. Historical science involves a forensic science type approach where you investigate past history with a certain model or hypothesis of what took place and then you examine physical evidence to determine whether it is consistent with the model or not. Ultimately you cannot conclusively determine whether a historical model is true, whereas in real-time observational science, you can. All the laws of science were developed based on real-time scientific investigation, including one which you probably dislike: the law of biogenesis (life only come from life). So while some scientists may dismiss the "construct" of observational vs historical science, the fact remains that both are two different types of science.
Your last comment on genetic evidence can also easily be explained in the creation model: God created whales with the genetic capability of teeth, some exhibited them, some did not. The fact that some whales today have lost the physical development of teeth does not really help evolution. Now show me an example of a whale in real-time that has mutated and produced something it did not previously have. That would be impressive, but of course, it is impossible given that there is no mechanism for such types of changes.
You did not defend your argument against my counter arguments. You used homology and the fossil record/geologic column as your main evidence, yet you did not defend those claims. I thank you for your time and your effort.