This AP news release sounds like it was written by someone with a pro-evolution agenda. The story headline reads, Japanese Researchers Find Dolphin With 'Remains of Legs.'
The story itself declares that, "Japanese researchers said Sunday that a bottlenose dolphin captured last month has an extra set of fins that could be the remains of back legs, a discovery that may provide further evidence that ocean-dwelling mammals once lived on land."
A paragraph later we read, "Fossil remains show dolphins and whales were four-footed land animals about 50 million years ago and share the same common ancestor as hippos and deer. Scientists believe they later transitioned to an aquatic lifestyle and their hind limbs disappeared."
Obviously, the conclusions one wants to make from this dolphin are more or less predetermined by what one believed before the dolphin was found.
Personally, I found something else of interest in this story — something that does not necessarily support the idea of macro-evolution much at all.
Most folks, like myself, who question the fundamental assumptions of macro-evolution as championed by many scientists, believe what we are is what we will always be.
What I mean is that each species contains a vast but limited pool of genetic diversity. While various combinations of this genetic mix can produce incredible variations within a species (consider the species [canis] lupus [familiaris], i.e. domesticated dogs, for example) the very genetic material that sets one type of creature apart as a species makes it impossible for that one type of creature to "evolve" into some other type of creature or species.
The fact that a dolphin is found with a small set of fins where there are not usually fins to be found is, as the story itself implies, evidence this particular dolphin had inherited some recessive genetic strand that had been long-ago displaced by more dominant genetic traits inherent in being a "dolphin."
Article comments
— go to most recent comments1 - krbrown
*sigh*
I don't think any would convince you of macro-evolution, would it?
2 - RJ Elliott
I write this as a supporter of evolution:
The news that some mutant dolphin has four fins instead of two is proof of dolphins having directly evolved from hippos about as much as some mutant human baby being born with eight eyes is somehow proof of humans having directly evolved from spiders.
3 - John E.
You have good citations of a variety of articles about dolphins, and it is true that a headline of "dolphins with legs" is a bit of a stretch. However, the point of a lot of headlines is to attract attention to make people read the article. Your headline attracted me to read your article, but I'm slightly disappointed. I felt that your argument was very well supported. Your logic was confusing and I still don't know what your connection was that showed how the dolphin actually refutes the theory of evolution. The center of the article (around paragraphs 7-10) didn't read very well and left me feeling confused. If you could explain your argument a little more clearly it would be a great help to me as a reader.
4 - JR
I just found a strawman with fins.
5 - JR Spagnuolo
Coming from a background of microbiology I would have to point out that what you are saying is fundamentally flawed. Evolution occurs but at a rate which we, as humans, cannot possibly comprehend. The genesis of species occurs very slowly, many many small changes over a long period of time - and I'm talking on a geological time scale here. Speciation can be seen here and now in pathogenic bacteria with the recent emergence of new highly resistant Mycobacterium tuberculosis, this happened within the last century and was driven by humans using antibiotics. HIV evolved from the Simian Immunodeficiency Virus. Evolution in microorganisms can and does occur at extremely fast rates because of the selection pressures we expose them to. Why else do you think the medical community is so alarmed at the increasing rate of antibiotic resistance emergence? This mutation in the dolphin is probably just an ancient gene which is now being expressed due to a mutation in the promoters. Chickens are the same, their genome still contains the genes for teeth, but it isn't expressed, that is it is switched "off".
6 - Dan
Bird's of Paradise's argument against evolution makes it clear that he/she does not fully understand evolution. Due to this fact his/her argument holds no weight. How can you make a valid argument against something you don't understand?
7 - Bird of Paradise
JR, I respect your knowledge and your background. It sounds as though you are not supportive of Eldredge & Gould's suggestion of "punctuated equilibrium," preferring to assert the more traditional neo-Darwinist view of speciation over vast periods of time.
Personally, I think "puctuated equilibria" matches the fossil record more acurately (and not simply as an explaination for the Cambrian explosion, either).
While it may be a better explaination it is still not satisfying insofar as it does not provide a reasonable process through which so much genetic transformation can take place in so short a time. Maybe I am too picky, but I have yet to find a process for macro-evolution that actually makes enough sense to convince me.
To me, much of it smells like Aristotle's flies, appearing with spontaneous generation out of manure.
As far as variation within species (as you illustrate with viral and bacterial mutation) there can be rapid adaptation in these microbes as the process of natural selection takes place. While this is a good point it is not particularly relevent since the process it describes is (literally!) micro-evolution (which is self-evident in nature) rather than macro-evolution (which is far less apparent or demonstrable).
And Dan, what exactly is it that I do not understand? Please help me on this!
8 - MoNKeYest1
Ok so you say here that "Macro-evolution might have gotten a boost if this dolphin had shown us something that clearly hadn't been in the genetic structure of dolphins in the past" then wouldn't that mean that the dolphins with the genetic structure of the past had to some how change to the genetic structure of the present?
9 - Christopher Rose
BoP: you don't understand anything because your mind is already shaped by your faith. Enquiring minds want to know, you merely grasp desperately at shards of info and seek to shape them to your arrogant views. Scientists are much more humble in their approach, maybe you should try it some time...
10 - JR Spagnuolo
Bird of Paradise,
Your concept of macro and micro evolution still seem incorrect. Micro-evolution is small changes occurring steadily, an example of this is the occurence of biotypes in bacteria; race in humans; breeds in dogs, chickens, horses and pretty much every other mammal/etc.
Macro-evolution stems from micro-evolution - many small changes make one big one. For example, Influenza recombines itself to form markedly different strains (In microbiology we very often have to look below species level because there is a lot more variation than can be quantified at species level).
The fossil record can only show the large changes because the small ones cannot be detected by normal means. By which I mean genetic and macroscopic.
Genetic drift (short term, ie small changes) and shift (long term - big changes) occur cooperatively. Shift cannot occur without drift since many small things add up to one big one. That is to say, variation and speciation have a critical point, at which the amount of variation will mean that the resultant organism is markedly different from the ancestral organism. I cannot stress the importance of the fact that the evolutionary tree is not a black & white thing, more of a continuum. Unfortunately for scientists DNA degrades over time and does not survive fossilisation very well. For the evolutionary tree this means the constant genetic drift of organisms cannot be infinantly tracked.
You will find it quite impossible for a species to suddenly divide in such a way that a new species can be defined. Dolphins cannot suddenly sprout legs and walk around. What you will find is structural homology. That is to say, the basic structure of all animalia is relativley the same. If you compare the skeleton of birds, fish, mammals and reptiles you will observe similar structures (NOT the same). If you look at the human foetus in development you will observe that it goes through several phases in which it will look similar to reptiles, fish, etc. I suggest you read a 100 level biology textbook (I recommend Biology by Neil Campbell et al) it will at least give you an understanding of the mechanisms involved in evolution.
11 - Jim
The article about extra fins on Dolfins brought to mind the TV article I watched just last night. It was about children and some adults that are born with extra digits. One fellow from India had 2 extra usable fingers and 6 toes on each foot. Clearly this is NOT proof that human evolution is a fact at all. It merely shows that genetic mistakes take place occassionally. Sadly, evolutionists scientists claim to have discovered proof of evolution when in fact they have run across a mistake now and then.
Jim
12 - Donnie Marler
The last Dolphin with a leg was Garo Yepremian.
13 - Matthew T. Sussman
Donnie wins.
14 - Bird of Paradise
JR, You reflect a tremendous "leap of faith" when you say, "Macro-evolution stems from micro-evolution - many small changes make one big one." (and yes, I understand that this is the predominant belief of most scientists and science teachers and science textbooks). While micro-evolution involves natural selection taking place from within a finite gene pool macro-evolution (on the other hand) involves either the transformation of genetic matter from one kind to another or the creation of new genetic material where it not previously existed.
A St. Bernard and a Chihauhau may seem quite different and may not, in fact, be able to be bred together but they are, nonetheless, still the same species derived from natural selection from the same gene pool. Similarly, Hawthorn Flies may become Apple Flies (see Wikipedia "Evolution") but this is not the creation of a new species (as the Wikipedia article suggests) but simply micro-natural selection. There is no "new" genetic material appearing from out of "nowhere" which is a necessary step for macro-evolution to take place.
15 - Bird of Paradise
MoNKeYest1, That IS my point. Dolphins of the past and dolphins of the present DO share the same genetic structure (although modern dolphins may have a smaller genetic diversity than those from long ago (due to natural selection).
16 - Joan Hunt
Evolution occurs when the parameters for a being's very existence change, forcing them to change.
JR is correct in the examples he gives, as micro-organisms have a much shorter life and the overall life cycle can be easily measured by humans.
Another example of some of the more common changes we can measure NOW adding up to larger changes down the line are in frogs. We can measure the polypeptides in frogs and other amphibians. Snakes and other reptiles in Australia have also shown evolutionary changed, based on their changing environment and adaptations to those changes.
A species has three choices in an ever-changing world: move, go extinct, or adapt. Animals instinctively opt for survival. Even moving causes adaptations due to changes in available food and shelter options, as well as encountering new predators.
Short life cycles of many species allows us to witness evolution first hand. For the first time, we are technically savvy enough to measure the smallest of these changes and document the various phases of evolution.
17 - Victor Plenty
Representing this news item as a "setback" for supporters of the idea that the earth orbits the sun would be approximately as relevant to science as the conclusions Bird of Paradise draws from it.
18 - kavis
JR,
Thank you for adding your comments in response to this opinion piece. I found your explanation of the matter at hand to be elucidating and informative.
19 - bdworzak
If you look up fossils for dorudon and basilosaurs, you'll see whales with complete pelvises & legs.
The genes that code for these in modern whales are no longer expressed due to mutations. A mutation in these deactivated genes may occur, allowing modern organisms to reveal structures present in ancestral forms.
That is probably what happened in this dolphin, and what happens in human babies with tails, and horses with three toes on each foot. There is a lot of work currently being done with Hox genes, which account for changes in an organism's body plan. These hox genes have been duplicated several times through evolutionary history, and the mutations of duplicate copies allow for the development of new functions and structures.
Deactivation of Hox genes in mouse embryos have revealed features that were found in ancestral forms, such as ribs on every vertebra, (like our fish & reptilian ancestors), jaws with bone structures of therapsids, (the reptiles mammals evolved from) and more than five fingers on each hand, like in ichthyostega and acanthostega.
Evolution does not occur by a hippo popping out a dolphin baby. There is no doubt that whales evolved from land-living mammals; they breathe air, give their babies milk, have five fingers in each flipper, and still show the remains of pelvic bones. As embryos, whales show legs, which disappear, outer ears, which disappear, and as mentioned above, the fossil record leaves little doubt; again, see dorudon & basilosaurs.
Thanks
Bruno
20 - Mick
Jim, what you're describing is a duplicate mutation and your point would only stand if the new fins were duplicates of the ones already there. They are not, these are rear-fins, not fore-fins.
21 - DDeden
There's just one gene pool.
22 - Bird of Paradise
Sorry, Mick, I am saying that the genetic potential that produced these rear fins was not caused by an appearance of "new" or "mutant" genetic material but by genetic traits that have always been present in modern dolphins. I have no doubt that the fossil record can or may one day show that some ancient dolphins in fact had two rear fins, either functional or not. My point is that these fins may be "new" to us but they are not "new" genetically as would be necessary for this to be an example of macro-evolution (And it does seem as though many of these comments do not understand the profound genetic difference between the concepts of micro- and macro-evolutionary processes.
Joan's post almost conjures up the images of animals stretching their necks to reach distant foliage and being able to pass that "stretched" neck characteristic on to their offspring ala Cuvier Lamark, eventually giving us the giraffe. If, on the other hand, this were to happen through natural selection we would then expect the subsequent creature to have LESS genetic diversity than its ancestors, since all the non-long-necked genes would have been filtered out. Is that the case?
23 - Scott
The genetic diversity that is responsible for variations in form is the result of mutations that either alter the nature, function, or expression of genes. It is true that when a variant trait becomes genetically fixed in a species, it can be said to be a part of the genome of the species, but that is as close as your argument gets to making sense.
Under the conditions implicit in your argument, the phenotypes associated with the various allele combinations possible in the dolphin genome will express according to statistical probability that can be predicted at the level of a population. The occurence of the "leg" mutation however is random and below the levels that fit with the well understood models of genetics and inhertance. This clearly marks the phenotype as a product of random mutation that arises from time to time, and not because it is in fact some recessive allele that lurks in the hidden recesses of "dolphiness".
The evidence does fit the hypothesis of evolution very well however, since all dolphins express evidence of their former land life with internal vestiges of a hip and leg bones. Because of the close genetic heritage with land mammals, relatively minor mutations are necessary to augment the growth of these features so that the express themselves externally.
Your argument is simply an agenda driven use of semantics and not a reasoned analysis of the evidence. In pursuing the conclusion you embrace so singlemindedly, you point up a much more interesting evoultionary question.
What is the adaptive value of eschewing reasoned logic in favor of faith in dogma in the plain sight of contradictory evidence?
Or, if you prefer, why would God imbue humanity with a marvelous mind capable of astounding feats of intellectual reason, only to demand that we not use it or face eternal damnation?
24 - Bird of Paradise
bdworzak, I agree with all you have said. There does, in fact, appear to be vestigial genetic material that links modern species to older (sometimes extinct but not always) ones. This is compelling evidence and I affirm it as so.
On the other hand this does not necessarily prove the "origin of species." It can only prove that human genetic structure includes code that can produce a vestigial tail from time to time. Anything more than this is simply "theory" or "speculation."
Any theory then needs to explain how this came about and/or how one thing, over time, turns into a very different thing.
As I have said earlier, natural selection predicts that the gene pool in any given species will get smaller over time, not larger. It would also predict that, over time, organisms would become less complex rather than more complex for the same reason.
The difficulty with JB's defense of a slow process of speciation over very long spans of time is that complex symbiotic systems (such as the eye or the ear) can not mutate piece by piece into a coherent whole over thousands/millions of years. If this was the actual practice we would see literally millions of half-way devolped transitional forms within every species . . . slowly but surely adding new genetic material unpon new genetic material to create, in the end, a perfect unity of form and function that, in the end, happened more or less by chance. (which is actually an anti-natural selection position to take).
On the other hand, if such speciation takes place rapidly (as Gould suggests) then there needs to be some explainatory model for just how all this new genetic material is formed and where it comes from.
Science has yet to come up with such a model.
I am not saying it hasn't happened (try quoting me for saying this). I am simply saying that there is, to date, no clear or convincing process proposed that explains it.
I'm not denying that macro-evolution takes place (if it does then I would be inclined to find the most likely culprit to be some form of recombitant genetic process). And, at least in this posting, I am not suggesting some supernatural explanation, either. I am happy to keep with the science. I am also happy to say that "saying" and "believing" and "asserting" that something happens is not the same thing as demonstrating how it happens. This is where I am not yet convinced.
I really am not offering any answers . . . only questions and observations.
I also believe that science would be far more compelling and useful if it also was more forthright in admitting that it does not really know as much as it pretends to!
25 - Christopher Rose
BoP: scientists are always talking about how much they don't know so where you get the idea from that they pretend to know everything is as baffling as your incoherent understanding of science itself...