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Darwin’s finches not a good example of Darwinian evolution?

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Yes, we are discussing the icon of Darwinism that you heard about at school. They interbreed so much, it is hard to know how much they are separate species. From the BBC

The most extensive genetic study ever conducted of Darwin’s finches, from the Galapagos Islands, has revealed a messy family tree with a surprising level of interbreeding between species.

It also suggests that changes in one particular gene triggered the wide variation seen in their beak shapes.

The study also revealed a surprisingly large amount of “gene flow” between the branches of the family.

This indicates that the species have continued to interbreed or hybridise, after diversifying when they first arrived on the islands.

“It’s been observed that the species of Darwin’s finches sometimes hybridise – Peter and Rosemary Grant have seen that during their fieldwork,” Prof Andersson told the BBC.

“But it’s difficult to say what the long-term evolutionary significance of that is. What does it contribute?”

What it contributes is that one would be hard pressed to show that there is any evolution going on, in the face of this much hybridization. A friend sends along a key point from the Discussion of the paywalled Nature paper:

Evidence of introgressive hybridization, which has been documented as a contemporary process, is found throughout the radiation. Hybridization has given rise to species of mixed ancestry, in the past (this study) and the present [30]. It has influenced the evolution of a key phenotypic trait: beak shape. Similar introgressive hybridization affecting an adaptive trait (mimicry) has been described in Heliconius butterflies [32]. The degree of continuity between historical and contemporary evolution is unexpected because introgressive hybridization plays no part in traditional accounts of adaptive radiations of animals [1, 2]. For young radiations it complements the better-known role of natural selection.

In short, Darwin’s finches are not a very good schoolbook illustration of the neo-Darwinian synthesis (Darwinism). How does one sort out what is Darwinism (natural selection acting on random mutation) and what is hybridization? Here’s the abstract:

Darwin’s finches, inhabiting the Galápagos archipelago and Cocos Island, constitute an iconic model for studies of speciation and adaptive evolution. Here we report the results of whole-genome re-sequencing of 120 individuals representing all of the Darwin’s finch species and two close relatives. Phylogenetic analysis reveals important discrepancies with the phenotype-based taxonomy. We find extensive evidence for interspecific gene flow throughout the radiation. Hybridization has given rise to species of mixed ancestry. A 240 kilobase haplotype encompassing the ALX1 gene that encodes a transcription factor affecting craniofacial development is strongly associated with beak shape diversity across Darwin’s finch species as well as within the medium ground finch (Geospiza fortis), a species that has undergone rapid evolution of beak shape in response to environmental changes. The ALX1 haplotype has contributed to diversification of beak shapes among the Darwin’s finches and, thereby, to an expanded utilization of food resources. (paywall)

But we will probably see the finches in the schoolbooks anyway, because Darwin’s name is, like, a brand. There is Darwin Day, there isn’t Hybrid Day.

It’s a brand  lots of people have invested lots of time and money in. They won’t let that go to waste. Let the spin begin!

Follow UD News at Twitter! This is what they used to think and may well continue to say:

Comments
Zachriel:
It’s entirely consistent with evolutionary theory for it to be difficult to distinguish between species and subspecies as there is no strict dividing line.
Please reference this alleged evolutionary theory so we can see what it says.Joe
February 17, 2015
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However, with biological evolution, the variations are random with respect to fitness.
That is incorrect. With unguided evolution the variation is random, as in happenstance/ accidental.Joe
February 17, 2015
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fifthmonarchyman: How could possibly you know this? Because of fairly extensive knowledge of humans. See, for instance, Lavenda & Schultz, Anthropology: What Does It Mean to Be Human?, Oxford University Press, 2nd edition 2011. There's quite an extensive literature on the subject. Very quaint creatures humans are. You might take a gander. fifthmonarchyman: Of course according the new definition there is no strict dividing line. It has nothing to do with definitions. It's a statistical finding. Clustering by trait is not perfect. Furthermore, we can show why this is so. It's because of common ancestry and limited gene flow between closely related populations. fifthmonarchyman: According to the old common sense definition there is a strict dividing line ... If you draw strict lines, they will often be statistically arbitrary. fifthmonarchyman: that is why the old approach did not have a “problem of species”. That is incorrect. There was a species problem long before Darwin. That's because taxonomists were dealing with the same set of facts as Darwin. They frequently saw quite distinct species, so they assumed everything fit into clearly delineated boxes, but as they looked at more and more cases, it didn't work out that way. They argued about where to draw the line, but it turns out that there is no distinct line in many cases.Zachriel
February 17, 2015
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zac says In this case, the variations are due to direct selection for the desired shape. I say. How could possibly you know this? I say, However, with biological evolution, the variations are random with respect to fitness. I say, the variations in the shapes are also random with respect to fitness as far as we know. You say, It’s entirely consistent with evolutionary theory for it to be difficult to distinguish between species and subspecies as there is no strict dividing line. I say, Of course according the new definition there is no strict dividing line. That is why your approach can not solve "problem of species". According to the old common sense definition there is a strict dividing line that is why the old approach did not have a "problem of species". That is the whole point. I'll give you the last word for the second time ;-) peacefifthmonarchyman
February 16, 2015
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fifthmonarchyman: If I was to attempt to explain the shapes in the bucket by appealing to the random variation in the copies filtered by the child’s selection what would you say. In this case, the variations are due to direct selection for the desired shape. However, with biological evolution, the variations are random with respect to fitness. fifthmonarchyman: Brush wolf is the local term for what is called the red wolf in the field guides. Okay. It's apparently also a colloquial term for the red wolf. Let's look at your original statement again. fifthmonarchyman: According to Darwinism instead of the two separate species whose obvious differences we can see with our own eyes we actually have one species with two distinct types that look different and act in very different ways. That is incorrect. There is some uncertainty, but most biologists consider Canis rufus to be a separate species from both the gray wolf and the coyote, though closely related. It's entirely consistent with evolutionary theory for it to be difficult to distinguish between species and subspecies as there is no strict dividing line. This is supported by the molecular evidence. See Chambers et al., An account of the taxonomy of North American wolves from morphological and genetic analyses, North American Fauna 2012: "Genetic data support a close relationship between eastern wolf and red wolf Canis rufus, but do not support the proposal that they are the same species; it is more likely that they evolved independently from different lineages of a common ancestor with coyotes."Zachriel
February 16, 2015
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please disregard the phrase "He then repeats this process over and over again" in 71 sorry about that peacefifthmonarchyman
February 16, 2015
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Zac asks Um, brush wolf is just another name for an Eastern Coyote. Are you confusing that with the Eastern Wolf perhaps? I say, Brush wolf is the local term for what is called the red wolf in the field guides. check it out http://www.outdooralabama.com/red-wolf peacefifthmonarchyman
February 16, 2015
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Zac says. Have no idea what your analogy is supposed to mean. I say, Why do I always have to spoon feed stuff to you. You are not as slow as you pretend to be Zac Here goes Imagine you give an autistic kindergartner a single paper cut out of the continent of Australia. The kid proceeds to take his safety scissors and make two copies of the shape. He throws one away and places the other one into a bucket along with the original. He repeats the same task again and again monotonously as autistic children sometimes do. Which shapes get tossed in the trash and which ones get placed in the shape bucket is entirely dependent on the unspoken desires of the child. After a period of time you check the bucket and find that the shapes inside can be grouped into several unique categories. There are squares and triangles and circles and octagons. If I was to attempt to explain the shapes in the bucket by appealing to the random variation in the copies filtered by the child's selection what would you say. You would be right to characterize my explanation as vacuous. peace He then repeats this process over and over againfifthmonarchyman
February 16, 2015
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Zachriel:
Species refers to differences between populations, not within populations.
Speciation can occur from within a population.Joe
February 16, 2015
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Zachriel:
Organisms descend through a process of reproduction.
All but the first.
The similarities between coyotes and wolves are because they share a common ancestor
Or a common design.
The differences are due to divergence since that common ancestor
Or due to different design requirements.Joe
February 16, 2015
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fifthmonarchyman: For my Grandpa who was not bound by the paradigm of Darwinism the identity of the creatures were obvious the were brush wolves. Um, brush wolf is just another name for an Eastern Coyote. Are you confusing that with the Eastern Wolf perhaps?Zachriel
February 16, 2015
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fifthmonarchyman: You would not explain the difference between the circles and the squares by claiming that they all came from the same stamping process and pointing out that there are differences between the circles and the squares. Organisms aren't stamped out. Have no idea what your analogy is supposed to mean. Organisms descend through a process of reproduction. The similarities between coyotes and wolves are because they share a common ancestor. The differences are due to divergence since that common ancestor.Zachriel
February 16, 2015
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Zac says, Species refers to differences between populations, not within populations. I say. alright, suppose you found a bucked of shapes. You would not explain the difference between the circles and the squares by claiming that they all came from the same stamping process and pointing out that there are differences between the circles and the squares. Such an explanation would be vacuous peacefifthmonarchyman
February 16, 2015
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Zac said, Did you have some biological examples to consider? I say, Not for you but for those actually interested. ;-) We have already been discussing one glaring example. When I was growing up my Grandpa told me stories of the brush wolf that used to live around here. It was large 60 pounds or bigger and it hunted in packs and took adult deer and livestock. It had been absent from the hills for decades apparently hunted to extinction. Then in the late 80s we started to hear about large wild canines in our area that were again taking large prey and hunting in packs. For my Grandpa who was not bound by the paradigm of Darwinism the identity of the creatures were obvious the were brush wolves. Period end of story. On the other hand to the Darwinist the creatures weren't brush wolves at all but coyotes that had filled the vacant niche of the brush wolf and undergone rapid convergent evolution until their characteristics matched those of the wolf species they had replaced. That explanation is fine as far as it goes except it does not account for the small coyotes that inhabit these same hills yet did not undergo this rapid transformation but remained just as they were all along. According to Darwinism instead of the two separate species whose obvious differences we can see with our own eyes we actually have one species with two distinct types that look different and act in very different ways. So we have two explanations for the canines in our neck of the woods one older explanation that is simple and with out complications and one newer one that is complex with multiple "draw-backs". All this doesn't make the newer explanation wrong it just makes it complicated and confusing. That is what you would expect when you try to shoehorn a new definition of species based on theoretical mating potential into an older classification method based on shared characteristics. peacefifthmonarchyman
February 16, 2015
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Zachriel: we can show that reproductive isolation is why species retain their individual characteristics, so a definition based on reproductive isolation is generally consistent with one based on phenotype. fifthmonarchyman: yea it works except when it doesn’t. If you have a point to make, you should make it. Did you have some biological examples to consider? fifthmonarchyman: Explaining phenotypic species by appealing to variation in populations is vacuous. If it's vacuous it's because your statement, as it stands, appears incoherent. Species refers to differences between populations, not within populations.Zachriel
February 15, 2015
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Different vole species look alikeJoe
February 15, 2015
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Darwin explained variation within and between phenotypic species.
Baraminology already explained that. For example all extant birds are ancestors of some 365 original bird kinds. Curly Howard is still confused over what is being debated.Joe
February 15, 2015
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Curly Howard says, My understanding is that with the introduction of evolutionary thought, the switch to a “fuzzy edged population with relative reproductive isolation” is a necessity. I say, Yes if you want to explain the differences in species without reference to intelligent design you need to redefine the term so that it has no real objective meaning. Darwin knew that that is why he made the switch. you say, Today there are a number of species concepts, each with their own drawbacks.Your species concept seems to have the drawback of ignoring evolution I say, It's not that the older concept ignores evolution it's just that it recognizes that evolution is not sufficient to explain speciation. The older concept, the common sense concept that we use everyday has the single "draw back" of requiring an objective intelligence to define the Forms/Kinds. That is the only reason it was abandoned. Darwin just could not abide a concept of "species" that required a designer. Now we are left with naturalistic understandings that just don't work. It's been true for 150 years and will continue to be so as long as we try to shoehorn a definition that does not belong. That is what the problem of species is all about. For some folks it's worth the drawback of paucity as long as we don't let the divine foot in the door. you say, Toodaloo I say, todaloo to you too peacefifthmonarchyman
February 15, 2015
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zac says, However, we can show that reproductive isolation is why species retain their individual characteristics, so a definition based on reproductive isolation is generally consistent with one based on phenotype. I say, yea it works except when it doesn't. Big surprise. you say, Darwin explained variation within and between phenotypic species. I say, Explaining phenotypic species by appealing to variation in populations is vacuous. You don't explain the difference between circles and squares by pointing out that individual shapes vary. That much should be obvious peacefifthmonarchyman
February 15, 2015
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My understanding is that with the introduction of evolutionary thought, the switch to a "fuzzy edged population with relative reproductive isolation" is a necessity. This is how evolution works, species undergo change and branching, and stepping back at a specific time (today) you will see species at different degrees of change. You could try to classify them all as they are today, but many years from now they will not be the same. That is, if you accept evolution of course. Today there are a number of species concepts, each with their own drawbacks. Your species concept seems to have the drawback of ignoring evolution, but hey that's your prerogative. I'll leave you to it. ToodalooCurly Howard
February 15, 2015
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fifthmonarchyman: What was redefined was the term “species”. It went from being a term to describe the objective groupings that can be made in polygons or birds to a subjective fuzzy edged population with a relative reproductive isolation. Actually, the phenetic species concept is still the primary way to determine species. However, we can show that reproductive isolation is why species retain their individual characteristics, so a definition based on reproductive isolation is generally consistent with one based on phenotype. Both definitions are used depending on utility. fifthmonarchyman: Once the term “species” was redefined Darwin proceeded to explain variation in and between populations by appealing to…….. wait for it ……random variation filtered by survival of the fittest. Darwin explained variation within and between phenotypic species.Zachriel
February 15, 2015
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Curly Howard says. That sounds exactly like what they teach in evolutionary biology classes today, fifth. How is it different? I say, Perhaps you should take some time to catch up by reading this thread it will save a lot of time for both of us. Here is what I said way back in comment 21...... What was redefined was the term “species”. It went from being a term to describe the objective groupings that can be made in polygons or birds to a subjective fuzzy edged population with a relative reproductive isolation. Once the term “species” was redefined Darwin proceeded to explain variation in and between populations by appealing to…….. wait for it ……random variation filtered by survival of the fittest. All that can be said in response to that is…… well duh and in comment 47......... You can’t change the definition and expect the system to work. That is exactly what we have found for 150 years the finches are just the latest example ====== That is the difference between the two definitions in a nut shell. For more information read the thread peacefifthmonarchyman
February 15, 2015
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That sounds exactly like what they teach in evolutionary biology classes today, fifth. How is it different?Curly Howard
February 15, 2015
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Curly Howard says a lot of different species have numerous common characteristics and qualities. How would you go about making the distinction between one kind/sort and another? I say, It's a nested hierarchy. A Y-Axis. The higher up you go the more restricted the grouping, Circles ovals and squares are all shapes so they are related in some ways. If we move up on the axis squares are excluded and we are left with ovals and circles Still further up on the axis and circles stand alone. It's exactly the same process that Carl Linnaeus was perfecting. Ive already explained this check out comment 45 and following peacefifthmonarchyman
February 15, 2015
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fifthmonarchyman: Once again what happened was Darwin changed the definition of species but continued to use the old categorization. It did not work still doesn’t. The definition is the categorization. The idea of fixity is a theory about the nature of species. fifthmonarchyman: The “typical” wolf is the “Ideal” wolf. A particular individual deviates from the Ideal wolf when it’s features are atypical. In other words, the ideal is just another name for the typical member of (what everyone else calls) the species. Calling it an ideal doesn't add anything to the empirical understanding, but just indicates your own state of mind. fifthmonarchyman: We are not talking about what qualifies as a species but conflicting definitions of the term species There are many definitions of species, but they generally differ only on the margins and are chosen for their utility in a given field. If you want to propose a new biological taxonomy, then you shouldn't use the term species, which hasn't changed all that much since Linnaeus. fifthmonarchyman: Species- a class of individuals having some common characteristics or qualities; distinct sort or kind. ffm: If you define Species as Form or Kind there is not any ambiguity there is only various individuals that imperfectly correspond to the Ideal immaterial form. Species identification has generally been based on the phenetic species concept, that is, grouping of species by characteristics. If we plot organisms by traits, we can objectively show that they clump, the clumps being called species. We can show that these characteristics are maintained because there is limited gene flow between the various populations. What you call the ideal form is either a typical member of the species, or the type specimen designated for the species. You apparently think Darwin changed the definition of species, when what he did was show that traditional phenetic species boundaries are various in degree. You can talk about the ideal wolf and the ideal coyote, but there is no objective ideal form. There are just wolves and coyotes.Zachriel
February 15, 2015
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Fifth, a lot of different species have numerous common characteristics and qualities. How would you go about making the distinction between one kind/sort and another?Curly Howard
February 15, 2015
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Curly Howard said, How would you define a species I say, no need to reinvent the wheel from here http://dictionary.reference.com/browse/species quote: Species- a class of individuals having some common characteristics or qualities; distinct sort or kind. end quote: peacefifthmonarchyman
February 15, 2015
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How would you define a species, FifthMM?Curly Howard
February 15, 2015
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zac says, Darwin’s finches were identified as separate species before Darwin published “Origin of Species”. I say, Of course, Once again what happened was Darwin changed the definition of species but continued to use the old categorization. It did not work still doesn't. big surprise You say According to biologists before Darwin working within Linnaean taxonomy, the coyote was a different species. I say, Of course, a coyote is not a wolf. You say, You had claimed they were different manifestations of the same ideal form, which you have yet to describe. I say, No, Pay attention I said a coyote was a wolf to the extent that it corresponds to the Ideal wolf. The same way that an oval is a circle to the extent that it corresponds to the ideal circle. This is not difficult stuff. I'm not sure what a "manifestation of the same Ideal form" is supposed to mean but it was not my phrase. You say, Which looks like a descriptive definition of a typical wolf, not an ideal version. I say, The "typical" wolf is the "Ideal" wolf. A particular individual deviates from the Ideal wolf when it's features are atypical. Come on Zac use your head. you say, Your history of the species concept is not consistent with the facts. I say, no apparently your understanding of this history of this thread is not consistent with the facts. We are not talking about what qualifies as a species but conflicting definitions of the term species Since it's obvious that you are not interested in any kind of actual discussion feel free to have the last word. That is unless you have a genuine comment pertaining to what I actually said. Peacefifthmonarchyman
February 15, 2015
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fifthmonarchyman: quote: grey wolf, the largest extant member of its family, with males averaging 43–45 kg (95–99 lb), and females 36–38.5 kg (79–85 lb)like the red wolf, it is distinguished from other Canis species by its larger size and less pointed features, particularly on the ears and muzzle. Which looks like a descriptive definition of a typical wolf, not an ideal version. Furthermore, your citation treats the gray wolf as a different species than the coyote, not different manifestations of an ideal form you have yet to describe. fifthmonarchyman: I do it every time I look out the window of my car and see a canine and say to those with me “look at that coyote” Sure. Coyote is a different species from the wolf, and has distinguishing characteristics. fifthmonarchyman: Linnaeus concept of species is not the same as Darwin’s it is as simple as that. The delineation of species was the same. According to biologists before Darwin working within Linnaean taxonomy, the coyote was a different species. You had claimed they were different manifestations of the same ideal form, which you have yet to describe. fifthmonarchyman: That is exactly what we have found for 150 years the finches are just the latest example Darwin's finches were identified as separate species before Darwin published "Origin of Species". Your history of the species concept is not consistent with the facts.Zachriel
February 15, 2015
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