Darwin lobby: Don’t teach epigenetics, kids won’t understand

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September 20, 2013

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Readers may recall that yesterday we noted that Darwin’s darling Zack Kopplin didn’t want to talk about epigenetics (the way in which interactions with the environment affect our genetic instructions).

A friend writes to say that soon-to-retire “Darwin in the schools” lobbyist Eugenie Scott thinks it’s fine not to teach students about epigenetics because

It was almost a relief when an antievolutionist contended that the books should be rejected because they don’t include epigenetics. At least the epigenetics argument is relatively recent (perhaps only 5-8 years old). In creation-think, including epigenetics in biology textbooks will weaken evolution because epigenetics is evidence against evolution. Yeah, I know it isn’t, but to creationists, any process that isn’t natural selection weakens natural selection as an evolutionary mechanism, and if natural selection isn’t strong enough to produce evolution, that means that evolution didn’t take place, and…and…You get the picture. Never mind that epigenetics isn’t in the TEKS, the state science education standards, and generally isn’t a topic for beginning biology learners. [colour emphasis added]

What’s really interesting here is how important Darwin’s hot 19th century theory about natural selection acting on random mutation seems to her. To doubt its near—or actual (I don’t have the script in front of me)—divine power is to doubt that any kind of evolution occurs.

In short, the best-known Darwin lobbyist thinks the evidence for evolution in general is so weak that doubts about the power of natural selection to randomly produce intricate new equipment must mean that evolution never happens. Good thing she said it herself.

By the way, here’s more evidence that some media sources were floating the story that “Texas law bans teaching about evolution in books” as of late yesterday. Who are these airheads, and why do you rely on them for news, if you do?

Comments

Hi Wd400, in an earlier post I mentioned this article in Science: http://m.sciencemag.org/content/341/6150/1055.full As it mentions, epigenetics "raises hackles" for some evolutionary biologists, but not all. The "some" I think the article is referring to are those like Eugenie Scott who have made an idol out of Darwinism. Darwinism requires that cells be as simple as possible, which means challenges to teach students more than a 20th Century understanding of DNA are unacceptable, and/or brushed aside as "too difficult". Eugenie Scott is a Darwinist, not a scientist, and she will convince a lot of gullible people to suppress 21st Century science in an effort to protect her sacred cow.gensci_{September 21, 2013
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Second it may be a problem for Darwinian thinking by showing that many of the examples of so called evolution may be just gene expression and not changes to the genome. You;re still not understanfing the Grants' studies. The traits they looked at where heritable - it's just a gene expression program that is flipping based on the environment. They didn't need to know anything about epigenetics to prove that, just the quantatative genetics developed in the 1920s. It's imaginable that the beak traits are transgenerationally inherited epigenetic tags, but there is no evidence for that idea and hardly any studies that show transgenerational inheritence at all (at none in brids, so far as I know). Even if they were, the finch studies would be an example of selection: differential survival of heritable variation leading to a change in the population. Then you start on teh regulatrory sequences attached to genes, seemingly as if they aren't themselves part of the genome presentation of the Galapagos finches by the Grants in which they said the difference between the various forms of the birds was not in the coding part of the genome but in the regulators of the various genes such as those responsible for beak size. How much of the genes get expressed is due to regulators not the genes themselves. These non coding regions could be selected for so in the future we have to consider that it may not be alleles that are changing but their control areas. If there are two different versions of the same regulatory sequence floating around in a population then those are alleles which are subject to selection. The idea that much evolutionary change is the result of differences in gene expression (themselves coded by changes in transcription factors and regulatory sequences) is not new, nor is it a problem for evolutionary biology.wd400_{September 21, 2013
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Thank you for your views Jerry. "I am just trying to lay out the issues. I could certainly be off because this is a very new area and it may take time to think it all the way through especially with new research appearing all the time." I applaud your approach Jerry. No dogmatism and a willingness to inquire. Your opinion definitely has a lot going for it. As for the neurons...well what can one say! "Gosh!" I suppose says it best. 'Blueprint' certainly seems the mot juste from my perspective. 'Recipe' I'm not so sure of. One an throw a recipe in a cement mixer and just let it churn itself together, but 100,000,000,000 neurons forming a cohesive network, does seem to be asking for something a little more rigorous in description. Thank s for book recommendations. I have not yet had the pleasure of sampling Dr Meyer's latest efforts. It is on my list now though. As for Dr Dawkins, one cannot deny that he can whittle a good sentence and spin a good yarn. Most adroit with the pencil. Although, whilst I find his jottings enjoyable for their lyrical lilt, they always leave me with the sense of 'I shot an arrow in the air, it fell to earth I know not where.' if you follow my meaning. Not that I have anything against the man (as some people do, for understandable reasons), he just isn't my cup of tea in the thinking department. Once again, thank you for sharing, Jerry.Ho-De-Ho_{September 21, 2013
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There is no blueprint. The genome is more akin to a a recipe
I am afraid some people disagree with this. I once saw a lecture on the brain that talked about the origin of neurons in a human brain during gestation. The body produces 85-100 billion neuron during a 24 month period starting shortly after conception. That is about 13-14 thousand every second for a two year period. And all these billions of neurons knows exactly where to go and end up forming one of the most complex configurations on the earth. Absolutely amazing without any blueprint or direction.
Dr Dawkins’ book The Greatest Show on Earth
I read this book by Dawkins. What is amazing about the book is what is not there. There is no explanation for the origin of complex novelties except deep time. Otherwise he just present trivial examples some of which may have epigenetic explanations and may not be Darwinian.jerry_{September 21, 2013
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You are not saying that epigenetics is completely against any form of evolution, and specifically not neo-darwinian evolution.
I reworded your comment a little. Some aspects of epigenetics are certainly compatible with the Darwinian paradigm but others are very problematic.
Plus we have been told that random mutations were the cause of changes, and now we know they are not.
I personally do not believe that random mutations can explain evolution, in the sense of providing the richness of information that is necessary for everything to happen. But you will get a lot of dissenters to this from those who visit here. I am just trying to lay out the issues. I could certainly be off because this is a very new area and it may take time to think it all the way through especially with new research appearing all the time. Two books to read are Meyer's "Darwin's doubt" and Eva Jablonka, "Evolution in Four Dimensions." Meyer references Stuart Newman who is an expert in developmental biology, specifically "Origination of Organismal Form: Beyond the Gene in Developmental and Evolutionary Biology." Available via Amazon: http://www.amazon.com/Origination-Organismal-Form-Developmental-Evolutionary/dp/0262134195 And some of it can be found on the internet.jerry_{September 21, 2013
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Jerry, I don't think I've said hello before, so 'How do you do?' Jerry, I really liked your explanation and take on the epigenetic issue. And the problem it poses for evolution, as you have elucidated quite masterfully, is a bit of sticky one. I will chew over your comments during my evening stroll. May I ensure that I have your viewpoint clear. You are not saying that epigenetics is completely against any form of evolution, but specifically neo-darwinian evolution. One step at a time mutation and selection sure seemed to have its work cut out in creating sensible code in the first place and now this! We have a tagging code (like bar-codes I've heard some say) and lots of other stuff above the DNA, chivvying it about as it were. How in blazes can an organism randomly generate a code to operate another code without having the faintest idea what it is doing? Plus we have been told that random mutations were the cause of changes, and now we know they are not. Have I grasped it correctly Jerry? Excuse my colloquial interpretation, it is my scourge. On the flip side, Jerry, is there any means of evolution that you would think epigenetics lends itself too? Not saying you believe it, but just your thoughts. Thanks.Ho-De-Ho_{September 21, 2013
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One of the most interesting concepts in Meyer’s book, which I bet will be a major focus of discussion in the future is just where is the blue print for the organism in the zygote. It is seems certain that it is not in the genome but someplace else.
There is no blueprint. The genome is more akin to a a recipe. Certain instructions are turned off and on depending on what stage of the process has been reached. The is a very good and accessible discussion of this in Dr Dawkins' book The Greatest Show on Earth. I'm sure there are other places where it's explained but that's the one that came to my mind.Jerad_{September 21, 2013
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I will repeat my comment about the definition of epigenetics.
I don’t think there is a specific definition for epigenetic except that it is anything not in the genome that affects gene expression. A lot of what is called epigenetics is methylation which is a major factor that affects gene expression. Other non-genetic factors during gestation are in the embryo which also affects body layout and gene expression. Little is known about this except it is most likely in the egg cytoplasm or cell wall.
I suggest that those interested go to Wikipedia and look at the discussion of methylation. But this is only a start. http://en.wikipedia.org/wiki/Methylation In Meyers book he devotes 3 chapters to epigenetics. So anyone commenting should read this to get one perspective on the term. One of the most interesting concepts in Meyer's book, which I bet will be a major focus of discussion in the future is just where is the blue print for the organism in the zygote. It is seems certain that it is not in the genome but someplace else. One of the main points of Meyer's book is just how do these blueprints arise and how are they potentially modified. It is here that the discussions of body plans will most likely center. It is there that real evolution has to take place, not just in modification of certain parts of the genome.
How does epigenetics pose a problem for Darwinian thinking?
One it indicates that the process is much more complicated that originally thought by many levels of intricacy of precisely interacting parts. How does such an incredibly complex system arise? Could the nickel and dime accumulation ascribed to Darwinian processes really add up to all the major innovations in life? It just got incredibly more complicated. Second it may be a problem for Darwinian thinking by showing that many of the examples of so called evolution may be just gene expression and not changes to the genome. So in this case is there any evolution going on? A related example. There was a presentation of the Galapagos finches by the Grants in which they said the difference between the various forms of the birds was not in the coding part of the genome but in the regulators of the various genes such as those responsible for beak size. How much of the genes get expressed is due to regulators not the genes themselves. These non coding regions could be selected for so in the future we have to consider that it may not be alleles that are changing but their control areas. After 2-3 million years on the Galapagos, all the finch varieties could still inner breed. There was no genetic barriers. So was there any evolution going on in this example? We are only just beginning to get beneath the surface of adaptation and biological change. But everyone knows how it happened. Right.jerry_{September 21, 2013
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Oh, and Mung, thank you for your response at post 32, very courteous of you. I am chewing it over. You make a lot of sense and I enjoy your comments.Ho-De-Ho_{September 21, 2013
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This has been most entertaining and interesting to read. Thank you everybody. It seems that epigenetics has potential to be a thorny issue. There was something about this thread that sounded a tad familiar but I couldn't put my finger on it. A slumber on the straw mattress has served to bring it back to me though. There is a short ditty, or anecdote if you prefer, recorded about the artist Amedeo Modigliani that puts me in mind of the back and forth of this splendid discussion. Here it is. Modigliani had an admiration of Maurice Utrillo, another artist. He thought his work was the cat's pajamas. As luck would have it, Utrillo didn't think Modigliani was all that bad either. One evening, they began to get complimentary. Modigliani said "Utrillo, you are the best painter in the world." "No, you are the world's greatest painter." said Utrillo. "I forbid you to contradict me." "I forbid you to forbid me." Naturally the argument escalated with one of them saying "If you say that again then i'll biff you on the nose." "You are the greatest painter." said the other and a brawl ensued all over the carpet. Later on they made friends again over a few bottles down the local establishment. Then, as they walked down the street together, one of them said "You are the world's greatest painter." Lo and behold! the next morning they were found sleeping in the gutter covered in mysterious whelps and bruises. What has always caused me to scratch the old bean about this tale, is that the two artists sketched such different things. Modigliani liked painting people, Utrillo's forte was in city-scapes. They didn't have - and now I come to my point - a common platform on which to base their assertions. Do we think that this is what needs to be addressed here perhaps? What is the commonly agreed upon definition of epigenetics in this debate? Perhaps not all the T's can be crossed and one or two I's may end up dotless, but wouldn't a mutually agreed upon definition of epigenetics prove rather valuable here. Otherwise, all arguments might end up in the gutter with Modigliani and his chum Utrillo. Maybe the great minds of both sides could thrash out a mutually agreed upon platform and then discuss the implications of such to both world views. Just a thought. Thank you for bearing with me on my little ramble.Ho-De-Ho_{September 21, 2013
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Mung:
Which version is true? Which version ought to be taught?
Your question reminds me of a class I once had to run, to prepare students for an exam. The exam required essays to be written in response to questions, and as the students were science students, some were worried about essay questions, hence the class. The questions generally took the form: "discuss the hypotheses X and Y for Z, and present evidence for and against the two hypotheses". I started off with a general pep-talk about hypothesis testing and the nature of scientific models. Then I went through some specific hypotheses, and the evidence for and against. Then one student raised her hand and asked "so which hypothesis is right?" This is why, on another thread, I tried to put forward the idea that science isn't about a body of facts, but about iteratively improving the fit of our models to data. Sadly, many teachers, and students, still think that science is a body of facts, and that the job of science teachers is to teach the right facts not the wrong ones. I'd rather see poor models taught along with a good method for testing them, than good models taught with a poor or no method for testing them. So to me, it doesn't matter "which version" of a very new model is taught. What matters is that students learn that all "versions" of scientific models, are provisional, including extremely well-established models, and all are subject to update in the light of new evidence. But of course they do also need to learn a vast amount about extremely well supported models, in which differences between "versions" are small print details. They should not be given the erroneous idea that because a model needs an update (e.g. the model that DNA is the answer to how we inherit traits from our parents) that the entire model is thrown into doubt. There isn't a very great difference between "We inherit features from our parents because we inherit their DNA" and "we inherit features from our parents because we inherit their DNA, and also possibly sometimes a few features, some of which are pathological, and some of which might be beneficial, via epigenetic marking on the DNA". But if there is time for the longer version, sure, teach it.Elizabeth B Liddle_{September 21, 2013
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Mung:
Now, if in fact I do not understand or I am confused, then I’d surely like to rectify that deficiency.
I think I can explain, Mung, but as you seem so determined not to understand, this may not work. But, hey ho: Cells reproduce themselves. If a cell has a particular variant in its DNA sequence, or if it is methylated in some way, or has certain other novel features, the resulting reproduced cells will inherit that variant. Multicellular organisms develop - grow from a single cell to an adult with differentiated organs and tisses - because that first cell reproduces itself billions of times. During that process, some cells are altered in such ways that affect gene expression, and some of these changes are inherited by subsequent generations of that cell. Where those heritable changes are not genetic (i.e. changes to the DNA sequence) they are called "epigenetic". And the consequences of such heritable changes to a particular population of cells is that those cells become a specific tissue. They cease to be "totipotential" as the original single cell was, and as stem cells are, and become largely incapable of forming any kind of tissue other than that of the parental cell. So a liver cell cannot become anything but a liver cell, although a bone marrow cell can become a number of things including more stem cells, which is why they are useful for general repair jobs in the body. Cancer cells often have genetic (DNA) changes that their offspring inherit, but some cancers are due to epigenetic changes. Any heritable change in a cell can potentially give rise to a tumour. However, epigenetic changes can also happen in gametes, i.e. germline cells. This means that in sexually reproducing species, those changes affect the zygote, a new organism completely and thus passed on not only to cells within the same organism, but cells in the offspring organism. The key concept to grasp in this context is that "heritable" refers to both within-organism inheritance (e.g. the inheritance down generations of liver cell, or indeed a cancer cell) and between-organism inheritance (down the lineage of the whole organism. For some reason, I gather from the enthusiasm for "epigenetics" among anti-Darwinians, the idea has got about that because epigenetic changes can affect the germline, giving us an additional vector for between-organism inheritance of phenotypic variation, that this presents some kind of problem for evolutionary theory that "evolutionists" want to keep high schoolers from discovering. Which is rather ironic, seeing as Darwin did not now how phenotypic variation was inherited, and considered acquired characteristics (Lamarckian variation) a possible candidate. The mechanism he proposed does not, obviously, require that heritable variance in reproductive success is passed on via DNA, because he didn't even know about DNA. And while germline epigenetic marking is very interesting, it remains a tiny subset of the topic of epigenetics, and a small-print footnote to the general principle that DNA is the vector of heritable phenotypic features. What is of possible interest to those who are obsessed with "neo-Darwinism" is that it extends the synthesis of genetics and Darwinian principles to include epigenetics. It is also, in my view, exciting from an evolutionary theory point of view, because of possible implications for natural selection (i.e. heritable variance in reproductive success) above the level of the individual within a population, to population within populations, and thus the evolution of mechanisms by which populations can more readily adapt to environmental changes. But HS students have a lot to learn, and while I'm all for presenting cutting edge research to HS students, the sad truth is that a lot of science education does consist in learning extremely well understood and well-supported phenomena, and it is far too early to include epigenetics in that body of phenomena. So by all means teach HS students about epigenetics. But don't expect them to mug up on the details of how it works just yet, because by the time they reach college the details may well have changed.Elizabeth B Liddle_{September 21, 2013
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I just noticed how desperate News is to spin Dr Scott's statement:
In short, the best-known Darwin lobbyist thinks the evidence for evolution in general is so weak that doubts about the power of natural selection to randomly produce intricate new equipment must mean that evolution never happens. Good thing she said it herself.
That's so pathetic it's not even funny.Jerad_{September 20, 2013
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That's certainly something someone that is advocating the teaching epigenetica should be asking... For me, high school biology students should learn that the control of gene expression is a central topic in molecular biology, that gene expression both controls development and allows organisms to react to environmental cues, and that DNA methylation is important mechanism for this in mammals (but entirely absent from many other creatures that nevertheless get through life fine). I don't think trans-generational epigenetics deserves more than a mention at high school level.wd400_{September 20, 2013
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wd400:
What version of epigenetics is “now common knowledge to biologists”?
Which version is true? Which version ought to be taught?Mung_{September 20, 2013
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What version of epigenetics is "now common knowledge to biologists"?wd400_{September 20, 2013
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Still want to teach epigenetics in HS? Definitely! What about you wd400? Give students what is now common knowledge to biologists, or handicap them for a decade?gensci_{September 20, 2013
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... still want to teach epigenetics in HS? The very old definition of epigenisis (not epigenetics...) that Dawkins is talking about is the idea that organisms develop from undifferentiated forms (as opossed to simply scaling up from miniature pre-formed versions of themselves). The debate between those schools was more nuanced than that, but that's the central point. Then Waddington gave us the term epigenetics to describe the genetic basis of that unfolding process - which is more or developmental biology. Somewhere along they way epigenetics also came to mean stable changes in gene expression that could be heritable across cell divisions. Or even between generations, although there is still little evidence for that process. Even more lately, people think epigenetics as any chemical modification to DNA that changes it's expression, or in fact any modification to DNA expression (which Wikipedia seems to suggest). So, if you are using term only to describe trans-generation epigenetics inheritance then you shuold explain that. You should also be aware that most epigenetic research doesn't relate to that idea.wd400_{September 20, 2013
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wd400:
Epigenetic is, traditionally, the inheritance of gene expression traits from one cell division to the next.
IOW, epigenetics has nothing to do with heredity? Epigenetics is what takes place during development? So is epigenetics simply a misnomer? Dawkins writes:
The early history of embryology was riven between two opposing doctrines called preformationism and epegenesis.
You agree with Dawkins? wd400:
Epigenetic is, traditionally, the inheritance of gene expression traits from one cell division to the next.
Is that what you mean when you speak of heredity? Because if it is, I can understand why you don't understand what I am talking about. Wikipedia:
In biology, and specifically genetics, epigenetics is the study of changes in gene expression or cellular phenotype, caused by mechanisms other than changes in the underlying DNA sequence—hence the name epi- (Greek: ???- over, above, outer) -genetics. Some of these changes have been shown to be heritable.
Now, if in fact I do not understand or I am confused, then I'd surely like to rectify that deficiency.Mung_{September 20, 2013
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The short version: Epigenetic is, traditionally, the inheritance of gene expression traits from one cell division to the next. These patterns have been known about since at leas the 1970s, and there are many ways to achieve them. For instance, some genes set up "feed back" loops where the presence of their gene's product in the cytosol is enough to ensure their continued production. Recently, people have got excited about another method of epigenetic inheritance called DNA-methylation. Basically, some "C"s in the DNA are tagged with a chemical group, which results in gene silencing. This is important in mammalian development and plants (less so is most other well-studied organisms). They tagging and maintanance of methy- groups is controlled by proteins in the genome, and target to specific regions in the cells based on DNA-sequence. Other modifiers (histone modifications, miRNAs etc) are sometimes called epigenetic but it's not clear that many of them are. There is also trans-generational epigenetics (which I think Elizabeth has called "germiline" epigenesis) in which altered states of gene expression can make it through no just normal (mitotic) cell division but through meosis and into the next generation. It's not at all clear how wide-spread this process is in nature, but there are a few example that suggest it's possible. How do you model it? Well... just the same way as normal. For population genetics you can just add "epi-alleles" with a very high (epi)-mutation rate to the model. In terms of teasing out environmental and genetic effects of gene expression and how they interact with selection, well, that's what quantative genetics was invented for. So. You can see I'm a little bit lost as to why this is a big problem. It's interesting for sure, and amazing that we can directly measure the methylation state of whole genomes. But it seems to me like the me that the anti-evolution team is just grasping at anything "new" and hoping it fits their case. (Which is how lots of folks have reacted to modern epigenetics, I should say)wd400_{September 20, 2013
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wd400:
I agree entirely with those statements Mung. I think you might be confused about what epigenetics is, and how it works
Well, first, I appreciate that you still post here at UD. But does any one really understand yet "how it works"? Now I'm always willing to learn. So what is epigenetics and how does it work? How do you model epigenetics in Darwinian theory?Mung_{September 20, 2013
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Mung: in future I will try to remember to use the locution "I don't know what you mean by that term" in future. Thank you for the hot tip.Elizabeth B Liddle_{September 20, 2013
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Mung:
What do you think epigenetics means, Elizabeth?
Well, there are a number of definitions in use, but broadly, the term refers to heritable changes in a cell that do not involve changes to the DNA sequence. Specifically, this means that if a gene is "switched off" in a DNA sequence in one cell, the daughter cell inherits not only the DNA sequence but the "switched off" state of that gene as well. The most well-known mechanism is methylation of cytosine, which is a chemical alteration to one of the bases in the DNA, so the methylated cytosine is inherited along with the rest of the DNA. Regulatory sequences (sequences that control the switching on or off of coding genes) can be "silenced" by methylation. This is extremely important for multicellular development, as it means that once a cell has been differentiated to produce a particular set of proteins, all daughter cells will do the same thing, allowing tissues of a particular type to form in a particular place. This is called "somatic" epigenetics as it affects the cells within a single multicellular organism. However, epigenetic changes can also affect germline DNA, so that those changes are inherited by the organisms offspring. So environmental factors that cause methylation in the germline can cause phenotypic effects in the offspring, which in turn may be passed on to the next generation. Many of these effects are problematic, as gensci says, so that an environmental change that affects the parent can result in germline epigenetic changes that cause pathology, e.g. diabetes, in the offspring, and possibly the offspring's offspring. However, there are a few examples of where environmental changes in the parent environment can result in germline epigenetic changes that are beneficial for the offspring in that environment. That is what I mean when I said that the overwhelmingly great proportion of heritable phenotypic traits passed on via genetics, but there are a few that may be passed on via epigenetic marking, and of these, a few may be beneficial to the offspring in the current environment. I have no idea why this is perceived to be problematic for Darwinian evolution. It is certainly a source of heritable phenotypic variance, and therefore subject to natural selection (i.e. heritable variance in reproductive success), and more interestingly, it offers the prospect of natural selection operating at a higher level than that of the individual. But clearly the anti-Darwinian community have got excited about it. I have yet to discover why.Elizabeth B Liddle_{September 20, 2013
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Mung, you are using "Darwinian" in a way that exludes Darwin's own theory. And you're surprised that Liz doesn't know what people hear mean by "Darwinism"?wd400_{September 20, 2013
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(I should say, there is yet a fourth definition of epigenetics that limits itself to direct-environmental effects of methylation etc. That would be interesting if it was big player in biology, but there is little evidence that it is, and ti would not be very relevant to evolution since the tags would presumably switch back and forth over generational time scales)wd400_{September 20, 2013
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I don’t think there is a specific definition for epigenetic except that it is anything not in the genome that affects gene expression. A lot of what is called epigenetics is methylation which is a major factor that affects gene expression. OK. But for the most part methyl- tags are placed on genes by proteins which are "in the genome" and specific regulatory elements are targeted for methylation in different cells based on those sequences which are "in the genome". So it's not as if something "other" than what's in our genomes and subject to the usual evolutionary forces is what's contributing to these epigenetic patterns...wd400_{September 20, 2013
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wd400:
Mung, how does epigenetics challenge the Darwinian model of HEREDITY?
The Changing Role of the Embryo in Evolutionary Thought: Roots of Evo-Devo What Darwin Got WrongMung_{September 20, 2013
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Mung: "Because it’s not Darwinian" wd400:
I find that very hard to understand, since Darwin himself believed in epigenetic inheritance.
Then you also probably know that there's very little of Darwin left in "the modern synthesis."Mung_{September 20, 2013
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Hi WD400, I think everyone here understands epigenetics, so no need to define it, correct? Have you read this thread! There are least 3 definitions of epigenetics that go around, and people seem to chop and change among them as suits. That's why it's important for people to actually clearly define what they mean when they use the word. As I say. I've asked several times in each of several threads for someone to simply state who epigenetics, as they define the term, is a problem for evolutionary biology. The fact I'm yet to get answer seems pretty telling...wd400_{September 20, 2013
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Elizabeth:
I know a lot about Darwinian evolution, Mung, as you well know.
Yes, you often speak as though you do. So pardon those of us who are confused when you say you don't know what you are talking about. If you "know a lot" about "Darwinian evolution" then if quite logically follows that you know "a lot about" what is included and what is excluded. So when you say, "'Darwinism' is a mystery to me" it really is a mystery to many of us here at UD how and why that could be the case. In fact, Darwinism is not a mystery to you at all, you have simply mis-identified what it is that you are confused about: Elizabeth Liddle:
It seems to mean whatever the writer using it wants it to mean.
So your confusion is about what a specific person means when they use the term. So why don't you say, "I don't know what you mean when you use that term," instead of saying, I don't know what that term means? Have you ever paused to think about why none of us here at UD are confused about what you mean when you say you know a lot about "Darwinian evolution"? We are not confused when you use the term "Darwinian evolution" but you are confused when people here use the term "Darwinism." How so? Seriously, I'd really like to know, as would many others here.Mung_{September 20, 2013
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