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Monday, October 14, 2013

Misrepresentations of Evolution in Textbooks: Definition of Evolution According to Kevin Padian

Kevin Padian is a professor at the University of California, Berkeley and Curator of Paleontology at the University of California Museum of Paleontology. He is also President of the National Center for Science Education (NCSE).

He wrote an article for Evolution: Education and Outreach in which he describes misrepresentations of evolution in textbooks (Padian, 2013). Since he is a prominent leader in the fight against creationism, we need to pay attention when he tells us how evolution should be taught in public schools.

Before examining some of those "misconceptions," let's review some earlier papers in Evolution: Education and Outreach. The very first issue contained an article by John N. Thompson where he defined evolution as ...
Evolution is quite simply heritable change in the genetic structure of a population. There is nothing in this or any similar standard definition of evolution that requires that genetic change in the average size, shape, or any other trait be maintained for a hundred, a thousand, or a million years before it can truly be called evolution. (Thompson, 2007)
Unfortunately, Thompson is under the mistaken impression that natural selection is the only significant mechanism of evolution but that's not the point. The point it that he, and many others, see evolution as a continuous and ongoing process that includes the minor fluctuations that Kevin Padian dismisses.

Here's how Thompson described it in his 2007 article ...
These continual small evolutionary changes in populations result in those populations meandering back and forth in their average sizes, shapes, physiological tolerances, and behaviors over time. These ongoing small evolutionary changes are what keep species in the evolutionary game. The average appearance of a species may not change much over time but populations are continually evolving as they respond to slight changes in their environments.
I don't agree with Thompson because he attributes changes in allele frequencies to slight changes in the environment when, in fact, these are due to drift. However, the point is that small changes in populations are the basic stuff of evolution.

Kevin thinks we should be teaching more macroevolution in school (Padian, 2010). He is partly motivated by a desire to confront creationists who, by and large, don't have a problem with microevolution. In his 2010 article, Kevin says ...
For decades this problem has been staring us in the face: creationists are fine with microevolution (changes within populations), because they just see it as noise in the system, variation within created kinds. But they abhor macroevolution because it implies that major groups can evolve from other major groups, there is a continuum of life, and therefore even humans might be part of that continuum.

It has not been much appreciated until now how deficient our textbooks and instructional materials are in explaining to students how we know what we know about macroevolution, the patterns and processes that describe the major changes in the history of life. There is no reason at all to develop this in textbooks so as to convince the 25% of our populace who are fundamentalist Christians of the reality of large-scale evolution. This effort is about the 40–50% of people in the middle, who are reasonable and uncommitted, but otherwise uneducated about the problem. If they are able to understand how we know what we know about macroevolution, creationists are further marginalized as irrational and unreasonable.
I'm not sure there's a real deficit in teaching macroevolution and the history of life but I do think students lack understanding of population genetics—the essence of microevolution. Sure, they may be taught that bacteria evolve drug resistance but do they really understand why this is called evolution and how it relates to the big picture view of the history of life (macroevolution)?

I believe that the best way to teach evolution in the 21st century is to begin with genetics and population genetics and make sure that students understand the minimal definition of evolution. This is how we learn evolutionary theory and this is how we make sense of the rest of biology, including the fossil record. It's not good enough in this day and age to simply point to a fossil record—like the transitional fossils leading to modern whales—and say that this is "descent with modification." We have a pretty good idea how that process actually occurred; it involved speciation events and changes in the allele frequencies within populations. So why not teach that?

... it's important to appreciate that natural selection isn't the only process of evolutionary change. Most biologists define evolution as a change in the proportion of alleles (different form of a gene) in a population.

Jerry Coyne in Why Evolution Is True (page 122)
Now let's look more closely at the 2013 article by Kevin Padian. This is the one where he discusses misrepresentations of evolution in textbooks. He discusses a whole bunch of problems but he doesn't once mention that textbooks—other than evolutionary biology textbooks— are extremely adaptationist in their presentation of evolution. It's pretty clear from his article that Kevin Padian doesn't think about any mechanisms of evolution other than natural selection (and sexual selection). Because he's an adaptationist, he doesn't see that problem.

I'm just going to discuss his view of the definition of evolution to illustrate the way Kevin Padian's view of evolution differs from mine. Kevin says,
... how does one choose a definition of evolution to use? Because science has no catechisms, there is not a single, standard definition of evolution. But some are more and less useful. A popular one, especially among scientists who work on population biology, is ‘a change in gene frequency in a population’. This means, for example, that an allele with a frequency of 0.75 in one generation can change to 0.73 in the next, and this is evolution. Well, sort of. In the next generation, the frequency can change back to 0.75. So what has evolved? It is like defining a football game as the process of hiking the ball. This simple (or simplistic) definition gets to one level of the processes of evolution (yet it misses many processes from speciation to what causes changes in gene frequencies in populations). Other definitions, such as ‘the history of life’, get to the patterns of evolution, but do not describe their causes. So both kinds of definitions are inadequate on their own.
Most population-based definitions of evolution include the idea that the changes in allele frequencies have to occur over many generations. This is to avoid the very trivialization that Kevin mentions. When you teach a course on evolution you start by explaining how changing allele frequencies will (almost) inevitably lead to fixation of one allele and elimination of another. Then you teach that there are several mechanisms that can cause this. The most important mechanisms leading to fixation of alleles in a population are random genetic drift and natural selection.

There's a good reason why you don't include the explanation (mechanism) of allele frequency change in the definition of evolution. It's because there are many possibilities and we don't know for sure that we have discovered all of them [What Is Evolution?]. Kevin's other complaint, that the minimal definition doesn't include other important parts of evolution, such as the splitting of population (cladogenesis), is quite valid. That's a higher level process that we can teach once students have mastered the basic population genetics concepts of natural selection, random genetic drift, population size etc.

Kevin thinks there's a better way ...
Darwin’s definition, which he used in On the Origin of Species, was ‘descent with modification’. Although it may seem at first glance simplistic or vague, it embodies both the patterns of evolution (descent) and its processes (modification). It is as useful on a short timescale as on a long one; it suggests minor evolutionary modifications as well as major ones. In the last paragraph of Chapter 6 of the Origin, Darwin used this simple definition to settle a century of debate about what controls the morphology of form in the first place (Figure 1). Geoffroy St.-Hilaire and others had stressed ‘unity of type’, the features that characterize major groups of animals (mollusks, arthropods, vertebrates) and seperated them from others. Baron Georges Cuvier had emphasized ‘conditions of existence’, circumstances that made it advantageous for herbivorous animals to have cropping teeth, complex guts, and hooves for fleet escape. Darwin brushed away this conflict in a single paragraph by showing that common descent could explain the common body plans of related organisms, and that natural selection could explain their adaptive differences as they were modified to fit the conditions of existence.
There's a reason why most of us think that "descent with modification" is "simplistic or vague." That's because it IS simplistic and vague.

That definition doesn't include the basic concept that it is populations that evolve and it doesn't include the basic concept that the changes have to be due to changes in the genes. Darwin didn't know about genetics and population genetics but we do. It is not a misrepresentation for textbooks to define and teach evolution from a population genetics perspective. We know so much more that Darwin did in 1859.

It's troubling that a leading evolutionary biologist and President of NCSE has a view of evolution that is strictly adaptationist, and opposed to population genetics as a core concept in teaching evolution.


Thompson, J.N. (2007) Use the word evolution. Evolution: Education and Outreach 1:42-43. [PDF]

Padian, K. (2010) How to Win the Evolution War: Teach Macroevolution! Evolution: Education and Outreach 3:206-214 [doi: 10.1007/s12052-010-0213-5]

Padian, K. (2013) Correcting some common misrepresentations of
evolution in textbooks and the media. Evolution: Education and Outreach 6:11 (published online June 25, 2013) [doi: 10.1186/1936-6434-6-11]





30 comments :

Jon Peters said...

I'd like to comment about the macroevolution issue. Padian is right on here. Only one out of the three basic types of creationism can remotely accommodate macroevolution. If you can demonstrate that, you've just silenced the majority of all the creationist writings. Do you know how valuable that is? The only game in town when speaking about the evolution-creation controversy now is macroevolution. Period. It's where we should be spending our time trying to reach the public. You can talk about mechanisms later. But let's get evolution - macroevolution - established first. Using whales as an example is excellent and that is what I do in my lectures: atavisms, DNA protein sequence similarities between hippos and whales, transposon comparisons between whales and hippos, modern whale vestigial structures, and the 30 genera of fossil whales showing transitional changes should overwhelm anyone who still proclaims "there's no transitional forms". Which is what they keep saying because if there are these evidences available all the YEC and subtypes of OECs are invalidated.

Neil said...

Along similar lines as Jon Peters, I think you are opposing complementary strategies (and it might be said that Kevin Padian is doing the same, at least based on the quoted excerpts you have posted).

It seems that there are two goals here (not mutually exclusive): 1) exposing as broad an audience as possible to the rich tapestry of evidence and theory that supports and informs our understanding of biological evolution; 2) cultivating a solid understanding of how evolution "works" in a mechanistic sense.

Both are essential, but I think it is overly reductionist (and possibly counter-productive) to expect that students and the public at large has to master 2 before they can truly appreciate 1. As you allude to toward the end of your post, Darwin was able to compile and articulate a truly magisterial account of 1 while only advancing in a limited (albeit revolutionary) direction toward 2. And he swayed a great many of his scientist and non-scientist contemporaries that all organisms share a common descent, even while many remained skeptical (or openly disdainful) of natural selection.

I think we have to be honest that a significant portion of the population is never going to master Hardy-Weiberg or even Punnett squares. They probably also won't master cladistics or the geologic timescale or allometry or K-selection vs. R-selection. That doesn't mean that they are a lost cause when it comes to a appreciating (limited) understanding of biological evolution. Obviously it gets trickier when it comes to "defending" those ideas to a hostile YEC armed with a pamphlet of talking points. But if we (and the educational system as a whole) have done our jobs properly their critical thinking skills will be sufficiently developed that they won't be swayed by facile logic even if they fail to deconstruct and counter creationist propaganda on the spot.

That said, I suspect you are right that history of life and macroevolution are reasonably well represented in introductory texts these days. Partly hat reflects a recent improvement--much of the treatment of "macroevolution" in older [Modern Synthesis] texts is really just Lamarckian strawman beating. And if we are talking about prospective evolutionary scientists, I wholeheartedly agree that they should be be mastering the arts of population genetics. And biogeochemistry and functional morphology and sedimentary geology and systematics and phylogenetics and ecology and paleoclimatology. Not necessarily in that order.

Larry Moran said...

... think it is overly reductionist (and possibly counter-productive) to expect that students and the public at large has to master 2 before they can truly appreciate 1.

I believe that students in a university course MUST master 2 (understanding how evolution works). I find it difficult to believe that they can truly appreciate 1 without 2.

I believe that high school students should also be taught evolution from a basic population genetics perspective.

Teaching the general public is a different kettle of fish. However, if we teach evolution properly in high school then after one generation the ignorance of the general public will be much less of a problem.

I think we have to be honest that a significant portion of the population is never going to master Hardy-Weiberg or even Punnett squares.

I agree. There will always be a segment of the population whose intellectual skills are not sufficient to enable them to graduate from high school. You do agree, don't you, that anyone who can't handle a binomial expansions or a simple matrix should never be given a high school graduation diploma?

That said, I suspect you are right that history of life and macroevolution are reasonably well represented in introductory texts these days. Partly hat reflects a recent improvement--much of the treatment of "macroevolution" in older [Modern Synthesis] texts is really just Lamarckian strawman beating.

I have a collection of introductory biology textbooks (mostly university level) going back five decades. Since 1990 (twenty years ago) they have (almost) all begun the evolution section with population genetics and a description of fundamental mechanisms such as random genetic drift and natural selection. Then they have a chapter on speciation and speciation mechanisms. Then they cover the history of life with many examples of macroevolution (usually horses, whales, and birds. Most of the textbooks have a separate chapter on the evolution of hominids.

I don't really see why Kevin Padian is complaining about the lack of coverage of macroevolution.

Larry Moran said...

The only game in town when speaking about the evolution-creation controversy now is macroevolution. Period. It's where we should be spending our time trying to reach the public.

Really? That's the only game in town? Why then do I find myself spending so much time defending molecular evolution and population genetics from the likes of Jonathan Wells, Michael Behe, and Stephen Meyer?

You can talk about mechanisms later. But let's get evolution - macroevolution - established first.

How can you possibly understand the history of life if you don't understand the scientific explanation of that history? You can show the public all kinds of facts about whales and their ancestors but the most important point is that we have an explanation for those facts based on evolutionary theory.

Using whales as an example is excellent and that is what I do in my lectures: atavisms, DNA protein sequence similarities between hippos and whales, transposon comparisons between whales and hippos, modern whale vestigial structures, and the 30 genera of fossil whales showing transitional changes should overwhelm anyone who still proclaims "there's no transitional forms"

It's one thing to show students that there are similarities in the amino acid sequences of hippos and whales and it's quite another to offer an explanation of how that happened. There are several possible explanations including those that are defended by creationists. Your job as a teacher is to show students that the explanation based on evolutionary theory is not only reasonable but well-supported by evidence for natural selection and drift in populations (microevolution).

I don't know how you can do this if you don't talk about mechanisms and the fundamental concepts of population genetics and modern evolutionary theory.

Don't forget that many creationists will accept the existence of transitional forms and descent with modification but still reject evolution as the complete explanation of the history of life.

Also, don't forget that textbooks and the proper teaching of evolution are not restricted to the United States of America. You and Kevin may be focusing on how to solve the creationist problem but your solution may not be applicable elsewhere. (Personally, I don't think your solution will work in America, either.)

Anonymous said...
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Anonymous said...

Nothing makes me laugh out loud more than evolutionary scientists who claim to be the experts on evolution and who can't agree on the fundamental principles of evolution; such as its mechanism (s).

I have not been following this blog for a long time, but almost ever week Larry complains about another "topnotch scientist" who either doesn't understand evolution or its mechanism (s).

Thanks to their mutual disagreement, especially among such big-shots like Dawkins, Coyne, Moran, and the rest, my kids don't have to attend biology classes anymore, when evolution is being taught.

I met with the principal and most of the biology teachers at my sons' school and asked them to write down on a piece of paper what the definition of evolution and its mechanism (s) were. Can you predict what happened? It was a lot of fun. Anyway, since my kids do well at the rest of biology, the teachers let them skip most of the classes, so that they don't have to deal with embarrassing questions from my sons. Well, it worked out well lol.

Neil said...

You do agree, don't you, that anyone who can't handle a binomial expansions or a simple matrix should never be given a high school graduation diploma?

I hope you don't feel the same about writers of typo-riddled blog comments (i.e. me).

Whether I think they should receive a diploma or not is beside the point. Frankly, many students make it through without mastering these elementary skills, or worse only learn them to the extent that they can marginally pass a standardized test that treats education as an apparently arbitrary set of abstract drills with no obvious connection to the "real world."

The question is, do we simply write off the segment of the population without a solid working knowledge of population genetics as hopeless and insufficiently intellectual to participate in a broader dialogue about our place in the natural world?

To be clear I'm not talking about "dumbing down" science at the college or high school level. Rather I am advocating pluralism. There are those who could not care less about fossil whales, but are fascinated by human health or crop science or protein folding. I know gifted geneticists that think Dimetrodon is a dinosaur. It's OK. I think we should expose everyone to as broad and rigorous a biological education as possible. But also I think we should be careful about being overly rigid or fundamentalist in pursuit of pedagogical purity.

I would be interested to compare textbook treatment of macroevolution across decades in a systematic way. I do think that the treatment of has improved, thanks in part to recent fossil discoveries that illuminate some key transitions. Anecdotally, I can tell you that my high-school education (in the 90s) was relatively heavy on genetics and cell biology and mighty thin on macroevolution. There was some ridiculing of Lamarckian giraffes and, yes, some very misleading and dated treatment of horses that could have come straight from Cope (Eohippus to Equus in four easy steps).
But I turned out OK anyway. Maybe. My matrix and binomial algebra skills are mighty rusty.

John Harshman said...

So you want your kids to be ignorant of the main organizing principle of biology? Why is that, exactly?

AllanMiller said...

Can you predict what happened?

No.

steve oberski said...

The only thing I find more disturbing than the fact that Quest is allowed access to an Internet connection is that he is responsible for the upbringing of impressionable children.

I take comfort in the fact that like every thing else Quest has posted, this is most likely unadulterated bullshit.

Anonymous said...

John, You are one of the very few who questions Larry's authority on evo/mechs. Why are you questioning me? Why?

Oberewski doesn't even know what it is about and he still objects... I love this blog....

Anonymous said...

I don't know why John questions you Quest, but, whether we agree or disagree with Larry on one or two or one million issues does not change the fact that you are an ignorant fool. One who takes pride in keeping his/her children in abject ignorance. You want your kids to be as scientifically illiterate as yourself. Hopefully they did not get their intelligence from you.

John Harshman said...

Quest,

You seem to believe that opinions are a matter of choosing sides. Nope. Larry and I disagree about various things, but most of them are more trivial than you seem to think. Most disagreements among the scientists you have mentioned above are more trivial than you seem to think, and at any rate are on a few points that are unlikely to turn up in a grade school or high school class. We all agree that natural selection and drift are both major mechanisms of evolution. The disagreement between Larry and some others is on the relative emphasis we should give to them. My argument with him is even less interesting and concerns the adequacy of a short definition. Any short definition. Your little challenge to the biology teachers was pointless.

Anyway, why am I questioning you? Because your decision to keep your children ignorant of the central organizing principle of biology, for very silly expressed reasons, is pernicious. I answered your question. Now will you answer mine? Why do you want your children to be ignorant of the central organizing principle of biology?

Anonymous said...
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Anonymous said...

John, Have you ever seen or talked to a 10 year old kid that can defend his beliefs really well? I mean in biology? I have never, ever stopped them (my boys) from investigating anything they wanted; they challenged me many, many times. They still do. I don't like it sometimes but.... I do too.... It makes crappy science look really bad... coz children expose it....

John Harshman said...

No, I haven't. And I'm not going to take your word that yours can. I have no doubt they could argue rings around you, but that isn't much of a standard. Are they less ignorant of evolution than you are?

And I will note that you still have not answered my question. Why do you want your children to be ignorant of the central organizing principle of biology?

Anonymous said...

John, What evolution? You have to be precise. 90-95% of stuff you guys are talking about here is evolution nobody in the right frame of mind questions. Even some very prominent YEC have recently accepted that "natural selection" is a real deal or something. Well, that is great that after 150 years they acknowledge something that people like Darwin saw and pretty much proven with their own eyes and some experiments. That is not what I'm talking about. I'm talking about science that reaches beyond Darwin's imagination; the science leading to the point where "evolution" can even begin. This part of science stinks so bad, that my brother in law, very well know scientist doesn't even mention it during thanksgiving dinner. He flies in on his private jet to eat turkey with us, but he doesn't want to talk about that.

Then we have so called macro. I don't buy it for many, many, many reasons but one of them is the Darwin's Finches. I have gone to the isles personally many times. I have seen the changes of the beak with my own eyes. There is no doubt in my mind that the beak size and shape does change within one generation. However, does it mean that finches will become other species later on? No. Next generation or two return to being small beak finches. No macro or any other evolution takes place. No way. My wife and I have big noses. I mean pretty big. My sons have small ones. Would they turn into superhuman or would their offspring? No frickin way. I predict that NegEntroc would rather turn into a creationist than this to take place ;lol

JimV said...

All the wild statements Quest has made recently increase my (previously-mentioned) suspicion that he is the unfortunate victim of some brain malfunction, such as being bi-polar. I am not being sarcastic or intending to be mean. I have known one such person personally and heard of two others, and all three became fixated on creationism (as a consequence of biblical literalism) in their late 20's or early 30's once their syndrome occurred. There is not much point in arguing with such people and no point at all in becoming angry with them.

John Harshman said...

Quest,

Three posts later and you still haven't answered my question. Why do you want your children to be ignorant of the central organizing principle of biology?

I suspect that your first paragraph is talking about the origin of life. Is that correct? In what way is our lack of understanding of how life began a concern for you?

I find it very difficult to believe that you have gone to the Galapagos many times and have seen the changes in finch beaks, which are the sort of thing you can only really measure with a bird in hand. Do you have a tendency to make up stories? The rest of the paragraph is gibberish. We know that macroevolution happens not because of finch beaks but because we have a clear phylogenetic tree that relates many quite different species, including, incidentally, all of Darwin's finches and their Caribbean and South American relatives. Do you think that each species of finch was created in place, separately, in the islands? Now that's silly. And by the way, evolution has nothing to do with superhumans; you've been reading too many old comic books.

Tim Tyler said...

If evolution is defined to be confined to changes in genes, then the concept of a "gene" had better cover all kinds of cultural and environmental heritable variation - or the definition will be in conflict with modern theories of cultural and environmental evolution.

Larry Moran said...

We're talking about biological evolution. This is clear from the context. We are not talking about stellar evolution or any other kind of evolution, including cultural evolution.

Pedro A B Pereira said...

I totally agree with Moran. Intelligent Design thrives precisely due to ignorance of mechanisms. The way you seem to be teaching evolution amounts to stamp collecting. You show all the evidence from transitional fossils, compared anatomy, etc, but unless you show (based on population genetics and molecular evolution) HOW that occurs then one of your students could just say that that God willed it or that evolution is Lamarkian.

There was a period after Darwinism was introduced called "The Eclypse of Darwinism". The reason was that the evidence for evoultion's ocrrurence was there (as Darwin presented it) but there were no mechanisms to explain it. Filling the textbooks with pretty pictures of comparisons of sekeletons and molecules by itself explains nothing. Without population genetics and molecular evolution to inform HOW macroevolution occurs we are back at square one, the only difference being that the data we have is bigger and more refined.

Pedro A B Pereira said...

"This part of science stinks so bad, that my brother in law, very well know scientist... "

lol.


"He flies in on his private jet... "

lol

"Then we have so called macro. I don't buy it for many, many, many reasons but one of them is the Darwin's Finches. I have gone to the isles personally many times..."

lol

You're full of shit.

Tim Tyler said...

Larry, that's simply a fundamental fallacy. Culture is part of biology - since biology is the study of life. So cultural evolution is part of biological evolution. Stars are not part of biology. However, culture is part of living systems. Without life, there's no culture.

Claiming that cultural evolution is not part of biological evolution goes against all the literature on the topic. See, for instance the article "Culture is Part of Human Biology" by Boyd and Richerson. It is just a categorization mistake.

Pedro A B Pereira said...

""Larry, that's simply a fundamental fallacy. Culture is part of biology - since biology is the study of life. So cultural evolution is part of biological evolution. Stars are not part of biology. However, culture is part of living systems. Without life, there's no culture.

Claiming that cultural evolution is not part of biological evolution goes against all the literature on the topic. See, for instance the article "Culture is Part of Human Biology" by Boyd and Richerson. It is just a categorization mistake.""


There's no fallacy here. Pretty much everyone on this forum is familiar with Sociobiology, inlcuding it's offshoot Gene-Culture Co-Evolution. It also happens to be completely irrelevant for the issue we are discussing at the moment.

Piotr Gąsiorowski said...

Without life, there's no culture.

Absolutely. Also, without chemistry, there's no life; without physics, there's no chemistry: ergo, culture is part of physics. What's wrong with that? Maybe the fact that physics, chemistry, biology, the social sciences and other disciplines are not objectively existing domains of the universe but fields of study defined by us humans for our own convenience, each with its own field of interest.

steve oberski said...

Tim Tyler Stars are not part of biology.

As far as I know all the elements other than hydrogen, helium, lithium and beryllium, which were produced during the big bang nucleosynthesis, are the result of fusion processes in stars.

This would include all of the other elements that are utilized in biological processes.

Tim Tyler said...

Pedro, cultural evolution is closely involved with the definition of evolution given in textbooks. Check the definition in Ridley's 'Evolution' textbook. It gives a definition of evolution and then says: oh yes, but cultural changes and changes during development don't count. That's a daft and ugly way of defining a scientific subject area. There's now a large literature on cultural and somatic evolution. This textbook is just wrong.

Piotr, only partly. Physics, chemistry and biology are distinct academic subjects, but they are *also* partly-overlapping domains, such that: (physics (chemistry (biology))). Biology and culture can have their own academic departments, while it nonetheless remains true that (physics (chemistry (biology (culture)))). Saying that cultural evolution is not part of biological evolution is like saying that biological evolution is not part of physical evolution. Both are equally dubious statements.

Steve, that's rather different. Biology doesn't study stars much. Stars are not alive. Biology is the study of living systems. That's not to say that there's no link - just the rather tenuous one of providing raw materials.

Piotr Gąsiorowski said...

Tim: Saying that cultural evolution is not part of biological evolution is like saying that biological evolution is not part of physical evolution.

Actually, there are close analogies between (some aspects of) "cultural evolution" and "biological evolution", since the cultural transmission of knowledge, skills, language constituents, etc. is a process involving faithful but not-quite-error-proof copying, like biological replication. Therefore, the use of the word "evolution" with reference to cultural phenomena is more than a fanciful metaphor, and insights borrowed from biology are valuable e.g. in my own area of research, historical linguistics (not that biological models can be straightforwardly imported without taking into account the differences between the two domains). But I have no idea what you mean by "physical evolution", so the final part of the sentence makes no sense to me.

Tim Tyler said...

I just meant physical change - but you should be made aware that inorganic physical systems evolve along Darwinian lines too. Perhaps review my articles "positional inheritance", "velocity inheritance" and "Darwinian physics", "universal selection" and "observation of the observable" if you are interested in how Darwinism applies to physics.