Mutation rate refers to its frequency, not its speed.
I don’t think you understand genetic drift; it isn’t about “change within [a] barrier.” And Lynch’s definition of drift is exactly the same as everyone else’s.
That’s all wrong.
Roger, you seem to have interpreted my posting exactly the opposite of my intended meaning.
My point was that even though crocs don’t look different, genetically they probably Are very different from the crocs of 20 million years ago.
And how would you prove or disprove that a genetic change was or was not part of drift? I never said that drift was more important than natural selection. What I was trying to say was since the imperfect replication of genetic material from generation to generation continues to happen whether there is ecological changes or not, it would be unrealistic to think that when the environment is not changing that genetic mutations will just sit still and wait until it does.
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[quote=“sfmatheson, post:41, topic:35065”]
Mutation rate refers to its frequency, not its speed.
I don’t think you understand genetic drift; it isn’t about “change within [a] barrier.” And Lynch’s definition of drift is exactly the same as everyone else’s.
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Stephen,
Frequency and speed are directly related, are they not?
You say that Michael Lynch is a leading researcher in this field, and then you contradict this important paper that he wrote. His view of genetic drift is certainly different from the textbook’s view you provided to me and other views I have read.
It is now your responsibility to try to understand the scientific literature that you claim to read. As a subject expert, I can tell that you do not understand it and are far from even a basic understanding. This is no longer my problem. It’s yours. And it is a matter of fundamental integrity. Your pattern is to type inaccurate claims, then demand citations when you are told by actual experts that you are wrong. This is followed by citations, often selected from hundreds or even thousands of studies. And then you type further inaccurate claims that show that you do not understand the basics of evolutionary genetics.
This is now your problem to solve. There are subject matter experts here who can answer questions and help you find the right reading materials. Now you must decide whether that’s what you really want.
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I have engaged with hundreds people on evolution, many of them experts, and none of them have told me that I do not understand them basics of evolution. Now maybe this is because they do not view evolution through the narrow window of evolutionary genetics, and neither do I.
So if you are an expert on evolutionary genetics, that is fine. If I choose to be better acquainted with this field I will buy Lynch’s textbook in this field and read it. However I do not think that I do not think I need to be an expert in a field to understand it.
I understand evolution as it appears that you do not. That is my field of expertise in science. It is sad that our expertises do not mix.
Are you sure about this?
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Oh come on, @Relates, sure they have…
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Just for the fun of it. All that has been said I am going to throw a fly in the ointment and digress on this conversation to my initial point. I dont agree that evolution constitutes just any simple change in the genome. That happens all the time and really is not evolution. So lets define evolution as an adaptation of an entity that enhances the fitness or survival of the entity in its environment.
Furthermore, though human genes have probably changed or evolved if you like somewhat over the last number of millennia the main form of our evolution has been adaptive behavior that has enhanced our fitness and survivability in our world. Our evolution in the last 10,000 years has less to do with our genes but more with our knowledge and behavior. Instead of growing fur or blubber to survive the cold we make clothes and build fires. Instead of dependence on a hunter gatherer lifestyle for food source we grow our own food. Our brain is an evolution machine that creates evolutionary adaptations. It can create adaptive changes without changing the genome Would you agree?
@Skoshland… so you are just going to redefine Evolution to mean whatever you want it to mean?
So is that okay if I say that I am going to define the Trinity as just One deity, with three faces? After all, you can make up new meanings… why can’t I? Because that’s not what the relative experts on these different topics have demonstrated.
If the gene pool changes… that is evolution … period. There is no such thing as de-volution either.
Ok George. Don’t get all caught up in the evolution word. Call it what you want. I really don’t care which end of the egg that you crack. Call it adaptive selective fitness whatever, the point is that entities are adapted to survive in their environment where fitness and survival have been or are selected. My point stands, human adaptive selective fitness has been driven by our behavior and knowledge more than by genetic or physical modification over the last 10,000 years. Our brain is creating adaptations advancing our species fitness and survival. Changes in the human population genome have probably not as significantly affected our fitness and survival over that period.
Exactly! I’m no scientist but genetic drift was my first counter-example. Evolution happens. Period. There is no known process that stops evolution—other than total extinction by some nearby supernova or a visit from a hostile battlestar.
Evolution is changes in allele frequencies in populations over time. Even total environmental stasis can’t stop genetic drift. Again, I’m not a specialist in any evolutionary biology field, but I don’t see how anything could stop that genetic drift.
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This seems as ad hoc as it gets - you seem to equate human agency (which is more an argument against the commonly accepted notion of the ToE) with biological variation and so called natural selection. There is nothing “natural” about human agency, as it presents possibilities for our species, and other species, that contradict any notion of natural variation.
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Genetic drift would be absent for an infinite population, for an organism with a mutation rate of zero, and for an organism for which all mutations were lethal. Otherwise, it happens. It’s trivial to observe and it’s overwhelmingly the most frequent kind of evolution.
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Of course, that is valid only if measured by how much of the adaptation passes on through the gene pool to following generations. In humans it gets sort of mixed up by our social and reproductive habits. Intelligence may be seen as positive at times, but if more intelligent people have fewer kids, then evolution will select less intelligent people as better adapted.
Yes. For example, we don’t have to watch diabetics die. Instead, we give them insulin.
Or we could just call it ‘adaptation’. Because evolution is genetic change in populations, and it’s not acceptable to re-define it away from that.[quote=“Skoshland, post:48, topic:35065”]
though human genes have probably changed or evolved if you like somewhat over the last number of millennia
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Not ‘probably’.[quote=“Skoshland, post:48, topic:35065”]
Our brain is an evolution machine that creates evolutionary adaptations. It can create adaptive changes without changing the genome Would you agree?
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I think there are only two ways to approach your question.
One is to say that behavior is just a phenotype, and so no, the brain can’t create adaptations without genetic change, simply because the brain is the adaptation, and it came about via genetic change. This approach acknowledges that evolution, by definition, involves heritable change, and also acknowledges that brains and behaviors are natural phenotypes that should not be cleaved away from biology or genetics.
The second is to ask whether ideas can be thought of as “heritable” in some sense, given that they are transmitted across generations and separately from mortal bodies. This response is similar (or identical?) to the concept of ‘memetics’ that Richard Dawkins first explored in The Selfish Gene. It’s a fun concept to chew on, but IMO it ends up running parallel to – but not physically intersecting with – plain old physical biological evolution.
In either case, no one should doubt that ideas (technology, language, reading, big stuff like that) fundamentally change the environment within which genes do their thing. Undeniably, humans can convert lethal alleles to mere inconveniences, or drive sexual selection in completely different directions using billboards. (Or at least we think they can.) In that sense, yes, human behavior influences evolution. But that’s not biologically new or even interesting. It has ever been so. Just ask a peacock.
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Phil. Of course, that is valid only if measured by how much of the adaptation passes on e gene pool to following generations.
Phil. Thank you for your comments. I think that this may fall more in the field of Anthropology than Genetics. Genetics doesn’t really apply to human fitness now as much as our behavior. Of course we have the genetic makeup to learn and cognitively think and communicate but our fitness and survival have been and are dependent on our behavioral adaptations. And like the genetic heritability of evolution we have cultural structure and context that maintain and pass (learning) of this adaptive behavior that enhances survival and fitness from generation to generation. Kind of makes one think about the Bible, the Word of God in this context.
It does make you think. One thing that we do that I wonder about is somehow when talking about human behavior, society in general tends to remove humans as part of nature. Human environmental impact, evolution, selection of corn varieties etc is somehow outside of nature in common speech.
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Actually, the answer these days seems to be leaning toward a “both/and” rather than an “either/or” solution. Some interesting research in this regard. How culture shaped the human genome: bringing genetics and the human sciences together
Here is the NY Times article reporting on the above study.
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Oh, Scott! Don’t get caught up in the phrase “enhancing adaption”! Because using that phrase is making you refer to the invention of colleges by civilziation as a form of Evolution.
Certainly University schooling can help a person survive. Or it can teach him things that make for more dangerous living. But none of t his has anything to do with Evolution as a genetically-centered process.
You can make up terms all day long … but what you just called Evolution isn’t.