The scientific method applied to the theory of Evolution

[otseng]

The theory of evolution is the dominant theory to explain life that we see on Earth. This theory is the gold standard in which to compare all other theories of life since it is by far the most widely accepted theory in society in regards to life.

What I would like for us to explore is to apply the scientific method to the theory of evolution.

So, for discussion:
What are the relevant terms that must be defined in discussing biological evolution?
What is the hypothesis?
What are the predictions?
What are the evidences that correlate (or does not correlate) with the predictions?

If there are any other things you feel should be added to the list of questions, feel free to bring them up.

I anticipate this will become a lengthy thread. So, I would like to encourage people to spawn off new threads if an area is brought up that requires deeper discussion.

[steen]

So, here again are the questions for debate:

What are the relevant terms that must be defined in discussing biological evolution?

Well, obviously "evolution" needs to be defined. I do not agree with the definition so far given in this tread. It focuses solely on speciation and common descent, neither of which need to ever have occurred for the Scientific Theory of Evolution to have merit.

What is the hypothesis?

That under changes in environments, populations will change genetically to respond to these changes in an "optimal" (as in better fit and adaptation) to that new environment.

What are the predictions?

When environments change, populations of organisms will change along with it.

What are the evidences that correlate (or does not correlate) with the predictions?

Again a bit broad. The flippant answer would be "all data of 150 years of research." But it wouldn’t be useful. Rather, when researchers explore aspects of evolutionary changes, the results consistently support the Scientific Theory of Evolution.

As for the first question, rjw has offered this definition of the theory of evolution:

ToE is the theory that all extant life forms are related through a lineage of common descent, that began with a replicating molecule some billions of years ago and through a series of changes (mutations?), life adapted in various ways (was selected) to a multitude of environments. In the process a series of related genetic systems (and hence morphologies) developed, leading to the patterns we see in life today.

I can accept this definition.

I can not. This is the definition of an ASPECT of evolution, namely phylogenesis (speciation over time). But it doesn't cover the changes within a population without leading to speciation. So again, it needs to be more broadly defined. The best definition I have seen is that of "a change in populations over generational time (in response to environmental changes)"

[steen]

Another point I see missed here. There is a distinction between "evolution" and "the Scientific Theory of Evolution.

Evolution is the change in a population. It is witnessed, documented and is factual. We have direct evidence that it occurs.

The Scientific Theory of Evolution is the overarching explanation that ties all the evidence of occuring Evolution together in one comprehensive process/explanation.

[juliod]

I would not regard understanding GAR protein relationships as fundamental to understanding the theory.

But you don't use the SM to analyse the "fundemental principles" of a field of science. In fact, once someone has written a book called "Fundementals of...." that field has long since ceased to be an active area of research.

When you do the SM, you use the explanatory and predictive capabilities of a theory to form a hypothesis. Then you test the hypothesis with experiment or observation. This is not the same process as rhetoric and logic.

You might get some insight into this by trying to formulate a hypothesis based on creationism and suggest how you might test it.

Here's an example of what a creationist might come up with. Let's say we have an angel. Angels are unique individual creations, and are not descended from other beings. Therefore, the genetic material of an angel (if any) should be radically different from other ordinary animals. You can test this hypothesis by isolating and characterizing the genetic material of an angel. Of course we can't do this because there are no known examples of angels to study.

Can you come up with a valid example?

DanZ

[juliod]

There is a distinction between "evolution" and "the Scientific Theory of Evolution.

Yes. I often say "Evolution is both a fact and a theory". Of course, the problem is that often creationists deny the factual basis of evolution, without looking at the evidence for it...

DanZ

[Jose]

Welcome, steen! It's always good to have another voice in the conversation.

I find myself on the edge of agreeing with you, but I have a vague notion that maybe I don't. I think that your prior discussion of populations changing during times of environmental change is one of those "thousands of concepts" that juliod mentioned. I would consider it to be a part of the overall process, and one that is critical to understanding. But I wouldn't yet rewrite our definition. Part of the reason I say this is that on these forums, "evolution" means (to some of our members) the overall pattern of common descent, but (curiously) excludes changes in allele frequencies in populations. Why? Because changes in allele frequencies have been observed (so we must accept them), but no new "kinds" of animals result from them. The issue seems to be how to make the link between microevolution and the overall pattern (and timescale) of evolutionary history.

[Jose]

I would suggest first providing evidence that leads to the formulation. Then we can proceed to evidence in supporting the predictions. (This would be similar to how we approached the Global Flood model first and then the Flood as science next.)

Sounds workable to me. Perhaps lower down I'll think of something to suggest.

I'd like for us to lay the fundamental groundwork first before jumping into debate.

Just for laughs, I'll ressurect a comment I made some time ago. This isn't an issue that can be "won" by debate. It's more a discussion of evidence. We could steal a line from the ID crowd, and refer to it as a "critical analysis of evolution."

The example is the relationship of members of the GAR protein family in species as distinct as mammals and yeasts...

I think we differ on what we view as a "major concept". A major concept of the theory of evolution to me would mean something along the lines of the mechanism of evolution that Jose brought up earlier. It would be a fundamental point of evolution that is required to be presented in order to understand what is the theory of evolution. I would not regard understanding GAR protein relationships as fundamental to understanding the theory.

I agree with juliod. The GAR proteins are part of one of these major concepts--gene families. There are many other gene families. The GAR proteins, like many others that have highly-conserved domains (in this case the Gly-Arg-Arg repeat) are particularly interesting because they provide clues about the shuffling of functional domains among genes. "Simple" genes like the hsp70 family may be somewhat easier to handle, since they occur in nearly everything, rarely have introns, so each gene sequence tends to relate more directly to the lineage in which it is found. [I note that "gene families" is now among the list of things that anti-evolutionists are now trying to explain as irrelevant, so they must be important.] Exon shuffling, which is a mechanism that may explain proteins with common domains, but differences outside these domains, would be one of the things that would be justifiable as a question or uncertainty about evolution. But, by the time most of us have the background to talk about exon shuffling, we've pretty much absorbed enough of the data to recognize this as a question of how it happened during evolution, not a question of whether evolution happened at all.

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fundamental observation #1: Hierarchical Relationships

Operating on your suggestion that we start with the broad issues that led to the proposition that there is common descent, I'll raise the issue of hierarchical relationships. Simply described, this is the observation that for every species (as far as I know), there are multiple varieties. Species themselves clump into genera of slightly different, but clearly related organisms. Genera clump into what we call families....and so on down to Kingdoms, or more properly, the Three Domains of Life.

This is such an obvious feature of life that Linnaeus worked out the nomenclature system that we now use. He grouped species into this hierarchy based on what they look like.

There are two main explanations that we've kicked around in these forums. One is: things are related this way because they are genetically related, by common descent. This is the Big Picture which my prior post describes through a simple means of modeling the mechanism. The second explanation is that similar species are similar because they had a common designer. This explanation can never be examined, because it is impossible to devine the motives of a god. Even Genesis says nothing about the hierarchical relationship of living things, so our only way to figiure out this Overall Pattern of Life is to study life itself.

As I understand it, the really-compelling evidence for this overall pattern came from Natural Theology, of which Darwin was a part: describe all of god's creation, the better to glorify him. As the description became more and more extensive, people began to question whether these apparent relationships might have a reason besides god's whimsy. The idea of evolution was kicking around among naturalists for some time before Darwin proposed a plausible mechanism by which it could occur.

What, then, are your thoughts about this particular fact of hierarchical relationships?

[steen]

Welcome, steen! It's always good to have another voice in the conversation.

I find myself on the edge of agreeing with you, but I have a vague notion that maybe I don't. I think that your prior discussion of populations changing during times of environmental change is one of those "thousands of concepts" that juliod mentioned.

Well, it is the fundamental part. When all other is stripped away, what is necessary for evolution is a change in genetic expression between generations. That is all that is necessary to show that evolution occurred.

I would consider it to be a part of the overall process, and one that is critical to understanding. But I wouldn't yet rewrite our definition. Part of the reason I say this is that on these forums, "evolution" means (to some of our members) the overall pattern of common descent, but (curiously) excludes changes in allele frequencies in populations. Why? Because changes in allele frequencies have been observed (so we must accept them), but no new "kinds" of animals result from them. The issue seems to be how to make the link between microevolution and the overall pattern (and timescale) of evolutionary history.

AH, but that it not the same as looking at the basic component of Evolution. Regardless of whether new species were generated or not, an evolutionary change occurred between generations. It was just the entire population that changed.

This is also the basic point that is made ion the talk.origin site, BTW. And whether "some of our members" have generated an alternative definition of "evolution" to be mainly phylogenesis/speciation, that really isn't a problem with the Scientific Theory of Evolution, but rather with the general understanding of what Evolution actually is.

I tend to be rather dogmatic and opinionated on that point, as I have see many hundreds of examples of creationists trying to discredit evolution by misrepresenting it as something it is not and then attack that fabrication. Strawmen are not facts. (And that is even aside from the attempts at portraying abiogenesis, the Big Bang and whatnot as "evolution." You will see a lot of creationists talk about "adaptation, but that's not evolution." That is the kind of misrepresentation that is used to create artificial and irrelevant arguments. I tend to NOT let them get away with that trick which I tend to see as a "creationist dirty trick" (CDT). That is why I insist that if somebody actually want to criticize "evolution," they first must show that they actually know what they are criticizing. Otherwise, it is just a meaningless interaction.

[otseng]

Another point I see missed here. There is a distinction between "evolution" and "the Scientific Theory of Evolution.

Evolution is the change in a population. It is witnessed, documented and is factual. We have direct evidence that it occurs.

The Scientific Theory of Evolution is the overarching explanation that ties all the evidence of occuring Evolution together in one comprehensive process/explanation.

Welcome to the forum and to the debate steen.

Perhaps we need to step back a bit here and clarify on the terminology for the purposes of this thread before we go too far. "Evolution" is one of those overloaded terms that means many different things to many different people.

Some meanings could be:
- Change
- Development
- Microevolution
- Macroevolution
- Mutations + Natural selection
- A change in allele frequencies in a population of organisms over time
- Micromutation
- Macromutation
- Common descent
- Biological evolution
- Cosmological evolution
- Social evolution
- Darwinian evolution
- Neo-Darwinian evolution
- Theory of evolution
- Fact of evolution
- Journey's fifth studio album

And I'm sure there are many other meanings than the ones I just listed.

As to "evolution", I simply see it as "change". And as to the issue of do things "change", there is no dispute that things "change".

As to the "Theory of Evolution", I would say it involves more than simply explaining that things change. For me, I would break it down into two major components. One is that organisms microevolve through mutation and natural selection. The other major part is that all organisms have come about by common descent through the process of microevolution.

Feel free to add/correct my view of evolution and the ToE.

Can you come up with a valid example?

I have already mentioned the Global Flood thread and the Flood as science thread. These were my attempt from a non-scientist to present a hypothesis based on evidence and predictions with supporting evidence. I would admit those threads would not be the best examples to follow in regards to the SM since frankly I have little experience with the SM. But, that's what this thread is for. To show how the SM method can be applied to the dominant and prevaling theory on life.

Yes. I often say "Evolution is both a fact and a theory". Of course, the problem is that often creationists deny the factual basis of evolution, without looking at the evidence for it...

I suggest a clean slate. Present your evidence and your facts. And we can proceed from there. If I deny the facts presented, then you can freely accuse me of denying the factual basis of evolution.

Part of the reason I say this is that on these forums, "evolution" means (to some of our members) the overall pattern of common descent, but (curiously) excludes changes in allele frequencies in populations. Why? Because changes in allele frequencies have been observed (so we must accept them), but no new "kinds" of animals result from them.

I think this goes back to a lack of a standard definition of "evolution". If we can work with a commonly accepted definition, then it would be easier to determine exactly what one does or does not believe.

The issue seems to be how to make the link between microevolution and the overall pattern (and timescale) of evolutionary history.

For me, this would be the fundamental difficulty of the ToE.

This isn't an issue that can be "won" by debate. It's more a discussion of evidence. We could steal a line from the ID crowd, and refer to it as a "critical analysis of evolution."

I would agree that it would be more of "analyzing the evidence" rather than "winning a debate". A good example of such a discussion would be the Plate tectonics thread (which IMHO still ranks as the best debate thread of 2005).

The GAR proteins are part of one of these major concepts--gene families. There are many other gene families.

I don't want to spend much time quibbling over semantics, but again, a major concept to me would involve a high level concept that is an essential element for understanding the theory. Major concepts would be more what would be taught in Evolution 101. Whereas details of major/minor concepts would be in Evolution 201 and higher. And as someone who has never taken a class on evolution, let's start with Evolution 101 before jumping into higher level courses. And when I pass Evolution 101, then I'll be better prepared to go to the next class.

As I understand it, the really-compelling evidence for this overall pattern came from Natural Theology, of which Darwin was a part: describe all of god's creation, the better to glorify him.

I do not get any impression from my readings that Darwin had any motive of glorifying god in his publication of The Origin of Species. Actually, it seemed to be more of the opposite effect, whether intended or not.

What, then, are your thoughts about this particular fact of hierarchical relationships?

Hierarchical relationships could either result from a common designer (like you mentioned) or a common ancestor. Also, Linnaeus did not believe in evolution nor common descent. So, when he categorized life, common descent was not a factor in his taxonomy. So, from the evidence presented so far, a common designer cannot be ruled out.

That is why I insist that if somebody actually want to criticize "evolution," they first must show that they actually know what they are criticizing. Otherwise, it is just a meaningless interaction.

Certainly. That is why it would be ideal if we can come up with a standard working definition of evolution and the ToE for the purposes of this thread.

[steen]

Another point I see missed here. There is a distinction between "evolution" and "the Scientific Theory of Evolution.

Evolution is the change in a population. It is witnessed, documented and is factual. We have direct evidence that it occurs.

The Scientific Theory of Evolution is the overarching explanation that ties all the evidence of occuring Evolution together in one comprehensive process/explanation.

Welcome to the forum and to the debate steen.

Thanks.

Perhaps we need to step back a bit here and clarify on the terminology for the purposes of this thread before we go too far. "Evolution" is one of those overloaded terms that means many different things to many different people.

Sorry, I tend to use the actual scientific terminology. I feel that most other terms are in some form misrepresentations, often devised for the purpose of misrepresentation to then attacks and then say "see, evolution is wrong." And then we go on for 50-100 posts with the "is/aint" stuff. Trust me, I have seen that many times. When somebody need to twist definitions in order to make the point, then there isn‘t much of an argument to begin with, only contrivance.

Therefore, it is much less ambiguous to use the words as they are actually defined.

Some meanings could be:
- Change
- Development

Both of which are generic, non-scientific muddying terms

- Microevolution
- Macroevolution

Really? What is the difference? In my experience, it is “new species” until that gets disproved, then it becomes something else, generally applied to the situation to show that “macroevolution isn’t possible” with an ongoing change in the definition of what that term is and what the border is, until we end up with the then expected accusations of ill faith in the arguments, lots of accusations about lying and dishonesty, after which the moderator deletes the tread. That’s about the only thing you get out of trying to impose that artificial distinction, generally because the creationists are initially clueless about the actual evidence and believe that no new species have ever been documented to evolve. They get testy when disproved.

- Mutations + Natural selection

Those are mechanisms, not the actual evolution. Evolution is the change itself.

- A change in allele frequencies in a population of organisms over time

This fits the scientific definition but is unspecific and unclear. The change is between generations, not in one individual over time. I do like that it covers populations and not individuals, as that is another mistake often seen from creationists who don’t really know what it is they are arguing against.

- Micromutation
-Macromutation

Both seem meaningless terms. Certainly, they are not scientific terms, but rather seems to be another set of contrived terms.

- Common descent

Dealing only with phylogenesis, a smaller branch of the study of evolution (but the one that creationists seem to exclusively be dealing with).

- Biological evolution

That would be a “popular” name. Unspecific and thus useless.

- Cosmological evolution

Whatever that is, it has nothing to do with the biological sciences and thus nothing to do with the Scientific Theory of Evolution. It again seems to be a creationist-generated term, perhaps to contrast “creationism” which in facts is opposing a lot of science beyond the biological science, also contradicting math, physics, cosmology etc. Because creationism claims end up actually contradicting all science, not just biology.

- Social evolution

Again nothing to do with biological science. Sounds like a sociology/philosophy term.

- Darwinian evolution

Outdated. What Darwin hypothesized 150 years ago is as relevant as the Wright Brothers work is for space shuttle design.

- Neo-Darwinian evolution

Unspecified. What does that mean? This term is not defined. Is it representing somebody who feel that the newer science is less accurate than Darwin’s hypothesis?

- Theory of evolution

Presumably this means the SCIENTIFIC Theory of Evolution? I have seen enough silly “only a theory” creationist claims to be leery of this one.

- Fact of evolution

Well, that would be the actual data, presumably?

- Journey's fifth studio album

Yeah, and there was some silly movie of that name as well, right? That’s why it is important to stick to accurate and precise definitions. It just happens that we have such accurate and specific definitions, namely the scientific definitions.

And I'm sure there are many other meanings than the ones I just listed.

With more or less accuracy and precision, yes.

As to "evolution", I simply see it as "change". And as to the issue of do things "change", there is no dispute that things "change".

So when I put clean socks on, I evolve? That’s a bit to vague for my liking. No meaningful debate or clarification can be derived through this.

As to the "Theory of Evolution", I would say it involves more than simply explaining that things change.

Again, just to clarify, you mean the SCIENTIFIC Theory of Evolution, right? Yes, the Scientific Theory also explains some of the speciation, fossil patterns etc that we have found. The Scientific Theory of Evolution has show is predictive ability, thus satisfying the final step in the Scientific Method. There are no significant surprises or discrepancies; the Theory stands on its own like a full-fledged Scientific Theory along all the other Scientific Theories, as well-documented and evidenced, as useful and accurate in predicting changes and research findings.

For me, I would break it down into two major components. One is that organisms microevolve through mutation and natural selection. The other major part is that all organisms have come about by common descent through the process of microevolution.

Presumably, the last was “macro,” not “micro”? Anyway, where is the difference? How do you distinguish “micro” and “macro”? See the quagmire you end up in when trying to go that route?

Because I don’t see a difference. The mechanism of mutations and natural selection applies to both of your scenarios. There is no difference, other than what you artificially seek to impose.
…..

Yes. I often say "Evolution is both a fact and a theory". Of course, the problem is that often creationists deny the factual basis of evolution, without looking at the evidence for it...

I suggest a clean slate. Present your evidence and your facts. And we can proceed from there. If I deny the facts presented, then you can freely accuse me of denying the factual basis of evolution.

That would be an entire Biology degree. I hope you are kidding. How about we pick one narrow focus and then pick it to pieces? That way we will get all the data and facts in question instead of the vague hit-and-miss of shifting arguments and debates.

Part of the reason I say this is that on these forums, "evolution" means (to some of our members) the overall pattern of common descent, but (curiously) excludes changes in allele frequencies in populations. Why? Because changes in allele frequencies have been observed (so we must accept them), but no new "kinds" of animals result from them.

I think this goes back to a lack of a standard definition of "evolution". If we can work with a commonly accepted definition, then it would be easier to determine exactly what one does or does not believe.

But both of the above have supporting evidence in the dataset that is the foundation for the Scientific Theory. Where is the discrepancy? In what one WANT to acknowledge? Either the data is real or not. This is not a cafeteria.

The issue seems to be how to make the link between microevolution and the overall pattern (and timescale) of evolutionary history.

For me, this would be the fundamental difficulty of the ToE.

Just to clarify, when you say ToE, you mean SToE, right? What is it that limits “micro-evolution and makes that same process impossible as “macro-evolution”?
…..

The GAR proteins are part of one of these major concepts--gene families. There are many other gene families.

I don't want to spend much time quibbling over semantics, but again, a major concept to me would involve a high level concept that is an essential element for understanding the theory. Major concepts would be more what would be taught in Evolution 101. Whereas details of major/minor concepts would be in Evolution 201 and higher. And as someone who has never taken a class on evolution, let's start with Evolution 101 before jumping into higher level courses. And when I pass Evolution 101, then I'll be better prepared to go to the next class.

So you want to go to Darwin’s finches, Welch Moth and so on?
…..

What, then, are your thoughts about this particular fact of hierarchical relationships?

Hierarchical relationships could either result from a common designer (like you mentioned) or a common ancestor. Also, Linnaeus did not believe in evolution nor common descent. So, when he categorized life, common descent was not a factor in his taxonomy. So, from the evidence presented so far, a common designer cannot be ruled out.

Nor proven, which makes it an issue for philosophy, not science. That aside, the only “evidence” for a designer is that “I can’t imagine that this happened ‘naturally.’” That of course fits both creationism and “intelligent design,” and has nothing to do with science, having only conjecture and no evidence.

That is why I insist that if somebody actually want to criticize "evolution," they first must show that they actually know what they are criticizing. Otherwise, it is just a meaningless interaction.

Certainly. That is why it would be ideal if we can come up with a standard working definition of evolution and the ToE for the purposes of this thread.

(StoE, right?) And we already have that. The scientific definitions are specific; they tend to not be creationist-friendly, though, and therefore it is hard to get a meaningful debate going because creationists don’t accept them.

[Jose]

(StoE, right?)

Absolutely. Evolution 101 must cover evolution itself. It can bring in the various caricatures of evolution, or misconceptions if that's a better term, when there appear to be discrepancies between the SToE and the colloquial notion of the ToE, as people challenge evidence that we provide or refer to.

creation, intelligent design, and common features due to a common designer
Steen has stated the conundrum about this accurately. It is inherently impossible to rule out, or to verify, that a designer/god created everything to look just as it does. Therefore, this will always be a statement that can follow everything we ever say. It's my summation of ID: "or maybe god did it." For evolution 101, we should assume that this is always true, but inaccessible. The question is "what is the evidence for evolution," not "what is the evidence for ruling out a god that can create everything just as it is, and may have done so yesterday, giving us memories of things that never happened." We must look at the evidence that exists, and see where it leads us.

microevolution and macroevolution
These terms were invented some years ago by evolutionary biologists to enable them to distinguish what seemed, at the time, to be "minor" evolutionary changes or "major" evolutionary changes. At that time, genetics was understood much as it is taught in high school biology: dominant and recessive alleles, patterns of inheritance, etc. The "one gene, one enzyme" evidence had come out, so it was clear that genes coded for enzymes. What was not clear (because the bithorax studies were still confusing, and Nusslein-Volhard and Wieschaus had not yet saturated the Drosophila genome for developmental mutations) was how genes control development. Therefore, lacking specific mechanistic knowledge, workers in the field invented the term "macroevolution" to refer to mutations that change morphology, and can therefore account for the easily-recognizable differences among organisms.

We have come farther since then. We know many of the genes that control development, and how they work. We know a lot about mutations that alter these genes, or the patterns of expression of these genes. We can, therefore, account for macroevolution--as initially defined--by the exact same process as microevolution. The only difference is which genes are involved.

As creationists like to use the term, macroevolution refers to the overall pattern of common descent. As you say, steen, there is no difference between this and microevolution--it's just what happens if ordinary, garden-variety microevolution goes on for a very long time. Creationists like to argue (and here's one of those misconceptions or misrepresentations) that micro and macro are fundamentally different--because they accept microevolution on the weight of overwhelming proof. Common descent, which they refer to as macroevolution, raises problems because it requires more time than a mere 6000 years, and implies that death existed before Adam and Eve were banished from Lucas, Kansas (where the Garden of Eden is), so the concept of salvation may be nullified. Some textbooks refer to macroevolution as this overall pattern, so there's some justification in the creationist definition. However, since it's vague, and has become "loaded," I suggest we not use the term at all.

changes of allele frequencies in populations

- A change in allele frequencies in a population of organisms over time

This fits the scientific definition but is unspecific and unclear. The change is between generations, not in one individual over time. I do like that it covers populations and not individuals, as that is another mistake often seen from creationists who don’t really know what it is they are arguing against.

This may be a good point at which to start. I'll phrase it this way:

Are we agreed, or is there uncertainty, that

• single, individual organisms cannot, and do not change over time--except by non-heritable modifications like getting punched in the nose, and having it heal crooked.
• every individual simply lives its life without any planning or "special mutating" for the future, because it's impossible to predict the future (especially if you're a plant or a coelacanth).
• therefore, if change occurs over time in a population, it must show up as changes in the numbers of individuals with various characteristics.
• that is, "changes in allele frequencies in populations" refers to changes from generation to generation of the numbers of individuals with certain characteristics.

The peppered moths are the classic example. The Beak of the Finch describes another exceptionally well-documented example.

I'll give another example, which I borrow from Sagan and Druyan's Shadows of Forgotten Ancestors (and which I've mentioned before, somewhere). Why are humans afraid of the dark when they're kids (and some of us as adults)? It's not learned behavior, because parents try to tell us not to be afraid. There are no monsters out there, or under the bed. This must be an instinct, if we are born with it, and unlearn it with teaching. How did it come about?

Picture our ancestors sitting around the fire (or in a tree). There is genetic variation in this trait, so some are afraid to go out, but some are not. One of the guys says "you guys are wimps. I'm going for a walk." He goes out and is eaten by dire wolves. Whose genes did we inherit?

Nobody "mutated in order to survive." Nobody changed during the course of their lifetime. No one said, "I bet we'll need to be afraid of the dark in a few million years, so let's figure out how to mutate so that our descendents have that trait." They just lived their lives. The ones who had more offspring are the ones whose genes became more common in the population.

In time, genetic variants who were born who were not afraid were selected against by being eaten. So, the trait didn't change much after it became established.

Not being afraid has advantages, though, if you belong to a species that seems to break up into groups (tribes, religions, ethnicities, etc), and then have fights between groups. So, I imagine that the need for warlike behavior counters the need for fear of the unknown, so we end up with a fair amount of genetic variation for this trait.

I use this example only to show that there's no planning, and no goal to evolution. Things happen because they happen, not because they are destined to. Individuals don't evolve; they just have more or fewer offspring. They have no idea that they are "intermediate forms" in a long-term progression from ancestors to descendents. They just live their lives.

Do we buy this mechanism? Are we agreed that we can rule out the mythic "changing individual" as a component of evolution?