Evolving Evolution

[Luc Turpin]

1 minute ago, dimreepr said:

How?

Short answer: I think therefore I change my behavior which in turn controls my survivabilty which in turn affects evolution. 

Long answer: see post on culture.

 

[swansont]

17 minutes ago, Luc Turpin said:

Short answer: I think therefore I change my behavior which in turn controls my survivabilty which in turn affects evolution. 

Long answer: see post on culture.

 

Is intelligence inherited genetically?

Does thinking cause a specific, chosen, adaptation? (e.g. if I want humans to evolve wings, what must we do?)

[Luc Turpin]

1 minute ago, swansont said:

Is intelligence inherited genetically?

Intelligence is highly genetically inheritable, but, may I dare say, what about consciousness?

[swansont]

3 minutes ago, Luc Turpin said:

Intelligence is highly genetically inheritable, but, may I dare say, what about consciousness?

No you may not dare to bring up consciousness. 

[Luc Turpin]

7 minutes ago, swansont said:

No you may not dare to bring up consciousness. 

understood!

26 minutes ago, swansont said:

Does thinking cause a specific, chosen, adaptation? (e.g. if I want humans to evolve wings, what must we do?)

Our control over adaptation would be limited, but not null and void as originally implied by evolution.

Giving extreme examples that cannot occur does not negate the fact that it could be limited but not complete control over adaptation.

The point is that the process is not entirely deterministic as presumed.

Organisms cannot directly choose their adaptation, but, through culture and to some degree, they can influence which traits moves along and which traits stays behind.

So, complete control over adapting to flight by growing wings is not possible, there is still room for influence, and that is the point that I am making here.

That intentionality and volution have some say and sway over the whole damned thing about living.

[Luc Turpin]

If culture may have a limited say or sway on evolution, what about technology?

[swansont]

49 minutes ago, Luc Turpin said:

If culture may have a limited say or sway on evolution, what about technology?

Sure. We warm the planet and that can affect evolution. So do beaver dams, since they also affect the environment.

You seem to be the only one here that sees this as being contrary to the theory.

[Luc Turpin]

26 minutes ago, swansont said:

Sure. We warm the planet and that can affect evolution. So do beaver dams, since they also affect the environment.

You seem to be the only one here that sees this as being contrary to the theory.

Many scientists, members of Science Forums and in the general population believe that evolution is all about determinism (that evolution follows a predictable and deterministic path) or is random (just happens that way; like random mutations) and leaves out the part about human agency (that of increasing the degree of control that we have over our own evolutionary trajectory). It’s the sandwich without the meat inside. Determinism on one side and randomness on the other without agency in the middle. Most probably, evolution is about all of the above. Also, this discussion is about control and direction over evolution, which is definitely not a generally accepted concept in the science field of evolution, because science sees evolution as an uncontrollable process. I repeat, thinking beings are not passive bystanders in evolution, but active participants; that’s my point. The nature of evolution has now to contend with conscious agency.

[TheVat]

3 hours ago, Luc Turpin said:

By including culture in our understanding of evolution, we realise that evolution isn't just about genetic changes through natural selection. Culture adds flexibility and speed to how organisms adapt, and this could lead to a more complex view of evolution, where both genes and culture play key roles.

Aren't we already arrived at a more complex view? - you are describing artificial selection with domesticated species or what is called gene-culture coevolution in humans, which is not a new concept.  Cultural preferences can select for certain traits, from dominant hand preference to food tolerances to mating preferences. The lactase persistence gene was selectively neutral until people shifted from H-G life to pastoralism (herding grazing animals).  Genes for reduced melanin were not adaptive until bands of humans decided to migrate to higher latitudes and needed more cutaneous vitamin D absorption.  Sexual selection has also been important in humans, and linked to breast shape, penile girth, voice pitch, facial hair, etc.  Such preferences can be culturally mediated.  (And some cultures sadly have tried to impose more control, with differential treatment and marital opportunities based on superficial physical traits.)

 

[CharonY]

I tried to figure out what OP sees as a contradiction to "conventional wisdom" but ultimately failed. Part of it is that different mechanisms in evolution keep getting mixed up, but also the introduction of "control" as an element. The latter plays no elevated role when it comes to the conventional wisdom of evolution.

It is helpful to recall what evolution really refers to: the change of the gene pool of a population over time. It does not matter how it changes, whether changes are reverted or not. Even epigenetic elements do not matter for that aspect. Formally we can describe evolution as a change from Hardy-Weinberg equilibrium, which describes the conditions needed for a static gene pool. So in short, conventional wisdom on evolution describes a condition that violates that Hardy-Weinberg equilibrium.

A teleological approach to evolution would therefore suggest a system, that moves the gene pool to a predetermined composition.

Selective pressures shape the gene pool, but they do not predetermine it. Even in a highly artificial conditions it is can be almost impossible to predetermine how the final gene pool would be. Say there is a strong selective pressure for size, while certain genes that favour size will be overrepresented, there are going to be broad variations in the final gene pool. In part because the existing population can change the overall selective pressures (e.g., in a population with large birds, some smaller individuals might find some advantages that didn't exist when the average population was smaller). Even in highly artificial conditions you can only somewhat control the gene pool, if you use highly inbred lines (and thereby inch your system closer to the Hardy-Weinber equilibrium.

 

 

[swansont]

1 hour ago, Luc Turpin said:

Many scientists, members of Science Forums and in the general population believe that evolution is all about determinism (that evolution follows a predictable and deterministic path) or is random (just happens that way; like random mutations) and leaves out the part about human agency (that of increasing the degree of control that we have over our own evolutionary trajectory).

Assertion without evidence, though it would not surprise me to find some spectrum of thought on the importance of various elements of evolution; we don’t know everything. Further, the responses you might get will depend greatly on the language you use, especially when you use ill-defined terms like control.

A far as the general population and belief are concerned: who cares? This is about science, not belief, and not what ill-informed people say.

[CharonY]

2 hours ago, Luc Turpin said:

Many scientists, members of Science Forums and in the general population believe that evolution is all about determinism (that evolution follows a predictable and deterministic path) or is random (just happens that way; like random mutations) and leaves out the part about human agency (that of increasing the degree of control that we have over our own evolutionary trajectory).

This is a false dichotomy and not one considered by the scientists (in the field). You won't find an evolutionary scientist claiming either. What you might hear is that evolution is probabilistic. You can find determinism in small scale on specific elements and they are highlighted because they are unusual, not because they are the rule. Conversely, there can be elements that are mostly random that determine the fate of a group (e.g. drift). Again, it is one of the elements that folks look at in order to understand a particular history.

What it says, though is that your premise is faulty and will unlikely go anywhere when you keep maintaining it.

[Luc Turpin]

2 hours ago, CharonY said:

I tried to figure out what OP sees as a contradiction to "conventional wisdom" but ultimately failed. Part of it is that different mechanisms in evolution keep getting mixed up, but also the introduction of "control" as an element. The latter plays no elevated role when it comes to the conventional wisdom of evolution.

It is helpful to recall what evolution really refers to: the change of the gene pool of a population over time. It does not matter how it changes, whether changes are reverted or not. Even epigenetic elements do not matter for that aspect. Formally we can describe evolution as a change from Hardy-Weinberg equilibrium, which describes the conditions needed for a static gene pool. So in short, conventional wisdom on evolution describes a condition that violates that Hardy-Weinberg equilibrium.

A teleological approach to evolution would therefore suggest a system, that moves the gene pool to a predetermined composition.

Selective pressures shape the gene pool, but they do not predetermine it. Even in a highly artificial conditions it is can be almost impossible to predetermine how the final gene pool would be. Say there is a strong selective pressure for size, while certain genes that favour size will be overrepresented, there are going to be broad variations in the final gene pool. In part because the existing population can change the overall selective pressures (e.g., in a population with large birds, some smaller individuals might find some advantages that didn't exist when the average population was smaller). Even in highly artificial conditions you can only somewhat control the gene pool, if you use highly inbred lines (and thereby inch your system closer to the Hardy-Weinber equilibrium.

 

 

If I haven't successfully helped you understand my point of view about the "difference" (not contradiction) between "conventional wisdom" and "contemporary wisdom," then I have failed.

By "conventional wisdom," I mean ideas like random mutations and natural selection. "Contemporary wisdom" includes ideas like epigenetics and the deliberate actions organisms take to survive (like tool use, environmental manipulation, and mating strategies). These actions influence survival and evolution, even if they don’t directly change the gene pool.

You're right that traditional biology focuses on changes in the gene pool, but it shoud also include more than just genetic mutations. For example, and as you know, epigenetics alters gene expression without changing the DNA itself, and these changes can affect survival traits that influence evolution. So, why should epigenetics be left out of the definition of evolution if it impacts survival?

In my view, evolution isn’t just about genetics; it’s also about deliberate actions organisms take to survive. These actions—along with genes, epigenetics, and the environment—work together to shape evolution. The process is more complex than simply changes in the gene pool.

[studiot]

Just now, Luc Turpin said:

Many scientists, members of Science Forums and in the general population believe that evolution is all about determinism (that evolution follows a predictable and deterministic path) or is random (just happens that way; like random mutations) and leaves out the part about human agency (that of increasing the degree of control that we have over our own evolutionary trajectory). It’s the sandwich without the meat inside. Determinism on one side and randomness on the other without agency in the middle. Most probably, evolution is about all of the above. Also, this discussion is about control and direction over evolution, which is definitely not a generally accepted concept in the science field of evolution, because science sees evolution as an uncontrollable process. I repeat, thinking beings are not passive bystanders in evolution, but active participants; that’s my point. The nature of evolution has now to contend with conscious agency.

The only people I can think of that believed (or invoked) determinism were victorian vicars, determined to prove 'God'. Some were amateur scientists, some were professional.

As far as I know none are members here.

 

I have an amateur interest in evolution, though I believe I have read widley enough to see that your conceptions on the subject are blinkered and at least a century out of date.

Are you aware of thye work of Hennig, Norell, Novacek, Jablonski, Raup and benton to name but a few from the last 60 years.

The modern theory of evolution has changed out of all recognition from the model you are putting forward here, as new data and experimental methods has become available.

 

Edited Tuesday at 08:41 PM by studiot

[CharonY]

26 minutes ago, Luc Turpin said:

If I haven't successfully helped you understand my point of view about the "difference" (not contradiction) between "conventional wisdom" and "contemporary wisdom," then I have failed.

It is not helpful to use your own definitions. In evolutionary sciences, conventional wisdom is not limited to natural selection for close to a hundred years.

27 minutes ago, Luc Turpin said:

You're right that traditional biology focuses on changes in the gene pool, but it shoud also include more than just genetic mutations. For example, and as you know, epigenetics alters gene expression without changing the DNA itself, and these changes can affect survival traits that influence evolution. So, why should epigenetics be left out of the definition of evolution if it impacts survival?

You are conflating multiple concepts here. I will try to disentangle them from you. The gene pool is the unit on which evolution happens. That is the definition, if you want to talk about something different, you need a different concept, but then we are not talking about evolution.

Survival is not a part of evolution itself. It is one of the factors, but not the main factor. Organisms need to survive to the point of reproduction, after that it does not matter. So for example a factor that increases survival dramatically but results in sterility, will have no impact on the gene pool, and therefore evolution.

As such, factors changing survival, but not changing the gene pool do not impact evolution.

For epigenetics, let's also use more precise definitions. Specifically, in terms of gene expression, epigenetics typically refers to DNA modification. While some modifications are hereditary, they are not stably inherited. As such, they are considered yet another mechanisms that can shape evolution (i.e. the gene pool) but due to their transient nature, they are not considered the element to be measured (i.e. the gene pool). That being said, there are some efforts underway to investigate whether certain modification patterns could be stably inherited, in which point the idea of gene pool might be modified with the addition of these chemical modifications.

Taking a step back: the idea of evolution was never as narrow as OP makes it seem to be. Again, if you focus on the concept of gene pools, there was already early the realization that there are many mechanisms that could shape these pools. Natural selection was one that was considered early on (i.e. the Darwinian concepts) others, such as Lamarckism were also considered, then largely discarded, and then gain integrated in a modified form due to the recognition of epigenetics (if it is not entirely clear, I can elaborate on that).

Biological sciences have never been dogmatic and formulaic and we are cognizant that more mechanisms will be discovered eventually. After all, we still have not really figured out some of the fundamental aspects of life. Heck, even what was considered to be the dogma of molecular biology has been remodeled from when I started studying biology. But nonetheless, the basic concepts still rely on certain definitions, which might or might not fully reflect biological complexity. Either way, they are the best models we got to date. If we want to discuss them, we have to follow those concepts, otherwise there is no basis for discussion.

As such, it makes no sense to expect a meaningful scientific discussion on the topic if you keep focusing on your personal definitions and concepts. Inevitably the discussion will keep trying to introduce you to established concepts, an exercise which is often is tiring for everyone involved.

 

13 minutes ago, studiot said:

The modern theory of evolution has changed out of all recognition from the model you are putting forward here, as new data and experimental methods has become available.

You are correct in details, but I would offer a slightly different perspective for biological sciences. In contrast to (I think) areas of physics (especially theoretical physics), biological models are far more open-ended. They tend to be more qualitative (to the frustrations to many statisticians), and generally only smaller, highly specific elements, have quantitative models (e.g., models for calculation mutation frequencies at specific loci). Conversely, large concepts, such as evolution (or even like a cell) can be defined pretty narrowly, but does not specifically enumerate all relevant parameters. There is a recognition that we do not have a full understanding of biology, which is why discovery is always going to be a core element of biological sciences. If, at one point we have a full understanding of all relevant elements, I fully expect a transformation of biology to something closer to chemistry and/or physics. But this seems so far away that I cannot even see the path.

 

[Luc Turpin]

The OP began this thead with the words "if correct" and made it clear that the intent was to review a "New Scientist article tittle "The extraordinary ways species control their evolutionary fate" by Kevin Lala,

Here are again, a few excepts of the article; not mine, but the author's own words.

• "The extraordinary ways species control their evolutionary fate"
• "Natural selection isn't just something that happens to organisms, their activities also play a role, giving some species - including humans - a supercharged ability to evolve
• "The desert woodrat is an example of how the things organisms do can affect their evolution.
• "It has become clear that many organisms influence their own evolution by creating non-genetic traits that can become subject to natural selection."
• "This challenges traditional Darwinian thinking, which sees evolution as a process rooted in random genetic mutation"
• "I am one of a growing group of evolutionary biologists who believe that non-gentic inheritance plays a vital role in evolvability."
• "Evidence is mouting that extragenetic adaptations, such as those found in desert woodrat, can rescue organisms from the brink."
• "This unusual, supercharged evolvability gives us more control over our evolutionary future than we might think".
• "Historically, evolutionary biologists have assumed that since all organisms evolve through natural selection acting on their genes, they should all change at roughly the same rate per generation. Only in recent years has it become clear that this isn't the case"
• "But emerging evidence indicates that extragenetic processes are important too".
• "A variety of processes are involved, but here I will focus on three of the most important and intriguing: epigenetics, symbiotic inheritance and culture. These phenomena aren't just analogous to biological evolution; they are biological evolution. They allow arganisms to invade new environments, cope with change and stress, evolve new phenotypes and resist extinction until adaptive genetic mutations appear".
• "Until recently, the idea that epigenetic variation is subject to natural selection was controversial. In 2018, publication of a an experiment in thale cress changed that.
• "Research published the following year backed up the idea that epigenetics can lead to adaptive evolution."
• "But epigenetic adaptation creates variation in characteristics, increasing the likelihood that some fraction of the population with persist long enough to adapt genetically".
• "One thing that makes symbiotic hinheritance so powerful is that it needn't be passed from parent to offspring - it can spread among unrelated individuals and even occur across species".
• "From the origin of life, organisms channelled and directed their own evolution."
• The upshot of all this is that natural selection isn't something that just happens to organisms: their activities and behaviours contribute to how it happens and whether it happens at all."
• Evolutionary biologists have maintained that humans evolve in a manner no different from fruit flies or yeast, that all comes down to natural selection of chance mutations.
• Human culture is off the scale compared with any other animal when it comes to symbolism, technology and informational content. The significantce of this becomes clear one we recognise cutural change for what it really is - not so much an analogue of biological evolution, but rather a key aspect of rapid-response eveolutionary adaptation. This means that we are far more evolvable than most other species - and we control our own evolution to a much greater extent."
• "Developmental plasticity is a kind of variation caused by environmental factors influencing the way that an organism develops. Although initially there is no change in the genes, plasticity can increase the ability to evolve."

I tried as faithfully as I could to represent the above in my posts, my use of words and my definition of terms. They were mostly based on the above.

17 hours ago, CharonY said:

It is not helpful to use your own definitions. In evolutionary sciences, conventional wisdom is not limited to natural selection for close to a hundred years.

It was random mutation and natural selection, not only natural selection.  They remain foudational elements of the theory of evolution. Mutations introduce variations, while natural selection acts upon variations, which leads to gradual changes and adaptations. What is more foundational than that?

17 hours ago, CharonY said:

You are conflating multiple concepts here. 

If I am doing so, then the author is also doing so.

17 hours ago, CharonY said:

The gene pool is the unit on which evolution happens. That is the definition, if you want to talk about something different, you need a different concept, but then we are not talking about evolution.

The gene pool is the unit on which evolution happens. Then what to do with cultural evolution which is a strong driver of evolvability, but is at times not captured in the gene pool? Do we ignore those as factors? Even if they increase an organism's chance of surviving and reproducing? Are they not considered adaptations? If they become common in a population and help the organisms, again, reproduce, then do they not contribute to evolution in a general sense?

17 hours ago, CharonY said:

Survival is not a part of evolution itself. It is one of the factors, but not the main factor. Organisms need to survive to the point of reproduction, after that it does not matter. So for example a factor that increases survival dramatically but results in sterility, will have no impact on the gene pool, and therefore evolution.

Surviving to reproduce was the intent in the use of the word "survival".

17 hours ago, CharonY said:

As such, factors changing survival, but not changing the gene pool do not impact evolution.

Factors changing survival, but not changing the gene pool impact evolvability, but are not condidered part of the theory of evolution.

17 hours ago, CharonY said:

For epigenetics, let's also use more precise definitions. Specifically, in terms of gene expression, epigenetics typically refers to DNA modification. 

According to the author, epigenetics "don't involve changes in the DNA sequence" and according to my understanding, they involve changes in gene expression, not alterations to the underlying DNA sequence. DNA methylation is the most studied concept of epigenetics. Even external factors such as stress, toxins and nutrition can influence the silencing or activation of genes.

17 hours ago, CharonY said:

Taking a step back: the idea of evolution was never as narrow as OP makes it seem to be. 

I was focussing on foundational traits and did not imply that it was all there was.

17 hours ago, CharonY said:

Biological sciences have never been dogmatic and formulaic and we are cognizant that more mechanisms will be discovered eventually. 

I beg to differ, but this is a matter of opinion.

17 hours ago, CharonY said:

After all, we still have not really figured out some of the fundamental aspects of life. 

Happy for the acknowledgement.

17 hours ago, CharonY said:

As such, it makes no sense to expect a meaningful scientific discussion on the topic if you keep focusing on your personal definitions and concepts. Inevitably the discussion will keep trying to introduce you to established concepts, an exercise which is often is tiring for everyone involved.

Not only my own personal definitions and concepts, but those shared by the cited author and growing numbers of evolutionary biologists. I guess that the author also has to be re-introduces to established concepts. Not my intention to tire anyone.

 

 

Edited yesterday at 01:44 PM by Luc Turpin

[CharonY]

Yes, assuming the quotes are not out of context, it does seem to me that it is possible that  the author is overselling concepts to lay audiences.

However, some of the later quotes are accurate:

2 hours ago, Luc Turpin said:

"But epigenetic adaptation creates variation in characteristics, increasing the likelihood that some fraction of the population with persist long enough to adapt genetically".

For example, this link with epigenetics makes sense- yet it was never an either or question, which seems to be implied. I presume that the typo was not part of the original article, though. Here it is acknowledged that there are separate mechanisms and I have no idea why the author would harp on about natural selection in the former quotes. But again, the presented quotes are not  great representation of the basics and it seems that certain concepts are overemphasized which is again not great for laypersons.

[Luc Turpin]

10 minutes ago, CharonY said:

Yes, assuming the quotes are not out of context, it does seem to me that it is possible that  the author is overselling concepts to lay audiences.

I don't think that they are out of context and agree that the author is most probably overselling concepts to lay audiences, for which I am one of them.

11 minutes ago, CharonY said:

For example, this link with epigenetics makes sense- yet it was never an either or question, which seems to be implied. I presume that the typo was not part of the original article, though. Here it is acknowledged that there are separate mechanisms and I have no idea why the author would harp on about natural selection in the former quotes. But again, the presented quotes are not  great representation of the basics and it seems that certain concepts are overemphasized which is again not great for laypersons.

All typos are mine, because I had to type it all up.

I am a layperson trying to understand the world through science. I count on experts like you to help me out.

[CharonY]

If I may make a suggestion: if there is genuine interest, it is always better to build your understanding from the ground up, rather on relying on articles that promise a shortcut to a concept that you might find drawn to. Pubsci articles heavily rely on the surprise factor, i.e. the promise that after reading that you will be privy to some insights that will somehow challenge existing knowledge. But consider this: existing knowledge is built on the work of many many folks, whereas any single article is the work of at best a handful for persons (or only one). It is exceedingly rare that one person will have some insights, missed by the whole community and even rarer to publish it in a no-specialist journal.

This also applies to discussion forums. Ultimately, there is no shortcut to knowledge and picking up a good book is still the best way.

[Luc Turpin]

19 hours ago, CharonY said:

If I may make a suggestion: if there is genuine interest, it is always better to build your understanding from the ground up, rather on relying on articles that promise a shortcut to a concept that you might find drawn to. Pubsci articles heavily rely on the surprise factor, i.e. the promise that after reading that you will be privy to some insights that will somehow challenge existing knowledge. But consider this: existing knowledge is built on the work of many many folks, whereas any single article is the work of at best a handful for persons (or only one). It is exceedingly rare that one person will have some insights, missed by the whole community and even rarer to publish it in a no-specialist journal.

This also applies to discussion forums. Ultimately, there is no shortcut to knowledge and picking up a good book is still the best way.

I admit that I might be somewhat too set in my ways, and perhaps a little too old in my thinking to completely overhaul my approach to how I engage on this forum. However, I’m always open to learning and would appreciate any book recommendations that could help my understanding.

While some of the ideas that I present are not fully formed and on the margins of science, isn't the process of presenting new concepts—where they can be reviewed and critiqued by experts like yourself—truly beneficial for all involved? Engaging in these conversations provides an opportunity to clarify what might be right and especially what might be wrong about the concepts.

As some of you in this forum may have noticed, I do not fully subscribe to the prevailing scientific consensus that mechanistic processes alone account for everything that occurs in the universe. While I respect the advancements and contributions that mechanistic approaches have provided in our understanding of the world, I find myself drawn to perspectives that challenge the notion that all phenomena can be reduced to mere physical processes. I am particularly interested in studies, research projects, and theses that might be uncovering gaps in the mechanistic worldview—where it appears that something beyond simple cause-and-effect chains might be at play. This interest isn't rooted in skepticism for science, but rather a curiosity about what may lie outside the boundaries of reductionist thought. Furthermore, I have a keen interest in interdisciplinary sciences, philosophy, and, what the heck, metaphysics, as I believe that the combination of these disciplines might offer alternatives that might bring to light aspects of reality that are yet to be understood. Again, I am not advocating for abandoning science, but rather seeking to expand the boundaries of what we consider valid avenues for exploration. 

Since joining 'Science Forums,' I have learned so much.

 

Edited 5 hours ago by Luc Turpin

[Phi for All]

2 hours ago, Luc Turpin said:

While some of the ideas that I present are not fully formed and on the margins of science, isn't the process of presenting new concepts—where they can be reviewed and critiqued by experts like yourself—truly beneficial for all involved?

We've found, over the years, that trying to "think outside the box" requires you to have a firm grasp of what's "inside the box". No offense, but your mistake is in thinking you know enough about the subject to present new concepts. You've skipped the formal study of the subject so you have a bad foundation for understanding, and now you want to propose new concepts to replace the ones that don't make sense to you, because you skipped the formal study. Haven't ALL of your "new concept" threads been shown to have major flaws? You get critiques by experts, but you keep posting your new concepts. At no point do you ever say, "It seems I should take a formal course in this", so I'm not sure where the benefits for all involved are.

[CharonY]

Unfortunately, the "unusual" is always more attractive as it holds the promise of skipping the "boring" stuff everyone is doing and skip right to the secrets that experts somehow are not able to access.

For books, Dough Futuyma "Evolution" is a solid read, I have heard it has been updated to provide more modern examples. Older editions are affordable and still provide a good intro and still highlights the scientific approach to evolution.  Mark Ridley's Evolution is perhaps a bit more narrative-driven from what I have heard, which makes it more readable and a better intro, but is more undergrad teaching than research-oriented.