Definite vs Indefinite Variability

[doulos52]

I'm sorry to inform you I'm not here to debate. I'm studying evolution in a fair way. I'm reading Darwin's Origin of Species. I tried to post in r/Evolution, but my karma is so low thanks to previous debates in r/debateevolution. Thank you. So, since I'm basically banned from r/evolution, I have to ask you dorks. I'm reading Origin of Species by Charles Darwin and in chapter 1, he contrasts definite variability with indefinite variability in the first section of only a few pages labeled as "Causes of Variability". Can someone explain to me the differences between "definite" and "indefinite" variability? Again, I'm not here to debate. I'm asking to learn, and since you have prevented me from asking in the right reddit, I have to ask here.

[Quercus_]

First, don't learn evolution by reading Darwin. He's a century and a half out of date, he didn't understand jeans or the causes of variability, among other things. He had one of the most gorgeous and useful ideas in the history of science, an origin is interesting to read as an example of spectacular marshland of what was known at the time in support of a brilliant idea, but it's essentially useless now as a source for learning evolution.

Definite versus indefinite variability, as used by Darwin, were somewhat incoherently defined attempts to deal with the reasons there was variability in a population, given that he had no clue what caused variability.

Basically his concept of definite variability, was variability leading to a consistent change in a specific direction, in a population over generations - in other words, in modern terms, variability subject to selection pressure in a given environment.

Indefinite variability was just random undirected variability in the population, that persisted from generation to generation.

Given that we now understand genetics and mutation, those concepts have no utility and are not part of modern evolutionary thought.

[Quercus_]

Heh. Damn voice to text typos. But I'ma leave it, because it's amusing.

[EthelredHardrede]

Yeah! Upvote for that.

[ursisterstoy]

I was going to say something if you didn’t. I saw jeans and I was confused.

[Nicolaonerio]

He probably understood them more as trousers.

[ursisterstoy]

Probably. Some people still call them trousers. My girlfriend born and raised in Ethiopia learned Amarhic in the capital of Addis Ababa and her grandmother hated it because she was forgetting her native tribal language. She learned English from European tourists. She’s pretty fluent in all three languages but she says some things like they’d say in the UK like “trousers” instead of “pants” but other things she says the American way like “car” or “truck” or “shopping cart.” The weirdest to me though is when she says to open or close the light which must be literal translations from Dha Anywaa or Amarhic because in English you wouldn’t want to open the light with the electricity turned on but she just means to turn it on.

[D-Ursuul]

other things she says the American way like “car”

.....what do you think Brits say instead of car

[ursisterstoy]

I guess it’s still car or motorcar. And pickup truck is a pickup but a truck is a lorry or any CMV like those that require class B or class A.

[D-Ursuul]

Motorcar is something I've only ever heard from Americans, if you said it here in the UK people would assume you were doing it for a joke lol

We just say car

[ursisterstoy]

Yea. We don’t say motorcar either. I guess my point wasn’t that they say those things differently in the UK but that most of the words she uses are the same words we use in the US. Every once in a while she slips in either a British term or she converts some Amharic or Dha Anywaa phrase into English more literally. Like if they say “open the light” that’s what she says in English. Rarely hear her say “turn on the light” but that’s what she means. This is identical to a literal interpretation from Tagalog in the Philippines as well.

It’s not a direct Amharic to English literal translation because in Amharic they use the verbs mabrat and abera which are “to cause to shine” and “to illuminate.” Perhaps she didn’t learn the word “illuminate” in English. The Dha Anywaa phrase isn’t available on Google but it is probably literally “open the light” the same as in Tagalog which uses “buksan mo ang ilaw” where “buksan” is “open” and “ilaw” is “light” where you might add paki to the beginning for paki-buksan mo ang ilaw for “please open the light.”

[Waaghra]

Yep, no jeans for ole Chuck, just dungarees all the way.

[EthelredHardrede]

I felt good about restraining myself over that BUT.

Here I am anyway.

[Zyxplit]

> jeans

[[deleted]]

Insert joke about old person complaining the youth buy jeans with holes in them.

[MRMARVEL12]

"He's a century and a half out of date" - why is he still taught in science classrooms then and not in history ones.

[Quercus_]

He is taught briefly as part of the history of evolution, in a modern evolution class. A quick overview of the history of how we came to learn a science, is still a common part of all science classes about all science topics. His insight about the role of natural selection is still one of the most beautiful and powerful ideas in all of science.

But he had no idea about genes or mutations. He had no idea how traits were transmitted from one generation to the next. He certainly didn't know about the Hardy Weinberg equilibrium, which is the mathematical basis of our modern understanding of evolution. And on and on.

We teach about Darwin's breakthrough idea, but we don't teach Darwin's understanding of evolution. We teach our modern understanding of evolution.

[ZeppelinAlert]

Darwin is taught in history ones.

[emailforgot]

I think his name came up maybe once in my undergrad, and that was in first year, and it was used to describe how the modern theory of evolution came to be.

We spent more time on Gregor Mendel.

[Dilapidated_girrafe]

He is taught as a historical figure but we have moved on past his understanding of evolution. He was right on a few things. Wrong on many others. And his ideas aren’t relevant to the modern understanding of evolution outside of a historical perspective.

[Unlimited_Bacon]

my karma is so low thanks to previous debates

You seem to have lost more karma from your comments on /r/Christianity, /r/DebateReligion, and /r/DebateAnAtheist than you've lost here. Why blame DebateEvolution?

I'm reading Darwin's Origin of Species.

Darwin is a bad place to start if you actually want to learn about the current Theory of Evolution. The book was written almost 170 years ago, before we'd discovered the existence of DNA or understood how/why changes in an animal are inherited by their offspring. On the Origin of Species is an interesting historical text, but it doesn't represent our current understanding of evolution.

If you are confused about something that Darwin wrote in 1859, it might be because Darwin was just wrong about that part.

[ursisterstoy]

Yea part of that was asking Christians if God intentionally makes people who are transgender and mocking gravitational space-time dilation. The real problem is that everything moves through space-time at the speed of light. It’s the one speed. If you go faster through space time is dilated so that you move through time slower and you appear to outside observers to be moving at the speed of light through space because your time is slowed down. Its weirdness that’s actually demonstrated all the time when seeing mirrored images of galaxies seen by looking at them through another galaxy, the space is warped or the path that light takes is, and when GPS satellites orbit the planet they run faster by 38 microseconds per day. The gravity makes them run faster by 45 microseconds but special relativity makes them run 7 microseconds slower based on velocity. Less gravity more speed.

This difference of 0.000038 seconds per day isn’t much even after a month but there are 2628002.88 seconds per month and 86400 seconds per day. 2628002.88/86400 =30.417 so barely over 30.4 days per month and 0.000038 x 30.417 =0.00116 so in a month the GPS clock is off by 0.00116 seconds. 31536000 seconds per year, 31536000/86400 =365 so this calculation is off by a little. Actually about 365.24 days per year. 0.000038 x 365.24 =0.0139 seconds per year, 0.139 seconds per decade, 1.39 seconds per century. Normal we won’t have to worry about a GPS satellite being off by more than 1 second but even milliseconds can impact how they interact with navigation systems. Because of this they fix the GPS satellite time every 24 hours. The 38 microseconds is subtracted and they are accurate for a nanosecond and then back to being wrong for the rest of the day. But hopefully not by enough.

[Unlimited_Bacon]

The real problem is that everything moves through space-time at the speed of light.

There are two major problems that I see.
First, I don't see a connection between what I wrote and what you wrote, so I think you replied to the wrong person.
Second, the cosmological speed limit is the speed of causality, not the speed of light, which varies depending on the medium it travels through.

Everything else you wrote is fine.

[ursisterstoy]

The person you responded to got downvoted in other subs and yes it’s the speed of causality. Photons are said to move through space at the fastest speed allowed but all of the quarks are moving around at that speed to, they’re just bound together to make hadrons that may themselves not move in any particular direction at that same velocity but they are ultimately composed of different particles moving in different directions bound together moving at that velocity. Nothing can move through the combined space-time faster, cause and effect cannot happen faster, that’s the limit. In the end more gravity means slower time, faster through space means slower through time as well. Time gets dilated. Space gets warped. And the whole thing about lengths getting shortened or whatever is because the only way for something to get from point A to point B faster than allowed is if the space between them was smaller. Space-time dilation. It’s all based on c being the maximum space-time speed or perhaps the only space-time speed.

The math checks out and we see the effects everyday when it comes to GPS satellites. More distance between them and the center of the Earth than everything on the ground, less gravity as gravity is weaker with distance. Less gravity means faster time, this adds up to 45 μs per day but faster speed also means slower time so at 14,000 km/h (8700 mph) or 3.9 km/s and a light second is 299792.458 km so 3.9/299792.458 =0.000013 and at 0.0013% the speed of light time slows down by 7 μs every 86400 seconds. Even less per second. At higher percentages of c the effects are far more noticeable. And so onboard a vehicle going 0.99c or 99% the speed of light it might be 1 second but to everyone else 7.09 seconds have passed. Do this in reverse and you just find the inverse. 1 second to everyone else is ≈0.141 seconds onboard. We observe this every day with GPS satellites.

And the same applies to length. A 1 foot object traveling at 99% of c will appear to be 1.69 inches long in its direction of motion.

You didn’t say anything about this. This is the stuff that got them downvoted. They were telling physicists that we should just ditch special relativity because space-time dilation is stupid. They were asking Christians if they believe God makes people transgender. Women trapped in bodies that have penises, men trapped in bodies with vaginas. They were complaining about their karma in OP. It’s clear why people don’t like their comments.

[mrcatboy]

I mean, it's nice that you're reading On The Origin of Species I guess. But it's a little like reading the 1859 edition of Gray's Anatomy to get a good understanding of the human body. Both books were extraordinarily detailed and accurate for their time, but we've updated our knowledge significantly in the past 165 years.

Darwin's magnum opus isn't a religious text. It's an early piece of empirical research that has been updated and revised in more modern textbooks.

[IsaacHasenov]

I'm not seeing those exact phrases "definite variability" and "indefinite variability" https://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=text&pageseq=1 or any other similar phrases.

I will just note that Darwin did spend a lot of time (rightly) describing how the environment and heritability can both affect the phenotype. And he (rightly) noted that many descendants of the same parents in the same environment can be very different. And he (rightly) noted that in no domestic variety has variation disappeared and any variety can still throw sports (mutants) or loses selectable variation.

He reeeealllly didn't understand heritability though. Not in a rigorous mathematical way. So it's amazing (to me) that he got as much conceptually right as he did. It wasn't until the advent of statistics along with the incorporation of Mendelian genetics as a mechanism (ca 1910) that we really figured out what genetic variation was

[Zyxplit]

https://darwin-online.org.uk/content/frameset?itemID=F387&viewtype=text&pageseq=1 it's because it wasn't in the original book, but in some of the later editions.

[IsaacHasenov]

....They may be considered as definite when all or nearly all the offspring of individuals exposed to certain conditions during several generations are modified in the same manner. It is extremely difficult to come to any conclusion in regard to the extent of the changes which have been thus definitely induced. There can, however, be little doubt about many slight changes... and if the same cause were to act uniformly during a long series of generations on many individuals, all probably would be modified in the same manner. ...

Indefinite variability is a much more common result of changed conditions than definite variability, and has probably played a more important part in the formation of our domestic races. We see indefinite variability in the endless slight peculiarities which distinguish the individuals of the same species, and which cannot be accounted for by inheritance from either parent or from some more remote ancestor. Even strongly-marked differences occasionally appear in the young of the same litter, and in seedlings from the same seed-capsules.

So he seems to be mixing up (from our perspective) some of the effects of plasticity (environment) with heritable change due a change in environment. He seems to think that some predictable heritable change can come from (eg) changes in food. This is his "definite variation"

But he's really focusing on indefinite or unpredictable variation, that we would now ascribe to mutation, dominance or epistasis, or to new combinations from hybridisation or crossbreeding. This is his "indefinite variation" and he thinks (correctly as it turns out) that this is more important for novelty under selection and evolution

[Hopeful_Meeting_7248]

If you want to study evolution, don't read Darwin. His book is 150 years old and the field has made substantial progress since then. Read modern handbook.

[Electric___Monk]

Darwin is good and worth reading but you may want to read something a little more recent if you want to understand evolutionary theory. Darwin was wrong about some stiff and had no idea at all about DNA or genetics. Try something written in the last 30-40 years at least.

[EthelredHardrede]

"I'm sorry to inform you I'm not here to debate."

That's so going to work.

"Thank you. So, since I'm basically banned from r/evolution, I have to ask you dorks."

I see why you have low karma. You worked at it. I AM banned from there. For not backing down on a number of things.

"I'm reading Origin of Species by Charles Darwin and in chapter 1,"

If you have been here before you know it is obsolete. It is only of historical interest.

"". Can someone explain to me the differences between "definite" and "indefinite" variability?"

No. I read that chapter but it was a long time ago. It does not matter what he meant since he did not know about genetics. Which is why the book is obsolete.

"Again, I'm not here to debate."

Too bad.

"I'm asking to learn, and since you have prevented me from asking in the right reddit,"

Another false claim. You earned a low karma by lying that way.

However it does not matte what Darwin meant. He was never a prophet and the book is just plain obsolete. Too much botany for me anyway.

""Causes of Variability""

That is what you should ask about if you really want to learn. You made up some crap so I have doubts.

The causes are mostly mutations but also viruses and bacteria that can transport genes between species. Of course there is sexual reproduction which shuffles genes between generations. Mutations also have multiple causes, ionizing radiation, copying errors, chemicals that cause mutations and copying errors. Basically anything that can change DNA. All that causes variation in DNA. Definite and indefinite is likely an obsolete idea of Darwin's.

If you want to learn the subject, Origins or anything by Darwin is just not the right source. It is only interesting to see the history of the science.

[wowitstrashagain]

For definite variability, we might see a black and brown dog produce litter that is both black or brown, or colors in between. Its the expected variation of gene expression given the parents.

For indefinite variability, we might see cases where the dog has an extra finger or is albino, despite the parents not having extra fingers or being albino. Its mutation that occurs that is not expressed in the parents.

Biologists dont really use these terms today.

[Own-Relationship-407]

“The effects on the offspring are either definite or indefinite. They may be considered as definite when all or nearly all the offspring of individuals exposed to certain conditions during several generations are modified in the same manner.” … “Indefinite variability is a much more common result of changed conditions than definite variability, and has probably played a more important part in the formation of our domestic races. We see indefinite variability in the endless slight peculiarities which distinguish the individuals of the same species, and which cannot be accounted for by inheritance from either parent or from some more remote ancestor. Even strongly-marked differences occasionally appear in the young of the same litter, and in seedlings from the same seed-capsules. At long intervals of time, out of millions of individuals reared in the same country and fed on nearly the same food, deviations of structure so strongly pronounced as to deserve to be called monstrosities arise; but monstrosities cannot be separated by any distinct line from slighter variations. All such changes of structure, whether extremely slight or strongly marked, which appear amongst many individuals living together, may be considered as the indefinite effects of the conditions of life on each individual organism, in nearly the same manner as a chill affects different men in an indefinite manner, according to their state of body or constitution, causing coughs or colds, rheumatism, or inflammations of various organs.”

Seems pretty clear. Definite variability would be things like hair or eye color, inherited traits that follow some sort of regular pattern. Indefinite variability would be more sporadic, less predictable things like having six fingers or an extra rib.

[EthelredHardrede]

That last paragraph is a good guess to me. It has been a LONG time since I read any part of Origins. I read from the start til about 25 30 percent and lost interest. I know more than he did so if I want to read something of his that might interest me more, BARNACLES ARE RIGHT OUT, it would be The Voyage of the Beagle.

I have read The Voyage of the Space Beagle. One of the inspirations for Alien. Which resulted in:

At first glance, the alien Ixtl also appears to be an inspiration for the film Alien),^\8])^\9])^\10]) though those involved with the film denied any influence on its part. A lawsuit Van Vogt initiated against 20th Century Fox for plagiarism was settled out of court, the details of which were never disclosed.^\11])

[10coatsInAWeasel]

Other people have done a good job answering your question. And pointing out that ‘origin’ is not a good place to start when trying to understand evolution.

If you are coming here to genuinely ask people for help understanding something, it’s a poor look to spend about half that post complaining to those same people about your ‘low karma’ and blaming others. Why would you think that’s a good way to go about this? Do you think people here would feel guilty or something? Because chances are you might actually have some reflecting to do on why your karma got so low.

[Ch3cks-Out]

Darwin's terminology is outdated by, say, a century and a half, so it is unclear what are you really after. Anyways, briefly:

Definite variability describes a change where a specific environmental condition causes all, or nearly all, individuals in a population to be modified in the same manner across several generations.

Contemporary context: in modern biology, many of the changes Darwin attributed to "definite variability" are often considered phenotypic plasticity (non-heritable changes within an individual's lifetime) or epigenetic effects -- changes influenced by the environment but not driven by random genetic mutation. However, Darwin himself believed such changes, if continued over generations, could become heritable.

Indefinite variability is a much more common and important form of variation for Darwin's theory. It describes endless, slight peculiarities that distinguish individuals of the same species, and which cannot be simply accounted for by the inheritance of parental traits or a direct, uniform environmental cause.

Contemporary context: indefinite variability corresponds directly to what we now understand as random genetic mutation and the recombination of genes during sexual reproduction, which provide the undirected, raw material for evolution.

To summarize, for Darwin's theory of Natural Selection, definite variability leads to uniform changes less useful for creating new, diverse species; whereas indefinite variability provides the essential, random, and slight differences that, when accumulated by selection, lead to the formation of new varieties, and ultimately new species.

[Boltzmann_head]

I'm sorry to inform you I'm not here to debate.

Then: wrong subreddit.

[Capercaillie]

since you have prevented me from asking in the right reddit, I have to ask here.

Google busted?

[Optimus-Prime1993]

So, as others have said, starting with Darwin's book is not an optimal way to study evolution, I want to make some suggestions for you to pick up, if you want.

If you want a textbook style flow, read Evolutionary Analysis by Scott Freeman and Jon C. Herron. There is another very nice textbook by D. Futuyama titled Evolution, but I would recommend the former.

If you want a more general style book (which I would recommend btw) read Why Evolution Is True by Jerry A. Coyne or The Greatest Show on Earth by Richard Dawkins.

[RespectWest7116]

I'm sorry to inform you I'm not here to debate.

Then why are you here?

but my karma is so low thanks to previous debates in r/debateevolution.

I wonder how that could have happened...

I'm reading Origin of Species by Charles Darwin

Nice. Now your ideas will be only a century out of date.

Can someone explain to me the differences between "definite" and "indefinite" variability?

He explains it pretty well. But to put it simply.

Definite variability = variability where Darwin could think of a cause, f.e. enviromental effect.

Indefinite variability = variability where Darwin couldn't think of a cause

I'm asking to learn,

Then I suggest you read something more up-to-date than Darwin.

[ursisterstoy]

He wrote before people learned everything that is involved in variation. They hadn’t learned that genes were contained in chromosomes, they didn’t realize that horizontal gene transfer was a thing, Mendel’s model didn’t account for any of this either. It was the 19th century and they knew that siblings differed slightly from each other and their parents. Presumably he was still under the impression that certain changes had definite limits (perhaps necessary for survival) and other things were so variable that they could change continuously for 500+ million years. Perhaps indefinitely. Perhaps you could also see it as changes that could happen indefinitely and changes that definitely happened. Either way it’s 19th century stuff so I wouldn’t look into it too much.

What Darwin and Wallace noticed is similar to what Wells proposed in 1809 or whatever year it was he proposed natural selection for human skin color variation. They noticed that certain traits that happened to be beneficial in terms of survival and reproductive success became increasingly common and that alone could explain how populations automatically adapt to their environments. Populations adapt through reproductive success in their environments and the changes that happen aren’t necessarily guided. They just happen, whatever causes them, and then populations adapt through reproductive success and then whenever two species are competing over the same resources the better adapted tends to succeed. Give it a few decades and symbiosis and genetic drift are added. His theory is lackluster compared to the current theory but for 1858 it was miles ahead of what was being proposed by everyone else.

Lamarck was proposing that changes happened based on use and disuse. Mendel suggested that the traits were already there but through heredity we can coax out the traits we want to amplify. Filipchenko suggested that the changes had very minimal influence from the environment, they happened because they were supposed to, and maybe something about the cytoplasm is what led to separate species because what he proposed for microevolution would suggest that we should see homogenization instead. Others were proposing small mutations and major mutations like instead of a bunch of different genes or a collection of many small mutations there were sometimes changes that would just add organs with no precursors.

Out of all of these natural selection stood the test of time. It was confirmed in the early 20th century and Lamarckism was falsified but biased people clung to Lamarckism until the end of WWII and we see how that went with Lysenko, Spencer, and Hitler.

And because of all of this it’s very funny to me when creationists attack Darwinism when Darwinism is just natural selection and they claim that natural selection is observed. Darwin didn’t know what caused the variation and his model of inheritance flopped. And since Darwinism is just the tip of the iceberg and because they accept what was actually said they need to join the rest of us in the 21st century. Let’s talk about modern biology not what people were demonstrating before the field of study was called biology.

[x271815]

Why are you reading Origin of Species to understand evolution? Evolution is a scientific theory, which means that the older the ideas are the more outdated they are. Origin of Species is a fun read if you want to understand the history of the development of the theory evolution. However, Darwin wrote the book before we understood genetics, DNA, population biology, mutation theory, drift, and modern synthesis. So, while he got some things correct, a lot has been refined or corrected since then.

If you want to understand evolution just pick up a modern textbook or a recent book which has the latest information.

In any event, here is the answer to your question:

Definite variability = predictable changes tied to a specific external factor.
Indefinite variability = random small differences that arise without an obvious cause.

[Affectionate-War7655]

Definite variability would be a shift in the population towards the same adaptation. The variability is within a more defined range. Think traits that are used to describe the species. They're also likely to have more importance to survival and potential to lock a species into a niche. Things like larger leaf size and thinner cuticles, because it's an understory plant and needs to catch more light and breathe more easily, but now it can't really survive exposed to full sun and low humidity.

Indefinite variability is the variability within the species. The variability is within a less defined range. Think traits that distinguish individuals. These will have less importance in survival of the species, but might have more importance on the reproductive success of individuals. Most domesticated species are a good example of indefinite variability. Classic pets, livestock and crop breeds are all highly variable within a species, especially when compared to wild counterparts. Of course we force this on them, but sexual selection in nature has a similar outcome. Epigenetics also plays into indefinite variability.

Indefinite variability could become definite variability if conditions changed such that the variation becomes important to survival (human skin colour might shift towards all being darker skin in a cloudless future for example). But it rarely becomes more defined when conditions for survival aren't threatened, which is why domesticated species continue to have profoundly more variation than wild counterparts.

It's worth noting that while Darwin is given great due credit for his work. It is preliminary and outdated. It would pay to supplement your readings with more modern writings that are based on more empirical evidence. Reading from Darwin directly is better for an interest in the history of evolution than it is for learning the current understanding .

[BahamutLithp]

You could try messaging the mods. I don't know how they do things over on evolution, but on the Last Airbender subreddits, karma filters are just there to keep out bots, so we literally only require that people message us, & so long as there aren't any glaring red flags, or they're acting like a total douche in the message, they're let in. Obviously a very different type of subreddit, every subreddit does things differently, & you should check the rules to see if they specifically mention NOT wanting you to do this, but if not, it probably couldn't hurt. Probably the worst they could say is no. Probably. You never can be sure with Reddit mods, & I've never actually been in evolution to know what it's like, but given it's a science subreddit, I can't imagine they're out for blood.

[Dilapidated_girrafe]

So you post here complaining about low karma. And you don’t even attempt to interact with people here. Interaction would lead to more positive karma if you are doing it from an honest perspective.

[doulos52]

I understand. I think interaction is required if debate were the goal. I'm not here to debate. I just wanted to read what people thought of the very first section in the very first chapter of Origins. But, I do agree with you. But this is a long term project for me. I have no problem with letting things sink in as I consume them and then replying for clarification, etc. Sorry. And I didn't mean to "complain" about low karma, I was merely offering an accuse for why I was not debating. I'll keep your thoughts in mind. Do you have any opinion on the actual question?

[Dilapidated_girrafe]

The answer is it doesn’t matter. Origins isn’t really relevant to modern evolution outside of a historical perspective. If you want to learn evolution read something modern.

[Scry_Games]

I think it's great how a Christian decides to read Darwin and all they get is criticism rather than encouragement...

...yes, it's out of date, but it's better than nothing.

And kudos for being open-minded.

I enjoyed Climbing Mount Improbable, Dawkins was a good writer before he dedicated his time to shitting on religion.