Craig's Science topics: #1. Evolution of complex features

[Mike64]

The next step is, WHY

There is no "why" about it. Evolution, and science in general, aren't about "why" (at least not in the way you're using the word), they're about "what" (and by extension, "how" in the physical, mechanistic sense.) For "why", you have to turn to religion, mythology and similar lore, and/or fictional literature, though of course that's completely pointless on an "intellectual"/real-world level...

ETA: This is really more a "how" sort of explanation than a true "why", but in a sense, one could say that the reason "why" some animals developed wings was/is that before such creatures existed, "the atmosphere" was an under-, or completely, un-occupied ecological niche available for population by creatures appropriately adapted to it. And since there weren't any predators there yet, there was nothing except gravity and the inherent lack of a physical ability to overcome gravity that prevented creatures inhabiting it So with appropriate changes in animal physiology to allow them to do so (probably little by little), life forms that could not or might not have been able to survive long enough to reproduce in significant numbers on land or in the water could do so in the atmosphere, by avoiding being eaten at an early age by existing land- and sea-dwelling creatures that were faster or more powerful than them in those environments.

Even the slowest-flying bird, for example, can leave the fastest-running land animal in the dust, simply by flying above the dust and nesting in a place that the land animal can't find a foothold to climb up on to reach the nesting place... And even an animal that can, at first, only sort of "fly-hop" 20 feet up onto the face of a cliff, for example, will gain a significant survival advantage. And then eventually, a few of those animals will bear young that can "fly" slightly further and cling to vertical, or near vertical, surfaces more securely, etc, and so end up surviving to reproduce in even larger numbers than their ancestors, etc., etc...

ETAF: But on the other hand, the ability to fly, for example, isn't an end-all-be-all survival trait. Flight is very, very energy intensive, so not only must a flying animal spend a huge amount of its time eating, there must be enough food available for it to eat, and it should ideally (though not invariably) be relatively small, and must weigh comparatively little, compared to land and especially water-dwelling, animals relative to its volumetric size. So in places where there isn't significant "environmental pressure" to fly (because of a lack of predators on land), the ability to fly might be lost (or never fully develop), also due to natural selection, or in that case, the lack of selection for flight. Hence ostriches (and emus) or penguins, for example, which have their own unique characteristics that suit them to their environments, allowing them to flourish despite being unable to fly. (Ostriches are big, strong, and can run very fast, while penguins happily inhabit places utterly inhospitable to most other large animals, can swim very fast, and both stay underwater for extended periods and maneuver in it adroitly....

And fwiw, presumably a broadly similar process is what accounts for land animals too, for that matter, since the available evidence so strongly suggests that all life on Earth evolved from creatures that originally (many, many eons ago) lived exclusively in water...

 

[agent00f]

It all rather makes sense why the OP doesn't understand these things.

This thread has taken a rather personally contentious tone not appropriate for this forum, and this post has finally gone completely over the line of acceptability here.

Perknose
Forum Director

 

[Dr. Zaus]

Every how is the beginning of another why.

 

[Mike64]

Every how is the beginning of another why.

Huh? That depends on the sense of the word "how" as you use it. "How" can be basically a synonym for "why", as in "how come?", but it can also just mean "in what way"? The fact that we humans (or some/many of us, anyway) seem to have some sort of inherent desire to know "why" about pretty much everything we come across has no bearing on what "science" is and/or isn't meant to, or capable of, explaining, at least by its own terms...

 

[Dr. Zaus]

Huh? That depends on the sense of the word "how" as you use it. "How" can be basically a synonym for "why", as in "how come?", but it can also just mean "in what way"? The fact that we humans (or some/many of us, anyway) seem to have some sort of inherent desire to know "why" about pretty much everything we come across has no bearing on what "science" is and/or isn't meant to, or capable of, explaining, at least by its own terms...

Science is just a way of knowing, a social artifact that changes over history and time, subject to paradigmatic revolutions and re definition.

Highly functional: but ultimately a pragmatic bargain with our limited knowledge and vision. Not an objective fact that exists outside of human perception any more than any other way of organizing knowledge.

In its present incarnation answering "why" in terms of general theory is fundamental, basic, science.

 

[Mike64]

Science is just a way of knowing

Of course it is, it doesn't pretend to be anything else. That was my point.

In its present incarnation answering "why" in terms of general theory is fundamental, basic, science.

Like the word "how", the word "why" also has several different, if vaguely related, meanings.. The way you used it in that sentence doesn't mean "wherefore", as in a metaphysical explanation for the fundamental existence of something (or for that matter "everything"), it means "in what way" (or in other words, "how"...)

 

[agent00f]

Of course it is, it doesn't pretend to be anything else. That was my point.

Like the word "how", the word "why" also has several different, if vaguely related, meanings.. The way you used it in that sentence doesn't mean "wherefore", as in a metaphysical explanation for the fundamental existence of something (or for that matter "everything"), it means "in what way" (or in other words, "how"...)

He's using "how" to mean the mechanical explanation, and "why" for the entirely different process of human wonderment which is presumably the motivational precursor to investigating said how.

 

[Craig234]

Why is a search for a reason, a cause, an explanation of something - it can be anthropomorphic when referring to a person's actions - why did they vote for trump? - or inanimate - why is the sky blue?

The question "why" is, why a creature evolved a certain way. The only answer the layman has for the topic is, because it helped the creature survive, and so the trait propagated. So, "why does a snake have venom (if it does)" fits pretty well to "why" with that explanation. The question why in this case goes beyond that, to the seemingly useless interim stages of a complex feature.

Why did a wing go through a thousand, ten thousand, a hundred thousand, I have no idea - maybe a biologist does - evolutionary steps of the wings mutating from 'none', likely 'arms', into the light, hollow-boned, feather-covered aerodynamic system now that allows flight - when survival appears not to explain all those interim steps going towards an unplanned result.

While I haven't read every post, my impression is that no one has yet posted a civil, plausible comment on the why or how complex features that IMO do not seem to be explained by helping with survival during a large number or partial mutations, develop as they do.

By analogy, things designed by people for a purpose do 'mutate' so to speak and can improve - with a goal in mind for the interim steps. For example, the way Windows has made improvements over time. The changes in evolution sometimes seem to fit the same thing so well, they can seem to not need any explanation because they resemble the improvements man might make.

But of course, it's different. Windows changes because of people trying to improve it. Evolutionary mutations happen, supposedly, more randomly, no goal behind the changes but survival each change.

I think there's likely an answer - but that it's not at all well publicized for the public, who are expected to view every step of mutation as helping survival, for many complex features.

 

[flexy]

Why did a wing go through a thousand, ten thousand, a hundred thousand, I have no idea - maybe a biologist does - evolutionary steps of the wings mutating from 'none', likely 'arms', into the light, hollow-boned, feather-covered aerodynamic system now that allows flight - when survival appears not to explain all those interim steps going towards an unplanned result.

There is no evolution "from" "into", no evolution that starts from "A" and ends at "B" as the final goal.
Say you're looking at the evolutionary steps of wings, each evolutionary step by itself fulfills its purpose, an earlier evolutionary step (in our case the precursor of today's wings) is not inferior "simply" because today we have winged and flying creatures.
How will birds, wings evolve *in*, say, 500,000 years in the future? Will we also look back at today's wings and say this is "interim steps", as compared to whatever will fly around in 500,000 years?

From that PoV asking "Why" doesn't make sense, evolution simply happens because it happens and I don't think there is a "goal", nature is a self-correcting system, but of course evolution is driving it.

Let's go even further, maybe "evolution" as such doesn't even "exist". (A legit thought if we say that there is no "purpose".) It's just a name we have given to whatever changes and adaption happen, where we observe the result and then interpret a (deeper) meaning into it. But here is the funny part, even if we say there is no purposeful, driving mechanism that we call evolution, it develops its purpose on its own, it gets and has a purpose even if it really has none. (Yes I know this sounds silly, but think about it).

 

[agent00f]

Why is a search for a reason, a cause, an explanation of something - it can be anthropomorphic when referring to a person's actions - why did they vote for trump? - or inanimate - why is the sky blue?

The question "why" is, why a creature evolved a certain way. The only answer the layman has for the topic is, because it helped the creature survive, and so the trait propagated. So, "why does a snake have venom (if it does)" fits pretty well to "why" with that explanation. The question why in this case goes beyond that, to the seemingly useless interim stages of a complex feature.

Why did a wing go through a thousand, ten thousand, a hundred thousand, I have no idea - maybe a biologist does - evolutionary steps of the wings mutating from 'none', likely 'arms', into the light, hollow-boned, feather-covered aerodynamic system now that allows flight - when survival appears not to explain all those interim steps going towards an unplanned result.

While I haven't read every post, my impression is that no one has yet posted a civil, plausible comment on the why or how complex features that IMO do not seem to be explained by helping with survival during a large number or partial mutations, develop as they do.

It's best to avoid repeating the mistake that the OP makes.

By analogy, things designed by people for a purpose do 'mutate' so to speak and can improve - with a goal in mind for the interim steps. For example, the way Windows has made improvements over time. The changes in evolution sometimes seem to fit the same thing so well, they can seem to not need any explanation because they resemble the improvements man might make.

But of course, it's different. Windows changes because of people trying to improve it. Evolutionary mutations happen, supposedly, more randomly, no goal behind the changes but survival each change.

I think there's likely an answer - but that it's not at all well publicized for the public, who are expected to view every step of mutation as helping survival, for many complex features.

Perhaps even better to at least read the wiki page on evolution first, which I'm pretty sure informs readers that evolution is just an abstract concept used to explain how empirically evident random genetic changes propagate, not any sort of goal driven process.

 

[agent00f]

There is no evolution "from" "into", no evolution that starts from "A" and ends at "B" as the final goal.
Say you're looking at the evolutionary steps of wings, each evolutionary step by itself fulfills its purpose, an earlier evolutionary step (in our case the precursor of today's wings) is not inferior "simply" because today we have winged and flying creatures.
How will birds, wings evolve *in*, say, 500,000 years in the future? Will we also look back at today's wings and say this is "interim steps", as compared to whatever will fly around in 500,000 years?

From that PoV asking "Why" doesn't make sense, evolution simply happens because it happens and I don't think there is a "goal", nature is a self-correcting system, but of course evolution is driving it.

Nature isn't a purposeful self-correcting system by your own definition in the same post. Human brains also have a bad habit of anthropomorphize things and giving them "purpose" even when these things are indifferent abstract system.

Let's go even further, maybe "evolution" as such doesn't even "exist". (A legit thought if we say that there is no "purpose".) It's just a name we have given to whatever changes and adaption happen, where we observe the result and then interpret a (deeper) meaning into it. But here is the funny part, even if we say there is no purposeful, driving mechanism that we call evolution, it develops its purpose on its own, it gets and has a purpose even if it really has none. (Yes I know this sounds silly, but think about it).

Case in point.

 

[SMOGZINN]

The only answer the layman has for the topic is, because it helped the creature survive, and so the trait propagated.

The answer is not that it helped it to survive. That is actually just a side effect. The real answer is that that creature was able to reproduce, and pass that trait on, for whatever reason. Perhaps it was just in the right place at the right time, or perhaps that trait gave it some advantage. Or perhaps that trait just didn't give it a disadvantage and was a dominate trait.

While I haven't read every post, my impression is that no one has yet posted a civil, plausible comment on the why or how complex features that IMO do not seem to be explained by helping with survival during a large number or partial mutations, develop as they do.

The answer is that either each step gave some tiny advantage, or at least did not give it too large of a disadvantage so that the trait managed to get passed down, even if only as a recessive trait that only got expressed occasionally, long enough to be combined with another trait that did make it advantageous enough so that many more of the creatures that expressed the trait managed to reproduce. Eventually only creatures that expressed the trait was able to reproduce, either from selective breeding, or from environmental pressures.

 

[agent00f]

The answer is not that it helped it to survive. That is actually just a side effect. The real answer is that that creature was able to reproduce, and pass that trait on, for whatever reason. Perhaps it was just in the right place at the right time, or perhaps that trait gave it some advantage. Or perhaps that trait just didn't give it a disadvantage and was a dominate trait.



The answer is that either each step gave some tiny advantage, or at least did not give it too large of a disadvantage so that the trait managed to get passed down, even if only as a recessive trait that only got expressed occasionally, long enough to be combined with another trait that did make it advantageous enough so that many more of the creatures that expressed the trait managed to reproduce. Eventually only creatures that expressed the trait was able to reproduce, either from selective breeding, or from environmental pressures.

As a simple example, earlier "birds" might've had to run really fast to semi-glide up a short tree. Eventually this became unnecessary as "wing" muscles developed. So folks who lack imagination today are left to ponder how they ever got off the ground.

 

[Craig234]

There is no evolution "from" "into", no evolution that starts from "A" and ends at "B" as the final goal.
Say you're looking at the evolutionary steps of wings, each evolutionary step by itself fulfills its purpose, an earlier evolutionary step (in our case the precursor of today's wings) is not inferior "simply" because today we have winged and flying creatures.
How will birds, wings evolve *in*, say, 500,000 years in the future? Will we also look back at today's wings and say this is "interim steps", as compared to whatever will fly around in 500,000 years?

From that PoV asking "Why" doesn't make sense, evolution simply happens because it happens and I don't think there is a "goal", nature is a self-correcting system, but of course evolution is driving it.

Let's go even further, maybe "evolution" as such doesn't even "exist". (A legit thought if we say that there is no "purpose".) It's just a name we have given to whatever changes and adaption happen, where we observe the result and then interpret a (deeper) meaning into it. But here is the funny part, even if we say there is no purposeful, driving mechanism that we call evolution, it develops its purpose on its own, it gets and has a purpose even if it really has none. (Yes I know this sounds silly, but think about it).

I can't make sense of part of that, but you do have an "A" at one point, and then multiple mutations, and at some later point a "B" - and yes, of course then there are more mutations.

You're glossing over the issue. You're stating that each of those mutations was somehow an improvement. But that's not clear.

Take a reptilian arm. As I said, imagine 100,000 mutations that gradually change it into the wing that can fly - the changes in shape and muscles, the feathers, etc. But step after step, those changes do not result in a wing that can fly. While it's easy to point at a wing and say "that's useful", it's not easy to point at a half-developed wing that can't fly and say the same.

You say 'evolution is driving it', but that's a circular statement - what does it mean? Other than each change supposedly propagating or not, what other 'driving' is there to lead to a wing?

 

[agent00f]

It's pretty obvious any explanation of evolution is completely immaterial to this thread.

 

[flexy]

Nature isn't a purposeful self-correcting system by your own definition in the same post. Human brains also have a bad habit of anthropomorphize things and giving them "purpose" even when these things are indifferent abstract system.

Case in point.

If for whatever reason, all white cats would die out (say, because predators see them easier at night) and in 100,000 years there is only black cats, I *could* say that nature "corrected" itself because it "magically" at some point produces only cats with a higher survival chance at night.
(I am aware that the expression "self-corrected" I used is sort-of unfortunate..but then again..it sort of isn't seeing it from this perspective)

 

[agent00f]

If for whatever reason, all white cats would die out (say, because predators see them easier at night) and in 100,000 years there is only black cats, I *could* say that nature "corrected" itself because it "magically" at some point produces only cats with a higher survival chance at night.
(I am aware that the expression "self-corrected" I used is sort-of unfortunate..but then again..it sort of isn't seeing it from this perspective)

Correcting implies some prior situation was incorrect and needs to be fixed.

The basis of really understanding "evolution" requires abandoning such notions, since what we can see of the massive tree are just the few happenstantial branches that incidentally worked out.

There is some instinctive feature of the human psyche which tells us we're special and not the result of arbitrary circumstance, which is why this thread isn't really about evolution except maybe why that feature evolved.

 

[flexy]

it gradually change it into the wing that can fly - the changes in shape and muscles, the feathers, etc. But step after step, those changes do not result in a wing that can fly. While it's easy to point at a wing and say "that's useful", it's not easy to point at a half-developed wing that can't fly and say the same.

No it didn't gradually "change it into" whatever, "evolution" doesn't know about the wing which may arise in a million years. That the wing is "useful", is your and my interpretation (as said, you do not know what becomes of a wing in 500,000 years, so how can you say the wing is "useful", maybe we're looking at a primitive form of something "better" in 500,000 years)

The wing we see today is not more or less useful than any interim steps. When there were interim steps, say, which were not 100% wings yet but already some sort of mutated arms, nature didn't produce some "faulty" freak. When the species lived and was able to reproduce, then this mutation WAS useful and, yes, in a sense an improvement.

Didn't we go over this already? The chicken example etc.? Even a supposedly "crippled" species, say some interim species would have had an advantage from hollow bones and a lighter structure, or feathers, even if it couldn't fly. If it allowed the thing to jump farther, or to fall to the ground with a higher survival rate (because it was lighter and had higher air resistance etc., like a chicken you throw), IT WAS an advantage. It was not an "imperfect" mutation because otherwise such a species could not have survived and carried on the genes.

That, much later, then after many more mutations, actual wings evolved, is merely a result of the mutations, that, for whatever reasons, each interim step "on the way" to the wings was beneficial...and then ultimately resulted in the wing.

Personally I'd say you COULD point at any species where we know they lived for some longer period of time and find why it developed this or that feature and that indeed it WAS useful, in some or the other way.

 

[flexy]

Correcting implies some prior situation was incorrect and needs to be fixed.

The basis of really understanding "evolution" requires abandoning such notions, since what we can see of the massive tree are just the few happenstantial branches that incidentally worked out.

There is some instinctive feature of the human psyche which tells us we're special and not the result of arbitrary circumstance, which is why this thread isn't really about evolution except maybe why that feature evolved.

"Corrected" in a sense that those varieties remain with the highest survival rate. The classic "survival" of the fittest. ("Fit" in this case the color of their fur).
Or an example I like, with the storm-battered island where ultimately only those plant types grow that have very strong roots.
From that point of view, I don't think it's entirely wrong to use "corrected", when taking the survival argument, it is actually sort of objective and not merely subjective..but of course with the usual caveats.

 

[agent00f]

"Corrected" in a sense that those varieties remain with the highest survival rate. The classic "survival" of the fittest. ("Fit" in this case the color of their fur).
Or an example I like, with the storm-battered island where ultimately only those plant types grow that have very strong roots.
From that point of view, I don't think it's entirely wrong to use "corrected", when taking the survival argument, it is actually sort of objective and not merely subjective..but of course with the usual caveats.

Thinking of evolution as process of corrections or such is what leads to the OP. It's obvious enough that's what he's grasping onto just above, of all the superior explanations offered.

 

[Craig234]

The wing is "useful" as a matter of fact, in how it is used and helps the animal survive. Do you question that flying is a benefit?

And it did "gradually change into" a wing, unless you are arguing that wings just suddenly appeared from one mutation. Only comic books do that.

"The wing we see today is not more or less useful than any interim steps."

The half-formed wing that cannot fly is not nearly as useful as the formed wing that can.

If half-formed wings were the wondrous benefit you suggest, we should see a lot more animals developing partial wings and feathers than we do.

The chicken does exist with minimally flying wings. It's not clear how that's much of a natural selection result either - much less the even earlier stages as even those minimal function wings developed and didn't even provide that little benefit.

On the other hand, some things seem strange not to have evolved. Leave a bowl of water out where are some moths and they might get stuck in it unable to get out. That seems like a pretty basic thing for moths to have evolved some feature to deal with. Other insects have no problem with it.

 

[Cerpin Taxt]

The half-formed wing that cannot fly is not nearly as useful as the formed wing that can.

Prove it, or retract it.

If half-formed wings were the wondrous benefit you suggest, we should see a lot more animals developing partial wings and feathers than we do.

Non sequitur. Not all animals are subject to the same selection pressures.

On the other hand, some things seem strange not to have evolved. Leave a bowl of water out where are some moths and they might get stuck in it unable to get out. That seems like a pretty basic thing for moths to have evolved some feature to deal with. Other insects have no problem with it.

You really need to understand what argumentum ad ignorantium is and then figure out why you employ it so frequently.

 

[PowerEngineer]

I know there's a fair amount out there on this topic, because it's a hot one for the 'intelligent design' debate, with some biologists trying to answer the issue.

But I don't yet have the answer so it makes sense.

Yes, indeed, so-called "irreducible complexity" is an argument that proponents of "intelligent design" (a.k.a. creationism) make against evolution. It was center stage in the trial documented in this NOVA episode:

https://www.youtube.com/watch?v=7HZzGXnYL5I

If you haven't seen it, IMHO it's worthwhile use of two hours. The snippets most directly dealing with the "irreducible complexity" issue are 0:39 to 0:47 and 1:05 to 1:15.

I'm regularly astounded by the willingness of many people to reject the best scientific explanations just because they are somehow in conflict with what they (on the basis of very little knowledge) judge to be possible.

As an example, all the evidence points to the conclusion that the ancient Egyptians built the pyramids -- even though their construction methods are still a matter of considerable debate. It boggles the mind that some people cite this uncertainty over their construction methods as a reason to leap to the conclusion that the Egyptians couldn't have built them by themselves -- they must have had help from aliens! Which seems more likely? That archeologists can still learn a thing or two from the ancient Egyptians, or that aliens crossed interstellar space to stack granite blocks in the desert?

Along these same lines, which seems more likely? That we still have a thing or two to learn about how evolution works, or that there must be an omnipotent "intelligent designer" assembling species after species?

 

[agent00f]

Yes, indeed, so-called "irreducible complexity" is an argument that proponents of "intelligent design" (a.k.a. creationism) make against evolution. It was center stage in the trial documented in this NOVA episode:

https://www.youtube.com/watch?v=7HZzGXnYL5I

If you haven't seen it, IMHO it's worthwhile use of two hours. The snippets most directly dealing with the "irreducible complexity" issue are 0:39 to 0:47 and 1:05 to 1:15.

I'm regularly astounded by the willingness of many people to reject the best scientific explanations just because they are somehow in conflict with what they (on the basis of very little knowledge) judge to be possible.

As an example, all the evidence points to the conclusion that the ancient Egyptians built the pyramids -- even though their construction methods are still a matter of considerable debate. It boggles the mind that some people cite this uncertainty over their construction methods as a reason to leap to the conclusion that the Egyptians couldn't have built them by themselves -- they must have had help from aliens! Which seems more likely? That archeologists can still learn a thing or two from the ancient Egyptians, or that aliens crossed interstellar space to stack granite blocks in the desert?

Along these same lines, which seems more likely? That we still have a thing or two to learn about how evolution works, or that there must be an omnipotent "intelligent designer" assembling species after species?

It's worth iterating that "debate/controversy" between informed experts is nothing like the "debate/controversy" between experts and ignoramus, even though those words are spelled the same. Con artists often use the quoted terms in the latter sense when their victims are too dim to realize that the same word can refer to different things.

 

[flexy]

The half-formed wing that cannot fly is not nearly as useful as the formed wing that can.

If half-formed wings were the wondrous benefit you suggest, we should see a lot more animals developing partial wings and feathers than we do.

Let's speculate that in 5,000,000 years, there is a type of animal that developed an extremely thick fur, thicker than any animal fur (bear, cat etc.) we know today. This COULD have evolved in 5M years due to a new ice age and a colder planet. <-- mind you this is only speculative for the sake of this discussion.

TODAY, however, animals have normal fur, and even DESPITE them having fur, animals need warmth to survive, or like a bear need to go into hibernation to survive the winter. These hypothetical animals with the "extremely thick fur" wouldn't need it, they could even survive the coldest cold.

Does this make today's fur "not nearly as useful"? Would you then say that today's fur is sort-of useless, because it cannot 100% protect animals from the cold, like the hypothetical fur that could evolve in some millions of years?