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SFNQuestions

Is there something wrong with the concept of migratory evolution?

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It seams pretty reasonable to presume that it's possible for an organism to move to or coincidentally find a geographical location where its survival is more optimal after mutating from a different species. Like for instance, if an mammalian animal in an often hot environment evolved a thick coat of fur that could regularly cause its internal temperature to increase out of its range of functionality, wouldn't it make sense for it to simply seek out a cooler environment like a cave or underground or gradually wander north towards the tundra with each generation and form a new species? But, I've never heard of that in evolution before and I want to know why.

Edited by SFNQuestions

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What? A mammal wouldn't evolve a thick coat in a hot environment. Why would it?

If it had thin skin in a cold environment, it would evolve a thick coat, but it if had thin skin, it wouldn't be in that cold environment in the first place.

 

So the question is not really valid.

 

Find one species that lives in the wrong environment. You'll find that there aren't any.

Animals don't change environment because of their genes. Their genes get changed because of the environment.

Edited by Lord Antares

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What? A mammal wouldn't evolve a thick coat in a hot environment. Why would it?

If it had thin skin in a cold environment, it would evolve a thick coat, but it if had thin skin, it wouldn't be in that cold environment in the first place.

If it was un-adapted to a cold environment, how would it be able to survive long enough to evolve a thick coat in the first place? Your own statement contradicts itself. "If it had skin, it would evolve...if it had skin, it wouldn't evolve..." What you're saying depends entirely on how exactly the cold came about, what I'm saying is that there's a possible circumstance among many that allows a species to evolve from its ancestors migrating to an environment that they were more adapted to.

 

The traditional theory would state something along the lines of a species un-adapted to the cold randomly develops a mutation, like fur or feathers, and then the weather chaotically becomes cold, eventually killing off the members of the species without fur or feathers and allowing those with the proper adaption to live on. But, maybe the evolution of every single species isn't exactly the same. Perhaps, for instance, there was a litany of fish species that were adapted to the near-surface, low pressure water in an ecosystem. Then, coincidentally, a fish adapted the ability to survive better in deeper, higher-pressure water, and if it randomly made the decision to move to that lower depth of water, it would experience more room to run from predators that typically dwell near the surface and individuals would face less competition from other species.

Edited by SFNQuestions

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It would be possible for a more densely furred variant to arise in a less than ideal environment. But how well would it survive and reproduce compared to it's relatives? That is, would it be perpetuated and ultimately be fixed within a population? On the face of it that trait would disadvantage rather than advantage but I don't think it's always so simple. Plenty of furred mammals occur in hot climates - and even hot climates can have cold seasons and unseasonal cold periods; even if it's often a disadvantage there can be times and situations where it becomes an advantage. It may be that those times are critical. I would also expect for populations in hot places that are still relatively near to places where it is colder - hot low altitude areas next to mountains with colder climates - those who move to higher altitudes could gain advantage as SFNQuestions has suggested.

 

There are going to be more variables than simply heavier or lighter coat; what means are available for thermoregulation - which may include panting, sweating and even, as with some Kangaroos, licking forelegs for evaporative cooling - will have a bearing. A heavier coat would hold more heat but better protect from intense sun, but does it shed water or hold onto it? If it better protects from being wet and cold, even if those circumstances are only periodic, it may be sufficiently advantageous and persist. Nocturnal or diurnal? It would matter whether the genetic differences are dominant or recessive as well.

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It would be possible for a more densely furred variant to arise in a less than ideal environment. But how well would it survive and reproduce compared to it's relatives? That is, would it be perpetuated and ultimately be fixed within a population? On the face of it that trait would disadvantage rather than advantage but I don't think it's always so simple. Plenty of furred mammals occur in hot climates - and even hot climates can have cold seasons and unseasonal cold periods; even if it's often a disadvantage there can be times and situations where it becomes an advantage. It may be that those times are critical. I would also expect for populations in hot places that are still relatively near to places where it is colder - hot low altitude areas next to mountains with colder climates - those who move to higher altitudes could gain advantage as SFNQuestions has suggested.

 

There are going to be more variables than simply heavier or lighter coat; what means are available for thermoregulation - which may include panting, sweating and even, as with some Kangaroos, licking forelegs for evaporative cooling - will have a bearing. A heavier coat would hold more heat but better protect from intense sun, but does it shed water or hold onto it? If it better protects from being wet and cold, even if those circumstances are only periodic, it may be sufficiently advantageous and persist. Nocturnal or diurnal? It would matter whether the genetic differences are dominant or recessive as well.

Whether or not a species can have any amount of fur in a hot environment isn't what's being debated, its a given for this topic that an animal species has enough fur to offset whatever other adaptions it has and threaten its survival, like a polar bear in the Sahara for instance. So, if a mammal like a bear did find itself with too much fur, what's it going to do in the day time in the scolding hot desert? Well, either find some place to cool off, or it's going to die. Thus, it seems reasonable to presume that there are circumstances where animals could willfully or coincidentally migrate to an environment they are more appropriately adapted to.

How about all land animals for instance? Starting from fish in the ocean, fish randomly evolved these more sturdy maneuverable fins. When a fish coincidentally moved into the land either to try and escape a predator, find a mate or because a wave knocked it onto the land, it found it was able to maneuver on the land better than other fish (though probably not consciously aware of that fact), but with each generation of fish that relied on that technique, there were random members of each successive generation of fish that mutated from that initial mutation that then mutated even long and stiffer fins, which were even more adapted to moving to land and a little less adapted to water, thus creating the circumstance that migrating to land lead to more optimal survival for those members that would eventually evolve to form a land-dwelling animal.

Edited by SFNQuestions

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Animals evolve to fit their environment. So the only way I can see your scenario happening is if the environment changes rapidly. So, if the climate gets warmer, for example, then animals may move north. This does happen.

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Animals evolve to fit their environment. So the only way I can see your scenario happening is if the environment changes rapidly. So, if the climate gets warmer, for example, then animals may move north. This does happen.

 

Yes, this is true. But generally speaking, his assumption doesn't hold water.

 

 

its a given for this topic that an animal species has enough fur to offset whatever other adaptions it has and threaten its survival, like a polar bear in the Sahara for instance. So, if a mammal like a bear did find itself with too much fur, what's it going to do in the day time in the scolding hot desert? Well, either find some place to cool off, or it's going to die.

 

No, this is wrong. A polar bear would never find itself living in Sahara. This cannot happen.

 

 

Starting from fish in the ocean, fish randomly evolved these more sturdy maneuverable fins. When a fish coincidentally moved into the land either to try and escape a predator, find a mate or because a wave knocked it onto the land, it found it was able to maneuver on the land better than other fish (though probably not consciously aware of that fact), but with each generation of fish that relied on that technique, there were random members of each successive generation of fish that mutated from that initial mutation that then mutated even long and stiffer fins, which were even more adapted to moving to land and a little less adapted to water, thus creating the circumstance that migrating to land lead to more optimal survival for those members that would eventually evolve to form a land-dwelling animal.

 

You seem to assume that evolution happens very rapidly, like in 1 generation or 2. Pinpoint any time in the evolution of fish and you won't find one instance where it lived in the wrong environment.

You are simplifying it too much and not considering that this happened over a million years and each change was tiny.

 

 

If it was un-adapted to a cold environment, how would it be able to survive long enough to evolve a thick coat in the first place? Your own statement contradicts itself. "If it had skin, it would evolve...if it had skin, it wouldn't evolve..."

 

No, it doesn't contradict itself. You can try to read posts more carefully. This statement (which came just after what you quoted) is the point:

 

 

but it if had thin skin, it wouldn't be in that cold environment in the first place

 

Do you see my point? It wouldn't have to be in that position in the first anyway.

So if it was FORCED to live in an unsuitable environment, it would adapt to it. But in nature, it wouldn't be living in that unsuitable environment in the first place.

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You seem to assume that evolution happens very rapidly

Except for the tiny little part where I explicitly stated that there were small changes from generation to generation, multiple times.

 

 

 

You are simplifying it too much and not considering that this happened over a million years and each change was tiny.

I already qualified the concept by saying it was one possibility among many others. The fact that not all species evolve in the suggested manner isn't what's being discussed.

 

You are simplifying it too much and not considering that this happened over a million years and each change was tiny.

And you're also providing 0 evidence for how anything anyone has said here is wrong in any way.

I see that you're a fan of the chicken or the egg paradox. "It wouldn't be in that position in the first place anyway," okay so that implies nothing has ever adapted or changed because everything started out somehow magically being automatically adapted to its environment. If a species is only now adapted to a particularly cold or warm environment, then there must have been previous generations that originally weren't as adapted. Life originally started out as something similar to photosynthetic algae, now look where it is, so clearly you're wrong.

 

 

 

No, this is wrong. A polar bear would never find itself living in Sahara. This cannot happen.

It can, you just get an airplane, get a polar bear, and fly to Africa. You also seem to be missing the point that it's an exaggeration to clearly illustrate the concept. But, it's also not wrong either, because if there was a snow-capped mountain with a sustainable ecosystem and the bear had a natural inclination to seek it out, it could survive there.

 

 

 

No, it doesn't contradict itself. You can try to read posts more carefully. This statement (which came just after what you quoted) is the point:

It does. If the skin was thick enough to adapt to a cold environment it would imply that its thin-skinned counterparts were adapted to a warm environment which would give the thick skinned animals a relative disadvantage in a warm environment which means if the thick-skinned generations of animals were a mutation from a thin-skinned animal, it would find itself in a warm environment it wasn't as adapted to to being with. If it was a think-skinned animal that was a generational mutation from a thick-skinned animal, it would find it was wasn't as adapted to a cold environment to being with, so either way it's a contradicts what you said. How long is it going to be before you accept that animals have legs and can swim and can fly? Movement clearly plays a role in evolution to begin with, birds and fish even have instincts for migrating across entire continents.

 

You are simplifying it too much and not considering that this happened over a million years and each change was tiny.

I already qualified the concept by saying it was one possibility among many others. The fact that not all species evolve in the suggested manner isn't wasn't being discussed. It's established that it is a plausible concept given the presented scenarios, the question is whether or not it's such a given that few bothered to write about it or if there's so little information that biologist can't determine that, or how, the choices/instincts of animals would allow their movement to new environments to directly impact their evolution.

Edited by SFNQuestions

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And you're also providing 0 evidence for how anything anyone has said here is wrong in any way.

 

Because no one said anything that is wrong. You did. Strange reinforced what I was saying.

 

 

I see that you're a fan of the chicken or the egg paradox. "It wouldn't be in that position in the first place anyway," okay so that implies nothing has ever adapted or changed because everything started out somehow magically being automatically adapted to its environment.

 

This is a more sensible question than the original one.

No, this doesn't imply that. This is the part you don't understand.

 

First of all, life DID start out ''magically'' adapted to its environment. The first living organisms developed where they did because the environment suited their needs. They didn't develop in the sky and then migrated to the ocean because it was more suitable to them.

 

 

If a species is only now adapted to a particularly cold or warm environment, then there must have been previous generations that originally weren't as adapted.

 

Yes, but those generations didn't live in the particularly cold and warm environment to begin with. I see what you're getting at. The good questions is: then why did the species start adapting in the first place if the environment suited them perfectly.

 

In that respect, you are somewhat right, but not to the extent that you're thinking. They adaptations are always very, very minor. A species would never be forced to go from a very hot to a very cold environment. That never happened.

 

The polar bear, if flown to Sahara, would seek the best sutiable environment for it and then adapt to it. This is correct. But in nature, it would never be forced to do this. I understand you're using an exaggeration, but the exaggeration doesn't work here.

 

So, to reiterate, a species would never require such a drastic change that it would need to seek a different environment.

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Because no one said anything that is wrong. You did. Strange reinforced what I was saying.

I expect you to show me precisely where I said the concept I was illustrating is impossible given that I already showed how even its most exaggerated form is possible. Furthermore, Strange did say it was possible when the environment changes quickly and that the proposed scenario does happen, as illustrated, though didn't provide any reference.

 

 

This is a more sensible question than the original one.

It's not a sensible question, it's a generalized answer. Whether or not evolution exists isn't being question, now you're just derailing the topic. You don't have the evidence to support that animals never migrated to a nearby environment that they are better suited for.

 

 

First of all, life DID start out ''magically'' adapted to its environment.

No, they developed purely randomly, as far as we know, in some archaic form that happened to get lucky in a very turbulent environment and coincidentally had random mutations that made them better adapted to various circumstances.

 

 

Yes, but those generations didn't live in the particularly cold and warm environment to begin with.

So somehow every single species starts out in a perfectly moderate climate? I know you know that's not true. There are species that start out in warmer environments and those that start out in colder environments, that shouldn't be a discussion. It is beyond reasonable that a small mutation could make a species slightly more adapted to an alternative environment nearby, and given enough time, adaptations to that environment can randomly compound with each successive generation.

How do you think land animals came about exactly? There wasn't a fish that just somehow started out with perfect legs as you seem to presume, there were near-surface fish that lived very close to the land, and purely randomly they developed fins that were better equipped for scouring across small patches of land and coincidentally they had the opportunity to take advantage of those fins. Then eventually, certain members of future generations randomly developed fins for traversing moderate stretches of land which were less adapted to dwelling solely in the water, but this was offset by the advantages of being able to move across those moderate stretches of land land such as less competition, plentiful food from the terrestrial plants, avoiding predators and finding mates over a wider area. Finally after many generations of random mutations compounding off of each other providing slightly better advantages for dwelling on land, there finally came fully terrestrial animals. That requires some form of movement. What you're saying directly implies that every single species never ever moves anywhere in any way and it's only the environment that can ever possibly change. That's wrong.

Edited by SFNQuestions

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Most evolutionary adaptations develop over generations by SMALL degrees. It is rare for a macro-mutation (like the sudden development of fur or feathers or great pressure tolerance) to develop all at once. A population of fish living at the surface will likely have the general adaptability to survive a range of pressures with some individuals having a greater range of tolerance than other individuals. Individuals with a greater range of tolerance might sometimes be outcompeted for resources closer to the surface and so may forage for food and mates lower down the water column but they are not actively seeking out the greater pressure per se. Sometimes greater food resources may exist in the deeper portions of their environment and individuals that can tolerate the greater pressure may fare better than their surface dwelling neighbors. Under such a change in regime, one would expect the population to change genetically over generations with the depth appreciating members having more offspring than the pressure sensitive members. This will change the depth to which the population will forage for resources. However conditions may once again change in the favor of the surface dwelling members of the population and they will begin having more offspring. Much of evolution involves these little back and forth changes in gene frequency due to shifting transient environmental changes.

 

Most evolutionary changes are subtle. The larger a population, the less likely any of the minor mutations will have any significant effect on the evolution of the species into a different form. A small group of individuals that are separated from their main population could establish a new form or behavior more easily due to the reduced competition from other genes.

 

Macro-mutations are often lethal or otherwise prevent an individual from reproducing.

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Furthermore, Strange did say it was possible when the environment changes quickly and that the proposed scenario does happen, as I illustrated.

 

Yes, and that's equivalent to the polar bear being flown to Sahara. I already addressed that and don't want to repeat myself.

 

 

though didn't provide any reference.

 

Because there is no reference. There is no known natural example of this, as I said.

 

 

No, they developed purely randomly, as far as we know, in some archaic form that happened to get lucky in a very turbulent environment and coincidentally had random mutations that made them better adapted to various circumstances.

 

Completely wrong. Life developed under perfect circumstances for it. It didn't develop in a random environment and then adapted to it. It wouldn't have come to existence if it was in the wrong environment.

 

So somehow every single species starts out in a perfectly moderate climate? I know you know that's not true. There are species that start out in warmer environments and those that start out in colder environments, that shouldn't be a discussion.

 

You're not listening at all and I have lost interest in replying to you.

You main issue is that you somehow assume that fish grew legs all of a sudden, then felt the need to move to land. They developed very small mutations over a very large period of time. Nothing that would warrant them changing the environment.

 

EDIT: ^ What he said. That's what I'm saying with this last point. There is no need to expand on this. It is sufficient.

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First of all, life DID start out ''magically'' adapted to its environment. The first living organisms developed where they did because the environment suited their needs. They didn't develop in the sky and then migrated to the ocean because it was more suitable to them.

 

 

 

Not accurate. Life arose from the conditions in which it was formed and as such was adapting to said environment. Nothing miraculous.

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But the conditions suited it enough to be able to spawn life in the first place. If the environment was too harsh for this life, it wouldn't have developed there. He seems to suggest that with his polar bear example.

 

And this just reinforces the idea that life adapts to the environment, not that life migrates drastically due to unsuitable environment. You and I both said that the conditions are never too harsh for an animals living there as it wouldn't be there. Any and all mutations are very small and very small. That is the main point.

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Yes, and that's equivalent to the polar bear being flown to Sahara. I already addressed that and don't want to repeat myself.

Well except that by definition they're not equivalent statements at all. One is a specific case of the other's general case.

 

Because there is no reference. There is no known natural example of this, as I said.

I've proposed three examples so far, but you are fixating on what I already explicitly stated is an exaggeration to avoid answering to a reasonable discussion because you know you are wrong.

 

Completely wrong. Life developed under perfect circumstances for it. It didn't develop in a random environment and then adapted to it. It wouldn't have come to existence if it was in the wrong environment.

If life developed under perfect circumstances then competition would never have existed, it would have never evolved into anything. Furthermore, happening to pass through a less than ideal environment is completely different than spending an entire lifetime solely in that environment. Even in the extreme polar bear example, the polar bear has the choice of finding a cool environment to dwell in during the day, but then at night it also has the opportunity to hunt nocturnally when it's very cold using its exceptional sense of smell, and there's plenty of examples of nocturnal animals, or if it's a different desert there might be a snow-covered mountain nearby with its own tundra-like ecosystem. Even if it finds itself in a hostile environment, it can use these things called "limbs" to *move* to a more hospitable environment and just avoid day-time altogether. Humans for instance happen to also live in the arctic tundra, but they still build homes that are warmer than the natural environment.

 

 

Completely wrong. Life developed under perfect circumstances for it. It didn't develop in a random environment and then adapted to it. It wouldn't have come to existence if it was in the wrong environment.

 

 

You're not listening at all and I have lost interest in replying to you.

You main issue is that you somehow assume that fish grew legs all of a sudden, then felt the need to move to land. They developed very small mutations over a very large period of time. Nothing that would warrant them changing the environment.

 

EDIT: ^ What he said. That's what I'm saying with this last point. There is no need to expand on this. It is sufficient.

A "wrong" environment is different than a "less than ideal" environment. A "wrong" environment is a polar bear being thrown into a volcano or the vacuum of space. It is completely possible that there are better conditions that those first life forms could have formed in, but they coincidentally had the mechanical/chemical threshold to survive in whatever less-than-ideal environment they formed in, and thus it is possible for populations in less than ideal conditions to have the time to evolve to become optimally adapted to that environment or either willfully/instinctually or coincidentally move to an environment where they wouldn't be gradually killed off if they cannot adapt to their original environment in time to surpass the competition of members that are more optimally adapted to it. Interest isn't what you lost, it's the argument you lost.

Edited by SFNQuestions

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Low lands vs high - big differences to minimum and average temperatures can exist in close geographic proximity. Grazing or hunting the high country in summer could extend, with more dense fur, to become wintering in the high country.

 

I'm not convinced that large differences to fur density are much less likely than small ones - small genetic changes might cause a growth process to switch on or off earlier or later with big impacts. Big impacts would exaggerate the survival differences compared to those without such mutations of course and most often those would be negative. The survival impacts would probably be more immediate. But mostly is not always. Unlikely perhaps, but evolution is a product of the unlikely; millions of years and generations across vast and varied geographic areas and populations leave room for the rare and unlikely.

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It's called extinction, when climate changes or other changes happen lots of animals die out, or pre-historic animals rather ( since humans have been the cause of many extinctions I only count the pre-historic animals ).

Lets say a place flood, obviously all the land walking animals will drown, flying animals will fly somewhere else and water dwelling creatures will just swim away, the landwalkers won't evolve to learn to swim ( cause they drowned ) and extinction happens, if an animal migrates it's for a reason, maybe there wasn't enough food for all of their spiecies and some of them migrated but still into an enviroment they feel comfortable in, and then they probably start to evolve to fit that enviroment better while the ones that stayed of their species will evolve differently since they stayed in their original enviroment.

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