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Punctuated Equilibrium

Danb6177
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3/1/2016 12:53:44 PM
Posted: 9 months ago
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx
DanneJeRusse
Posts: 12,623
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3/1/2016 2:12:27 PM
Posted: 9 months ago
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.
Marrying a 6 year old and waiting until she reaches puberty and maturity before having consensual sex is better than walking up to
a stranger in a bar and proceeding to have relations with no valid proof of the intent of the person. Muhammad wins. ~ Fatihah
If they don't want to be killed then they have to subdue to the Islamic laws. - Uncung
Without God, you are lower than sh!t. ~ SpiritandTruth
Danb6177
Posts: 433
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3/1/2016 2:24:58 PM
Posted: 9 months ago
At 3/1/2016 2:12:27 PM, DanneJeRusse wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.

My apologies I was referring to Lyell's version of Uniformitarianism dealing with all natural laws, including the tempo of change in evolution. But to avoid confusion lets strike that and just say gradualism vs punctuated equilibrium.
DanneJeRusse
Posts: 12,623
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3/1/2016 3:54:05 PM
Posted: 9 months ago
At 3/1/2016 2:24:58 PM, Danb6177 wrote:
At 3/1/2016 2:12:27 PM, DanneJeRusse wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.

My apologies I was referring to Lyell's version of Uniformitarianism dealing with all natural laws, including the tempo of change in evolution. But to avoid confusion lets strike that and just say gradualism vs punctuated equilibrium.

There is no problem with either, species can evolve with both methods depending on the mutations and the changing environment that would drive those mutations. Any given species can be gradually evolving and then have sudden changes because of it's changing environment, and then settle down to gradual chance once again, no problem.
Marrying a 6 year old and waiting until she reaches puberty and maturity before having consensual sex is better than walking up to
a stranger in a bar and proceeding to have relations with no valid proof of the intent of the person. Muhammad wins. ~ Fatihah
If they don't want to be killed then they have to subdue to the Islamic laws. - Uncung
Without God, you are lower than sh!t. ~ SpiritandTruth
Danb6177
Posts: 433
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3/1/2016 4:43:22 PM
Posted: 9 months ago
At 3/1/2016 3:54:05 PM, DanneJeRusse wrote:
At 3/1/2016 2:24:58 PM, Danb6177 wrote:
At 3/1/2016 2:12:27 PM, DanneJeRusse wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.

My apologies I was referring to Lyell's version of Uniformitarianism dealing with all natural laws, including the tempo of change in evolution. But to avoid confusion lets strike that and just say gradualism vs punctuated equilibrium.

There is no problem with either, species can evolve with both methods depending on the mutations and the changing environment that would drive those mutations. Any given species can be gradually evolving and then have sudden changes because of it's changing environment, and then settle down to gradual chance once again, no problem.

Right, so some species gradually evolve and some species evolve quicker (punctuated equilibrium). How does science decide which it is on a case by case basis?
DanneJeRusse
Posts: 12,623
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3/1/2016 4:56:26 PM
Posted: 9 months ago
At 3/1/2016 4:43:22 PM, Danb6177 wrote:
At 3/1/2016 3:54:05 PM, DanneJeRusse wrote:
At 3/1/2016 2:24:58 PM, Danb6177 wrote:
At 3/1/2016 2:12:27 PM, DanneJeRusse wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.

My apologies I was referring to Lyell's version of Uniformitarianism dealing with all natural laws, including the tempo of change in evolution. But to avoid confusion lets strike that and just say gradualism vs punctuated equilibrium.

There is no problem with either, species can evolve with both methods depending on the mutations and the changing environment that would drive those mutations. Any given species can be gradually evolving and then have sudden changes because of it's changing environment, and then settle down to gradual chance once again, no problem.

Right, so some species gradually evolve and some species evolve quicker (punctuated equilibrium). How does science decide which it is on a case by case basis?

Just like everything else, from the evidence.
Marrying a 6 year old and waiting until she reaches puberty and maturity before having consensual sex is better than walking up to
a stranger in a bar and proceeding to have relations with no valid proof of the intent of the person. Muhammad wins. ~ Fatihah
If they don't want to be killed then they have to subdue to the Islamic laws. - Uncung
Without God, you are lower than sh!t. ~ SpiritandTruth
Ramshutu
Posts: 4,063
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3/1/2016 5:45:50 PM
Posted: 9 months ago
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

It is in contrast to strict gradualism, but that's not really a problem when you actually consider what evolution actually is and how it works.

The primary mechanisms of evolution (but by no means all) are the processes of genetic drift (changes propagating throughout a small population by statistical chance), and natural selections (changes propagating throughout a population on the basis of selective advantage).

Population genetics and statistical factors show that in a small population, neutral changes propagated by drift, and positive changes propagated by selection will occur more rapidly than if the population of organisms is large.

What this means, is that the tempo of evolution is driven in part by population size. So there is inherently a variability in rates of evolution.

Secondly, and potentially most importantly, how much selective pressure an organism is subjected to depends on what that organism is, and what the environment is. If a small population of organisms is added into a new environment in which they can barely survive, they are subjected to a far greater pressure than an existing population living in the same environment that they and their ancestors have been living in for millions of years.

Organisms acquire changes that allow them to survive in a given environment. If the environment doesn't change, over time, these acquired changes make the organism well adapted for the environment, and the selective pressure for new changes is much lower. If giraffes can always find food, there is no pressure for their necks to get longer.

All these factors mean that the tempo of evolution will not be identical or even nearly identical across all organisms and all environments. How fast an organism changes is a product of whether the environment they are in is changing, and how large the population is.

A key consideration is that for selection pressure to increase, the death rate of an organism in an environment effectively needs to go up; which itself allows for much faster evolution as the population size would likely get smaller.

All this serves to show, is that if the environment changes in such a way that organisms have difficulty surviving; rates of evolution will rapidly increase as selective pressure increases, population size decreases, and genetic drift becomes more pronounced.

This can be due to a change to specific organisms or collection of organisms in a microenvironment, such as finding themselves in a new habitat (such as an island devoid of predators), a new disease, or an improved predator.

However, there are extreme possibility of changes to the macro-environment, shifts in climate or major events that change the environment for everyone. These occur repeatedly in earths history; and are responsible for mass extinctions, one example is the meteorite impact and volcanism of the K-T boundary. Such events drastically raise the selective pressure and reduce population size, leading to a significant boost in the tempo of evolution for the survivors and a rapid diversification as the survivors evolve into the new ecological niches that are formed as the environment stabilises.

This is effectively what punctuated evolution is; it is not magic, some voodoo explanation or as some Creationists like to state some ad-hoc explanation of no value or validity; but at a deep level, based on and underpinned by the fundamental processes of evolution.
Stronn
Posts: 318
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3/1/2016 7:13:12 PM
Posted: 9 months ago
At 3/1/2016 4:56:26 PM, DanneJeRusse wrote:
At 3/1/2016 4:43:22 PM, Danb6177 wrote:
At 3/1/2016 3:54:05 PM, DanneJeRusse wrote:
At 3/1/2016 2:24:58 PM, Danb6177 wrote:
At 3/1/2016 2:12:27 PM, DanneJeRusse wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.

My apologies I was referring to Lyell's version of Uniformitarianism dealing with all natural laws, including the tempo of change in evolution. But to avoid confusion lets strike that and just say gradualism vs punctuated equilibrium.

There is no problem with either, species can evolve with both methods depending on the mutations and the changing environment that would drive those mutations. Any given species can be gradually evolving and then have sudden changes because of it's changing environment, and then settle down to gradual chance once again, no problem.

Right, so some species gradually evolve and some species evolve quicker (punctuated equilibrium). How does science decide which it is on a case by case basis?

Just like everything else, from the evidence.

Evidence, for instance, from the fossil record. Sharks, for instance, have been around for 450 millions years, undergoing only slight changes. In fact, sharks have survived all five mass extinctions. But other species underwent rapid evolution, especially right after mass extinctions.
Danb6177
Posts: 433
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3/1/2016 7:40:47 PM
Posted: 9 months ago
At 3/1/2016 5:45:50 PM, Ramshutu wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

It is in contrast to strict gradualism, but that's not really a problem when you actually consider what evolution actually is and how it works.

The primary mechanisms of evolution (but by no means all) are the processes of genetic drift (changes propagating throughout a small population by statistical chance), and natural selections (changes propagating throughout a population on the basis of selective advantage).

Population genetics and statistical factors show that in a small population, neutral changes propagated by drift, and positive changes propagated by selection will occur more rapidly than if the population of organisms is large.

What this means, is that the tempo of evolution is driven in part by population size. So there is inherently a variability in rates of evolution.

Secondly, and potentially most importantly, how much selective pressure an organism is subjected to depends on what that organism is, and what the environment is. If a small population of organisms is added into a new environment in which they can barely survive, they are subjected to a far greater pressure than an existing population living in the same environment that they and their ancestors have been living in for millions of years.

Organisms acquire changes that allow them to survive in a given environment. If the environment doesn't change, over time, these acquired changes make the organism well adapted for the environment, and the selective pressure for new changes is much lower. If giraffes can always find food, there is no pressure for their necks to get longer.

All these factors mean that the tempo of evolution will not be identical or even nearly identical across all organisms and all environments. How fast an organism changes is a product of whether the environment they are in is changing, and how large the population is.

A key consideration is that for selection pressure to increase, the death rate of an organism in an environment effectively needs to go up; which itself allows for much faster evolution as the population size would likely get smaller.

All this serves to show, is that if the environment changes in such a way that organisms have difficulty surviving; rates of evolution will rapidly increase as selective pressure increases, population size decreases, and genetic drift becomes more pronounced.

This can be due to a change to specific organisms or collection of organisms in a microenvironment, such as finding themselves in a new habitat (such as an island devoid of predators), a new disease, or an improved predator.

However, there are extreme possibility of changes to the macro-environment, shifts in climate or major events that change the environment for everyone. These occur repeatedly in earths history; and are responsible for mass extinctions, one example is the meteorite impact and volcanism of the K-T boundary. Such events drastically raise the selective pressure and reduce population size, leading to a significant boost in the tempo of evolution for the survivors and a rapid diversification as the survivors evolve into the new ecological niches that are formed as the environment stabilises.

This is effectively what punctuated evolution is; it is not magic, some voodoo explanation or as some Creationists like to state some ad-hoc explanation of no value or validity; but at a deep level, based on and underpinned by the fundamental processes of evolution.

Thank you for the well detailed answer as usual Ram. That was pretty much exactly what I was looking for. The only other real question I have is the empirical evidence of punctuated evolution. I understand that a lot or most or all may be by inference. Is the fossil record something that may have played into the theory?
Danb6177
Posts: 433
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3/1/2016 7:43:13 PM
Posted: 9 months ago
At 3/1/2016 4:56:26 PM, DanneJeRusse wrote:
At 3/1/2016 4:43:22 PM, Danb6177 wrote:
At 3/1/2016 3:54:05 PM, DanneJeRusse wrote:
At 3/1/2016 2:24:58 PM, Danb6177 wrote:
At 3/1/2016 2:12:27 PM, DanneJeRusse wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Not sure what you mean, Uniformitarianism deals primarily with geological causes, not physico-chemical laws, which is more towards evolution.

My apologies I was referring to Lyell's version of Uniformitarianism dealing with all natural laws, including the tempo of change in evolution. But to avoid confusion lets strike that and just say gradualism vs punctuated equilibrium.

There is no problem with either, species can evolve with both methods depending on the mutations and the changing environment that would drive those mutations. Any given species can be gradually evolving and then have sudden changes because of it's changing environment, and then settle down to gradual chance once again, no problem.

Right, so some species gradually evolve and some species evolve quicker (punctuated equilibrium). How does science decide which it is on a case by case basis?

Just like everything else, from the evidence.

Yes was curious as well about the evidence. Is there empirical evidence of a more rapid change in the evolutionary process or is it that were gradualism is not then punctuated evolution is?
v3nesl
Posts: 4,494
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3/1/2016 7:48:16 PM
Posted: 9 months ago
At 3/1/2016 7:40:47 PM, Danb6177 wrote:
...

... Is the fossil record something that may have played into the theory?

Really?
This space for rent.
Danb6177
Posts: 433
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3/1/2016 8:09:04 PM
Posted: 9 months ago
At 3/1/2016 7:48:16 PM, v3nesl wrote:
At 3/1/2016 7:40:47 PM, Danb6177 wrote:
...

... Is the fossil record something that may have played into the theory?

Really?

I guess The better way to say it would be to what extent does the fossil record play into the theory.
Ramshutu
Posts: 4,063
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3/1/2016 8:49:23 PM
Posted: 9 months ago
At 3/1/2016 7:40:47 PM, Danb6177 wrote:
At 3/1/2016 5:45:50 PM, Ramshutu wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

It is in contrast to strict gradualism, but that's not really a problem when you actually consider what evolution actually is and how it works.

The primary mechanisms of evolution (but by no means all) are the processes of genetic drift (changes propagating throughout a small population by statistical chance), and natural selections (changes propagating throughout a population on the basis of selective advantage).

Population genetics and statistical factors show that in a small population, neutral changes propagated by drift, and positive changes propagated by selection will occur more rapidly than if the population of organisms is large.

What this means, is that the tempo of evolution is driven in part by population size. So there is inherently a variability in rates of evolution.

Secondly, and potentially most importantly, how much selective pressure an organism is subjected to depends on what that organism is, and what the environment is. If a small population of organisms is added into a new environment in which they can barely survive, they are subjected to a far greater pressure than an existing population living in the same environment that they and their ancestors have been living in for millions of years.

Organisms acquire changes that allow them to survive in a given environment. If the environment doesn't change, over time, these acquired changes make the organism well adapted for the environment, and the selective pressure for new changes is much lower. If giraffes can always find food, there is no pressure for their necks to get longer.

All these factors mean that the tempo of evolution will not be identical or even nearly identical across all organisms and all environments. How fast an organism changes is a product of whether the environment they are in is changing, and how large the population is.

A key consideration is that for selection pressure to increase, the death rate of an organism in an environment effectively needs to go up; which itself allows for much faster evolution as the population size would likely get smaller.

All this serves to show, is that if the environment changes in such a way that organisms have difficulty surviving; rates of evolution will rapidly increase as selective pressure increases, population size decreases, and genetic drift becomes more pronounced.

This can be due to a change to specific organisms or collection of organisms in a microenvironment, such as finding themselves in a new habitat (such as an island devoid of predators), a new disease, or an improved predator.

However, there are extreme possibility of changes to the macro-environment, shifts in climate or major events that change the environment for everyone. These occur repeatedly in earths history; and are responsible for mass extinctions, one example is the meteorite impact and volcanism of the K-T boundary. Such events drastically raise the selective pressure and reduce population size, leading to a significant boost in the tempo of evolution for the survivors and a rapid diversification as the survivors evolve into the new ecological niches that are formed as the environment stabilises.

This is effectively what punctuated evolution is; it is not magic, some voodoo explanation or as some Creationists like to state some ad-hoc explanation of no value or validity; but at a deep level, based on and underpinned by the fundamental processes of evolution.

Thank you for the well detailed answer as usual Ram. That was pretty much exactly what I was looking for. The only other real question I have is the empirical evidence of punctuated evolution. I understand that a lot or most or all may be by inference. Is the fossil record something that may have played into the theory?

Yes, absolutely.

Evolution up until Punctuated evolution was elaborated on and defined, was viewed as a Gradual process; in that any random creature you could find would be constantly evolving at roughly the same rate over time; in other words that the differences between any two species was gradually accumulated since they originally diverged.

This means, that one would likely find a sequential, flowing and constant change in the fossil record.

Such a gradual change was not found in the fossil record for most organisms; although there are several lineages for which such a gradual change is well documented over periods of time.

For a long while, this was explained by the fossil record being relatively incomplete, and that it wasn't that such gradualistic change didn't occur, but that the fossil record was too sparse to record it properly. So that when one species rapidly turned into another in the fossil record, it wasn't thought to be real, but that the record was imperfect and just so happened not to properly record the bits in between.

As more and more fossils were found, this position became more untenable, as species-species transitions were almost never found, despite having a broad range of geological time, and a diverse collection of creatures that appeared not to change a great deal for large periods of time. The coincidence of the fossil record just-so-happening not to record the species-to-species, but recording everything else was too unlikely to be accepted.

PE came about using the evolutionary processes I noted to explain why the specific type of gradualism that Darwin (and other scientists) thought we should see couldn't be found in the fossil record.

The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.

The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.
Danb6177
Posts: 433
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3/1/2016 9:44:04 PM
Posted: 9 months ago
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
At 3/1/2016 7:40:47 PM, Danb6177 wrote:

Yes, absolutely.

Evolution up until Punctuated evolution was elaborated on and defined, was viewed as a Gradual process; in that any random creature you could find would be constantly evolving at roughly the same rate over time; in other words that the differences between any two species was gradually accumulated since they originally diverged.

This means, that one would likely find a sequential, flowing and constant change in the fossil record.

Such a gradual change was not found in the fossil record for most organisms; although there are several lineages for which such a gradual change is well documented over periods of time.

For a long while, this was explained by the fossil record being relatively incomplete, and that it wasn't that such gradualistic change didn't occur, but that the fossil record was too sparse to record it properly. So that when one species rapidly turned into another in the fossil record, it wasn't thought to be real, but that the record was imperfect and just so happened not to properly record the bits in between.

As more and more fossils were found, this position became more untenable, as species-species transitions were almost never found, despite having a broad range of geological time, and a diverse collection of creatures that appeared not to change a great deal for large periods of time. The coincidence of the fossil record just-so-happening not to record the species-to-species, but recording everything else was too unlikely to be accepted.

PE came about using the evolutionary processes I noted to explain why the specific type of gradualism that Darwin (and other scientists) thought we should see couldn't be found in the fossil record.

The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.
DanneJeRusse
Posts: 12,623
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3/2/2016 2:47:00 AM
Posted: 9 months ago
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
At 3/1/2016 7:40:47 PM, Danb6177 wrote:

Yes, absolutely.

Evolution up until Punctuated evolution was elaborated on and defined, was viewed as a Gradual process; in that any random creature you could find would be constantly evolving at roughly the same rate over time; in other words that the differences between any two species was gradually accumulated since they originally diverged.

This means, that one would likely find a sequential, flowing and constant change in the fossil record.

Such a gradual change was not found in the fossil record for most organisms; although there are several lineages for which such a gradual change is well documented over periods of time.

For a long while, this was explained by the fossil record being relatively incomplete, and that it wasn't that such gradualistic change didn't occur, but that the fossil record was too sparse to record it properly. So that when one species rapidly turned into another in the fossil record, it wasn't thought to be real, but that the record was imperfect and just so happened not to properly record the bits in between.

As more and more fossils were found, this position became more untenable, as species-species transitions were almost never found, despite having a broad range of geological time, and a diverse collection of creatures that appeared not to change a great deal for large periods of time. The coincidence of the fossil record just-so-happening not to record the species-to-species, but recording everything else was too unlikely to be accepted.

PE came about using the evolutionary processes I noted to explain why the specific type of gradualism that Darwin (and other scientists) thought we should see couldn't be found in the fossil record.

The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

And, we appreciate your honest inquiries, Dan.
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a stranger in a bar and proceeding to have relations with no valid proof of the intent of the person. Muhammad wins. ~ Fatihah
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Stronn
Posts: 318
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3/2/2016 3:54:37 AM
Posted: 9 months ago
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
At 3/1/2016 7:40:47 PM, Danb6177 wrote:

Yes, absolutely.

Evolution up until Punctuated evolution was elaborated on and defined, was viewed as a Gradual process; in that any random creature you could find would be constantly evolving at roughly the same rate over time; in other words that the differences between any two species was gradually accumulated since they originally diverged.

This means, that one would likely find a sequential, flowing and constant change in the fossil record.

Such a gradual change was not found in the fossil record for most organisms; although there are several lineages for which such a gradual change is well documented over periods of time.

For a long while, this was explained by the fossil record being relatively incomplete, and that it wasn't that such gradualistic change didn't occur, but that the fossil record was too sparse to record it properly. So that when one species rapidly turned into another in the fossil record, it wasn't thought to be real, but that the record was imperfect and just so happened not to properly record the bits in between.

As more and more fossils were found, this position became more untenable, as species-species transitions were almost never found, despite having a broad range of geological time, and a diverse collection of creatures that appeared not to change a great deal for large periods of time. The coincidence of the fossil record just-so-happening not to record the species-to-species, but recording everything else was too unlikely to be accepted.

PE came about using the evolutionary processes I noted to explain why the specific type of gradualism that Darwin (and other scientists) thought we should see couldn't be found in the fossil record.

The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

Even Darwin never really thought the rate of evolution stayed constant. He did think it was gradual enough, though, to be troubled by the sudden jumps observed in the fossil record. At the time, he put it down to the incomplete nature of the fossil record, expecting that the jumps would be smoothed out as more fossils were discovered. But as the record has filled in, the jumps still remain. According to the PE view, this is because species tend to not change very much over long periods, during which they are in equilibrium with their environment. Then some sudden change in selective pressures causes them to rapidly adapt, until equilibrium with the new environment is reached. One cause of such changes is thought to be global disasters such as an impact event or a supervolcano. When change is too sudden, species that do not adapt rapidly enough go extinct. That is why we see hosts of new forms emerging shortly after mass extinctions, when they were not present before.
Danb6177
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3/2/2016 2:45:57 PM
Posted: 9 months ago
At 3/2/2016 3:54:37 AM, Stronn wrote:
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
At 3/1/2016 7:40:47 PM, Danb6177 wrote:

Yes, absolutely.

Evolution up until Punctuated evolution was elaborated on and defined, was viewed as a Gradual process; in that any random creature you could find would be constantly evolving at roughly the same rate over time; in other words that the differences between any two species was gradually accumulated since they originally diverged.

This means, that one would likely find a sequential, flowing and constant change in the fossil record.

Such a gradual change was not found in the fossil record for most organisms; although there are several lineages for which such a gradual change is well documented over periods of time.

For a long while, this was explained by the fossil record being relatively incomplete, and that it wasn't that such gradualistic change didn't occur, but that the fossil record was too sparse to record it properly. So that when one species rapidly turned into another in the fossil record, it wasn't thought to be real, but that the record was imperfect and just so happened not to properly record the bits in between.

As more and more fossils were found, this position became more untenable, as species-species transitions were almost never found, despite having a broad range of geological time, and a diverse collection of creatures that appeared not to change a great deal for large periods of time. The coincidence of the fossil record just-so-happening not to record the species-to-species, but recording everything else was too unlikely to be accepted.

PE came about using the evolutionary processes I noted to explain why the specific type of gradualism that Darwin (and other scientists) thought we should see couldn't be found in the fossil record.

The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

Even Darwin never really thought the rate of evolution stayed constant. He did think it was gradual enough, though, to be troubled by the sudden jumps observed in the fossil record. At the time, he put it down to the incomplete nature of the fossil record, expecting that the jumps would be smoothed out as more fossils were discovered. But as the record has filled in, the jumps still remain. According to the PE view, this is because species tend to not change very much over long periods, during which they are in equilibrium with their environment. Then some sudden change in selective pressures causes them to rapidly adapt, until equilibrium with the new environment is reached. One cause of such changes is thought to be global disasters such as an impact event or a supervolcano. When change is too sudden, species that do not adapt rapidly enough go extinct. That is why we see hosts of new forms emerging shortly after mass extinctions, when they were not present before.

Thanx for reply. If I understand correct, catastrophes happen in time and change the environment causing species to adapt to the new environment. what are some examples of new forms found in the record shortly after a mass extinction? I would certainly agree that environment shifts would cause species to adapt to survive. Food supplies may diminish causing a diet change etc.
Ramshutu
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3/2/2016 4:10:03 PM
Posted: 9 months ago
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

It's no problem.

I will correct you on a couple of things; firstly there is not a lack of clear transitional specimens. There are many hundreds of examples of transitional forms in the fossil record by even the strictest definition, and many thousands of examples in the fossil record too that aren't strictly transitional but show the clear progression of traits and features solely consistent with evolution and common descent.

The difference, however, is not that they're not found, but that the prediction of gradualism was that the distinct transitional forms between a variety of different species, families, orders, genera, classes, etc should be equally spaced in the fossil record, and we should be able to find many species-species transitions (IE: intermediates between two VERY closely related species). In reality, we have lots of transitions at higher levels (such as between families, classes, genera, etc), but not that many between species; for the very reason that when things change they can change quite fast; whereas the larger and longer transitions are easier to capture in the record.

Transitions are transitions, the definition hasn't changed, but in terms of PE vs Gradualism, in the case of the latter, the transitions should be spread out in time, rather than all in a relatively short period.

The molecular clock is something different. This is a measure of how many point mutations that are present in a particular organism compared to another. A specific number of mutations are acquired per generation (and in the case of mitochondrial DNA, only acquired from one parent). The molecular clock, therefore, isn't affected by PE or Gradualism, because even if an organism isn't evolving very fast, the individuals are still reproducing and are still acquiring these point mutations.

It was assumed to be constant, but in reality if the generation time changes (IE: stuff starts reproducing faster over time) or factors such as genetic drift in smaller or larger populations, or selection on the gene that is being measured that are non random, the number of point mutations in one organism compared to another won't always match up exactly, although they are normally within a margin of error.
Danb6177
Posts: 433
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3/2/2016 5:11:34 PM
Posted: 9 months ago
At 3/2/2016 4:10:03 PM, Ramshutu wrote:
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

It's no problem.

I will correct you on a couple of things; firstly there is not a lack of clear transitional specimens. There are many hundreds of examples of transitional forms in the fossil record by even the strictest definition, and many thousands of examples in the fossil record too that aren't strictly transitional but show the clear progression of traits and features solely consistent with evolution and common descent.
Right my meaning was to say a clear linear progression like from gradualism

The difference, however, is not that they're not found, but that the prediction of gradualism was that the distinct transitional forms between a variety of different species, families, orders, genera, classes, etc should be equally spaced in the fossil record, and we should be able to find many species-species transitions (IE: intermediates between two VERY closely related species). In reality, we have lots of transitions at higher levels (such as between families, classes, genera, etc), but not that many between species; for the very reason that when things change they can change quite fast; whereas the larger and longer transitions are easier to capture in the record.
So this would be the explanation for the last homo in our progression looking very different from ourselves. And the homo before him looking different etc? Due to the faster change so less chance of producing a linear fossil progression

Transitions are transitions, the definition hasn't changed, but in terms of PE vs Gradualism, in the case of the latter, the transitions should be spread out in time, rather than all in a relatively short period.
ok Gotcha

The molecular clock is something different. This is a measure of how many point mutations that are present in a particular organism compared to another. A specific number of mutations are acquired per generation (and in the case of mitochondrial DNA, only acquired from one parent). The molecular clock, therefore, isn't affected by PE or Gradualism, because even if an organism isn't evolving very fast, the individuals are still reproducing and are still acquiring these point mutations.
But they do have to figure out which specimens evolved by PE and which by gradualism no? The clock is used to go back and find where two species diverged correct? I may be off on this
It was assumed to be constant, but in reality if the generation time changes (IE: stuff starts reproducing faster over time) or factors such as genetic drift in smaller or larger populations, or selection on the gene that is being measured that are non random, the number of point mutations in one organism compared to another won't always match up exactly, although they are normally within a margin of error.
Ramshutu
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3/2/2016 6:46:27 PM
Posted: 9 months ago
At 3/2/2016 5:11:34 PM, Danb6177 wrote:
At 3/2/2016 4:10:03 PM, Ramshutu wrote:
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

It's no problem.

I will correct you on a couple of things; firstly there is not a lack of clear transitional specimens. There are many hundreds of examples of transitional forms in the fossil record by even the strictest definition, and many thousands of examples in the fossil record too that aren't strictly transitional but show the clear progression of traits and features solely consistent with evolution and common descent.
Right my meaning was to say a clear linear progression like from gradualism

The difference, however, is not that they're not found, but that the prediction of gradualism was that the distinct transitional forms between a variety of different species, families, orders, genera, classes, etc should be equally spaced in the fossil record, and we should be able to find many species-species transitions (IE: intermediates between two VERY closely related species). In reality, we have lots of transitions at higher levels (such as between families, classes, genera, etc), but not that many between species; for the very reason that when things change they can change quite fast; whereas the larger and longer transitions are easier to capture in the record.
So this would be the explanation for the last homo in our progression looking very different from ourselves. And the homo before him looking different etc? Due to the faster change so less chance of producing a linear fossil progression

Homo changed from far more ape-like ancestors in a mere 8my or thereabouts. So in that case, yes, changing from more basal ape to Human happened very, very quickly. The reason why we have such a large and well preserved Homo, and Australopithecus lineages, is because it didn't happen very long ago.

However, Homo are one of the examples where there is good linear and species-species transition; it is very, very much not the case that the last"homo" in our progression looks very different. Homo Erectus and Homo Eragaster are very, very similar to humans; even ignoring Homo Rhodensis, and Homo Antecessor which are not complete but show skull formations intermediate between those species and us.

There are, indeed, so many intermediates and forms found that the lineage is nearly complete without any significant gaps and hasn't been for the last 20 or so years.

Transitions are transitions, the definition hasn't changed, but in terms of PE vs Gradualism, in the case of the latter, the transitions should be spread out in time, rather than all in a relatively short period.
ok Gotcha

The molecular clock is something different. This is a measure of how many point mutations that are present in a particular organism compared to another. A specific number of mutations are acquired per generation (and in the case of mitochondrial DNA, only acquired from one parent). The molecular clock, therefore, isn't affected by PE or Gradualism, because even if an organism isn't evolving very fast, the individuals are still reproducing and are still acquiring these point mutations.
But they do have to figure out which specimens evolved by PE and which by gradualism no? The clock is used to go back and find where two species diverged correct? I may be off on this

No really. The molecular clock is really only used for working out when two individual species diverged. Whether their forms changed quickly after this point (PE), or changed more gradually doesn't really matter for the molecular clock.

It was assumed to be constant, but in reality if the generation time changes (IE: stuff starts reproducing faster over time) or factors such as genetic drift in smaller or larger populations, or selection on the gene that is being measured that are non random, the number of point mutations in one organism compared to another won't always match up exactly, although they are normally within a margin of error.
Danb6177
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3/2/2016 7:00:40 PM
Posted: 9 months ago
At 3/2/2016 6:46:27 PM, Ramshutu wrote:
At 3/2/2016 5:11:34 PM, Danb6177 wrote:
At 3/2/2016 4:10:03 PM, Ramshutu wrote:
At 3/1/2016 9:44:04 PM, Danb6177 wrote:
At 3/1/2016 8:49:23 PM, Ramshutu wrote:
The discussions, books and literature of around that time discussing the disparity between gradualism and PE are often massively misquoted by creationists, as the nuance of what the scientists are talking about is lost, but to be clear and to preempt that just in case:

1.) High level transitions are well evidenced in the fossil record. Fossil evidence and transitions of evolution at or around the Phyla, Class, Family and Genera level are pretty common, because these are indicative of big changes that can't happen all in one go.

2.) There is a rarity of low level transitions in the fossil record; such as from one single species to another. Or from one family to another. If this occurred gradually over time, the differences are pronounced enough that one would expect these to be fairly common.

3.) There are several periods of mass extinction followed by a period of rapid diversification many times in the fossil record; evolution still occurs in between in specific lineages, but many lineages in these between periods don't change a significant amount.


The theory, is basically as I stated in my previous post. It's an application of basic evolutionary principles; but as well as explaining the fossil evidence, it's separately demonstrable by looking at evolution of animals today. Invasive species, for example, are exposed to massively different environments and selective pressure, and in many cases exhibit rapid evolution as expected through PE.

So PE is meant to show the reasoning for a lack of clear transitional specimens, but how? Or why would there be less chance of a transitional? And how is it decided when a case is PE and when it is gradualism? Also the molecular clock. This was a constant when first popularized. Was the emergence of PE what changed the thinking on the constant rate to a non constant rate?

Sorry for the multiple questions, Im trying to understand this. And again I appreciate the detailed responses.

It's no problem.

I will correct you on a couple of things; firstly there is not a lack of clear transitional specimens. There are many hundreds of examples of transitional forms in the fossil record by even the strictest definition, and many thousands of examples in the fossil record too that aren't strictly transitional but show the clear progression of traits and features solely consistent with evolution and common descent.
Right my meaning was to say a clear linear progression like from gradualism

The difference, however, is not that they're not found, but that the prediction of gradualism was that the distinct transitional forms between a variety of different species, families, orders, genera, classes, etc should be equally spaced in the fossil record, and we should be able to find many species-species transitions (IE: intermediates between two VERY closely related species). In reality, we have lots of transitions at higher levels (such as between families, classes, genera, etc), but not that many between species; for the very reason that when things change they can change quite fast; whereas the larger and longer transitions are easier to capture in the record.
So this would be the explanation for the last homo in our progression looking very different from ourselves. And the homo before him looking different etc? Due to the faster change so less chance of producing a linear fossil progression

Homo changed from far more ape-like ancestors in a mere 8my or thereabouts. So in that case, yes, changing from more basal ape to Human happened very, very quickly. The reason why we have such a large and well preserved Homo, and Australopithecus lineages, is because it didn't happen very long ago.

However, Homo are one of the examples where there is good linear and species-species transition; it is very, very much not the case that the last"homo" in our progression looks very different. Homo Erectus and Homo Eragaster are very, very similar to humans; even ignoring Homo Rhodensis, and Homo Antecessor which are not complete but show skull formations intermediate between those species and us.
8my is a long time to me. Maybe not in the grand scheme of things. Im looking at the rise of humans in more depth now. Im sure Ill have more questions concerning the fossil record soon
There are, indeed, so many intermediates and forms found that the lineage is nearly complete without any significant gaps and hasn't been for the last 20 or so years.

Transitions are transitions, the definition hasn't changed, but in terms of PE vs Gradualism, in the case of the latter, the transitions should be spread out in time, rather than all in a relatively short period.
ok Gotcha

The molecular clock is something different. This is a measure of how many point mutations that are present in a particular organism compared to another. A specific number of mutations are acquired per generation (and in the case of mitochondrial DNA, only acquired from one parent). The molecular clock, therefore, isn't affected by PE or Gradualism, because even if an organism isn't evolving very fast, the individuals are still reproducing and are still acquiring these point mutations.
But they do have to figure out which specimens evolved by PE and which by gradualism no? The clock is used to go back and find where two species diverged correct? I may be off on this

No really. The molecular clock is really only used for working out when two individual species diverged. Whether their forms changed quickly after this point (PE), or changed more gradually doesn't really matter for the molecular clock.
Ill have to try and wrap my head around that. If two species evolved at different rates it seems that would interfere with the timelines. I look at it like an upside down triangle with straight lines that are the same length, maybe that's the issue. Either way you have been helpful, Thanx for the discussion.
It was assumed to be constant, but in reality if the generation time changes (IE: stuff starts reproducing faster over time) or factors such as genetic drift in smaller or larger populations, or selection on the gene that is being measured that are non random, the number of point mutations in one organism compared to another won't always match up exactly, although they are normally within a margin of error.
Ramshutu
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3/2/2016 7:16:10 PM
Posted: 9 months ago
At 3/2/2016 7:00:40 PM, Danb6177 wrote:
At 3/2/2016 6:46:27 PM, Ramshutu wrote:
No really. The molecular clock is really only used for working out when two individual species diverged. Whether their forms changed quickly after this point (PE), or changed more gradually doesn't really matter for the molecular clock.
Ill have to try and wrap my head around that. If two species evolved at different rates it seems that would interfere with the timelines. I look at it like an upside down triangle with straight lines that are the same length, maybe that's the issue. Either way you have been helpful, Thanx for the discussion.

To use a helpful analogy, think of it like a roulette table. Each spin is a like a generation of organisms, with individual mutations.

The molecular clock is a bit like a measure of how many times 39 black is spun since it was installed (how many generations since a species diverged from another). If you have the number of times 00 was spun, you could estimate when it the table was installed, although it is subject to random fluctuations (which balance out over a long time), and how changes to how many times it can be spun per hour which depends on staff, maintenance, etc, opening hours, which could change over time.

P.E vs Gradualism in this analogy is a prediction about how much money is won over time. Gradualism predicts that the amount of money won would be fairly constant over time. PE predicts that there will be peaks in the amount of money won followed by periods of stability.

You would have thought gradualism would be a good bet for a roulette table, but most of the time, there will be a few people on the table, betting small amounts; and it will only be at big events, holidays or when someone important turns up and plays for high stakes you have periods where lots of money is won or lost, and is not by any means gradual.
Mhykiel
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3/3/2016 12:20:55 AM
Posted: 9 months ago
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Evolution can't be falsified. So there are plenty of Evolutionary theories to make any evidence fit.

It's been calculated the Cambrian explosion had a rate of change 5 times higher than average. And yet no reason or rhyme for this difference.

Essentially there is no conflict as long as all of it is evolution. Evolution is slow gradual change, except when it's not then it is rather fast paced change.

ERVs are evidence of Evolution and ancestry, except when the animals shouldn't be related then they aren't.

Body plan of fossils demonstrate evolution of ancestors, except when the creature is extant, then we know body plans are adaptations to environmental niches.

the list goes on but you see my point.
distraff
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3/3/2016 3:39:23 AM
Posted: 9 months ago
At 3/3/2016 12:20:55 AM, Mhykiel wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Evolution can't be falsified. So there are plenty of Evolutionary theories to make any evidence fit.

Yes, it can. Dig in the fossil record and if you only find only a random collection of fossils with no evolutionary progression and no transitionals evolution has been refuted. Or find an advanced mammal species in the very lowest levels. That would definitely screw up evolution. Of find that mutations even with natural selection will slowly degrade a species and find that it is impossible for them to create complex structures, or find a mechanism that shows that macro-evolution is impossible.

There are lots of possible ways to disprove evolution but none of them have worked. You can only nitpick about whether the rate of evolution is constant or stops and sprints.

It's been calculated the Cambrian explosion had a rate of change 5 times higher than average. And yet no reason or rhyme for this difference.

First off, species from that era don't fossilize well so that is only an estimate. And 5 times higher doesn't seem too extreme? Why would one expect evolution to only go at the same pace all the time?

Essentially there is no conflict as long as all of it is evolution. Evolution is slow gradual change, except when it's not then it is rather fast paced change.

ERVs are evidence of Evolution and ancestry, except when the animals shouldn't be related then they aren't.

All animals are related so this statement is a bit odd. ERVs can be used to prove the relatedness of any two species if we have thoroughly studied their DNA for them.

Body plan of fossils demonstrate evolution of ancestors, except when the creature is extant, then we know body plans are adaptations to environmental niches.

the list goes on but you see my point.

I do not know what you mean by this point. Are you talking about the few cases of parallel evolution?
DanneJeRusse
Posts: 12,623
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3/3/2016 3:57:05 AM
Posted: 9 months ago
At 3/3/2016 12:20:55 AM, Mhykiel wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Evolution can't be falsified. So there are plenty of Evolutionary theories to make any evidence fit.

It's been calculated the Cambrian explosion had a rate of change 5 times higher than average. And yet no reason or rhyme for this difference.

Essentially there is no conflict as long as all of it is evolution. Evolution is slow gradual change, except when it's not then it is rather fast paced change.

ERVs are evidence of Evolution and ancestry, except when the animals shouldn't be related then they aren't.

Body plan of fossils demonstrate evolution of ancestors, except when the creature is extant, then we know body plans are adaptations to environmental niches.

the list goes on but you see my point.

Yes, your point is to come to the Science forum and be as dishonest and disingenuous as possible, and while it's expected over in the Religion forum, it shouldn't be here. Why do bother Mhykiel?
Marrying a 6 year old and waiting until she reaches puberty and maturity before having consensual sex is better than walking up to
a stranger in a bar and proceeding to have relations with no valid proof of the intent of the person. Muhammad wins. ~ Fatihah
If they don't want to be killed then they have to subdue to the Islamic laws. - Uncung
Without God, you are lower than sh!t. ~ SpiritandTruth
Stronn
Posts: 318
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3/3/2016 5:39:54 AM
Posted: 9 months ago
At 3/3/2016 3:57:05 AM, DanneJeRusse wrote:
At 3/3/2016 12:20:55 AM, Mhykiel wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Evolution can't be falsified. So there are plenty of Evolutionary theories to make any evidence fit.

It's been calculated the Cambrian explosion had a rate of change 5 times higher than average. And yet no reason or rhyme for this difference.

Essentially there is no conflict as long as all of it is evolution. Evolution is slow gradual change, except when it's not then it is rather fast paced change.

ERVs are evidence of Evolution and ancestry, except when the animals shouldn't be related then they aren't.

Body plan of fossils demonstrate evolution of ancestors, except when the creature is extant, then we know body plans are adaptations to environmental niches.

the list goes on but you see my point.

Yes, your point is to come to the Science forum and be as dishonest and disingenuous as possible, and while it's expected over in the Religion forum, it shouldn't be here. Why do bother Mhykiel?

The point I took is that that evolution is so well-established that one can only argue against it by intentionally misrepresenting it.
DanneJeRusse
Posts: 12,623
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3/3/2016 3:15:23 PM
Posted: 9 months ago
At 3/3/2016 5:39:54 AM, Stronn wrote:
At 3/3/2016 3:57:05 AM, DanneJeRusse wrote:
At 3/3/2016 12:20:55 AM, Mhykiel wrote:
At 3/1/2016 12:53:44 PM, Danb6177 wrote:
Punctuated equilibrium is a theory popularized by Niles Eldredge and Stephen Jay Gould to explain rapid changes in the evolutionary tree and perhaps gaps in the fossil record. It appears that this theory is in contrast with Uniformitarianism and the gradualist model of evolution.

Is the theory of Punctuated equilibrium an accepted replacement for gradualism or are both working accepted models in evolution?

Thanx

Evolution can't be falsified. So there are plenty of Evolutionary theories to make any evidence fit.

It's been calculated the Cambrian explosion had a rate of change 5 times higher than average. And yet no reason or rhyme for this difference.

Essentially there is no conflict as long as all of it is evolution. Evolution is slow gradual change, except when it's not then it is rather fast paced change.

ERVs are evidence of Evolution and ancestry, except when the animals shouldn't be related then they aren't.

Body plan of fossils demonstrate evolution of ancestors, except when the creature is extant, then we know body plans are adaptations to environmental niches.

the list goes on but you see my point.

Yes, your point is to come to the Science forum and be as dishonest and disingenuous as possible, and while it's expected over in the Religion forum, it shouldn't be here. Why do bother Mhykiel?

The point I took is that that evolution is so well-established that one can only argue against it by intentionally misrepresenting it.

Thumbs up on that. (:
Marrying a 6 year old and waiting until she reaches puberty and maturity before having consensual sex is better than walking up to
a stranger in a bar and proceeding to have relations with no valid proof of the intent of the person. Muhammad wins. ~ Fatihah
If they don't want to be killed then they have to subdue to the Islamic laws. - Uncung
Without God, you are lower than sh!t. ~ SpiritandTruth