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saltation

janesix
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11/6/2015 12:17:16 AM
Posted: 1 year ago
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time? I can only conclude evolution progresses by saltation, and this is good evidence for it.
kp98
Posts: 729
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11/6/2015 7:34:12 AM
Posted: 1 year ago
It's certainly very interesting. I have looked around the 'net but not come up with any follow-up studies so I don't know what genetic changes were involved. Without more to go on it's hard to draw any definite conclusion.

It reads as if complex adaptive changes occurred overnight. Even if that required a single mutation it would be remarkable that the 'right' mutation occurred and spread so quickly, and if multiple co-ordinated mutations happened then putting it down to random chance is pushing it.

But is that the case here? A lot of unusual findings are initially announced only to be revealed to have simple explanations on further investigation. Is there a follow up anywhere?
chui
Posts: 511
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11/6/2015 8:32:26 AM
Posted: 1 year ago
At 11/6/2015 12:17:16 AM, janesix wrote:
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time?

Without more detail than the article provides it is difficult to know why they made the million years estimate. As a guess I would imagine that they looked at the amount of change to the genome of the lizards and compared that to the observed changes to genomes in other species and compared the rate of change. For example lets say that the change was 1 part in a 1000 for the lizards but for all other species was one part in a billion on average over a similar time span. They could then conclude that other species take a million times longer for the same amount of change.

I can only conclude evolution progresses by saltation, and this is good evidence for it.

lol
RuvDraba
Posts: 6,033
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11/6/2015 8:52:11 AM
Posted: 1 year ago
At 11/6/2015 12:17:16 AM, janesix wrote:
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time? I can only conclude evolution progresses by saltation, and this is good evidence for it.

Jane, we've discussed this recently. These are the lizards of Pod Mrcaru, and the effect is called the Founder Effect [https://en.wikipedia.org...].

Recall that you began by asking me about the development of new organs -- which you believed had never been observed, and I told you that these have been observed. Now you've turned refutation into evidence just by changing the way you claim things work.

These shifts in the way you think are a product of your own unquestioned subjectivity: adapting your reasoning to suit your conclusions. They're part of the reason you find it so hard to understand science, because science requires consistency, falsifiability and recognition of one's own ignorance and error.

The key conclusion we can draw from studying your reactions is that your theories are not 'obvious' because their mechanisms weren't obvious even to you.
kp98
Posts: 729
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11/6/2015 9:10:16 AM
Posted: 1 year ago
why they made the million years estimate.

It's because what appears to have happened is that entirely new, complex, well adapted structures arose 'overnight'. What is supposed to happen is that novel structures begin as an inefficient small modification to some existing body part which is subsequently futher modified by successive mutations over an extended period until the new organ is complete. New organs aren't supposed to pop-into existence fully formed - that would be like a dinosaur suddenly sprouting efficient wings fully capable of flight from nothing.

As it stands, the story doesn't so much support saltation as a miracle!

Which is why more info. is needed before jumping to the conclusion that what appears to have happened is indeed what happened. Journalists are not reknowned for minimising the significance of their stories, and even National Geographic doesn't want to bore its readers!
janesix
Posts: 3,485
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11/6/2015 8:02:01 PM
Posted: 1 year ago
At 11/6/2015 7:34:12 AM, kp98 wrote:
It's certainly very interesting. I have looked around the 'net but not come up with any follow-up studies so I don't know what genetic changes were involved. Without more to go on it's hard to draw any definite conclusion.

It reads as if complex adaptive changes occurred overnight. Even if that required a single mutation it would be remarkable that the 'right' mutation occurred and spread so quickly, and if multiple co-ordinated mutations happened then putting it down to random chance is pushing it.

I agree.

But is that the case here? A lot of unusual findings are initially announced only to be revealed to have simple explanations on further investigation. Is there a follow up anywhere?
janesix
Posts: 3,485
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11/6/2015 8:05:56 PM
Posted: 1 year ago
At 11/6/2015 8:52:11 AM, RuvDraba wrote:
At 11/6/2015 12:17:16 AM, janesix wrote:
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time? I can only conclude evolution progresses by saltation, and this is good evidence for it.

Jane, we've discussed this recently. These are the lizards of Pod Mrcaru, and the effect is called the Founder Effect [https://en.wikipedia.org...].

Recall that you began by asking me about the development of new organs -- which you believed had never been observed, and I told you that these have been observed. Now you've turned refutation into evidence just by changing the way you claim things work.

These shifts in the way you think are a product of your own unquestioned subjectivity: adapting your reasoning to suit your conclusions. They're part of the reason you find it so hard to understand science, because science requires consistency, falsifiability and recognition of one's own ignorance and error.

The key conclusion we can draw from studying your reactions is that your theories are not 'obvious' because their mechanisms weren't obvious even to you.

"In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population."

The founder effect is LOSS of genetic variation. How is gaining a new organ a loss of genetic information?
janesix
Posts: 3,485
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11/6/2015 8:09:48 PM
Posted: 1 year ago
At 11/6/2015 9:10:16 AM, kp98 wrote:
why they made the million years estimate.

It's because what appears to have happened is that entirely new, complex, well adapted structures arose 'overnight'. What is supposed to happen is that novel structures begin as an inefficient small modification to some existing body part which is subsequently futher modified by successive mutations over an extended period until the new organ is complete. New organs aren't supposed to pop-into existence fully formed - that would be like a dinosaur suddenly sprouting efficient wings fully capable of flight from nothing.

As it stands, the story doesn't so much support saltation as a miracle!

Which is why more info. is needed before jumping to the conclusion that what appears to have happened is indeed what happened. Journalists are not reknowned for minimising the significance of their stories, and even National Geographic doesn't want to bore its readers!

The brute fact is this is evidence that new structures CAN appear overnight. If you don't have millions of years, the modern synthesis falls apart. But they will just sweep stuff like this under the rug and ignore it.
RuvDraba
Posts: 6,033
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11/6/2015 8:22:53 PM
Posted: 1 year ago
At 11/6/2015 8:05:56 PM, janesix wrote:
At 11/6/2015 8:52:11 AM, RuvDraba wrote:
At 11/6/2015 12:17:16 AM, janesix wrote:
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time? I can only conclude evolution progresses by saltation, and this is good evidence for it.

Jane, we've discussed this recently. These are the lizards of Pod Mrcaru, and the effect is called the Founder Effect [https://en.wikipedia.org...].

Recall that you began by asking me about the development of new organs -- which you believed had never been observed, and I told you that these have been observed. Now you've turned refutation into evidence just by changing the way you claim things work.

These shifts in the way you think are a product of your own unquestioned subjectivity: adapting your reasoning to suit your conclusions. They're part of the reason you find it so hard to understand science, because science requires consistency, falsifiability and recognition of one's own ignorance and error.

The key conclusion we can draw from studying your reactions is that your theories are not 'obvious' because their mechanisms weren't obvious even to you.

"In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population."

The founder effect is LOSS of genetic variation. How is gaining a new organ a loss of genetic information?

You tend to spit out tested ideas you don't like and them make up new ideas to replace them. So let's try approach it differently. Can you tell me:

Given what you know about reproduction and the way parents' traits can combine in offspring, how might reducing genetic variation increase the probability that differences will magnify over time?
janesix
Posts: 3,485
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11/6/2015 8:33:48 PM
Posted: 1 year ago
At 11/6/2015 8:22:53 PM, RuvDraba wrote:
At 11/6/2015 8:05:56 PM, janesix wrote:
At 11/6/2015 8:52:11 AM, RuvDraba wrote:
At 11/6/2015 12:17:16 AM, janesix wrote:
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time? I can only conclude evolution progresses by saltation, and this is good evidence for it.

Jane, we've discussed this recently. These are the lizards of Pod Mrcaru, and the effect is called the Founder Effect [https://en.wikipedia.org...].

Recall that you began by asking me about the development of new organs -- which you believed had never been observed, and I told you that these have been observed. Now you've turned refutation into evidence just by changing the way you claim things work.

These shifts in the way you think are a product of your own unquestioned subjectivity: adapting your reasoning to suit your conclusions. They're part of the reason you find it so hard to understand science, because science requires consistency, falsifiability and recognition of one's own ignorance and error.

The key conclusion we can draw from studying your reactions is that your theories are not 'obvious' because their mechanisms weren't obvious even to you.

"In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population."

The founder effect is LOSS of genetic variation. How is gaining a new organ a loss of genetic information?

You tend to spit out tested ideas you don't like and them make up new ideas to replace them.

Saltation is an old idea. Not something I made up.

So let's try approach it differently. Can you tell me:

Given what you know about reproduction and the way parents' traits can combine in offspring, how might reducing genetic variation increase the probability that differences will magnify over time?

Has nothing to do with gaining new organs.
janesix
Posts: 3,485
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11/6/2015 8:35:07 PM
Posted: 1 year ago
At 11/6/2015 8:22:53 PM, RuvDraba wrote:
At 11/6/2015 8:05:56 PM, janesix wrote:
At 11/6/2015 8:52:11 AM, RuvDraba wrote:
At 11/6/2015 12:17:16 AM, janesix wrote:
"Italian wall lizards introduced to a tiny island off the coast of Croatia are evolving in ways that would normally take millions of years to play out, new research shows.

In just a few decades the 5-inch-long (13-centimeter-long) lizards have developed a completely new gut structure, larger heads, and a harder bite, researchers say."

http://news.nationalgeographic.com...

Why do they said it should normally take "millions of years" when obviously, it only takes a miniscule fraction of that time? I can only conclude evolution progresses by saltation, and this is good evidence for it.

Jane, we've discussed this recently. These are the lizards of Pod Mrcaru, and the effect is called the Founder Effect [https://en.wikipedia.org...].

Recall that you began by asking me about the development of new organs -- which you believed had never been observed, and I told you that these have been observed. Now you've turned refutation into evidence just by changing the way you claim things work.

These shifts in the way you think are a product of your own unquestioned subjectivity: adapting your reasoning to suit your conclusions. They're part of the reason you find it so hard to understand science, because science requires consistency, falsifiability and recognition of one's own ignorance and error.

The key conclusion we can draw from studying your reactions is that your theories are not 'obvious' because their mechanisms weren't obvious even to you.

"In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population."

The founder effect is LOSS of genetic variation. How is gaining a new organ a loss of genetic information?

You tend to spit out tested ideas you don't like and them make up new ideas to replace them. So let's try approach it differently. Can you tell me:

Given what you know about reproduction and the way parents' traits can combine in offspring, how might reducing genetic variation increase the probability that differences will magnify over time?

Let me ask you this: How do you think this new organ showed up in the population?
kp98
Posts: 729
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11/6/2015 10:19:47 PM
Posted: 1 year ago
I'm in the middle on this one, so let me suggest how it could have happened in a slightly less than earth-shattering way.

If one of the original population was already a freak (ie already had the observed 'new' traits) then because it (and its descendants who have the traits) reproduce more successfully than the standard type, it would soon be the 'freak' form that came to form the majority of the population, and possibly even the whole of the population would be the freak form if the freak was much better suited to life on the island.

Note how the 'founder effect' works here. We started with genetic diversity (freaks and standards) but ended up with only freaks, so the genetic diversity of the popuation decreased, as per theory.

Presumably the freak form also occurs in the parent population on the mainland, but in that environment the freak form has no reproductive advantage (or is at an actual reproductive disadvantage) so it is kept rare there.

Wish I could find more info!
janesix
Posts: 3,485
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11/7/2015 12:39:10 AM
Posted: 1 year ago
At 11/6/2015 10:19:47 PM, kp98 wrote:
I'm in the middle on this one, so let me suggest how it could have happened in a slightly less than earth-shattering way.

If one of the original population was already a freak (ie already had the observed 'new' traits) then because it (and its descendants who have the traits) reproduce more successfully than the standard type, it would soon be the 'freak' form that came to form the majority of the population, and possibly even the whole of the population would be the freak form if the freak was much better suited to life on the island.

Note how the 'founder effect' works here. We started with genetic diversity (freaks and standards) but ended up with only freaks, so the genetic diversity of the popuation decreased, as per theory.

Presumably the freak form also occurs in the parent population on the mainland, but in that environment the freak form has no reproductive advantage (or is at an actual reproductive disadvantage) so it is kept rare there.

Wish I could find more info!

How does the freak survive while it is slowly forming an entirely new digestive organ?
kp98
Posts: 729
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11/7/2015 2:33:11 AM
Posted: 1 year ago
How does the freak survive while it is slowly forming an entirely new digestive organ?

Let's not get carried away! To quote the article:

Researchers found that the lizards developed cecal valves"muscles between the large and small intestine...

So we are talking about a ring of intestinal muscle, not an 'entirely new digestive organ' like a stomach or pancreas. I don't think it was a stark matter of life-or-death whether a lizard had a cecal valve or not. Most probably having one was better than not having one on the island, and possibly vice versa on the mainland.

I am suggesting - only suggesting because I haven't found any more on this despite a fairly lengthy search - that one of the founders was already somewhat pre-adapted to island life, that is it already had a cecal valve.

That is entirely possible; having a cecal valve may be of little or no use on the mainland but unless it is positively harmful to have one there is no reason why the genes for it would die out.

But that raises the question of why a cecal valve would appear in the first place if it is of no use to, or possibly even harmful for, mainland lizards. The answer would be that it is a hold-over from a previous phase of evolution. Possibly the lizards began on an island where the cecal valve evolved 'normally'. The lizards subsequently returned to the mainland where the cecal valve gene was not favoured so it became rare, but not yet totally eliminated from the gene pool.

Thus when the lizards found themselves back on the island at least one of them was already primed with the mutations suited to island life.

Now I am not saying that is what happened, but it seems to me to be a reasonable scenario based on the little we know from the article. That is not to say that it wasn't saltation, but saltation isn't the only possible explanation.

If pressed, I'd say it could have been a true saltation, but my bet would be it wasn't.