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Author Topic:   Punctuated Equilibria: The Basics
Pressie
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From: Pretoria, SA
Joined: 06-18-2010
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Message 16 of 25 (816231)
08-01-2017 8:44 AM
Reply to: Message 10 by CRR
07-31-2017 7:20 PM


CRR writes:

The PE model was developed to “explain” large morphological gaps in the fossil record, saltations...

I don't think that CRR wrote the truth about that here.
This message is a reply to:
 Message 10 by CRR, posted 07-31-2017 7:20 PM CRR has not yet responded

    
Taq
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Posts: 7029
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Member Rating: 3.7


(1)
Message 17 of 25 (816243)
08-01-2017 11:30 AM
Reply to: Message 10 by CRR
07-31-2017 7:20 PM


CRR writes:

The PE model was developed to “explain” large morphological gaps in the fossil record, saltations.

quote:
1. There are two common uses of "gradualism," one of which is more traditional, the other of which is equivalent to Eldredge and Gould's "phyletic gradualism."
2. Darwin was not a "phyletic gradualist," contrary to the claims of Eldredge and Gould.
3. PE is not anti-Darwinian; in fact, the scientific basis and conclusions of PE originated with Charles Darwin.
4. PE does not require any unique explanatory mechanism (e.g. macromutation or saltation).
5. Eldredge and Gould's PE is founded on positive evidence, and does not "explain away" negative evidence (e.g. a purported lack of transitional fossils).
http://theobald.brandeis.edu/pe.html

PE explains gaps between species in the fossil record, but it doesn't use saltation to explain it. A gap in the fossil record is a gap in the fossil record, not a gap in the actual evolutionary history of the species.

If you think you can see a fossil series showing many small steps then punk eek does not apply to that example.

That would also be false. Gould and Eldredge pointed to several instances where there was rapid evolution in the fossil record, complete with transitional fossils between species:

quote:
Because they feel that PE was concocted to "explain away" a purported lack of transitional fossils, some critics have maintained that Eldredge and Gould based their theory of PE on negative evidence. This is a strange argument, however, since the paper where they first proposed PE was completely based on two independent paleontological studies (on pulmonate gastropods and on Phacopsid trilobites), which they described in detail with extremely good temporal resolution. Using positive evidence, these studies showed stasis and rapid evolution that supports the PE model. Furthermore, Gould and Eldredge's second PE paper also extensively analyzed well-resolved paleontological evidence in support of their hypothesis.
http://theobald.brandeis.edu/pe.html

They were able to find positive evidence of allopatric speciation with transitional fossils between species, and then evidence of that new species replacing the less derived parent population.

Edited by Taq, : No reason given.

Edited by Taq, : No reason given.

Edited by Taq, : No reason given.


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 Message 10 by CRR, posted 07-31-2017 7:20 PM CRR has responded

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 Message 19 by CRR, posted 08-02-2017 6:33 AM Taq has responded

  
Tanypteryx
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From: Oregon, USA
Joined: 08-27-2006
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Message 18 of 25 (816254)
08-01-2017 2:29 PM
Reply to: Message 17 by Taq
08-01-2017 11:30 AM


Taq writes:

PE explains gaps between species in the fossil record, but it doesn't use saltation to explain it. A gap in the fossil record is a gap in the fossil record, not a gap in the actual evolutionary history of the species.

This gets right to the heart of the matter.


What if Eleanor Roosevelt had wings? -- Monty Python

One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie

If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy

The reason that we have the scientific method is because common sense isn't reliable. -- Taq


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 Message 17 by Taq, posted 08-01-2017 11:30 AM Taq has not yet responded

    
CRR
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Posts: 528
From: Australia
Joined: 10-19-2016
Member Rating: 1.3


Message 19 of 25 (816275)
08-02-2017 6:33 AM
Reply to: Message 17 by Taq
08-01-2017 11:30 AM


Terminology
More correctly I should have said "The PE model was developed to “explain” large morphological gaps in the fossil record, seeming saltations.
This message is a reply to:
 Message 17 by Taq, posted 08-01-2017 11:30 AM Taq has responded

Replies to this message:
 Message 20 by RAZD, posted 08-02-2017 7:02 AM CRR has not yet responded
 Message 21 by Taq, posted 08-02-2017 10:52 AM CRR has responded

  
RAZD
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From: the other end of the sidewalk
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Message 20 of 25 (816276)
08-02-2017 7:02 AM
Reply to: Message 19 by CRR
08-02-2017 6:33 AM


Re: Terminology
and again

"The PE model was developed to “explain” large morphological gaps

what are "large morphological gaps?"

Message 15:
... developed to “explain” large morphological gaps in the fossil record, ...

What is a "large morphological gap?"

Message 9:
... The isolated population has to ... appears as a sudden large scale change ...

What is "large scale change?"

In punk-eek the new species appears in the fossil record, but there are obvious multiple homologies with older fossils found in the same geographical location, showing a clear path of lineage, and no radical change (nothing beyond what we see in the variations of dogs).

So what is "large scale change?"

So what is a "large morphological gap?"

So, again, what is a "large morphological gap?"

Enjoy


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This message is a reply to:
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Taq
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Posts: 7029
Joined: 03-06-2009
Member Rating: 3.7


Message 21 of 25 (816284)
08-02-2017 10:52 AM
Reply to: Message 19 by CRR
08-02-2017 6:33 AM


Re: Terminology
CRR writes:

More correctly I should have said "The PE model was developed to “explain” large morphological gaps in the fossil record, seeming saltations.

That is false. PE was used to explain rapid evolution between species, followed by longer periods of stasis. The gap between species is not a large morphological gap.


This message is a reply to:
 Message 19 by CRR, posted 08-02-2017 6:33 AM CRR has responded

Replies to this message:
 Message 22 by CRR, posted 08-14-2017 11:54 PM Taq has responded

  
CRR
Member
Posts: 528
From: Australia
Joined: 10-19-2016
Member Rating: 1.3


Message 22 of 25 (817019)
08-14-2017 11:54 PM
Reply to: Message 21 by Taq
08-02-2017 10:52 AM


Re: Terminology
The idea of Punk Eek is that the evolution takes place "off stage" where it isn't recorded in the fossil record so that when it later reappears there is a large change, an apparent saltation. The evolution that takes place "off stage" is assumed to follow normal Darwinian processes.
quote:
According to this idea, the changes leading to a new species don't usually occur in the mainstream population of an organism, where changes wouldn't endure because of so much interbreeding among like creatures. Rather, speciation is more likely at the edge of a population, where a small group can easily become separated geographically from the main body and undergo changes that can create a survival advantage and thus produce a new, non-interbreeding species.

This hypothesis predicts that the fossil record at any one site is unlikely to record the process of speciation. If a site records that the ancestral species lived there, the new species would probably be evolving somewhere else. The small size of the isolated population which is evolving into a new species reduces the odds that any of its members will be fossilized. The new species will only leave fossils at the same site as the old one if it becomes successful enough to move back into its ancestral range or different enough to exist alongside its relatives.
http://www.pbs.org/wgbh/evolution/library/03/5/l_035_01.html



Note that evolution can potentially take place more quickly in a small population because the average time for a change to reach fixity is correspondingly smaller. On the other hand the smaller population has less chance of producing a favourable mutation.
This message is a reply to:
 Message 21 by Taq, posted 08-02-2017 10:52 AM Taq has responded

Replies to this message:
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 Message 24 by CRR, posted 08-15-2017 9:56 PM CRR has not yet responded

  
Taq
Member
Posts: 7029
Joined: 03-06-2009
Member Rating: 3.7


(1)
Message 23 of 25 (817062)
08-15-2017 11:23 AM
Reply to: Message 22 by CRR
08-14-2017 11:54 PM


Re: Terminology
CRR writes:

The idea of Punk Eek is that the evolution takes place "off stage" where it isn't recorded in the fossil record . . .

Gould and Eldredge cited two examples of PE being recorded in the fossil record:

"PE sometimes is claimed to be a theory resting upon the lack of evidence rather than upon evidence. This is a curious, but false claim, since Eldredge and Gould spent a significant portion of their original work examining two separate lines of evidence (one involving pulmonate gastropods, the other one involving Phacopsid trilobites) demonstrating the issues behind PE (1972). Similarly, discussion of actual paleontological evidence consumes a significant proportion of pages in Gould and Eldredge 1977. This also answers those who claimed that E&G said that PE was unverifiable."
http://www.talkorigins.org/faqs/punc-eq.html

The gap between species is not a large morphological gaps. On top of that, Gould has stated that there are plenty of transitional fossils filling those gaps:

"Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists—whether through design or stupidity, I do not know—as admitting that the fossil record includes no transitional forms. Transitional forms are generally lacking at the species level, but they are abundant between larger groups."--Stephen Jay Gould, "Evolution as Fact and Theory"

The evolution that takes place "off stage" is assumed to follow normal Darwinian processes.

That is false. The observation of a nested hierarchy demonstrates that the processes were Darwinian. It isn't assumed.

Note that evolution can potentially take place more quickly in a small population because the average time for a change to reach fixity is correspondingly smaller. On the other hand the smaller population has less chance of producing a favourable mutation.

Selection is often stronger at the edges of a species range meaning that mutations which are only slightly beneficial in the center of the species range can be much more strongly beneficial at the edges of the range. There is also the possibility that a neutral or even slightly deleterious mutation in the main population can be beneficial at the edges of the species range. Therefore, the subpopulation may already have the beneficial mutations it needs in low numbers.


This message is a reply to:
 Message 22 by CRR, posted 08-14-2017 11:54 PM CRR has not yet responded

  
CRR
Member
Posts: 528
From: Australia
Joined: 10-19-2016
Member Rating: 1.3


Message 24 of 25 (817221)
08-15-2017 9:56 PM
Reply to: Message 22 by CRR
08-14-2017 11:54 PM


Re: Terminology
The idea of Punk Eek is that the evolution takes place "off stage" where it isn't recorded in the fossil record so that when it later reappears there is a large change, an apparent saltation. The evolution that takes place "off stage" is assumed to follow normal Darwinian processes.

Using http://www.talkorigins.org/faqs/punc-eq.html as a reference
PE essential features are peripatric speciation in a geographically limited region and stratigraphically limited extent such that sampling of the fossil record will reveal a pattern of most species in stasis, with abrupt appearance of newly derived species being a consequence of ecological succession and dispersion.

While Eldredge and Gould acknowledge that geological processes contribute to the "gappiness" of the fossil record, they also assert that PE is by far the more important consideration in that regard.

Or in other words evolution takes place "off stage" where it isn't recorded in the fossil record so that when it later reappears there is a large change, an apparent saltation. The evolution that takes place "off stage" is assumed to follow normal Darwinian processes.


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Replies to this message:
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Taq
Member
Posts: 7029
Joined: 03-06-2009
Member Rating: 3.7


Message 25 of 25 (817282)
08-16-2017 11:25 AM
Reply to: Message 24 by CRR
08-15-2017 9:56 PM


Re: Terminology
CRR writes:

Or in other words evolution takes place "off stage" where it isn't recorded in the fossil record so that when it later reappears there is a large change, an apparent saltation. The evolution that takes place "off stage" is assumed to follow normal Darwinian processes.

They also cited instances where rapid peripatric speciation was recorded in the fossil record. Also, it isn't assumed to be a Darwinian process. We observe that the end result is a nested hierarchy which is evidence that it was a Darwinian process.


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