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Author Topic:   MACROevolution vs MICROevolution - what is it?
CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 159 of 908 (810223)
05-25-2017 6:35 PM


Definitions (or not)
Please define "macro"evolution - so we can be sure we are (a) talking about evolution and (b) we are talking about the same thing.

Also define "micro"evolution just to be sure we are talking about something different.

It should be easy eh?.


It should be, but it's not.

"Russian entomologist Yuri Filipchenko first coined the terms "macroevolution" and "microevolution" in 1927 in his German language work, "Variabilität und Variation". Since the inception of the two terms, their meanings have been revised several times." [wikipedia] Not only revised several times but there are several definitions for each. One result is that there are people on both sides of the debate who prefer not to use the terms at all.

Generally the demarcation seems to be speciation. Is this micro or macro.

Understanding Evolution http://evolution.berkeley.edu/evolibrary/article/evo_01 avoids the problem by separating the three terms

Microevolution - How does evolution work on a small scale?
Speciation - What are species anyway, and how do new ones evolve?
Macroevolution - How does evolution work on a grand scale?

When I did a course on Anthropology this demarcation was discussed in the course forum and using the definitions we had been given, concluded that speciation was microevolution. Others of course will stoutly defend speciation as being macroevolution.

In https://p2c.com/...oevolution-vs-macroevolution-two-mistakes, Kirk Durston suggests

...let me propose the following definitions, which I will continue to use:

Microevolution: genetic variation that requires no statistically significant increase in functional information.

Macroevolution: genetic change that requires a statistically significant increase in functional information.

Both statistical significance and functional information are already defined in the literature. We also have a method to measure evolutionary change in terms of functional information, so we are ready to move on, avoiding the two mistakes discussed above.
http://en.wikipedia.org/wiki/Statistical_significance
http://www.ncbi.nlm.nih.gov/pubmed/17494745
http://www.tbiomed.com/content/4/1/47


Somehow I doubt his proposal will be universally accepted any time soon.

Perhaps one thing we can do is avoid misnaming "microevolution" as "evolution". I am referring to using the Population Genetics definition of evolution as "a change in allele frequency in a population over time" as a term for evolution in general and for the theory of evolution. Let's keep this definition within PG. Outside of PG this definitely falls into the scope of microevolution. Within their discussion of microevolution Evolution 101 says "Biologists who study evolution at this level define evolution as a change in gene frequency within a population."

So where does speciation fall? My opinion, and many will say that's not worth much, is that it could be either micro or macroevolution depending on what caused it. Was it, as Durston says, a statistically significant increase in functional information? Can a statistically significant amount be accumulated over a number of insignificant changes? Add to this the problems of actually defining species and speciation. Among what are traditionally recognised as separate species we can get hybrids including some cross genera hybrids.

OK I think I've provided enough there to generate multiple responses so I await your comments.

[edit] Actually I don't know what Yuri Filipchenko's original definitions were because I don't have the book and I can't read German. At this stage it probably doesn't matter too much.

Edited by CRR, : No reason given.

Edited by CRR, : as marked

Edited by CRR, : Links added to Durston quote.


Replies to this message:
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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 162 of 908 (810226)
05-25-2017 7:53 PM
Reply to: Message 160 by Taq
05-25-2017 6:36 PM


Re: Definitions (or not)
It is easy, and has been done several times now.

Ok, I'll choose Durston's definitions and I'll expect you to follow those in any future discussion. You're right, it's EASY.
This message is a reply to:
 Message 160 by Taq, posted 05-25-2017 6:36 PM Taq has responded

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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 163 of 908 (810227)
05-25-2017 8:00 PM
Reply to: Message 158 by Taq
05-25-2017 11:32 AM


Re: reviving this thread ...
I have often found that human languages offer a good analogy for comparing microevolution and macroevolution.

The changes that have occurred in the Indo-European language family, for example, demonstrate that languages follow a ‘downhill’ simplification in inflections, etc. by natural processes. Adam Smith commented on this in one of his books.

Similarly observed evolution seems to follow a downhill path with loss of information so, using Durston's definitions, macroevolution is rare or nonexistent.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 167 of 908 (810248)
05-26-2017 1:24 AM
Reply to: Message 166 by Taq
05-26-2017 12:48 AM


Re: Definitions (or not)
Taq writes:


CRR writes:

Ok, I'll choose Durston's definitions and I'll expect you to follow those in any future discussion. You're right, it's EASY.

And those definitions would be . . . ?

As per Message 159
In Microevolution vs Macroevolution: Two Mistakes, Kirk Durston suggests
...let me propose the following definitions, which I will continue to use:

Microevolution: genetic variation that requires no statistically significant increase in functional information.

Macroevolution: genetic change that requires a statistically significant increase in functional information.

Both statistical significance and functional information are already defined in the literature. We also have a method to measure evolutionary change in terms of functional information, so we are ready to move on, avoiding the two mistakes discussed above.
http://en.wikipedia.org/wiki/Statistical_significance
http://www.ncbi.nlm.nih.gov/pubmed/17494745
http://www.tbiomed.com/content/4/1/47


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 169 of 908 (810283)
05-27-2017 4:10 AM
Reply to: Message 168 by Taq
05-26-2017 11:09 AM


Re: Definitions (or not)
Taq writes:


CRR writes:

Macroevolution: genetic change that requires a statistically significant increase in functional information.

Then I can point to an example of macroevolution.


Possibly; at least in the Pinacate population since different results were obtained in the Armendaris population.

I'm not sure how they define gain-of-function mutations except as they relate to colour. This is not necessarily the same as a gain of functional information. A broken switch can result in a light that is always on or always off, but the switch is still broken. Since "This difference is controlled in large part by the interaction of two proteins, the melanocortin-1-receptor (MC1R) and the agouti-signaling protein" the mutations could prevent normal interaction of this system; the equivalent to a broken switch.

Remember that beneficial is not the same as an increase in functional information. As has been found in bacteria a mutation that disables a normal function can be beneficial if it also prevents an antibiotic from working. A loss of pigmentation in the hair of polar bears has been beneficial to them.

Only 4 of the mutations are associated with the dark colour and it has not been established yet how many of these are actually producing the result, with the other piggy-backing.

A comparison could be with Nylonase which has been shown to be a fine tuning of an existing enzyme that already had some action on nylon, and this is acknowledged to be within the capability of the mutation-selection mechanism. As Douglas Axe said Darwinism is a good tinkerer but a poor innovator.

Whether this is actually a statistically significant increase in functional information I have neither the skills or resources to determine. So I will say again; Possibly.

btw, I take it then that you have accepted Durston's definitions for micro and macro evolution.

Edited by CRR, : btw added.

Edited by CRR, : No reason given.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 171 of 908 (810373)
05-28-2017 6:11 PM
Reply to: Message 170 by bluegenes
05-27-2017 12:00 PM


Re: Definitions (or not)
It's automatically a gain of functional information because there's a new function in the population,

More likely a loss of function since the interaction between the melanocortin-1-receptor (MC1R) and the agouti-signaling protein has been lost.

You accept then that it is in principal possible to measure genetic functional information in at least some cases.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 173 of 908 (810389)
05-29-2017 6:09 AM
Reply to: Message 172 by bluegenes
05-29-2017 4:13 AM


Re: Definitions (or not)
... the arrival of new genes ...

This is NOT a new gene. This is at best a new allele of the existing MC1R gene. It is also probably a defective version of the existing MC1R as I've already said.
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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 175 of 908 (810402)
05-29-2017 8:20 AM
Reply to: Message 174 by bluegenes
05-29-2017 6:57 AM


Re: Definitions (or not)
"Defective" would mean producing a disadvantaged phenotype,

Incorrect. Defective means no longer performing the original function, nor an improved one". Many cases of antibiotic resistance come from a defect that disables a feature, such as a binding site, that the antibiotic needs to be effective.

In the mouse case the new allele is defective since the interaction with the agouti-signaling protein no longer works. It is a defect but the result is beneficial when the mouse lives in the dark lava fields. However it is a disadvantage on the lighter coloured sand. Benefit depends on environment.

Edited by CRR, : No reason given.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 181 of 908 (810615)
05-31-2017 8:02 AM
Reply to: Message 1 by RAZD
02-13-2007 9:07 PM


There is no one canonical definition of micro- and macro-evolution. Elsewhere I have suggested that Durston's definitions might be used.
Microevolution: genetic variation that requires no statistically significant increase in functional information.

Macroevolution: genetic change that requires a statistically significant increase in functional information.


From Microevolution vs Macroevolution: Two Mistakes

This at least avoids the argument about where speciation falls between the two. Speciation could be either micro- or macro-evolution depending on the change that caused it.

Another view can be found at https://uncommondescent.com/faq/#macroismic where they say

... Macroevolution, in all its possible meanings, implies the emergence of new complex functions. A function is not the simplistic sum of a great number of “elementary” sub-functions: sub-functions have to be interfaced and coherently integrated to give a smoothly performing whole. In the same way, macroevolution is not the mere sum of elementary microevolutionary events.
...
Microevolution, in all its known examples (antibiotic resistance, and similar) is made of simple variations, which are selectable for the immediate advantage connected to them. But a new functional protein cannot be built by simple selectable variations, no more than a poem can be created by random variations of single letters, or a software written by a sequence of elementary (bit-like) random variations, each of them improving the “function” of the software.

RAZD links to an article The Foram Fossils from which he quotes

quote:

Drs. Tony Arnold (Ph.D., Harvard) and Bill Parker (Ph.D., Chicago) are the developers of what reportedly is the largest, most complete set of data ever compiled on the evolutionary history of an organism. The two scientists have painstakingly pieced together a virtually unbroken fossil record that shows in stunning detail how a single-celled marine organism has evolved during the past 66 million years. Apparently, it's the only fossil record known to science that has no obvious gaps -- no "missing links."

"We've literally seen hundreds of speciation events," Arnold added. "This allows us to check for patterns, to determine what exactly is going on. We can quickly tell whether something is a recurring phenomenon -- a pattern -- or whether it's just an anomaly.


However as far as I can tell from the article the record starts with forams and ends with forams. Rather than seeing "hundreds of speciation events" they have documented the development of hundreds of varieties of the same species. Thus we have not observed "macro"evolution in this case.

What is the difference between "genus" "family" "order" and all those other taxonomic classifications?

The Linnaean taxonomic system was developed ~200 years ago but the concept and definition of species has changed since. Since there are known hybrids between Linnaean species and genera it does not fit well the Biological Species concept based on the ability to produce viable offspring. Perhaps we should be using different words for Linnaean vs Biological species but for now the word "species" can have different meanings. For now at least the Linnaean taxonomic system provides a way for scientists to specify particular organisms.
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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 184 of 908 (810717)
06-01-2017 1:48 AM
Reply to: Message 183 by RAZD
05-31-2017 6:01 PM


"foram"
A "foram" is a single-celled ocean plankton, either free-floating or else bottom dwelling.
The series starts with a single-celled ocean plankton, and ends with a single-celled ocean plankton. Or more specifically the fossil shells of a single-celled ocean plankton.

The only evolution in evidence is the shape of the shells.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 186 of 908 (810728)
06-01-2017 7:30 AM
Reply to: Message 185 by RAZD
06-01-2017 6:17 AM


Re: The "foram" subphylum
Explain to me, precisely, how each new species is identified.
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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 188 of 908 (810895)
06-02-2017 10:55 PM
Reply to: Message 187 by RAZD
06-02-2017 6:36 AM


Re: The "foram" subphylum
You introduced them to the discussion. Since you're not willing to back it up I'll just assume we can neglect this as relevant to the discussion.

Hmmm. Time for my nap.

Edited by CRR, : nap time.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 190 of 908 (810906)
06-03-2017 4:05 AM
Reply to: Message 189 by Tangle
06-03-2017 12:27 AM


Re: The "foram" subphylum
Since FORAMINIFERA don't reproduce sexually classification of foraminifera has been based primarily on characters of the shell or test. Wall composition and structure, chamber shape and arrangement, the shape and position of any apertures, surface ornamentation, and other morphologic features of the shell are all used to define taxonomic groups of foraminifera.
Ref: http://www.ucmp.berkeley.edu/fosrec/Wetmore.html

Are these really separate species or are they persistent varieties?

So basically all that Arnold and Parker have identified is a change in shape of the shell. Speciation or just a gradual change in the phenotype of one species? Micro or macro evolution? Simply put, we don't know.

Speciation in itself is not necessarily a precise marker of macroevolution. The London Underground Mosquito is recognized as a new species but is still undeniably a mosquito. I suspect this is why Berkley in Evolution 101 have speciation as a separate entry between micro and macroevolution.

Microevolution
How does evolution work on a small scale?

Speciation
What are species anyway, and how do new ones evolve?

Macroevolution
How does evolution work on a grand scale?

In any case in the current taxonomic system we can get fertile hybrids between species and between genera. This is why I have said earlier that speciation could be either microevolution or macroevolution. This is why I think Durston's definitions have much to recommend them.

Have Arnold and Parker demonstrated speciation in the forams? Maybe, or maybe not.
Does this "speciation" demonstrate macroevolution? Maybe, or maybe not.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 192 of 908 (810932)
06-03-2017 8:00 AM
Reply to: Message 191 by RAZD
06-03-2017 5:37 AM


Re: The "foram" subphylum
Yes I followed the link and read the article. Nowhere does it say what criteria they used to say when speciation had occurred. What it did say was that it started with a single celled organism and ended with a single celled organism. The only apparent difference was the shape of the shell. Micro or macro? Maybe, maybe not.

Why don't you ask Tony Arnold
"Ask Tony Arnold about an antique mandolin or an Afghanistani saddle-bag and the stories begin. The soft-spoken, former Professor of Geology and Paleontology at FSU will gently lead you through a two-minute course in history, politics, geography and the finer points of sheep wool."
https://www.usatoday.com/...e-arnolds-oriental-rugs/81691546

Edited by CRR, : No reason given.


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CRR
Member (Idle past 496 days)
Posts: 579
From: Australia
Joined: 10-19-2016


Message 194 of 908 (811087)
06-05-2017 2:27 AM
Reply to: Message 193 by RAZD
06-03-2017 10:25 AM


Re: The "foram" subphylum and speciation
(2) The process of lineal change within species is sometimes called phyletic speciation, or anagenesis

This is also sometimes called arbitrary speciation in that the place to draw the line between linearly evolved genealogical populations is subjective, and because the definition of species in general is tentative and sometimes arbitrary.

If anagenesis was all that occurred, then all life would be one species, ...


and in case you missed it in Evolution 101, speciation is the development of two or more species from a parent species.

and in case you missed it, you've just contradicted yourself since phyletic speciation does not result in two or more species from a parent species.

The foraminiferal life-cycle involves an alternation between haploid and diploid generations

You might have to educate me on this. As far as I can tell the diploid generation has a Multinucleated cell and doesn't involve sexual reproduction with another foram.

I agree with you that "phyletic change (anagenesis) is seen in the foraminifera photo in the article." If anagenesis was all that occurred, then the entire series would be one species; as you said in your definition of anagenesis, and you haven't shown that divergent speciation has occurred.

So while the series could show speciation by anagenesis the entire series would be one species; which appears to be an oxymoron.

I told you where to find Tony Arnold, former Professor of Geology and Paleontology at FSU, so you could contact him for clarification if you wanted. I have sent an email to Dr Parker and I'll let you know if I get a response; although I don't think I should be doing your homework for you.


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