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Author Topic:   MACROevolution vs MICROevolution - what is it?
CRR
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Posts: 578
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Message 181 of 893 (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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Taq
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Message 182 of 893 (810625)
05-31-2017 10:40 AM
Reply to: Message 181 by CRR
05-31-2017 8:02 AM


CRR writes:

Elsewhere I have suggested that Durston's definitions might be used.

As soon as I demonstrated an increase in functional information you rejected that definition.

From the Uncommon Descent definition:

Macroevolution, in all its possible meanings, implies the emergence of new complex functions.

I think you, I, and everyone else would agree that the differences between humans and chimps equates to macroevolution. I would hazard a guess that you do not accept humans and chimps descending from a common ancestor.

So what complex functions separate humans and chimps? If you can't answer that question, then it would seem this definition doesn't work either.

However as far as I can tell from the article the record starts with forams and ends with forams.

Now you are using the creationist name game. This is where you claim it is microevolution if you can use the same word to group two species.

So let's see how that works out for you. Humans and apes evolving from a common ancestor would be microevolution because they are all still within Hominidae. Humans, bears, and echidnas evolving from a common ancestor would be microevolution because they started out as mammals and ended up as mammals. Those are just varieties of mammal species. Humans, frogs, and fish evolving from a common ancestor is also microevolution because the common ancestor was a vertebrate, and all the modern species are still vertebrates.

See a problem here?

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.

The biological species concept allows for hybrids, so it isn't a problem.

Edited by Taq, : No reason given.


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RAZD
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Posts: 18970
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Message 183 of 893 (810683)
05-31-2017 6:01 PM
Reply to: Message 181 by CRR
05-31-2017 8:02 AM


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.

You do realize that foraminifera is a subphylum ... right? So this is like saying you started with placental mammals and you ended with placental mammals and all that is documented is varieties of placental mammals ...

quote:
Foraminifera (/fəˌrζməˈnɪfərə/, Latin meaning hole bearers, informally called "forams") are members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm that among other things are used for catching food, and commonly by an external shell or "test" made of various materials and constructed in diverse forms. Chitin test is found in some very simple genera & believed to be most primitive type. Chitin test is characterize in genera Textularia. All but perhaps a very few are aquatic and most are marine, the majority of which live on or within the seafloor sediment (i.e., are benthic) while a smaller variety are floaters in the water column at various depths (i.e., are planktonic). A few are known from freshwater or brackish conditions and some soil species have been identified through molecular analysis of small subunit ribosomal DNA.[1][2]

Scientific classification
Domain: Eukaryota
(unranked): SAR
(unranked):Rhizaria
Phylum:Retaria
Subphylum:Foraminifera

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.

Yep the Linnaean system is becoming more and more unworkable as we develop the cladistics further, see the "unranked" categories above, inserted because the Linnaean system wasn't adequate to explain the evidence. Isn't it great how science adapt to new information, rather than cling with dogmatic fervor to unreasonable views? With cladistics we don't need to worry about problems cause by an artificial classification system such as Linneaus developed: it has served it's purpose, but it is time to retire.

Also with cladistics we see that the important element is genetic isolation -- the lack of breeding behavior is sufficient. There is also a braided pattern that occurs during the speciation process -- see Interweaving Evolution & Hybrid Vigor for more.

Enjoy


we are limited in our ability to understand
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This message is a reply to:
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CRR
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Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.2


Message 184 of 893 (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.


This message is a reply to:
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Replies to this message:
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RAZD
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Posts: 18970
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


Message 185 of 893 (810726)
06-01-2017 6:17 AM
Reply to: Message 184 by CRR
06-01-2017 1:48 AM


The "foram" subphylum
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.

Yes a rather generic description for the whole Subphylum. Just like a description of mammals as "... a clade of endothermic amniotes distinguished from reptiles (including birds) by the possession of a neocortex (a region of the brain), hair, three middle ear bones and mammary glands. Females of all mammal species nurse their young with milk, secreted from the mammary glands." ... and of course the descendants of mammals will always be mammals ...

The summary article you linked to is based on the one I provided in Message 1 and it goes on to say

quote:
The overall sequence is so enormous because the tiny fossils can fit between grains of sand, and escape being crushed. The sequence was very hard to study until recently, when a computerized system was developed. It can identify and classify forams, and it is connected to a microscope.

Classify the genus and species of the forams in the study. When we go to the article in Message 1 that this data is taken from they say

quote:
EVOLUTION AT SEA COMPLETE FOSSIL RECORD FROM THE OCEAN UPHOLDS DARWIN'S GRADUALISM THEORIES

About 330 species of living and extinct planktonic forams have been classified so far. ...

We've literally seen hundreds of speciation events," says Arnold. "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 anomally. This way, we cannot only look for the same things that have been observed in living organisms, but we can see just how often these things really happen in the environment over an enormous period of time.

As he speaks, Arnold shows a series of microphotographs, depicting the evolutionary change wrought on a single foram species. "This is the same organism, as it existed through 500,000 years," he says. "We've got hundreds of examples like this, complete life and evolutionary histories for dozens of species."

... scientists have theorized, but never been able to demonstrate, that in the absence of competition, an explosion of life takes place. The evolution of new species greatly accelerates, and a profusion of body shapes and sizes bursts across the horizon, filling up vacant spaces like weeds overtaking a pristine lawn. An array of new forms fans out into these limited niches, where crowding soon forces most of the new forms to spin out into oblivion similar to sparks from a bonfire.

The ancient record of foram evolution reveals that the story of recovery after extinction is indeed busy and colorful. "What we've found suggests that the rate of speciation increases dramatically in a biological vacuum," says Parker. "After the Cretaceous extinction, the few surviving foram species rapidly evolved into new species, and for the first time we're able to see just how this happens, and how fast."

As the available niches fill up with these new creatures, the speciation rates slow down, and the pressure from competition between species appears to bear down in earnest. The extinction rate then rises accordingly. This scenario, says Arnold, suggests that the speciation process is sensitive to how fully packed the biosphere is with other species, not the number of individuals. ...


Many speciation events, hundreds of species lineages, a virtually complete fossil record with all the transitionals ...

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

Yep little critters, but we get the whole skeleton in these fossils. Is this a problem for you?

As noted in Message 1: "This is the essence of the debate: when does change become sufficient to be "macro"evolution and how does it occur."

For scientists using the technical definition for "macro"evolution this occurs when we have speciation and the formation of nested hierarchies of descent. This is seen in multitudes in this record of the Foraminifera subphylum.

If you want to see more change than that, you are going to have to define when it will be enough to convince you. Like the people quoted in Message 1 that somehow never really got around to doing that.

It seems a common creationist ploy -- as long as you never define something like this then you can argue it hasn't occurred ... all you need to do is move the goalposts every time evidence is presented.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
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This message is a reply to:
 Message 184 by CRR, posted 06-01-2017 1:48 AM CRR has responded

Replies to this message:
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CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.2


Message 186 of 893 (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.
This message is a reply to:
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RAZD
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Posts: 18970
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


Message 187 of 893 (810847)
06-02-2017 6:36 AM
Reply to: Message 186 by CRR
06-01-2017 7:30 AM


Re: The "foram" subphylum
Why?

You should ask the scientists, I only report what they said (and that others agreed with). Of course that would mean effort on your part, but it is not my job to do your homework.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
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• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

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CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.2


Message 188 of 893 (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.


This message is a reply to:
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Replies to this message:
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 Message 191 by RAZD, posted 06-03-2017 5:37 AM CRR has responded

  
Tangle
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Posts: 5065
From: UK
Joined: 10-07-2011
Member Rating: 3.2


Message 189 of 893 (810898)
06-03-2017 12:27 AM
Reply to: Message 188 by CRR
06-02-2017 10:55 PM


Re: The "foram" subphylum
CRR writes:

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.

The thing about real science is that if you actually want to you can find anything you need to just by looking. Here's the World Foramifera Database.

http://www.marinespecies.org/foraminifera/

This comprises all the know species along with the biologist that described them. Now, as an armchair paeleontologist you'll no doubt dispute individual organisms and their place in the taxa, in which case you need to take that up with the Editors as that's what they're there for. So far they have upwards of 36,000 species.

So what exactly is your point of dispute - just more semantics?


Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien.

"Life, don't talk to me about life" - Marvin the Paranoid Android

"Science adjusts it's views based on what's observed.
Faith is the denial of observation so that Belief can be preserved."
- Tim Minchin, in his beat poem, Storm.


This message is a reply to:
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CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.2


Message 190 of 893 (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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RAZD
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Posts: 18970
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


(1)
Message 191 of 893 (810915)
06-03-2017 5:37 AM
Reply to: Message 188 by CRR
06-02-2017 10:55 PM


Re: The "foram" subphylum
You introduced them to the discussion. ...

Along with the link that an interested person would follow for questions like yours. You do realize that it looks like you are trying to use semantics rather than actually look at the science. As was noted in the excerpt from the link Arnold and Palmer were doing the classifications. If you want to know how they did it then you need to ask them. Here's more:

quote:
As he speaks, Arnold shows a series of microphotographs, depicting the evolutionary change wrought on a single foram species. "This is the same organism, as it existed through 500,000 years," he says. "We've got hundreds of examples like this, complete life and evolutionary histories for dozens of species."

By studying forams, Tony Arnold (front) and Bill Parker assembled many evolutionary sequences with virtually no missing links.

About 330 species of living and extinct planktonic forams have been classified so far. After thorough examinations of marine sediments collected from around the world, micropaleontologists now suspect these are just about all the free-floating forams that ever existed.


Do you see anything in there about them asking me how to do it? They were at Florida State University at the time -- contact them. If you dare.

... Since you're not willing to back it up I'll just assume we can neglect this as relevant to the discussion.

So you'll use any excuse to dodge the issue. Typical creationist, never follow the information.

Hmmm. Time for my nap.

You've been sleeping a long time dreaming a fantasy, maybe it's time to wake up to reality.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
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This message is a reply to:
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Replies to this message:
 Message 192 by CRR, posted 06-03-2017 8:00 AM RAZD has responded

  
CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.2


Message 192 of 893 (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.


This message is a reply to:
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RAZD
Member
Posts: 18970
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


(1)
Message 193 of 893 (810951)
06-03-2017 10:25 AM
Reply to: Message 192 by CRR
06-03-2017 8:00 AM


The "foram" subphylum and speciation
I really am getting tired of doing homework for creationists, especially when you don't read to learn but to cherry-pick one aspect and think that somehow refutes the whole work. Sorry, reality doesn't work that way.

... 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. ...

Let's explore this in a little more depth. What it also said was that they observed hundreds of speciation events ...

quote:
"We've literally seen hundreds of speciation events," says Arnold. "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 anomally. This way, we cannot only look for the same things that have been observed in living organisms, but we can see just how often these things really happen in the environment over an enormous period of time.

and in case you missed it in Evolution 101, speciation is the development of two or more species from a parent species. Not only is speciation observed here, and thus is a fact, the process of speciation forms a clade and thus this is biological macroevolution occurring.

Ah, you'll likely quip "they're single cell critters and single cell critters reproduce asexually so how do you determine speciation with the biological species definition?" but again you will be operating on incomplete information, as Wiki points out:

quote:
... The foraminiferal life-cycle involves an alternation between haploid and diploid generations, although they are mostly similar in form.[9][21] The haploid or gamont initially has a single nucleus, and divides to produce numerous gametes, which typically have two flagella. The diploid or schizont is multinucleate, and after meiosis fragments to produce new gamonts. Multiple rounds of asexual reproduction between sexual generations is not uncommon in benthic forms ...

This gives them the advantage to produce several generations of clones (only modified by mutations) and the advantage of sexual recombination to develop more individuals successful at survival and reproduction in a shorter time frame, and also incidentally to undergo speciation with the biological species definition.

Again, referring to evolution 101 on the types of speciation:

quote:
If we look at the continued effects of evolution over many generations, the accumulation of changes from generation to generation may become sufficient for individuals to develop combinations of traits that are observably different from the ancestral parent population.

(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, readily sharing DNA via horizontal transfer (asexual) and interbreeding (sexual) and various combinations. This is not the case, however, because there is a second process that results in multiple species and increases the diversity of life.

(3) The process of divergent speciation, or cladogenesis, involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other.

The reduction or loss of interbreeding (gene flow, sharing of mutations) between the sub-populations results in different evolutionary responses within the separated sub-populations, each then responds independently to their different ecological challenges and opportunities, and this leads to divergence of hereditary traits between the subpopulations and the frequency of their distributions within the sub-populations.

Over generations phyletic change occurs in these populations, the responses to different ecologies accumulate into differences between the hereditary traits available within each of the daughter populations, and when these differences have reached a critical level, such that interbreeding no longer occurs, then the formation of new species is deemed to have occurred. After this has occurred each daughter population microevolves independently of the other/s. These are often called speciation events because the development of species is not arbitrary in this process.

If we looked at each branch linearly, while ignoring the sister population, they would show anagenesis (accumulation of evolutionary changes over many generations), and this shows that the same basic processes of evolution within breeding populations are involved in each branch.

An additional observable result of speciation events, however, is a branching of the genealogical history for the species involved, where two or more offspring daughter species are each independently descended from the same common pool of the ancestor parent species. At this point a clade has been formed, consisting of the common ancestor species and all of their descendants.


This phyletic change (anagenesis) is seen in the foraminifera photo in the article:

... What it did say was that it started with a single celled organism and ended with a single celled organism. ...

Are you seriously going to suggest that all single cell organisms (plant or animal) are of one species because they are all single cell organisms? Really?

... The only apparent difference was the shape of the shell. Micro or macro? Maybe, maybe not.

And actually, both. As explained above.

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

Please don't stoop to the level of Davidjay in posting ridiculous non-sequitur silliness.

Now go take another nap and cogitate on the information you have received gratis, and maybe some of it will sink in.

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
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• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

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Replies to this message:
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CRR
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Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.2


Message 194 of 893 (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.


This message is a reply to:
 Message 193 by RAZD, posted 06-03-2017 10:25 AM RAZD has responded

Replies to this message:
 Message 195 by RAZD, posted 06-05-2017 7:51 AM CRR has responded

  
RAZD
Member
Posts: 18970
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 3.8


Message 195 of 893 (811107)
06-05-2017 7:51 AM
Reply to: Message 194 by CRR
06-05-2017 2:27 AM


Re: The "foram" subphylum and speciation
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.

Again you are cherry picking statements and ignoring others. Did this just disappear because you ignored it?

quote:
(3) The process of divergent speciation, or cladogenesis, involves the division of a parent population into two or more reproductively isolated daughter populations, which then are free to (micro) evolve independently of each other.

Looking at each branch and ignoring the other you will see anagenesis -- the process of evolution occurring in each generation -- but what you will be missing is that the anagenesis in each branch will be different after the split, different selection of different mutations.

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.

Conveniently ignoring the haploid generations? Forams, like many species (mosses for example) alternate sexual and asexual reproduction. You don't have sperm and egg sex, but haploid duplicates the nucleus then divides into two gamets which then combine with other gametes to produce a diploid cell.

quote:
The foraminiferal life-cycle involves an alternation between haploid and diploid generations, although they are mostly similar in form.[9][21] The haploid or gamont initially has a single nucleus, and divides to produce numerous gametes, which typically have two flagella. ...

quote:
A gamete (from Ancient Greek γαμετή gamete from gamein "to marry"[1]) is a haploid cell that fuses with another haploid cell during fertilization (conception) in organisms that sexually reproduce. ... In contrast, isogamy is the state of gametes from both sexes being the same size and shape, ...

quote:
Isogamy is a form of sexual reproduction that involves gametes of similar morphology (similar shape and size), differing in general only in allele expression in one or more mating-type regions. Because both gametes look alike, they cannot be classified as "male" or "female." Instead, organisms undergoing isogamy are said to have different mating types, most commonly noted as "+" and "−" strains, although in some species of Basidiomycota there are more than two mating types (designated by numbers or letters). In all cases, fertilization occurs when gametes of two different mating types fuse to form a zygote.

quote:
A zygote... is an eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information necessary to form a new individual. ... In single-celled organisms, the zygote can divide asexually by mitosis to produce identical offspring.

That wasn't too hard was it?

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.

And yet it is stated in the article that it was observed hundred of times.

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; ...

Apologies, I thought you were funnin' me by posting some arbitrary Tony Arnold found on the web. Please let me know if you get a response from Dr Parker.

But if you want examples of speciation there are many more. We can always bring in Pelycodus again.

Enjoy

Edited by RAZD, : .


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This message is a reply to:
 Message 194 by CRR, posted 06-05-2017 2:27 AM CRR has responded

Replies to this message:
 Message 196 by CRR, posted 06-05-2017 8:16 AM RAZD has responded

  
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