Macro and Micro Evolution, Real Terms?

[DeistPaladin]

Question:

Are terms like "macroevolution" and "microevolution" real, as in used by biologists, or are they terms that Creationists made up?

AronRa refers to "macroevolution" in his 11th Foundational Falsehood of Creationism as speciation. He's a source I have tremendous respect for but was wondering if there were other opinions on the matter.

 

[5810Singer]

Question:

Are terms like "macroevolution" and "microevolution" real, as in used by biologists, or are they terms that Creationists made up?

AronRa refers to "macroevolution" in his 11th Foundational Falsehood of Creationism as speciation. He's a source I have tremendous respect for but was wondering if there were other opinions on the matter.

I can go look for sources if you want, but I've definitely heard other knowledgable people saying that there is no "macro" or "micro", only evolution.

The process known as "micro-evolution" by creationists, is the same process that causes "macro-evolution" when we factor in the element of "deep time". That's why acceptors of evolution don't recognise the distinction between "macro" and "micro" evolution.

I know I haven't provided any new insight on the issue, but I can assure you that AronRa isn't the only one who rejects the terms "macro" and "micro" in relation to evolution.


EDIT: I'm not sure if we need sources to settle this, I'm going to try an arithmetical analogy instead.

Let's consider "micro-evolution" as analogous to "addition", and "macro-evolution" as analogous to "multiplication".

If I said: "The creation of new numbers by the combination of existing numbers is possible via the process of addition, but impossible via the process of multiplication, and not only that multiplication doesn't even exist." Then you would immediately recognise the fallacy of the statement. I believe the analogy fits the "macro/micro-evolution" issue pretty well.

 

[borrofburi]

Are terms like "macroevolution" and "microevolution" real, as in used by biologists, or are they terms that Creationists made up?

AronRa refers to "macroevolution" in his 11th Foundational Falsehood of Creationism as speciation. He's a source I have tremendous respect for but was wondering if there were other opinions on the matter.

The answer, so far as I can tell, is: sort of. It was brought up in one of the threads here (I have long since forgotten which), and I believe it was... c0nc0rdance? that pointed out there are sometimes genetic changes so profound (yet simple) that they create an entire species in one step, and that it makes sense to call that macroevolution (since in that sense it's not merely "time scale" differences). I have unfortunately forgotten what process, but I'm sure Squawk remembers (or whoever originally pointed it out, if (s)he happens to read this thread).

It can also be convenient, especially when speaking to laymen who aren't antagonistic and petulant, to have terms to easily distinguish what time-scale you are talking about, which is what I expect AronRa was doing, though I have not watched the video.

 

[5810Singer]

It can also be convenient, especially when speaking to laymen who aren't antagonistic and petulant, to have terms to easily distinguish what time-scale you are talking about, which is what I expect AronRa was doing, though I have not watched the video.

Here's a quote from AronRa's narration it occurs at 2:15 in the vid: "Speciation is the only taxonomic division which is genetically significant, and it's the only one which can be objectively determined, so it is the only possible point of division between the largely unnecessary distinctions of "macro" and "micro" evolution."

 

[sgrunterundt]

Microevolutioin is a term used by creationists, that is the equivalent to stating that the method you use to walk from your bedroom to your kitchen is incapable of getting you from New York to Los Angeles.

 

[borrofburi]

It can also be convenient, especially when speaking to laymen who aren't antagonistic and petulant, to have terms to easily distinguish what time-scale you are talking about, which is what I expect AronRa was doing, though I have not watched the video.

Here's a quote from AronRa's narration it occurs at 2:15 in the vid: "Speciation is the only taxonomic division which is genetically significant, and it's the only one which can be objectively determined, so it is the only possible point of division between the largely unnecessary distinctions of "macro" and "micro" evolution."

Ah. It's an interesting statement, and seems to encompass multiple ideas. He is correct, so far as my past discussions with taxonomists are concerned (read: what he says agrees with what I understood other informed people to say), in that speciation is the only taxonomic division which can be objectively determined; however he also does not seem to entirely reject "macro" or "micro" as potentially useful, merely largely unnecessary, which I (as a layman who has read quite a large amount of biology) would fully agree with, noting that "largely unnecessary" is not the same as "completely useless".

 

[Squawk]

both are real and and languages of convenience.

For the sake of argument lets equate genetic variation with distance. Where the unit of selection is the gene, the unit of distance is the milimeter.

If you wish to discuss every day objects it would make sense to discuss distances in small units. You might suggest your desk is 60cm across or you cup is 10cm high.

Likewise you might refer to a car journey in kilometers. To use cm to measure a car journey would be a bit silly, to use km to measure the size of a pencil would likewise be silly. It would lead to various unneccessary complications.

LIkewise with evolution, if we wish to discuss, say, tetrapod evolution, it's going to be of little use identifying individual mutations and tracking how they propogate through a species. We need to deal in geological time, in the order of millions of years, and across speciation events.

If you wish to discuss the propagation of sickle cell throughout africa, on the other hand, it makes sense to model the spread of a gene through a population.

Different scales are required to discuss the different events with enough rigour to make sense. Macro-evolution is simply the name given to events at or above the species level for ease of reference. Micro evolution is reservced for events below the species level.

In a way it's a discussion about reductionism. Creationists have just latched onto the term because it sounds plausible to the layman, but both are in use by scientists and convey meaning.

 

[SchrodingersFinch]

All of the (credible non-creationist) sources I remember reading define macroevolution as evolution at or above the level of species. Speciation is therefore macroevolution, and it has been observed.

Many don't like the terms macro- and microevolution because of the creationists' bastardisation of them. However, they are real terms still used by scientists. On PubMed 'macroevolution' gives you 193 results and 'microevolution' 354 results. In comparison, 'evolution' gives you almost 260 000 results. So only about 0.2 % of scientific articles that talk about evolution mention micro- or macroevolution.

 

[Aught3]

Macro and micro-evolution were real terms used commonly by biologists up to about the sixties when it was realised that the distinction was unimportant. Creationists like to revive them because it allows them to accept changes that are repeated frequently in the environment and in the lab but deny that a new species could ever come from another thus allowing them to reject human evolution. Their understanding of science is terrible but at least they are only out of date by about 50 years, which is actually an improvement if you think about it :?


Borr, the process to which you are referring might be polyploidy that the only thing I can think of that would create a new species in one go.

 

[obsidianavenger]

honestly, i think the distinction is bs. its the exact same principle on a matter of scale, either of time or of effect (a la genome doubling, which happened a lot in early plants). no one speaks of micro-metabolism when considering a single enzyme at work on a single polymer and macro-metabolism when speaking of the energy consumption activities of the organism as a whole. no one speaks of micro and macro aging, or micro and macro growth (though they might speak of microscopic or macroscopic growths, which is different).

i find having seperate terms actually creates more confusion rather than solves anything

 

[Squawk]

http://scholar.google.co.uk/scholar?hl=en&q=macroevolution&as_sdt=2000&as_ylo=2009&as_vis=0

A quick search in google scholar for macroevolution, limiting the search to 2009 or more recent, throws up 1230 results, though admitedly a number of those won't be in peer reviewed journals.

A similar search of the journal nature reveals 47 publications since 2001 that reference macroevolution, and those are without doubt peer reviewed articles.


These terms are not used overly frequently as any context can easily be inferred from the articles themselves, you don't have to say you are struding macro evolution when looking at fossils, for example, though of course you are. The terms are well defined and are still part of the lexicon of evolutionary biologists.

 

[Aught3]

Now compare it to the number that talk about evolution.

 

[Squawk]

Now compare it to the number that talk about evolution.

To serve what purpose? I'm demonstrating that it is a valid term in the scientific lexicon. What impact does frequency of use have?

A more interesting comparison, genetic drift

http://www.nature.com/search/executeSearch?sp-c=25&pag-start=1&exclude-collections=journals_palgrave,lab_animal&sp-q-1=NATURE,NEWS&include-collections=journals_nature,crawled_content&pag-end=201&sp-m=0&sp-q=genetic%20drift&sp-p=all&sp-s=date_descending

218 uses in nature, ie 4-5 times more likely to be used. That's less than an order of magnitude for a term that is of huge importance.

 

[Aught3]

So you'd agree that it is a scientific term that is rarely used anymore?

 

[Aught3]

I did a slightly different search to Squawk but still using Nature and articles since 2001 inclusive.

Macroevolution: 5 (two talking about the lack of distinction itself)
Microevolution: 4 (one talking about the lack of distinction)
Genetic drift: 67
Evolution: 3,789

 

[Squawk]

So you'd agree that it is a scientific term that is rarely used anymore?

1940-1950
Macroevolution referenced 38 times in google scholar
Evolution referenced 18900

1950-1960
Macroevolution referenced 58 times
Evolution referenced 32800 times

1990-2000
macroevolution 3810 times
evolution 194000

2000-2010
macroevolution: 8870
evolution: 230000

And thats the game

 

[Aught3]

Well alright since the game is over I'll just summarise what I think.

Macro and micro-evolution certainly are scientific terms, I agree with that. They were around in the Twenties to separate the process of natural selection described by Darwin which occurred over a long (macro) time period and the genetics of Mendel where changes occurred to genes over short (micro) time periods. After the synthesis of the Fifties and the details of genetics that were worked out it the Sixties it was no longer possible to make a credible case that macro and micro-evolution were different processes. I stand by my previous statement that at this point the distinction became, scientifically, unimportant.

What I didn't take into consideration was the revival of the terms by Steven Gould for his punctuated equilibrium hypothesis. This did generate a lot of discussion but I don't think there was ever a clear case for separating macro and micro-evolution. So while it has been talked about there has not been a scientific distinction (apart from degree) since the synthesis.