Why Is Only "Micro Evolution" Acceptable?

[vhawk01]

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2 and 3 are wrong, and I think 4 is by extension.

Microevolution is simply change in allele frequencies within a population. Alleles are the different versions of a given gene. Macroevolution typically deals with larger scale evolutionary phenomena. An example given on wiki is how feathers appeared from birds when they diverged from one group of dinosaurs.

Speciation isn't really a micro/macroevolution question. It occurs on both levels, depending on how you look at it. It is of course related to changes in allele frequencies, as these changes alter the reproductive capabilities of the animals. And it's related to macro as well b/c you're looking beyond a single simple population.

I'm not sure I understand #5. What does "GM'd parents" mean? If you're wondering if the offspring are "separate species", the answer is no because they cannot interbreed at all.

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Why is two wrong? This is part of why I said "I don't know WHAT people mean when they use the absurd version of the term 'macroevolution.' What makes a "large change" and what represents shifting allelic frequencies? Feathers on birds count but lighter and lighter skin doesn't? Feathers are just the extreme end of the scales scale, pardon the pun.

[hitch1978]

So do you disagree with vhawk's post? If you don't then I am missing something.

"GM'd parents" Meant genetically modified parents, but you've allready covered that one.

The problem I am having is in definition then. It is all well and good saying when this animal developed feathers, it went through macroevolution, and when this animal turned brown it went through microevolution. But what are the set in stone, 100%, definitions of the two terms?

[hitch1978]

LOL, I basically made the same post as you vhawk! Maybe there is hope for me yet.

[vhawk01]

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So do you disagree with vhawk's post? If you don't then I am missing something.

"GM'd parents" Meant genetically modified parents, but you've allready covered that one.

The problem I am having is in definition then. It is all well and good saying when this animal developed feathers, it went through macroevolution, and when this animal turned brown it went through microevolution. But what are the set in stone, 100%, definitions of the two terms?

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It is EXACTLY the point that "there used to be 20% blue eyed people and now there are 28%" and "they used to have scales but now they have feathers" are the same thing. It is only a matter of degree. The ONLY non-arbitrary line between micro and macro is speciation. And although its not arbitrary (Rduke yells at me when I say it is) it is still flawed or at least misleading to the lay public.

[Matt R.]

I think #3 is wrong because it's far too specific. Of course microevolution is a subset of macroevolution... at least I mean "subset" in the sense that you need micro in order for macro to occur.

The example on wikipedia actually was talking about the appearance of feathers on birds when/after they diverged from dinosaurs. As I understand it, the reason it is "macroevolution" is because it deals with 2 separate species -- dinosaurs to birds. If it was simply talking about alteration of feathers (due to changes in allele frequency) in one population of birds, then it would not be considered "macro"

This is why changing skin color over time isn't considered under the domain of macroevolution.

It's been a few years since my biology days, but I think the above is reasonably correct.

[hitch1978]

So the only ambiguity lies in what is considered 'species change'?

[Matt R.]

Also, to clarify,

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3) The accepted meaning of 'macroevolution' is where a change in an animal's genetic makeup is made, but where that change does affect what species said animal can mate with.


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is incorrect, in my opinion, because when someone uses the term "macroevolution" they aren't talking about any one, specific, genetic change that alters the reproductive capabilities of an organism. Even microevolution can do this (not every individual has an equal chance of mating with another individual, even of the same species, for instance). When you talk of macroevolution, it typically involves many generations and a large shift in allele frequencies, not any "one" mutation that instantly makes one individual incapable of reproducing with others of his/her species.

[Matt R.]

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So the only ambiguity lies in what is considered 'species change'?

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I'm not sure what you mean. Species don't change from one to another. They diverge from one species to two distinct species. Could you clarify?

[hitch1978]

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So the only ambiguity lies in what is considered 'species change'?

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I'm not sure what you mean. Species don't change from one to another. They diverge from one species to two distinct species. Could you clarify?

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The line is blurred as to when two distinct sepcies have developed. Iow, feathers=new species, lighter skin=no new species, or feathers=no new species, lighter skin=new species.

I am going to take some time away to try and digest it now, so I won't be responding for a few hours. I need to get my head around where we are at, and what I do/don't understand.

[Matt R.]

No no no. You're almost there. Ignore the feathers for now -- sorry for making it confusing.

The feathers example was just to illustrate a purely random question regarding the development of a phenotype (physical characteristic) after a species diverges. Basically, the point was "Here is an evolutionist examining the development of feathers from a bird's ancestors. He is thinking in terms of "macroevolution" when he questions it from a dinosaur to bird perspective". The feathers aren't the reason they are considered different species. The reason they are different species is because no members of the bird population can successfully breed with a member from the dinosaur population (or whatever that dinosaur population evolved into).

So basically, the feathers was just a side point showing that this is a question a biologist might ask, and how it can be framed as a macroevolution question.