Microevolution

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(Microevolution, according to the creationists)
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However, they then need to be careful not to allow one species to be descended from another -- which concept they term [[macroevolution]] -- and propose that there are mechanisms that stop this from happening. Thus far, no creationist, of a scientific bent or layman, has ever proposed just exactly what those mechanisms are, nor have they provided one data point to support their idea.<ref>Some, for the sake of argument, have speculated that it would be possible if there was two types of DNA, one that could mutate and one that couldn't. The same people were then quick to point out that this clearly isn't the case and only one type of DNA is found in this respect. But hey, they at least tried!</ref> Their only justification for their position is wishful thinking and as yet, in spite of their best efforts, very few people are willing to allow wishful thinking to be considered scientific evidence.
 
However, they then need to be careful not to allow one species to be descended from another -- which concept they term [[macroevolution]] -- and propose that there are mechanisms that stop this from happening. Thus far, no creationist, of a scientific bent or layman, has ever proposed just exactly what those mechanisms are, nor have they provided one data point to support their idea.<ref>Some, for the sake of argument, have speculated that it would be possible if there was two types of DNA, one that could mutate and one that couldn't. The same people were then quick to point out that this clearly isn't the case and only one type of DNA is found in this respect. But hey, they at least tried!</ref> Their only justification for their position is wishful thinking and as yet, in spite of their best efforts, very few people are willing to allow wishful thinking to be considered scientific evidence.
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Another attempted justification is that mutations can only destroy information, and can't make new information.  No creationist has ever provided a clear way of measuring "information" in genes.
  
 
== Can I accept microevolution but not macroevolution? ==
 
== Can I accept microevolution but not macroevolution? ==

Revision as of 15:12, 15 May 2009

Microevolution, when used by creationists, is a term that is the evolutionary equivalent of the belief that the mechanism you use to walk from your bedroom to the kitchen is insufficient to get you from New York to Los Angeles.

When used by scientists, microevolution is the term for the gradual adaptation and evolution by a species which does not result in multiple new species. Microevolution is distinct from macroevolution, but the two are inextricably linked (see below).

Contents

Microevolution, according to the creationists

Warning: Your brain may hurt after reading the following. Ibuprofen may be required.

Microevolution is a concept generally used by creationists to denote evolution within a species, or adaptation. The reason that creationists even use the term at all is that they feel the need to provide some mechanism to explain the variations observed in the animal kingdom, when they also subscribe to the view that not all life on the planet is related via variation and natural selection.

Given that many creationists lack faith[1], they then require the support of science to validate their worldview, and science cannot support the unfeasibly large wooden vessel required to save the plethora of varieties within each species we see today, as well as the obviously large number of species that are now extinct, but which creationists claim were extant at the time of the flood and have since died out. Thus they fall back on kinds and microevolution to salvage any pretension of scientific rigour. For example: If only two of the cattle kind are required on the ark, all they then need is to explain how those two animals can be responsible for the diversity of cattle we see today, and microevolution is their chosen explanation.[2] Chosen, perhaps, in the mistaken belief that if science attacks their concept it will effectively be attacking the whole concept of evolution. They care little that the rate of evolution required to account for their beliefs is orders of magnitude greater than any rate proposed by science, even for periods of great species diversification such as the Cambrian Explosion.[3]

However, they then need to be careful not to allow one species to be descended from another -- which concept they term macroevolution -- and propose that there are mechanisms that stop this from happening. Thus far, no creationist, of a scientific bent or layman, has ever proposed just exactly what those mechanisms are, nor have they provided one data point to support their idea.[4] Their only justification for their position is wishful thinking and as yet, in spite of their best efforts, very few people are willing to allow wishful thinking to be considered scientific evidence.

Another attempted justification is that mutations can only destroy information, and can't make new information. No creationist has ever provided a clear way of measuring "information" in genes.

Can I accept microevolution but not macroevolution?

Sure, why not. No one's telling anyone what they can and cannot accept...that would be wrong. But...

You'd be mistaken.

All descent with variation is microevolution. Macroevolution is what we call the accumilation of those small variations over millions of years.

Macroevolution vs. microevolution

Put simply, macroevolution is what results when microevolution occurs in two or more populations within a species. Or maybe one might think of macroevolution as the net sum of all the microevolution that occurs within a species. Either way, the unavoidable conclusion is that it's impossible to have one without the other!!!!

Perhaps an example would help clear things up. Suppose there was a large population of Species A (let's just suppose, for fun, that they're salamanders) that lives in a hilly terrain. Everything's fine and dandy until some event (like an ice age) comes along, and isolates different groups on the mountaintops. Hopefully, that makes sense so far.

It shouldn't be much of a jump to assume that those different populations, no matter how similar, still have slightly different mutations and develop under slightly different conditions. Given enough time (or enough of a difference in conditions) these two groups will develop into very different populations, and when they come back together, they may not be able to inter-breed. Et voila! New species.

So there we have it: "microevolution" is what happened to each individual group. "Macroevolution" is the result when the two groups develop under different conditions. And it may sound like an esoteric example, but guess what?! It's actually happened!!!! The "theoretical" situation accounts for the diversity of salamanders in Appalachia.

Is it possible to have microevolution without macroevolution occuring? Sure – if there's no reproductive isolation, the species will keep micro-evolving quite merrily, no matter how long it has. But as soon as something isolates two or more groups, it sows the seeds for new species via macroevolution. And is it possible have macro without the micro? Absolutely, and there are documented cases (see macroevolution)!

See also

Footnotes

  1. By which we mean irrational belief in that for which there is no evidence, as opposed to the Judaeo-Christian understanding of faith as commitment to what one "knows" to be true
  2. In fact, Genesis clearly states that seven pairs of all kosher animals were brought on board, allowing for 28 distinct chromosomes of genetic information in the cattle baramin. Dogs and cats are another matter.
  3. Because they claim diversification of species occurred in terms of "devolution," or the loss of genetic information from heterozygous created kinds. This is because they learned some genetic and evolutionary science terms and proceeded to misuse them.
  4. Some, for the sake of argument, have speculated that it would be possible if there was two types of DNA, one that could mutate and one that couldn't. The same people were then quick to point out that this clearly isn't the case and only one type of DNA is found in this respect. But hey, they at least tried!


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