"micro" and "macro" evolution

[einstein314emc2]

I don't see how you can accept micro evolution, and at the same time reject macroevolution. If you think about it, macroevolution is the natural outcome of microevolution.
First I'll start with the definitions:

macroevolution- A term introduced by Theodosius Dobzhansky in 1937, referring to evolution at levels higher than the populational. His view was that evolutionary change at the level of speciation and above. Recently, the term has been used simply to refer to large scale change, mostly at the superspecies level, eg, by Niles Eldredge.

Microevolution- A term referring to evolutionary changes beneath the level of the species. It includes, but is not limited to, adaptation to local environments. See also macroevolution.

Species- (1) a group of organisms that have a unique set of characteristics (like body shape and behavior) that distinguishes them from other organisms. If they reproduce, individuals within the same species can produce fertile offspring. (2) the basic unit of biological classification.

The difference between micro/macroevolution is that one is changes beneath the level of the species, the other is changes above the level of species.
Now when you have microevolution over time, you will be able to see noticable changes in species if the environment has changed, even new species. A species could split into two species if one subspecies/group evolves seprately from another, like a change in diet or habits. This is actually one thing that darwin studied. He saw how finches specialized for certain foods, and became different species.
I think the problem is the misunderstanding of the term macroevolution. Many people may think that the change in species occurs over a generation or two, not over hundreds or thousands, or even longer.

 

[Bushido216]

Micro- is just species adapting to different conditions using genetic information already available. Macro- is the addition of new information. That hasn't been shown to happen.

And just so you don't start randomly attacking me, those are the creationist definitions.

 

[einstein314emc2]

Micro- is just species adapting to different conditions using genetic information already available. Macro- is the addition of new information. That hasn't been shown to happen.

And just so you don't start randomly attacking me, those are the creationist definitions.

How is information defined?
By most definitions it has been shown that information can be added.

 

[caravelair]

... is the addition of new information. That hasn't been shown to happen.

in case anyone actually buys that argument, i've refuted it here.

 

[gluadys]

Creationists also tend to confuse the issue by saying macro-evolution requires "new information" or "more complexity" or change from one "kind" to another.

But the only real difference is that micro-evolution occurs within the species and macro-evolution occurs beyond the species. The same mechanisms apply throughout.

The reason for making a distinction is that a species barrier sets limits to how far a new mutation can spread. If a mutation occurs in a population in which there are no geographical, physical, sexual or other barriers to keep it from being shared with other members through reproduction, that is micro-evolution.

But if something happens to separate part of the population from the rest then:
1. Any mutation occurring in one part will not be shared with the other part, and
2. If this situation continues for a significant length of time, a whole group of mutations will occur in one part of the population that is not transmitted to the other part, and
3. a whole group of mutations will occur in the second group that is not transmitted to the first group.

As a result, if the two groups get together again they may not be able to interbreed with each other, or they may refuse to interbreed with each other. Now you have two species and each will continue to evolve separately.

At this point they won't look all that much different from each other, but over time they can become significantly unlike each other.

And that is ALL macroevolution is--different groups in a population separating from each other, no longer sharing a common gene pool, each accumulating its own unique mutations and developing its own unique characteristics.

 

[Bushido216]

How is information defined?
By most definitions it has been shown that information can be added.

Honestly, I don't know. No creationist has ever given a good definition.

 

[pureone]

Honestly, I don't know. No creationist has ever given a good definition.

We all know that that is the secret weapon of creationism. never define anything.

 

[Bushido216]

Heh, yeah. That's probably why the infamous "kind" still runs loose amongst creationist circles.

[Steve Erwin Voice]Oye! She's a wily one, she is![/Steve Erwin Voice]

 

[Nathan Poe]

We all know that that is the secret weapon of creationism. never define anything.

Except there's nothing "secret" about it. It's as plain as a sunrise.

 

[Loudmouth]

Indeed, definitions are avoided like the plague amongst the creationist flock. I am just waiting for the day when a creationist will claim that reptiles evolving into mammals is microevolutin since they are still just vertebrates. Or a dogfish evolving into a dalmation is microevolution since they are both dogs. Impenetratable ignorance is a tough nut to crack.

 

[joelazcr]

Macroevolution must be extrapolated from microevolution. There is nothing
natural about it. Only if you assume all biodiversity is the result
of evolution does the outcome seem natural.

The extrapolation seems natural, until you start looking at the details
like in the finch study.

Unpredictable Evolution in a 30-Year Study of Darwin's Finches
Science, April 26, 2002.

"The long-term study of Darwin's finch populations illustrates evolutionary unpredictability on a scale of decades. Mean body size and beak shape of both species at the end of the study could not have been predicted at the beginning. Moreover, sampling at only the beginning and at the end would have missed beak size changes in G. fortis in the middle. The temporal pattern of change shows that reversals in the direction of selection do not necessarily return a population to its earlier phenotypic state. Evolution of a population is contingent upon environmental change, which may be highly irregular, as well as on its demography and genetic architecture."

"Regardless of the precise chain of causality, field studies such as ours, in conjunction with multigenerational studies of microorganisms in the laboratory and experimental studies of selection in the field,provide an improved basis for extrapolating from microevolution to patterns of macroevolution; in the present case, from evolutionary dynamics of populations on the scale of decades to speciation and further adaptive radiation on the scale of hundreds of thousands of years. In conclusion, the long-term unpredictability of evolutionary change that arises from unpredictable ecological change, together with the need to strengthen generalizations about the frequency and importance of selection and hybridization, are reasons for encouraging additional, continuous, long-term studies of evolution in nature."

In a January 15, 2004 Nature article, David Penny commented on the significance of chimp genome being mapped. Again the details need to be worked out on the great ape to human transition.

Evolutionary biology: Our relative genetics

"The fundamental issue here is Darwin’s bold claim that "numerous, successive, slight modifications" are sufficient for all of evolution. This can be paraphrased, in later terms, as "microevolution is sufficient to explain macroevolution". The historical context is that evolutionary biology can be divided into two phases: first, the acceptance in the 1860s that evolution (macroevolution) had indeed occurred; second, the realization in the mid-1900s that the processes of microevolution (natural selection working through genetics) were necessary for evolution to occur.

The full sequence will be available later this year, and further comparative analyses should lead to a definite answer as to whether there is anything in the human genome that is not accounted for by the normal microevolutionary processes. Is there a genetic continuum between us and our ancestors and the great apes? If there is, then we can say that these processes are genetically sufficient to fully account for human uniqueness - and that would be my candidate for the top scientific problem solved in the first decade of the new millennium."

 

[Loudmouth]

Macroevolution must be extrapolated from microevolution. There is nothing natural about it. Only if you assume all biodiversity is the result
of evolution does the outcome seem natural.

Macroevolution has been observed in speciation events that result in two, non-interbreeding populations (otherwise known as "kinds").

Biology only makes sense in the light of evolution. It is the unifying principle of the natural sciences and has passed test after test independent of the assumptions. If we assume that all creatures were around since the beginning of time, nothing in biology or geology makes any sense.

 

[monkenstick]

The full sequence will be available later this year, and further comparative analyses should lead to a definite answer as to whether there is anything in the human genome that is not accounted for by the normal microevolutionary processes. Is there a genetic continuum between us and our ancestors and the great apes? If there is, then we can say that these processes are genetically sufficient to fully account for human uniqueness - and that would be my candidate for the top scientific problem solved in the first decade of the new millennium."

I can't wait to see a detailed comparison of the chimp and human genomes, i'm confident it'll show that random mutations are quite capable of explaining the amount of divergence

 

[gluadys]

Macroevolution must be extrapolated from microevolution. ... The extrapolation seems natural, until you start looking at the details like in the finch study.

Unpredictable Evolution in a 30-Year Study of Darwin's Finches
Science, April 26, 2002.


"Regardless of the precise chain of causality, field studies such as ours, in conjunction with multigenerational studies of microorganisms in the laboratory and experimental studies of selection in the field,provide an improved basis for extrapolating from microevolution to patterns of macroevolution; in the present case, from evolutionary dynamics of populations on the scale of decades to speciation and further adaptive radiation on the scale of hundreds of thousands of years. In conclusion, the long-term unpredictability of evolutionary change that arises from unpredictable ecological change, together with the need to strengthen generalizations about the frequency and importance of selection and hybridization, are reasons for encouraging additional, continuous, long-term studies of evolution in nature."

Emphasis added.

Seems like the researchers found it natural and instructive.