Microevolution vs. Macroevolution

[Student Nurse]

Last semester I took Microbiology. Before then I was a Christian and believed in creation, but what I studied and what I saw undoubtedly proved evolution - hence the "switchover" or "atheistic conversion" or whatever you want to call it.

I hear a lot of Christians say "the microbiological world proves microevolution" (i.e. evolution on the small scale such as bacteria adapting to new hosts/environments and incorporating plasmids into their DNA in order to become resistant to antibiotics), "but that doesn't prove macroevolution" (ie human evolution)

If this isn't true, then what does it prove to you? How can something be true on the small scale and not on the large? (give examples please)

[Goat]

Do you not think that the mutation and adaptation of viruses and bacteria are evolution?

Yes, virus and bacteria can evolve. And I'm not saying that evolution cannot happen. But, what I am saying is that just because evolution can happen on the small scale, we cannot automatically say that it can happen on the large scale.

Hence the debate on microevolution vs macroevolution. I believe everyone (including creationists) do not dispute small scale evolution. But, it's much more difficult to prove large scale evolution.

I've been trying to argue that as we increase in complexity, it's more difficult to empirically demonstrate evolution. And the level that we've so far reached to demonstrate empirically is protein evolution in regards to interacting with chemicals.

How about ring species then? How can you explain ring species?

And , in your opinion , what is the difference between 'micro' evoultion and 'macro' evolution?

[QED]

The rejection of evolution so far seems to have been a two-stage affair. The first stage of rejecting the mechanism of natural selection as an agent for self-organization has evidently failed in the face of all the empirical evidence supporting it. Rather than capitulate fully to Evolutionary Theory however, the acceptance now seems to have been qualified by the adoption of the term "micro-evolution".

I would like to know on what grounds the extrapolation of this mechanism (or principle of self-organization) to the full-scale ordering of living things is being rejected? When we look at the self-induced changes in the ordering of bacteria and viruses we are satisfied with the logic that underlies the adaptations. I feel that this ability to automatically adapt, having been demonstrated at the level of a working principle, can only be justifiably rejected by providing yet another principle which shows its supposed limitations. Simply coming up with a series of supposedly impossible transitions (adaptive gaps to bridge) provides a never-ending supply of ammunition to those who wish to remain in the second stage of rejection. I don't think this is in itself a particularly justifiable position.

[otseng]

Look at the the enzyme beta-galactosidase gene deletion experiment of Barry Hall in 1982. The deletion of this gene meant the bacteria which was being expermented on could not digest lactose. After allowing the bacteria to replicate in the billions, it was given nothing but lactose. Most of the bacteria died, but a number had evolved a new set of regulatory genes (three pieces needed to allow lactose to get into the cell, to break it down to useful substances, and to regulate the system, so 3 new genes were needed).

Hall removed the lacZ gene which produced the lactose enzyme. And another gene (ebg) mutated to produce a lactose enzyme. It is an example of evolution. Or perhaps is it an example of design? The functionality of the ebg gene is unknown. Perhaps its purpose is to serve as a backup system for the lacZ gene. Also, it was a point mutation of the ebg gene that enabled it to produce an enzyme. Further, when both the lacZ and ebg genes were removed, the bacteria was never able to produce a lactose enzyme.

Most descriptions of Hall's experiments end with E. coli evolving the lactase function back again. This is very interesting because Hall's actual experiments did not end there. After his initial success, Hall wondered if any other genes would be able to evolve the lactase function. So, he deleted the ebg gene as well as the lacZ genes to test this hypothesis. And, something most interesting happened - nothing. No new gene or portion of DNA evolved the lactase function despite tens of thousands of generations of time, a huge population size, high selection pressure, and a high mutation rate.

Upon isolating cells from the hyphae, Hall saw that they frequently had two mutations, one of which was in a gene for a protein he called "evolved ß-galactosidase," (ebg) which allowed it to metabolize lactose efficiently. (Despite considerable efforts by Hall to determine it, the natural function of ebg remains unknown)

Hall did in fact delete the lacZ gene (as well as other lac genes with other related functions) in E. coli bacteria. These mutant bacteria then evolved the ability to use lactose over a very short period of time in a non-lethal lactose enriched environment. They were able to do this with the use of a very fortuitous "spare tire" gene (ebg) that, with a single point mutation, was able to achieve enough lactase activity to give the cell a selective survival/reproductive advantage

http://www.detectingdesign.com/galactos ... ution.html

[Confused]

The rejection of evolution so far seems to have been a two-stage affair. The first stage of rejecting the mechanism of natural selection as an agent for self-organization has evidently failed in the face of all the empirical evidence supporting it. Rather than capitulate fully to Evolutionary Theory however, the acceptance now seems to have been qualified by the adoption of the term "micro-evolution".

I would like to know on what grounds the extrapolation of this mechanism (or principle of self-organization) to the full-scale ordering of living things is being rejected? When we look at the self-induced changes in the ordering of bacteria and viruses we are satisfied with the logic that underlies the adaptations. I feel that this ability to automatically adapt, having been demonstrated at the level of a working principle, can only be justifiably rejected by providing yet another principle which shows its supposed limitations. Simply coming up with a series of supposedly impossible transitions (adaptive gaps to bridge) provides a never-ending supply of ammunition to those who wish to remain in the second stage of rejection. I don't think this is in itself a particularly justifiable position.

Why is it that every post I read of yours, I must read at least three times to understand what you are saying. Anytime I think I might be smart, I read your posts and realize I don't even compare (that is a compliment, not complaint).

I see your point, but I go one step further and say look at the human body's ability to adapt. Viruses are great, but require a host, so they are very limited. Bacteria are great but require specific conditions to grow in order to adapt and cannot mutate into resistant strains without this adaptation so they are limited by their environment. The human immune system shows mutations constantly. It builds resistances, creates new allergies, rejects old allergies, alters the function of other organs on a constant basis. It negates the needs for antibiotics in some cases, neccesitates the need of anti rejection medications in some cases, and in some cases, has mutated enough to dispell the need for certain immunizations and meds because it builds a self tolerance such as with malaria, etc.. We are in a constant state of mutation and adaptation. And we are self sufficient and though we require a male and female to procreate, it can now be done in a test tube making at least the female the most independent, self sufficient, mutation with the highest level of adaptation thus far. (no offense men, but no aritifical womb yet until baby is at least 24 wks gestatation in incubator in NICU and even then high mortality rate). We see evolution through mutation and adaptation on a small scale inside the human body but on a large scale as we pass these traits along to offspring.

[Goat]

Look at the the enzyme beta-galactosidase gene deletion experiment of Barry Hall in 1982. The deletion of this gene meant the bacteria which was being expermented on could not digest lactose. After allowing the bacteria to replicate in the billions, it was given nothing but lactose. Most of the bacteria died, but a number had evolved a new set of regulatory genes (three pieces needed to allow lactose to get into the cell, to break it down to useful substances, and to regulate the system, so 3 new genes were needed).

Hall removed the lacZ gene which produced the lactose enzyme. And another gene (ebg) mutated to produce a lactose enzyme. It is an example of evolution. Or perhaps is it an example of design? The functionality of the ebg gene is unknown. Perhaps its purpose is to serve as a backup system for the lacZ gene. Also, it was a point mutation of the ebg gene that enabled it to produce an enzyme. Further, when both the lacZ and ebg genes were removed, the bacteria was never able to produce a lactose enzyme.

Most descriptions of Hall's experiments end with E. coli evolving the lactase function back again. This is very interesting because Hall's actual experiments did not end there. After his initial success, Hall wondered if any other genes would be able to evolve the lactase function. So, he deleted the ebg gene as well as the lacZ genes to test this hypothesis. And, something most interesting happened - nothing. No new gene or portion of DNA evolved the lactase function despite tens of thousands of generations of time, a huge population size, high selection pressure, and a high mutation rate.

Upon isolating cells from the hyphae, Hall saw that they frequently had two mutations, one of which was in a gene for a protein he called "evolved ß-galactosidase," (ebg) which allowed it to metabolize lactose efficiently. (Despite considerable efforts by Hall to determine it, the natural function of ebg remains unknown)

Hall did in fact delete the lacZ gene (as well as other lac genes with other related functions) in E. coli bacteria. These mutant bacteria then evolved the ability to use lactose over a very short period of time in a non-lethal lactose enriched environment. They were able to do this with the use of a very fortuitous "spare tire" gene (ebg) that, with a single point mutation, was able to achieve enough lactase activity to give the cell a selective survival/reproductive advantage

http://www.detectingdesign.com/galactos ... ution.html

It wasn't just one mutation that allowed it, it was 3. Three parts had to change to allow this to happen.. it wasn't merely a replacement of the old gene.

Yes, it was 'fortutius', but there were many billions of indviduals that didn't have it.
It was a random variation, followed by the selection.. the definition of evolution.
Hall didn't CHOOSE the specific mutaions..he just controled the environment, and
let the organism do what organisms do, live eat and die.

Your 'detecting design' doesn't address the fact it needed 3 different mutations to allow for lactose to be disgested, nor does it take into account that what genes were used to provide the new function. Your detecting design had errors in their analysis. It misrepresented the results of that experiement too.

They totally miss out on the entire concept of what evolution is. .. small changes that can provide new function. Yes, they were using other preexisting structures in this case, but so what? It still is a change that provided a beneficial change (the ability to use lactose), just as the nylon disgesting bacteria had small changes that allowed it to digest nylon. Quite plainly, evolution in action. It is exactly what the TOE expects.

I don't see how getting the exact results expected isn't evidence for something.

[otseng]

And the human immune system. The fact that it mutates every 6 months (approx) isn't consider larger scale than proteins?

I'm not sure what you mean by mutating every 6 months. But, even if it does, it would not be considered part of the theory of evolution. Evolution only emcompass inheritable mutations.

How about ring species then? How can you explain ring species?

How do animals speciate? Does anybody really have a good answer for this? People might be able to describe it, but I have yet to see anybody explain it.

And , in your opinion , what is the difference between 'micro' evoultion and 'macro' evolution?

Microevolution is small changes. Macroevolution is big changes.

OK, I admit I don't have a good definition of microevolution or macroevolution. But, I don't think I'm alone in this.

The meaning modern authors give to the terms "macroevolution" and "microevolution" is often confusing, and varies according to what it is they are discussing. This is particularly the case when "large-scale" evolutionary processes are being discussed. For example, R. L. Carroll, in his undergraduate textbook (1997: 10) defines microevolution as "involving phenomena at the level of populations and species" and macroevolution as "evolutionary patterns expressed over millions and hundreds of millions of years". Eldredge says, "Macroevolution, however it is precisely defined, always connotes "large-scale evolutionary change" (1989: vii) and throughout his book speaks of macroevolution as roughly equivalent to the evolution of taxa that are of a higher rank than species, such as genera, orders, families and the like. In his book Evolution, Mark Ridley defines the terms thus (2004: 227):

Macroevolution means evolution on the grand scale, and it is mainly studied in the fossil record. It is contrasted with microevolution, the study of evolution over short time periods, such as that of a human lifetime or less. Microevolution therefore refers to changes in gene frequency within a population .... Macroevolutionary events events are much more likely to take millions of years. Macroevolution refers to things like the trends in horse evolution ... or the origin of major groups, or mass extinctions, or the Cambrian explosion .... Speciation is the traditional dividing line between micro- and macroevolution.

http://www.talkorigins.org/faqs/macroevolution.html

We know that small changes occur. And we deduce that large changes occur. Where do we draw the line between small and large? I don't think it's something that people can universally agree on.

[Galphanore]

We know that small changes occur. And we deduce that large changes occur. Where do we draw the line between small and large? I don't think it's something that people can universally agree on.

How does it make sense to draw a line at all? Why do you think that numerous small changes over time cannot result in large changes?

[McCulloch]

Microevolution is small changes. Macroevolution is big changes.

OK, I admit I don't have a good definition of microevolution or macroevolution. But, I don't think I'm alone in this.
[...]
We know that small changes occur. And we deduce that large changes occur. Where do we draw the line between small and large? I don't think it's something that people can universally agree on.

The difference is in methodology. We know that small changes occur. We also know that large changes occur, unless we assume supernatural intervention. There was a time when there were no mammals, birds, sunflowers or bony fish, now there are. Therefore, either large changes occurred or a supernatural intervention occurred every time that a large change was required. The thing is, evolution does not support the idea that any large changes really occurred. In any generation, there are no large changes from the previous generation. Just as on any day, there are no large changes in the weight of my son. Yet, once he was only 4½ kilos and now he is over 70 kilos. That's a large change. When did it happen?

In evolution we observe small changes over small numbers of generations using a certain group of techniques. There are a completely different set of techniques used with regard to the larger changes.

[micatala]

We also know that large changes occur, unless we assume supernatural intervention. There was a time when there were no mammals, birds, sunflowers or bony fish, now there are. Therefore, either large changes occurred or a supernatural intervention occurred every time that a large change was required. The thing is, evolution does not support the idea that any large changes really occurred. In any generation, there are no large changes from the previous generation.

Yes, virus and bacteria can evolve. And I'm not saying that evolution cannot happen. But, what I am saying is that just because evolution can happen on the small scale, we cannot automatically say that it can happen on the large scale.

I more or less agree with both of these statements. Yes, the small scale changes by themselves don't imply large scale changes. The main point for me, however, is that we have ample evidence that large scale changes have occurred, even if we don't know exactly how, or exactly what 'pathways' were taken on the way from species A to species B.

This might be a worthless analogy, but I will make it anyway.

If we look up at the stars, things look basically static. We cannot detect any motion. However, we are told that the stars we see are moving, relative to us, at incredible speeds, mostly away from us. We know this indirectly from the 'red shift' of the light. Assuming this motion has been happening for a long time, we can predict that the relative positions of stars in the distant past was much different than it is now. Should we disbelieve that this motion has occurred because we cannot see it happening in 'real time?'

Now, perhaps with very sensitive instruments, we can detect miniscule relative motions in the stars. In our lifetimes, or even in the recorded history of humanity, these miniscule motions wouldn't amount to much. Should we assume there is a limit on how far these motions can go? why or why not?

[otseng]

How does it make sense to draw a line at all?

That is why I rarely spend much time arguing about what is micro or macro. If the experts can't even agree on it, how are we laymen going to resolve it?

Why do you think that numerous small changes over time cannot result in large changes?

Small changes plus time is necessary, though not sufficient, to achieve large changes. My reasoning against large changes has already been presented by the stepping stone argument.

The difference is in methodology. We know that small changes occur. We also know that large changes occur, unless we assume supernatural intervention. There was a time when there were no mammals, birds, sunflowers or bony fish, now there are. Therefore, either large changes occurred or a supernatural intervention occurred every time that a large change was required.

I would agree that if we limit discussions to a naturalistic cause, then macroevolution is a logical step from microevolution. Primarily because there is no other possible explanation for life. But, if we do not presuppose a naturalistic cause, then microevolution does not automatically lead to macroevolution.

Now, perhaps with very sensitive instruments, we can detect miniscule relative motions in the stars. In our lifetimes, or even in the recorded history of humanity, these miniscule motions wouldn't amount to much. Should we assume there is a limit on how far these motions can go? why or why not?

And based on the red shift and background radiation, it's logical to conclude geocentrism and a moment of creation.

But just like evolution, I think the philosophical aspect plays a major part in our interpretation of the evidence. But, are we truly able to be philosophically unbiased? In regards to important matters such as these, I doubt it.

But, back to your analogy. Two things it's missing - randomness and selection. Let me offer another analogy.

Suppose a blind man tries to back a car out of a garage and into the road. He backs up, and when he senses the car is off the driveway, he pulls forward and tries again. Eventually he pulls out of the driveway and into the road. This would be micro-driving. Now, a large amount of time passes. He is no longer at his original location in New York, but is in the same car in Seattle. We did not witness him driving the car from New York to Seattle. What can we conclude? Well, he micro-drived out of his driveway, so he must've macro-drived across the country. That is one possibility. Another is perhaps someone else drove him there. Or maybe he had the car transported in a moving truck while he just sat in it.

The key difference is, was there another person involved? If we assume no other person was involved, the only possibility is that he macro-drove. But, if we don't assume that, then there are many other possibilities.