The evolution of evolution

[Skaloop]

I don't know. As I said, I don't know how would evolution continue beyond mutation.

Who says it does? Mutation leads to all the differences and variety we see. Evolution doesn't need to continue beyond mutation; multiple small mutations lead to large changes. That's undeniable.

 

[juvenissun]

We observe mutation. We observe the effect of mutations on character traits (i.e. variation). We observe the impact of natural selection on organisms in relation to their combination of character traits. And we observe speciation. So none of this is theoretical.

Variations are individual differences in character traits. For example, when Mendel did his early work on pea plants, he recorded the results in terms of the frequency of character traits (yellow or green seed, smooth or wrinkled seed, tall or dwarf plants, white or purple flowers, etc.) Darwin also pointed to the diversity of individual differences in various character traits.

Mendel theorized the existence of "units of heredity" which he called "genes" to explain his results. We now know that variations are due to genetic differences.

Mutations change genes, introducing new genetic differences. And new genetic differences may be expressed as a new variation in the population. Alternatively, mutations can change transcription factors which change how a gene is expressed (whether it is turned off or on and for how long) and this too may produce a new variation in the population.

Is human race an example of variation? Or is different kinds of dogs an example of variation?

Do we really "see" the happening of variation? Or do we simply "discover" variations? Have we really observed that mutation leads to stable variations? I don't want example on plants. I want to see example on animals. I remember the experiment on E. Coli a while ago and it seems suggested that after the mutation of thousands of generation, a variation of E. Coli was finally observed in lab. Is that a good example? E. Coli is not even an animal.

 

[29apples]

I know (I really don't) mutation. Then I am lost.
For example, I don't see the mutation of us (or cat, or dog) can lead to a new species. So I don't believe the mutation of apes could lead to us. In other words, what we learned in lab does not apply to the old theory of evolution. Yes, you have told me that many conditions have to be met so a new species could emerge from mutation and adaptation process. I assume it could true. But I don't see any example yet.

May be sfs likes to say: not yet.
Yes, not yet. That is what I meant.

Ok I am going to try and provide a brief example of how new species can arise.

Suppose we have a species of beetle in the rain forrest. It is equally spread. Now man comes along and builds a highway right through the middle of the forrest. These beetles have an incredibly difficult time crossing this highway, and stay on their side of the road 99% of the time.

Now we have all heard the term "micro-evolution." Suppose "micro-evolution" is occurring for the beetle on both sides of the highway. This "micro evolution" is affecting the reproductive organs of two populations differently. One side is starting to micro evolve to square shaped organs. The other is "micro evolving" circle shaped organs. One day, after enough "micro-evolution", the square shaped organs will no longer fit with the circle shaped ones. These two populations of beetle are now reproductively isolated from one another (think about the baby toys where you try and fit the square peg in the wrong hole). Now these populations can continue to "micro-evolve" distinct physical characteristics. One population might evolve really big horns for fighting, and the other population might evolve really long legs for running from predators. These beetles now barely (or not at all!) resemble the original beetle population before man came along and built his highway.

This is an example of allopatric speciation.

 

[juvenissun]

Who says it does? Mutation leads to all the differences and variety we see. Evolution doesn't need to continue beyond mutation; multiple small mutations lead to large changes. That's undeniable.

I am not sure. I think this idea is theoretical rather than experimental.

That is the difference between the old theory and the new theory. No connection.

 

[Skaloop]

I am not sure. I think this idea is theoretical rather than experimental.

That is the difference between the old theory and the new theory. No connection.

What you think is irrelevant.

There is no significant difference between the "old" theory and the "new" theory. They are essentially the same theory.

 

[juvenissun]

Ok I am going to try and provide a brief example of how new species can arise.

Suppose we have a species of beetle in the rain forrest. It is equally spread. Now man comes along and builds a highway right through the middle of the forrest. These beetles have an incredibly difficult time crossing this highway, and stay on their side of the road 99% of the time.

Now we have all heard the term "micro-evolution." Suppose "micro-evolution" is occurring for the beetle on both sides of the highway. This "micro evolution" is affecting the reproductive organs of two populations differently. One side is starting to micro evolve to square shaped organs. The other is "micro evolving" circle shaped organs. One day, after enough "micro-evolution", the square shaped organs will no longer fit with the circle shaped ones. These two populations of beetle are now reproductively isolated from one another (think about the baby toys where you try and fit the square peg in the wrong hole). Now these populations can continue to "micro-evolve" distinct physical characteristics. One population might evolve really big horns for fighting, and the other population might evolve really long legs for running from predators. These beetles now barely (or not at all!) resemble the original beetle population before man came along and built his highway.

This is an example of allopatric speciation.

This is not a complete example.
It has a part which is the observation (fact). And it has another part which is a suggested process.
The two parts are linked together by a hypothesis.

Who actually continuously sample the beetle to observe the process of the so-called micro-evolution? Your example fits the old theory, but not the new one.

 

[juvenissun]

What you think is irrelevant.

There is no significant difference between the "old" theory and the "new" theory. They are essentially the same theory.

So, is this your answer to the OP?

 

[29apples]

This is not a complete example.
It has a part which is the observation (fact). And it has another part which is a suggested process.
The two parts are linked together by a hypothesis.

Who actually continuously sample the beetle to observe the process of the so-called micro-evolution? Your example fits the old theory, but not the new one.

It was a hypothetical example. The fact is that speciation takes such a long time (relative to us). The example does fit new the theory of evolution.

Evolution = the change in allele frequency in a population over time
change in allele frequency= change in beetle sex organs
population= the beetles

The bottom line is that it is incredibly difficult to observed speciation because of the time involved for the process to occur.

Only example I can think of is E. coli evolving the ability to utilize citrate by Richard Lenski et al, and this experiment took 20 years. (It also got the crazy folks at conservapedia in a twist).
Even if it is just "microevolution", why can't enough microevolution occur that the two populations can not interbreed anymore?

 

[Skaloop]

So, is this your answer to the OP?

There was no question in the OP. But my response to the OP is that the OP is wrong and ill-informed.

 

[Drekkan85]

First, it's not that observed a mutation in the E. Coli that was so astounding. It's that they observed a new species of E. Coli develop - one which can metabolize citrate. The reason this is so important is that an inability to metabolize citrate is a defining characteristic of E. Coli - it's one of the major ways we categorize E. Coli as E. Coli. They went back and tracked through frozen samples that had been carefully preserved and found a gradual development of citrate metabolizing capacity in the mother strains of that particular sample going all the way back to the original. None of the "cousin" samples (those raised differently from the original ancestor strain) showed any ability to metabolize citrate.

This is like finding the gradual evolution of a humane that breathes hydrogen cyanide - heck, it prefers to breath hydrogen cyanide. It's that big of a deal. They also tracked the genomes and found, over time, (IIRC) twenty something different point mutations that led to the new mechanism.

In terms of complete speciation in the wild - loko up London Underground mosquitos. A few of them got into the underground in the 19th century, and they've been developing differently from the wild type ever since. In that short time their wing structure has changed, their genome has change,d their behaviour has changed and, most importantly, both mating behaviour and gentalia have changed (making it nearly impossible for underground mosquitos to mate with regular mosquitoes).

More species macro-evolution that we're seeing everyday (and this rules out the absolute wealth of fossil and genomic evidence).

Second - please for the love of heaven define things like "kind" or macro evolution. Until you tell us exactly where you think the barrier is we can't break it down. Clearly if you're going to hold onto it you must set it above the species level, but how far up? Are we going to have to show a change in Phyla?

Third - really, the issue is settled. You can fall into one of two camps, acceptance or rejection of science. The ability to make a creationist argument on the back of scientific evidence is long dead. There are some like AV that have taken their side (Science is wrong, God did it, enough said). At very least he's not being academically dishonest and is very open about his beliefs. It's folks like those creationists at the Discovery Institute that try and pass off what they're doing as science that draw my ire.

 

[gluadys]

Is human race an example of variation? Or is different kinds of dogs an example of variation?

There is only one human race, Homo sapiens, but it shows many thousands of individual differences: those are variations.

You may be confusing "variation" with "variety". Same root, but slightly different meaning.

When Darwin spoke of variations, he was referring to those differences which distinguish one individual from another. These are the kinds of differences where mutations have a role.

But "variety" or "sub-species" refers to a group, not to individuals. These are groups which are identified by common similarities not differences. Within these groups, you still get individual differences or variations.

To summarize: variation refers to differences in a character trait such as colour of hair (black, brown, blond, red). Variety refers to a group in which all members share certain similarities. So if I say Greyhound or Chihuahua, you have in each case a very definite image of one variety of dog, and you know that all dogs of that type share many features in common. Yet if you were to examine many Greyhounds or many Chihuahuas you would still find variation within each variety, as you still get many individual differences.

Or do we simply "discover" variations?

We observe variations. Some are easy for anyone to see: hair colour, eye colour, shape of nose, whether or not a person has Asian eyes. Others call for tests to be made--like blood samples to determine blood type. Others can be seen with careful study with a microscope because the differences are small and subtle (how many hairs on a fly's leg?)

What we may then discover are which genes are responsible for the characteristic and how differences in the genes account for differences in the characteristics. You are probably familiar with the term "allele". An allele is any one of the various versions of a gene. The individual differences we see in any population are due to them having different alleles for certain characteristics. So, in the pea plants he studied Mendel found that there were two alleles for seed colour. One version (allele) of the gene for seed colour produced yellow seed. A different version produced green seed.

How do mutations fit into this? Well, why do genes show differences? Why do we have many different alleles of the same gene? Mutations are the answer. If you think of a gene as being a sort of recipe for making a protein, then if you get a change in the DNA sequence of a gene, you make a change in the protein, and that means it may act a little differently and you get a different result--like a new seed colour or a new eye colour, or a differently-shaped nose, or whatever.

So, to sum up: we see variations (individual differences) because genes vary. And genes vary because their DNA sequences are changed i.e. they mutate. And this is not just theoretical. There have been many, many experiments showing both of these statements are true. Genes mutate, and changed genes produce variations that distinguish one indivdual from another.

But what is important at this stage is to note that we are talking individual differences, not group differences. Getting to group differences is another chapter.

Have we really observed that mutation leads to stable variations?

I think what you really mean here is "variety" (See above). This is part of the next chapter. How do individual differences contribute to forming group differences. There are a number of new factors we have to bring in here. Mutations alone do not suffice to explain this. Mutations account for individual differences, but for a stable variety to form, you also have to develop a set of similarities.

I remember the experiment on E. Coli a while ago and it seems suggested that after the mutation of thousands of generation, a variation of E. Coli was finally observed in lab. Is that a good example? E. Coli is not even an animal.

E. coli is a species of bacterium. Even before the experiment began, there were many varieties of E. coli. Here is a sampling of them: http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi

That experiment was not notable for turning up a new variety of E.coli---since there were already plenty of those. In fact, they began with 12 different varieties and had been documenting various changes that had occurred over 30,000 generations. What made this particular change significant was an unusual innovation shown in this particular variety, and the evidence that it was due to a building up of later mutations on top of earlier ones.

http://myxo.css.msu.edu/lenski/pdf/2008, PNAS, Blount et al.pdf

This is certainly a good example of how mutations change character traits.

 

[juvenissun]

That experiment was not notable for turning up a new variety of E.coli---since there were already plenty of those. In fact, they began with 12 different varieties and had been documenting various changes that had occurred over 30,000 generations. What made this particular change significant was an unusual innovation shown in this particular variety, and the evidence that it was due to a building up of later mutations on top of earlier ones.

http://myxo.css.msu.edu/lenski/pdf/2008,%20PNAS, Blount et al.pdf

This is certainly a good example of how mutations change character traits.

First, thanks for the explanation. I am learning.

But I think it is much more than just a good example. It is the most exciting news which could happen to the new theory of evolution so far.

If so, that says how much the new theory gets to. To me, bacterium is not even a life.

 

[gluadys]

To me, bacterium is not even a life.

Well, then, one can understand that you are not a biologist. What biological characteristic of life do they lack?

 

[juvenissun]

Well, then, one can understand that you are not a biologist. What biological characteristic of life do they lack?

Good question. The answer is long. I define life according to Biblical criteria, not biological criteria (even there is no contradiction as a result). This will solve many other hard theological questions. I am still exploring that and am not sure how to share the idea.

 

[gluadys]

Good question. The answer is long. I define life according to Biblical criteria, not biological criteria (even there is no contradiction as a result). This will solve many other hard theological questions. I am still exploring that and am not sure how to share the idea.

Biblical criteria? Does that mean that any kind of life you need a microscope to see would not be life by your criteria---even if it is a complex life form?

 

[juvenissun]

Biblical criteria? Does that mean that any kind of life you need a microscope to see would not be life by your criteria---even if it is a complex life form?

[BIBLE]Le 17:11 For the life of a creature is in the blood, and I have given it to you to make atonement for yourselves on the altar; it is the blood that makes atonement for one's life.[/BIBLE]

So, if a creature has blood, then it is a life. Biological enough?

 

[Assyrian]

So you believe sheep blood can literally atone for our souls?

Anyway, this raises interesting possibilities. If unicellular orgnisms are not alive, even simple multcellular organisms without a circulatory system, then you should have no problem with these bacteria and eukaryotes evolving over billions of years before 'life' appeared. And when God formed all the different plants and animals from clay, the non living clay would have contained simple non living organisms like eukaryotes that share much of the same DNA as we do. Presumably God did not have to recreate the DNA all over again, but used the evolved eukaryote DNA along with the rest of the clay to form all the living creatures.

 

[juvenissun]

So you believe sheep blood can literally atone for our souls?

Anyway, this raises interesting possibilities. If unicellular orgnisms are not alive, even simple multcellular organisms without a circulatory system, then you should have no problem with these bacteria and eukaryotes evolving over billions of years before 'life' appeared. And when God formed all the different plants and animals from clay, the non living clay would have contained simple non living organisms like eukaryotes that share much of the same DNA as we do. Presumably God did not have to recreate the DNA all over again, but used the evolved eukaryote DNA along with the rest of the clay to form all the living creatures.

I don't know. But what you said is not that hard to accept. That is why the speciation of bacteria does not bother me at all, even I argued against it to my best ability.

I have trouble in using these words. If a functional biological system is not to call a life, then a "non-living life" or a "living non-life" are both quite funny terms. So I like to use the term "functional biological system" instead, even it is not a good one.

 

[Assyrian]

That is 'biological' from the Greek bios, meaning life?

 

[juvenissun]

That is 'biological' from the Greek bios, meaning life?

OK, I am stuck. No word for the "living non-life". Big problem.