Evolution?

[Vene]

I don't know. You are hiding the scale bar of the bigger image. I guess it is an optical image. So the size are very different. I guess the smaller one is an image of some sub-cell particles? Would you give answer to your tricky question? Did you get me?

Whatever these two things are, can you explain the similarity on their morphology, which you used to trick me? Did I get you?

Let's put it this way, one of them is essential for us to live and the other kills us. Do you really think those two deserve to be called the same species?

 

[Naraoia]

Very good. I like you to correct my understanding:

My limited understanding on speciation is something like a population of one species is isolated into two populations. So the two groups stopped interbreeding and developed independently on their own traits. This is not a strict definition, but is a description. Biologist could phrase this idea by a more precise language.

Yes, that's roughly the biological species concept I mentioned: a set of organisms capable of interbreeding. Speciation in this case means reproductive isolation. It's quite obvious why this doesn't apply to any asexual creature (not just bacteria: even some lizards reproduce without sex).

So, bacteria split to populate. I am not sure how does algae or fungi populate themselves.

Sorry, I don't understand this bit

But until they evolved into something which will "give birth" (bisexual?) to their offsprings, there is no speciation to me.

A correction: "giving birth" and sexual reproduction don't necessarily go together. Many single-celled eukaryotes have proper sex (as in undergo meiosis and fuse two sex cells). I wouldn't call that "giving birth" but it's definitely sex.

Any life populated itself before the bisexual function kicked in, is grouped and labelled by me as a "life not evolved". I know there are/were a lot different life forms fall into this category and need some systems to subdivide.

And that is why your lumping of all bacteria into one giant "species" is unfortunate. It makes it sound like they were somehow less diverse or disparate than eukaryotes, which is very definitely not true.

But that is a problem left to biologist, not to me. So if you don't like this definition, you are extremely welcome to replace it with another term of a similar meaning.

I don't feel the need to replace the biological species. I'm not sure we should even use the word species where the BSD isn't applicable. But then I'm not technically a biologist (yet )

So, to me, bacteria are all in one species, which is the (non-sexual + single cell) species. I will be convinced in this thread that bacteria evolved if someone showed me some bacteria that is populated by a sort of sexual function, I guess, in that case, it must have been a multicellular creature.

As I said earlier, you don't have to be multicellular to have sex (unless you have your own definition of sex, too, but I prefer to stick with the official one).

You may want to consider that bacteria do exchange genetic information (and lots of it), although they don't do it in the strictly regulated eukaryotic way. They also do it with very distantly related "mates" - horizontal gene transfer even occurs between bacteria and archaea, which are about as far as it gets on the tree of life.

So, Naraoia, to your question, my thought is that the word species is not a proper word for the classification of bacteria. A different word should be used.

In that we agree. I still maintain that your conclusions that bacteria somehow don't evolve are simply wrong, though.

My scheme on this biological issue is very primitive and simple.

No problem with that, so long as you are willing to learn from people who know more about it.

But unless I am corrected on the fundamental level of definition and process, my logic on this issue stands. I understand miscommunication happened due to the different content of definition. But until this post, nobody is asking me what is my definition of anything (big credit to Naraoia, excellent student).

Didn't you have a whole discussion about the definition of evolution?

The only message I read is that my definition is wrong. If you do not know what it is, how could you say it is wrong?

Well, as for evolution, you clearly rejected the official definition. Of course "just change" is not the only way you can define evolution, but it has become accepted like that. And one of the good things about science is that you use terms with known, agreed-upon definitions so others know what you are talking about. If you mean a different thing then use a different word. If everyone just started arbitrarily redefining scientific terms chaos would quickly ensue.

 

[Naraoia]

Ugh. Nobody is really addressing the problem with speciation in the first place, and I'm talking about speciation in all organisms, not just bacteria. The problem with speciation is that nobody is entirely sure what makes a species. The biological species concept, while simplistic and beautiful in theory, is not a practical concept. If two animals can reproduce viable offspring, can they really be considered of the same species? Many biologists would then ask, "What are the circumstances?" You wouldn't have hybrid zones if two different species could not reproduce with each other. You'd think the problem would be less messy in animals than in bacteria.

You make a good point (which I personally didn't neglect because I'm not aware of it but because I thought it wasn't important to the discussion. You changed my mind). The problems with the biological species seem like a good way to illustrate how silly it is to define evolution by speciation. Here we have a nice and simple definition that even denotes something like natural entities, but even the best man-made containers leak when it comes to nature.

 

[Vene]

I don't feel the need to replace the biological species. I'm not sure we should even use the word species where the BSD isn't applicable. But then I'm not technically a biologist (yet )

Hey, chemists use the word "species" too.
http://en.wikipedia.org/wiki/Chemical_species

 

[Naraoia]

Hey, chemists use the word "species" too.
http://en.wikipedia.org/wiki/Chemical_species

How could I forget that. If anyone's in any doubt, I was talking about biology

 

[Vene]

How could I forget that. If anyone's in any doubt, I was talking about biology

*sniff* Nobody thinks about the poor chemists.

 

[[serious]]

Interesting. Thanks.

Is the gene exchange one way only (so, a donor) or is it a two-way exchange?

I may want to sit in the cell biology class sometime later.

It's one way. The F plasmid allows the pilus to be constructed and then a copy of the plasmid and any other genes that have been integrated are transferred.

 

[Bombila]

45 million year old yeast, new beer.

Posted because it's so darn cool and stuff. And unicelled.

http://dsc.discovery.com/news/2008/09/23/ancient-yeast-beer.html

 

[juvenissun]

Ugh. Nobody is really addressing the problem with speciation in the first place, and I'm talking about speciation in all organisms, not just bacteria. The problem with speciation is that nobody is entirely sure what makes a species. The biological species concept, while simplistic and beautiful in theory, is not a practical concept. If two animals can reproduce viable offspring, can they really be considered of the same species? Many biologists would then ask, "What are the circumstances?" You wouldn't have hybrid zones if two different species could not reproduce with each other. You'd think the problem would be less messy in animals than in bacteria.

In bacteria, what is a species? A lot of what is characterized as a species is done by examining morphological characteristics and physiology, but even that can be tricky. For a more accurate measurement, they use 16s rRNA genes. The difficulty of defining a species tells us that species isn't a discrete entity--it's continuous. It's looking at a spectrum of blue turning into purple zoomed in and trying to determine the exact boundaries of blue and the exact boundaries of purple. You really can't, but you can tell apart extremes.

This argument is not going to go anywhere because juvenissun thinks that the definition of species is so clearly defined.

Good argument.

My concept of species and speciation came from the knowledge of biology and biological evolution. I am using it in this thread on bacteria. I knew it could be inappropriate. But that was exactly the original intention. An inevitable question then is: why doesn't this concept apply any more? In this discussion, I realized that even the idea of sex becomes different in the system of bacteria.

So, there is a huge gap (differences) between the lives of bacteria and plants/animals. My OP simply want to make these differences stand out as clearly as possible. So, I said the bacterial did not evolve. It may not be a precise description. But it effectively pointed out where the problem is.

I may be called a layman in biology or in cell biology. Exactly because I know little about gene, DNA stuff, I only see these life forms in a much bigger picture. As I talked to biologists, they don't hesitate to use the word "low level life" to describe bacteria, in contrast to other (highly evolved) "high level lives". Again, the question is that why use these terms like "low" or "high"? Do they obviously imply the "degree of evolution"? If bacteria sit low in the evolution history, then what is (are) the correspondent "higher level life" evolved from bacteria? No matter how do bacteria "change", they are still confined as the "low level" lives. Aren't they?

I appreciate you, Naraoia and few others talked about the genetic aspects of bacteria. I understand little. But I think it is fascinating.

 

[juvenissun]

45 million year old yeast, new beer.

Posted because it's so darn cool and stuff. And unicelled.

http://dsc.discovery.com/news/2008/09/23/ancient-yeast-beer.html

In this article, it said:

Part of that taste comes from the yeast's unique metabolism. "The ancient yeast is restricted to a narrow band of carbohydrates, unlike more modern yeasts, which can consume just about any kind of sugar," said Cano.

Is this the best illustration of "evolution" bacteria can give? If it is, then it is not much. And I would still say that bacteria do not evolve.

 

[Maximum]

No, its just an example.

Ancient yeast -> one type of sugar
Modern yeast -> many kinds of sugar

Yeast changed and therefore evolved.

 

[thaumaturgy]

In this article, it said:

Is this the best illustration of "evolution" bacteria can give? If it is, then it is not much. And I would still say that bacteria do not evolve.

Wow, if I could survive by eating meat OR non-reyclable plastic I bet that would make me pretty impressive. I mean they are both made of carbon and hydrogen and a few odd other elements.

Would I be "evolved" if I could do that?

 

[Bombila]

Guys... there was beer...

Juvenissun, it was an example, yes, but I mostly posted it because here we have an organism that is still viable and will live, eat, grow and reproduce after being dormant for forty-five million years.

Plus, they used it to make unique beer, which I would like to taste. Tasters said it was 'spicy'.

 

[Naraoia]

As I talked to biologists, they don't hesitate to use the word "low level life" to describe bacteria, in contrast to other (highly evolved) "high level lives". Again, the question is that why use these terms like "low" or "high"? Do they obviously imply the "degree of evolution"?

As far as I can tell these terms are more cultural heritage than scientific description. I myself try to avoid them but then I'm young and never learnt to view evolution as some sort of absolute progress (and I think that's another point where I should thank Stephen Jay Gould and the other contributors of The Book of Life. I really owe a lot to that book worldview-wise.)

Creatures may get better at some tasks, such as capturing solar energy or swimming or eating other creatures, and they sometimes do outcompete and replace other creatures, but the outcome depends at least as much on the environment as the competitors. Being large and complicated doesn't make you unconditionally better than being small and simple.

I appreciate you, Naraoia and few others talked about the genetic aspects of bacteria. I understand little. But I think it is fascinating.

I don't understand much either but I'm always happy to share what I've learnt.

 

[Vene]

45 million year old yeast, new beer.

Posted because it's so darn cool and stuff. And unicelled.

http://dsc.discovery.com/news/2008/09/23/ancient-yeast-beer.html

This is more interesting than the rest of the thread.


And I take this opportunity to call juvenissun a dumbass again. He has not only been shown examples of how horribly wrong he is, but he continuously changes the definition of evolution. In case anybody hasn't picked up on it, that is a strawman argument. It is a logical fallacy and can be safely ignored. Juv, we all know you are a fraud. There is no way you are a professional geologist. I still maintain I know more geology than you. And that's just sad.

 

[Vene]

I understand little.

Hey look! Something we can agree on.

 

[Tomk80]

Hey look! Something we can agree on.

Indeed. For me, it's not so much juvenissuns ignorance that makes me call him a dumbass, but rather the fact that he makes his statements as if they show anything more than his ignorance. That and the fact that he willfully ignores data that has been presented to him, obviously.

 

[juvenissun]

This is more interesting than the rest of the thread.


And I take this opportunity to call juvenissun a dumbass again. He has not only been shown examples of how horribly wrong he is, but he continuously changes the definition of evolution. In case anybody hasn't picked up on it, that is a strawman argument. It is a logical fallacy and can be safely ignored. Juv, we all know you are a fraud. There is no way you are a professional geologist. I still maintain I know more geology than you. And that's just sad.

I am not surprised. You may even think you are God or even better than God.
I don't care a bit.

 

[thaumaturgy]

I am not surprised. You may even think you are God or even better than God.
I don't care a bit.

Let's see...

Vene says he thinks he knows more geology than Juvenissun (demonstrably most people do), so Juvie assumes that Vene may think he is God or better than God.

Now maybe I'm making a mistake here, but does this mean that Juvenissun thinks his geology knowledge is "god like"?



(To be fair: If God wanted to wholesale change the definitions of words, then presumably He could do so at will...so perhaps Juvenissun is God.)

 

[thaumaturgy]

As far as I can tell these terms are more cultural heritage than scientific description. I myself try to avoid them but then I'm young and never learnt to view evolution as some sort of absolute progress (and I think that's another point where I should thank Stephen Jay Gould and the other contributors of The Book of Life. I really owe a lot to that book worldview-wise.)

QFT! This is key. It is an aspect that Creationists either never understand or simply refuse to accept. Evolution isn't a drive toward anything in particular. It's just survival of those factors that are not weeded out by natural selection.

The fact that it is so simple may be of concern to Creationists because it renders their strawmen unnecessarily complex.

I don't understand much either but I'm always happy to share what I've learnt.

It is unlikely Juvenissun is actually taking anything from this discussion. So as for sharing, in reality you are merely casting your bread upon the water. But it is absolutely the right and proper thing to do. Keep up the good insights!