Aldehyde

How did one specie become another brand new specie? According to Darwinism, it takes environmental distress along with ample of time for a specie to evolve into a brand new specie in order to strive through the environmental distress.

In a microbiology lab, we have this pure colony of, let's say for instance, Staphylococcus aureus. I can subculture the organism as many time as I wish and I can put as much antibiotics to the culture medium as I wish.

If subculturing = generation = time *and*
if antibiotics = environmental vector against the organism, **DOES** this satisfy Darwin's 'pre-requisites' for an evolution and can I get a brand new bug growing there anytime soon?

The answer of my rhetorical question is NO. So if time and the environment do not result in evolution, what does?

Anyone wants to disprove my statement? (or are you too fuzzy and have no clue in what I am talking about?)

Albion

Phylogenetics has shown relationships between bacterial species and has given an idea of the length of time ago when closely related species diverged from the common ancestor. You're talking hundreds or even thousands of years ago. Bacteria don't replicate any faster in the lab than in the wild, so there's no reason why those speciation events should take a shorter time in the lab.

Also, when bacteria such as S. aureus are in their natural environment, there are a lot of environmental pressures on them other than antibiotics, all of which aren't present in the artificial environment of a petri dish, so it isn't that close a model. The other thing is that antibiotic resistance is usually transferred intact between bacteria on plasmids, so once that transfer has taken place, the growth of the resistant organism just carries on until another environmental constraint is added. If the only outside influence you're providing is the single one of antibiotic resistance, you aren't giving the bacterium much scope.

Aldehyde

One generation for bacteria can occur relatively very very fast (1 generation within probably 4hrs depending on which bacteria) compared to monkeys. Possibly million times faster. Or do multicellular organisms evolve more readily given an 'x' number of generations? I admit that this is a big 'hole' in my 'theory'/though/etc.

As for natural environmental factors, temperature, humidity, radiation, food source, and even introduction of other species of bacteria or viruses all can be altered.

It is true that any bacteria can acquire plasmids to achieve antimicrobial resistance but we do not get a brand new specie. (Example would be S. aureus and MRSA - methicillin resistant S. aureus)

Doubting Didymus

Actually the answer to your rhetorical question is a resounding yes. You just try that experiment you propose. If you subculture a bacterium over and over, applying a new antibiotic environmental stress each time, you will get a new species (i.e. a strain of staphlococcus that cannot breed successfully with the original stock)

In reality, you don't need to do the experiment because it has already been done. Speciation has been observed both in the laboratory and in the wild a great many times.

Look <a href="http://www.talkorigins.org/faqs/speciation.html" target="_blank">HERE</a> for a breif list of some observed instances of speciation, complete with references for further reading.

One bad creationist argument down, many more bad creationist arguments to go. Batter up!

Doubting Didymus

Actually you can do it in the lab in a few years, maybe less.

Albion

Oh, I'm sure you can. But then there'll be the inevitable complaints that this is an artificial environment and that this sort of forcing doesn't say anything about the real world and so on and so on. Especially since species differences in bacteria tend to be measured in percent similarity rather than ability to interbreed because bacteria tend to reproduce asexually. You can just see all sorts of creationist objections to the appalling arbitrariness of the criteria used to determine species differences in bacteria.

Albion

Yes, but one generation for bacteria in the lab isn't relatively very fast compared to one generation under natural conditions for the same species, which is what you were talking about comparing. Your original post was specifically about bacteria, not about bacteria versus monkeys. If an event tends to take a long time in bacteria in the environment, it won't take a much shorter time in those same bacteria in the lab.

The main difference is that under natural conditions, the bacteria spend quite a lot of their time in different conditions. S. aureus spends time as a harmless inhabitant of certain niches in the host; it's very much affected by the immune system of the host under certain conditions; it spends time in the environment; it grows in food and water; I'm not sure without looking it up, but I think it can also infect animals. You just can't reproduce that in the lab; you might as well simply do a study in the field. And it's those sorts of factors that will be a driver of selection.

Yes, I know. That was part of my point. Resistance to certain antibiotics comes ready packaged on a plasmid, it doesn't have to occur by mutation and selection. All you have to do is expose your strain to a resistant strain, and you have instant resistance.

There are experiments under way in a lot of labs to understand the conditions for speciation of bacteria - just google for the keywords and see what's being done. The thing is that you seem to be expecting that speciation will somehow occur a lot faster under lab conditions, and I'm just saying that I don't think that's the case.

[ July 22, 2002: Message edited by: Albion ]

[ July 22, 2002: Message edited by: Albion ]</p>

Doubting Didymus

What he's saying is that speciation simply doesn't occur. This is completely untrue, and if he followed my link and then followed up on some of the references therein, he might still be reading about observed instances of speciation.

Like I said, one creationist argument down.

Albion

Yes, it'll be interesting to see how those examples somehow don't count. There are examples of experiments on bacterial speciation out there too. I wonder where the original poster came up with that very definite negative answer to the lab experiment. Talk about assuming your conclusion.

Peregrine

Evolution is not always the product when there are adverse environmental change -- extinction is a possible outcome.

For natural selection to occur in your "experiment", there must be alleles for antibiotic resistance in the gene pool of your "population." If there isn't, the population will become extinct.