Bacterial Evolution

[flaja]

Since bacteria, as a group, occupy the greatest number of ecological niches that collectively include the greatest diversity of habitats, what drove the first bacterial cell to evolve into a eukaryote? Based on the number of habitats they now occupy and the environmental extremes they can tolerate bacteria are the most successful organisms known, i.e., no other group of species is better adapted and thus no other group of species has any advantage over bacteria. So why did bacteria evolve into non-bacterial organisms?

There is not one single habitat where humans can live but bacteria cannot live. So what selection pressure was there to start the bacteria to human chain of evolution in motion?

 

[Vanskills]

None..

 

[sfs]

Since bacteria, as a group, occupy the greatest number of ecological niches that collectively include the greatest diversity of habitats, what drove the first bacterial cell to evolve into a eukaryote? Based on the number of habitats they now occupy and the environmental extremes they can tolerate bacteria are the most successful organisms known, i.e., no other group of species is better adapted and thus no other group of species has any advantage over bacteria. So why did bacteria evolve into non-bacterial organisms?

There is not one single habitat where humans can live but bacteria cannot live. So what selection pressure was there to start the bacteria to human chain of evolution in motion?

The number of niches successfully filled doesn't do anything to inhibit adaptation into a niche that isn't filled, or isn't filled very well. A eukaryote evolved because it could fill one niche better than any available bacterium; that's all it takes. One obvious niche that eukaryotes would be better at: eating bacteria.

 

[gluadys]

Since bacteria, as a group, occupy the greatest number of ecological niches that collectively include the greatest diversity of habitats, what drove the first bacterial cell to evolve into a eukaryote?

Was it a bacterial cell? Was it a cell?

Check out archea. Also the possible contribution of symbiosis to the evolution of eukaryotes.

 

[notto]

One obvious niche that eukaryotes would be better at: eating bacteria.

Head shot.

 

[flaja]

The number of niches successfully filled doesn't do anything to inhibit adaptation into a niche that isn't filled, or isn't filled very well.

That is not what I asked.

A eukaryote evolved because it could fill one niche better than any available bacterium;

How so considering that many bacteria use multicellular eukaryotes as their niche?

Bacteria can live anywhere man can because bacteria can live inside the human body. But man cannot live everywhere bacteria can. So which is the better adapted? An organism would have to give up some of its habitat possibilities in order to evolve into a human. How is this adaptation? By becoming more sophisticated, man reduced his chance of survival.

 

[flaja]

Was it a bacterial cell? Was it a cell?

Check out archea. Also the possible contribution of symbiosis to the evolution of eukaryotes.

By definition a bacterium is a cell. It is a self-contained unit that can exhibit all of the characteristics by which we define what a living thing is.

BTW: For the purpose of this discussion I am grouping Archae in with the other bacteria. Not every type of bacteria can live everywhere bacteria are found, but as a group the bacteria occupy the greatest number of ecological niches of all living things.

 

[flaja]

One obvious niche that eukaryotes would be better at: eating bacteria.

Eating bacteria doesn’t automatically mean that you kill it or that it cannot thrive even after being eaten. Consider botox and E. coli.

The fact that bacteria can survive a digestive system, simply means yet another set of niches where bacteria can live.

 

[sfs]

That is not what I asked.

You asked, "Since bacteria, as a group, occupy the greatest number of ecological niches that collectively include the greatest diversity of habitats, what drove the first bacterial cell to evolve into a eukaryote?" Your question, as phrased, implies that occupying many ecological niches should somehow have prevented bacteria into evolving into something else. Maybe that wasn't what you meant to ask, but that's what you wrote, and that's what I addressed. If you meant to ask something else, try again, because your first question made no sense.

How so considering that many bacteria use multicellular eukaryotes as their niche?

Your questions continue to baffle. A bacterium evolved into a eukaryote because the latter could fill some niche better. A billion or so years later, some eukaryotes developed into multicellular organisms, which some bacteria later evolved to inhabit. Why would the second event have any bearing on the first one happening a billion years earlier?

Bacteria can live anywhere man can because bacteria can live inside the human body. But man cannot live everywhere bacteria can. So which is the better adapted?

Neither is better adapted. Humans are vastly better at being human than bacteria are, and bacteria are vastly better at being bacteria. Each is quite successful in their own set of niches.

An organism would have to give up some of its habitat possibilities in order to evolve into a human. How is this adaptation?

Humans are very well adapted for their niche, which is not one that bacteria fill.

By becoming more sophisticated, man reduced his chance of survival.

Were you under the impression that humans had become extinct? Or that all eukaryotes have become extinct? They seem to me to have survived very well for billions of years.

Evolution is not about planning for what would be best for the future. It's about change happening randomly, and whatever survives survives. Some combination of bacteria became a proto-eukaryote, and the prote-eukaryote was able to survive and pass on its genes. That's all that matters; it's the only test that counts.

 

[sfs]

Eating bacteria doesn’t automatically mean that you kill it or that it cannot thrive even after being eaten. Consider botox and E. coli.

The fact that bacteria can survive a digestive system, simply means yet another set of niches where bacteria can live.

Um, yes. So? What do vertebrate digestive systems have to do with the initial evoltion of eukaryotes? Many single-celled eukaryotes eat bacteria and digest them quite nicely. That means there was a major niche open for the first eukaryotes to adapt to. The fact that a couple of billion years later bacteria would be able to adapt to multicellular eukaryotic digestive systems means what, exactly?

 

[flaja]

Your question, as phrased, implies that occupying many ecological niches should somehow have prevented bacteria into evolving into something else.

You still don’t get it. I am asking what drove the bacteria to evolve. Bacteria occupy the greatest number of ecological niches, so why did they need to evolve? When bacteria evolved into eukaryotes they restricted the niches they could survive in, so why evolve?

Your questions continue to baffle. A bacterium evolved into a eukaryote because the latter could fill some niche better.

And in the process it demands a more specialized set of environmental conditions, thus putting its survival at risk.

Neither is better adapted.

Didn’t you just say “A bacterium evolved into a eukaryote because the latter could fill some niche better”? But now you say neither bacteria nor man is better adapted than the other. Make up your mind.

Humans are very well adapted for their niche, which is not one that bacteria fill.

Again you are ignoring the issue. Substitute dependent for adapted. Humans are dependent on a set of environmental conditions that are more stringent than what bacteria are dependent on. There is a greater chance that humans will go extinct. So why bother to evolve? How can you trade short-term adaptiveness for long-term survivability?

Were you under the impression that humans had become extinct? Or that all eukaryotes have become extinct? They seem to me to have survived very well for billions of years.

No, I’m saying that man is more susceptible to adverse environmental changes than bacteria are. Bacteria are more likely to survive changing environmental conditions than man is.

 

[flaja]

Um, yes. So? What do vertebrate digestive systems have to do with the initial evoltion of eukaryotes?

Nothing other than the fact the stomachs illustrate the fact that bacteria have a plethora of habitats, while stomach-laden eukaryotes do not.

A man cannot live in a cow’s digestive tract, but bacteria can. A cow cannot live in a man’s digestive tract, but bacteria can. Bacteria have more habitat choices than either cows or men do.

Many single-celled eukaryotes eat bacteria and digest them quite nicely. That means there was a major niche open for the first eukaryotes to adapt to.

Only as long as the bacteria last. What happens to these eukarotes if the bacteria goes extinct?

 

[notto]

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When bacteria evolved into eukaryotes they restricted the niches they could survive in, so why evolve?

To survive better in the new niche they were in with the adaptations they currently had via mutation.

Do you think they knew of other possible niches that they were limiting themselves to? Do you think they could know what mutations were headed their way and avoid the ones that provided an advantage at the current time?

They way you are phrasing this makes it sound like bacteria knew the future and could predict niches and mutations.

That is a bit of an unreasonable conclusion and without it your argument doesn't really make any sense.

 

[notto]

A man cannot live in a cow’s digestive tract, but bacteria can. A cow cannot live in a man’s digestive tract, but bacteria can. Bacteria have more habitat choices than either cows or men do.

I thought we were talking about niche's, not habitats.

Bacteria and mammals do not fill the same niche.

Why are you comparing the entire kingdom of bacteria to a family of mammals?

Shouldn't you be comparing bacteria to animalia to be consistent? I hear that worms can live in side a cow so your argument really doesn't hold up.

 

[sfs]

You still don’t get it. I am asking what drove the bacteria to evolve. Bacteria occupy the greatest
number of ecological niches, so why did they need to evolve?

Oh, I do get it. What you don't get is that your question reveals a substantial misunderstanding of evolution. Bacteria didn't need to evolve. Mutations don't happen because an organism needs them. They just happen. If the mutated organism survives and reproduces, then the mutation survives. That is all evolution is. There was a way for the proto-eukaryote to survive and reproduce, and it did. No one was there to count the number of available niches for different kinds of cell and advise the proto-eukaryote not to acquire its new characteristics -- they just happened.

When bacteria evolved into eukaryotes they restricted the niches they could survive in, so why evolve?

Because the relevant mutations (and/or symbiotic events) happened, and the offspring survived. What do all of those other niches filled by other organisms have to do with whether this particular mutated bacterium reproduces or not? And its not like eukaryotes have done badly. They've been around for a couple of billion years, have diversified nicely and are in no danger of going extinct.

And in the process it demands a more specialized set of environmental conditions, thus putting its survival at risk.

I'm not sure it's true for the development of eukaryotes -- they're really not very specialized -- but it is true overall. Highly specialized species are more likely to go extinct. So? Evolution doesn't plan for the future. So what happens is that highly specialized species evolve . . . and go extinct. Generalists also evolve, and also go extinct, but they're apt to last longer.

Didn’t you just say “A bacterium evolved into a eukaryote because the latter could fill some niche better”? But now you say neither bacteria nor man is better adapted than the other. Make up your mind.

<blink> Yes, I said both of those things, because they're both true. (More or less -- humans have a smaller population size than most bacterial species, and are therefore less well adapted.) Bacteria are well adapted to their niches, and humans (and most other eukaryotes) are well adapted to their niches. When there is an open niche, an existing species is likely to split into two species, one still in the old niche and one adapted to the new one. Where's the contradiction?

Again you are ignoring the issue. Substitute dependent for adapted. Humans are dependent on a set of environmental conditions that are more stringent than what bacteria are dependent on. There is a greater chance that humans will go extinct. So why bother to evolve? How can you trade short-term adaptiveness for long-term survivability?

Why "bother to evolve"? What does that mean? You trade short-term adaptation for long-term survivability by adapting in the short term and then adapting again later, if you're a fortunate species, or by going extinct. The latter happens all the time. What's the mystery?

You might note, by the way, that bacteria represent an entire kingdom (or two, if you include archaea), while humans are a single species. Comparing the ecological range of the two is somewhat dubious.

 

[sfs]

[A man cannot live in a cow’s digestive tract, but bacteria can. A cow cannot live in a man’s digestive tract, but bacteria can. Bacteria have more habitat choices than either cows or men do.

Habitat is not the same as niche. Bacteria cannot raise cattle, but humans can. Bacteria cannot gather nuts, but humans can. Most bacteria can't even drink alchohol.

Only as long as the bacteria last. What happens to these eukarotes if the bacteria goes extinct? [/FONT]

If the bacteria go extinct, then organisms that feed on bacteria will either adapt to another food source or also go extinct.

 

[gluadys]

[You still don’t get it. I am asking what drove the bacteria to evolve. Bacteria occupy the greatest number of ecological niches, so why did they need to evolve? When bacteria evolved into eukaryotes they restricted the niches they could survive in, so why evolve?

And in the process it demands a more specialized set of environmental conditions, thus putting its survival at risk.

I am puzzled by this line of questioning too. Yes, bacteria occupy the greatest number of ecological niches, but that doesn't mean than any particular species of bacteria can live in every ecological niche. Each species of bacteria is just as restricted, just as dependent on a specialized set of environmental conditions as eukaryotes.

Obviously, bacteria evolved to fill those niches. What is the big deal with filling another niche by evolving into eukaryotes? The risk for survival to eukaryote species is no greater than the risk to survival of bacterial species.

Didn’t you just say “A bacterium evolved into a eukaryote because the latter could fill some niche better”? But now you say neither bacteria nor man is better adapted than the other. Make up your mind.

Being better adapted to one niche automatically means a species is less well adapted to another. Use different species names if necessary to see the point. Are bats or whales better adapted? Obviously, you have to consider "better adapted to what?" Does flight make bats better adapted than whales? Not for a life in the ocean. Does the fact that they cannot survive as sea mammals mean bats are not as well adapted as whales? Nonsense, bats are quite well-adapted to their own niche.

Same goes for bacteria (which are really a whole super-kingdom of species, each adapted to one niche) and humans. On a species-by-species comparison, humans are more generalized than many bacteria.

Again you are ignoring the issue. Substitute dependent for adapted. Humans are dependent on a set of environmental conditions that are more stringent than what bacteria are dependent on. There is a greater chance that humans will go extinct.

Because humans are one species and bacteria are many species. One could wipe out many bacterial species and still have many bacteria. Just as one could wipe out humanity and still have many mammals.

So why bother to evolve? How can you trade short-term adaptiveness for long-term survivability?

A species doesn't have much choice about evolving. It is a more-or-less automatic process that cannot be halted. How do you stop mutations from happening? How do you stop species from reproducing? How do you arrange for environmental conditions not to favour some combinations of features over others? Hpw can you make any part of the process take a long-term point of view?

 

[flaja]

To survive better in the new niche they were in with the adaptations they currently had via mutation.

What good does it do to survive better in a new niche if you risk your long-term survival? How is that an even trade, let along a beneficial one?

 

[notto]

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What good does it do to survive better in a new niche if you risk your long-term survival? How is that an even trade, let along a beneficial one?

Do you think the bacteria know that they are risking long term survivability?

They are not making a trade. They cannot think or know what adaptations lie ahead or what niches will present themselves.

Your thinking is nonsensical in that regard.

What good does it do to survive better in a new niche?
Surviving better in a new niche. period.
Nothing more, nothing less.

 

[flaja]

I thought we were talking about niche's, not habitats.

In terms of Darwinism you cannot have one without the other. Your habitat is inextricably connected with your niche because how you can interact with your physical environment determines how you must interact with other living things.

Why are you comparing the entire kingdom of bacteria to a family of mammals?

I guess you haven’t been paying attention. I am considering all bacteria as a group and I am comparing this group with the group that includes every other type of organism. The bacteria group outnumbers the other group both in terms of number of individuals and in number of habitats.