Bacteria? Viruses? Protazoa? Prions? Nature's selector?

[Syntho-sis]

I've been wondering lately: Has it ever been postulated if perhaps certain forms or maybe even all forms of microorganisms were 'engineered' by nature to help keep populations under control?

 

Seems a bit far fetched, but what if, that is their sole purpose? I mean when we talk about ecosystems, we talk about certain organisms having specific niches right?

 

That's one reason we get so out wack when a species becomes extinct, because we are not aware of what function or 'purpose' it played in the larger ecosystem. Right?

 

Hypothesis: Microorganisms have their requirements for survival met by performing the function of keeping population under control (and possibly varying other jobs).

 

I mean we talk about certain environmental factors being an example of natural selection. Are organisms apart of that?

 

Can someone please explain?

[swansont]

Purpose? I don't think that enters into the discussion.

[insane_alien]

no, they are nomore population limiters than wolves are for their prey.

 

they simply fill a niche of being able to survive inside a host and multiply. they do not keep tabs on the population of their particular host species and they don't kill someone only if the population is too high.

 

the only 'purpose' they have is reproduction. just like us.

[dttom]

I would say it is the matter between Creationism and Darwinism.

In Creationism, all the living things are made by a cotroller for a certain purpose.

In your viewpoint, every living things have their 'niche' for a certain functions, the understatement would then be there is a controller, because without a controller the functions of living things would not be 'certain' but change with environment.

[Ophiolite]

Anything that is 'engineered by nature' does so through the mechanisms of evolution. The word 'engineered', even in quotation marks, will cause some biologists considerable discomfort since it carries with it the suggestion of purpose and direction in evolution.

 

The only 'purpose' is to encourage organisms that work and discourage those that don't. That is neatly expressed in the tautology, survival of the fittest. And there seems to be no direction, other than a tendency to increase in complexity at the highest level, a tendency that is readily explained by the Drunkard's Walk.

 

In short, Swansont and InsaneAlien's dismissal of any 'purpose' is accurate.

 

Perhaps you meant function. Function does not carry the teleological baggage of purpose. Here, however we see no more predatory/control behviour amonst micro-organisms than amongst macro-organisms. All nature works in approximate balance much of the time. That balance is achieved through the behaviour and interactions of all organisms with each other and with their physical environment. In that regard organisms (large and small) are very much a part of the environment within which their neighbours live, breed and die.

[Syntho-sis]

no, they are nomore population limiters than wolves are for their prey.

 

they simply fill a niche of being able to survive inside a host and multiply. they do not keep tabs on the population of their particular host species and they don't kill someone only if the population is too high.

 

the only 'purpose' they have is reproduction. just like us.

 

I understand that they are not aware of anything really. I read a thing recently that explained to some extent why humans are not immortal (it was by a neurosurgeon I think). It's because our genetics limit us. We are born to fail. If things like cancer and other diseases didn't take us what would? We have no predators so our own bodies are responsible for deactivating us.

 

We have just enough time to get our genetic material out there and then we die..

 

How is it that natures "knows" (wrong word) that we need to die or we would overpopulate and use all the resources?

 

Say we lived in an environment where resources were everlastingly abundant (speculation here) would natural selection one day decide to make us immortal because there was no danger to overpopulation and starvation? Maybe even increase the longevity of our race?

 

Why is it some animals, like turtles and humans, can live so much longer than other organisms?

 

Where does natural selection come into play here?

[insane_alien]

thats the point, nature doesn't know or care about whether we are overpopulating or not. its got as much to do with over population as the price of cheese in cheshire.

[Syntho-sis]

thats the point, nature doesn't know or care about whether we are overpopulating or not. its got as much to do with over population as the price of cheese in cheshire.

 

How come we aren't immortal then?

 

^ That probably sounds condescending. What I meant was, why are some organisms such as...the Hydra and some jellyfish biologically immortal?

 

http://en.wikipedia.org/wiki/Biological_immortality

 

What impedes us (and most other organisms)? When we lived in the trees, it was predators. When we didn't have germ theory is was microorganisms. Now that we can live to be 80 and beyond it is our own bodies degenerating.

 

By the way I'm reading Origin of the species (again). It's amazing how much one can miss the first time around.

Edited September 11, 2009 by Syntho-sis

[JillSwift]

I understand that they are not aware of anything really. I read a thing recently that explained to some extent why humans are not immortal (it was by a neurosurgeon I think). It's because our genetics limit us. We are born to fail. If things like cancer and other diseases didn't take us what would? We have no predators so our own bodies are responsible for deactivating us.

 

We have just enough time to get our genetic material out there and then we die..

 

How is it that natures "knows" (wrong word) that we need to die or we would overpopulate and use all the resources?

 

Say we lived in an environment where resources were everlastingly abundant (speculation here) would natural selection one day decide to make us immortal because there was no danger to overpopulation and starvation? Maybe even increase the longevity of our race?

 

Why is it some animals, like turtles and humans, can live so much longer than other organisms?

 

Where does natural selection come into play here?

As I understand some of the more recent looks into aging and dying, genetically speaking it isn't that we're designed to die, it's that we're not programmed to perfectly defend against internal cellular damage.

 

For instance, free radicals released by mitochondria do all manner of damage to a cell's mechanisms, including the DNA, which get duplicated during cell division. There are mechanisms that repair or mitigate this kind of damage, but they are eventually overwhelmed and the organism can no longer function properly, and eventually dies.

 

Some organisms do a better job of mitigating this kind of internal systematic degradation than others.

 

It appears that better damage control is selected for in organisms that are also in environs that select for slower maturation of individuals, or environments that require long periods of waiting between opportunities for mating. Like most things in nature, however, this is no hard-n-fast rule.

 

If I recall correctly, the oldest living organism still able to reproduce is a tree in northern California, 5000 years old and still producing viable pine cones. The trees around it that share in its genetic code are of average life spans for the species. This would make it appear that longevity has more than just a genetic factor.

 

HTH

[Syntho-sis]

As I understand some of the more recent looks into aging and dying, genetically speaking it isn't that we're designed to die, it's that we're not programmed to perfectly defend against internal cellular damage.

 

For instance, free radicals released by mitochondria do all manner of damage to a cell's mechanisms, including the DNA, which get duplicated during cell division. There are mechanisms that repair or mitigate this kind of damage, but they are eventually overwhelmed and the organism can no longer function properly, and eventually dies.

 

Some organisms do a better job of mitigating this kind of internal systematic degradation than others.

 

It appears that better damage control is selected for in organisms that are also in environs that select for slower maturation of individuals, or environments that require long periods of waiting between opportunities for mating. Like most things in nature, however, this is no hard-n-fast rule.

 

If I recall correctly, the oldest living organism still able to reproduce is a tree in northern California, 5000 years old and still producing viable pine cones. The trees around it that share in its genetic code are of average life spans for the species. This would make it appear that longevity has more than just a genetic factor.

 

HTH

 

 

That's makes alot more sense.... specifically-

 

It appears that better damage control is selected for in organisms that are also in environs that select for slower maturation of individuals, or environments that require long periods of waiting between opportunities for mating. Like most things in nature, however, this is no hard-n-fast rule.

 

 

So again what exactly is the function of natural selection?

 

Is it to- get as much genetic material out there as possible? Or is it to get as much variation in that genetic material as possible?

 

I guess it would be both wouldn't it?

[insane_alien]

all natural selection does is remove organisms that are not fit for the environment.

 

it filters out bad genes. there is no goal, there is no purpose, it just is.

[JillSwift]

all natural selection does is remove organisms that are not fit for the environment.

 

it filters out bad genes. there is no goal, there is no purpose, it just is.

^^^ That. Though I'd phrase it "Natural selection is the name given to the fact that phenotypes that do not work in a given environment disallow some or all opportunity for duplication." to avoid terms that may suggest value judgments or purpose.

 

Longevity is a phenotype like any other aspect of an individual organism, and as such is equal parts an aspect that functions well in a given environment as well as part of the environment for other phenotypes in the organism.

[CharonY]

Precisely. Natural selection is not something that has a function. It is just something that happens. The outcome is just that different phenotypes happen to have different reproductive success. And in retrospect we call whatever happened, natural selection. Incidentally it also explains why immortality is not universal. A simplified view is that more varied and complex the tissue of an organism becomes the harder it is to control cell replication in a way that avoids negative effects (e.g. as manifested by cancer). Hydras as well as unicellular organisms have a very simple arrangement and have little trouble to be virtually immortal. Yet the complex structures of e.g mammals allows them to use different ecological niches than the simple organisms. Longevity also does not increase fitness, if the time frame of possible reproductions is not equally enhanced. Except, of course, in social animals and maybe even some other situations in which one promotes the fitness of closely related individuals.

Edited September 11, 2009 by CharonY

[GDG]

So again what exactly is the function of natural selection?

 

Is it to- get as much genetic material out there as possible? Or is it to get as much variation in that genetic material as possible?

 

I guess it would be both wouldn't it?

 

Don't think of natural selection (or evolution) as having a purpose or function: it is just the name given to an observed phenomenon. You might as well ask what the function of moonlight is: it doesn't have a "function", it just is.

 

As for why we're not all immortal, probably there is no evolutionary advantage for us -- we haven't been selected for immortality. Consider that once you have finished reproducing, you are competing with your offspring for the same resources (food, shelter, water, etc.). Yes, your parents and grandparents (and great-grandparents) may also provide substantial support, and pass along their knowledge and wisdom (or not), but how much extra benefit would you get from being around your great^10 grandfather, telling you how he farmed as a serf during the Dark Ages?

 

I suspect we have the lifespans we do because, as we evolved over the past several hundred thousand years, it provided an optimal balance between the advantage of having elders, and the extra resources those elders consume.

[Syntho-sis]

Don't think of natural selection (or evolution) as having a purpose or function: it is just the name given to an observed phenomenon. You might as well ask what the function of moonlight is: it doesn't have a "function", it just is.

 

As for why we're not all immortal, probably there is no evolutionary advantage for us -- we haven't been selected for immortality. Consider that once you have finished reproducing, you are competing with your offspring for the same resources (food, shelter, water, etc.). Yes, your parents and grandparents (and great-grandparents) may also provide substantial support, and pass along their knowledge and wisdom (or not), but how much extra benefit would you get from being around your great^10 grandfather, telling you how he farmed as a serf during the Dark Ages?

 

I suspect we have the lifespans we do because, as we evolved over the past several hundred thousand years, it provided an optimal balance between the advantage of having elders, and the extra resources those elders consume.

 

That makes sense. I have another question though. If DNA evolved the way we understand it, and DNA is itself subject to the laws of natural selection and mutations are really just mistakes on the proof-reading RNA molecules part, wouldn't the DNA that makes the least amount of mistakes in reproduction be the one that is chose by natural selection? Or is it a useful mistake?

 

I'm still trying to understand- Complexity vs Efficiency in reproduction.

[Sisyphus]

"Useful mistakes" is exactly right. Assuming that the mechanism for DNA itself is subject to natural selection (it would have to be, just not in quite the same way), a mechanism with too few "mistakes" would become static and lose the ability to adapt. I don't see how organisms that can't evolve could possibly compete in the long run with organisms that do.

[Syntho-sis]

"Useful mistakes" is exactly right. Assuming that the mechanism for DNA itself is subject to natural selection (it would have to be, just not in quite the same way), a mechanism with too few "mistakes" would become static and lose the ability to adapt. I don't see how organisms that can't evolve could possibly compete in the long run with organisms that do.

 

Wow. DNA would have to subject to natural selection. It isn't found amongst the inorganic molecules of the universe. So do you think that maybe there are a different set of rules by which DNA might have evolved?

 

That would be something interesting to discover wouldn't it? How much research has actually been done in regards to how DNA evolved?

[GDG]

Wow. DNA would have to subject to natural selection. It isn't found amongst the inorganic molecules of the universe. So do you think that maybe there are a different set of rules by which DNA might have evolved?

 

That would be something interesting to discover wouldn't it? How much research has actually been done in regards to how DNA evolved?

 

Perhaps not DNA per se, but the bases are found naturally in meteorites. See, e.g., V.A. Basiuk et al., Adv Space Res (1999) 24:505-14. The study of how DNA and RNA arose crops up in abiogenesis (and surfaces periodically in this forum as well).

[Syntho-sis]

Perhaps not DNA per se, but the bases are found naturally in meteorites. See, e.g., V.A. Basiuk et al., Adv Space Res (1999) 24:505-14. The study of how DNA and RNA arose crops up in abiogenesis (and surfaces periodically in this forum as well).

 

What Amino acids from outer space? Can amino acids form naturally in space?

 

http://en.wikipedia.org/wiki/Miller-Urey_experiment

 

This indicates that as long as the right ingredients and correct stimulation are involved, amino acids can easily form.

 

If that's so, how come we don't witness abiogenesis everyday? I mean if the correct chemicals are involved, and the correct stimulation....

[insane_alien]

we don't see abiogenesis every day because we have an oxidising atmosphere(compared to the reducing atmosphere present when life first formed). so organic molecules decompose before they can form complex organic molecules outside of a biological system. not to mention bacteria and other organisms eat the simple organic molecules.

[GDG]

What Amino acids from outer space? Can amino acids form naturally in space?

 

http://en.wikipedia.org/wiki/Miller-Urey_experiment

 

This indicates that as long as the right ingredients and correct stimulation are involved, amino acids can easily form.

 

If that's so, how come we don't witness abiogenesis everyday? I mean if the correct chemicals are involved, and the correct stimulation....

 

See, e.g., Sandra Pizzarello, et al., Proc Natl Acad Sci USA (2008) 105(10):3700-04.

 

As to why it doesn't occur today: how would you know? It would be hard to pick out against the background of existing life. Chances are pretty low, though, that anything new would survive: things that look like nutrients can get snapped up pretty quickly...