A Shadow Biosphere

[Airmid]

Here's an article that I found very interesting: http://http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2161&mode=thread&order=0&thold=0

In it, prof. Carol Cleland discusses the possibilty of a "Shadow Biosphere" on Earth, alternative lifeforms that coexist with life-as-we-know-it. She also discusses the arguments that scientists use to show that such an alternative biosphere is not possible.

 

I find her train of thought very appealing. I would very much like to know what your opinions are on the subject. Do you think she has a point, or do you have arguments to say otherwise?

 

Airmid.

[Mokele]

One thing she neglects is the problems rarity causes. Rare 'alternate microbes' would fulfill her criterion of being hard to find, culture and detect, but like all rare groups, they would also be more prone to extinction.

 

Mokele

[Dr. Dalek]

One thing she neglects is the problems rarity causes. Rare 'alternate microbes' would fulfill her criterion of being hard to find, culture and detect, but like all rare groups, they would also be more prone to extinction.

 

Mokele

Bu then again Mokele their have been discoveries before of untapped cave with all manner of strange creatures living inside of them. As I recall they found one just a few years ago that had been sealed up for several million years, it had all sorts of new species of scorpians and crustacians in it; why couldn't their be ecosystems of microorganisms doing the same thing. In my oceanography class recently the professor talked about this theory of microrganisms living near the earths mantle producing hydrocarbons. Also there are new theories about bacteria that can live inside clouds, and I read some time ago that there is a reasearcher claiming that if thermosynthetic organisms existed they would be almost undetectable by current methods. So their could be something to this.

 

(I'll try to get you some websites for these things I mentioned)

[Airmid]

One thing she neglects is the problems rarity causes. Rare 'alternate microbes' would fulfill her criterion of being hard to find, culture and detect, but like all rare groups, they would also be more prone to extinction.

 

Mokele

 

That's a good argument, but only if you couple it with the "if they weren't rare we would have found them by now"-argument. Common sense tells me that if alternate life forms exist, they indeed must be rare. But on the other hand that might be a pitfall. According to Carol Cleland, we haven't seen 99% of earth's critters yet; according to others 80%. And it's not good (statistical) science to base major conclusions on 1% (or 20%) of a population.

 

Airmid.

[Airmid]

Bu then again Mokele their have been discoveries before of untapped cave with all manner of strange creatures living inside of them. As I recall they found one just a few years ago that had been sealed up for several million years, it had all sorts of new species of scorpians and crustacians in it; why couldn't their be ecosystems of microorganisms doing the same thing. In my oceanography class recently the professor talked about this theory of microrganisms living near the earths mantle producing hydrocarbons. Also there are new theories about bacteria that can live inside clouds, and I read some time ago that there is a reasearcher claiming that if thermosynthetic organisms existed they would be almost undetectable by current methods. So their could be something to this.

 

(I'll try to get you some websites for these things I mentioned)

 

We seem to have read quite a lot of the same things! And yes, new organisms are being discovered like every day, and new pathways, and even new biotic key elements, like amino acids. I'm excited about all this, but also quite disappointed. Excited, because it shows how versatile earth life is and how much there's still out there to be discovered. But also disappointed, because all those new discoveries are essentially more of the same.

The shadow biosphere discussion essentially is about the question: How rare is life in the universe? If life in the universe is common, then there's a chance that it didn't emerge once, but twice or even more often on Earth. In that case we might be able to find creatures on Earth, that don't follow the familiar DNA-based pattern.

 

Airmid.

[Mokele]

The problem is, it's all just speculation until someone *does* find it. Yeah, it's a nice idea, but so is the idea of an entire civilization living on a dust-speck. Neither can be proven wrong, but neither has any evidence.

 

Mokele

[Dr. Dalek]

The problem is, it's all just speculation until someone *does* find it. Yeah, it's a nice idea, but so is the idea of an entire civilization living on a dust-speck. Neither can be proven wrong, but neither has any evidence.

 

Mokele

I don't know, a firend of mine hears Whos quite frequently.

[Brian]

If this is true, it would be very interesting indeed. But if this is true...what would be the practical applications. Sure, mapping out 100% percent of the world would be ideal, but this would definitely extend beyond the perception of "shadow biosphere" we would first need to discover the rest of the "normal" population in order to view a rare specimen. In essence, the "shadow biosphere" is saying that there is life other than we know it, but that does not make sense because that would be saying our planet is full of life that we do not know of. So really, what the author of this study may be thinking, is simply discovering the other microbial inhabitants on Earth...so the term "shadow" is not really accurate...more like an "unknown" biosphere. Just a thought.