3 Creations

[Zkribbler]

We've all been taught in science class, that life sprang from the protein soup in our oceans. --But that would have only been plant life.

Plants breathe in carbon dioxide and breathe out oxygen. After eons of our world having plants as the only life form, Earth was facing "oxygen poisoning." Then animals evolved, breathing in oxygen and breathing out carbon dixoide. --But does Darwinian Evolution permit new species to evolve with a totally different kind of metabolism?? How does a mutant specie spring from a predecessor, breathing an entirely different gas, ignoring photosynthesis, and eating other species.

And then there's the newly discovered life forms, deep in the oceans, located near hydrothermic vents. They live in the superheated water on the sulphuric minerals and poisoness gasses emitted there. That type of life form couldn't have evolved from either of the other two. It's as if God pulled off THREE separate Creations.

****************
On the other hand, having three types of life forms on this planet improves the chances for life having developed elsewhere in the Universe.

[germanos]

Re: 3 Creations

Originally posted by Zkribbler
We've all been taught in science class, that life sprang from the protein soup in our oceans. --But that would have only been plant life.

No

[Zkribbler]

Re: Re: 3 Creations

Originally posted by germanos


No

...because...???

[DaShi]

Bacteria came later. From Mars!!!!!!!!!!!

[DaShi]

Remember your 5 kingdoms:

1. Animals 2. Plants 3. Fungi 4. Bacteria 5. And um. . .uh. . .Magical Beings (Arcania. Yeah, that's it)

[germanos]

I'm not a biologist.

I should ask you why the proteine-soup would produce plant life per sé, I guess


But in an effort to explain:

The proteine soup (as per how understand evolution in it's first stages on earth) led to single cellular organisms.
These (or should I say: some of those) evolved into multiple-cellular organisms, for example plants (but not exclusively).

edit: and thus your presumption that after plants evolution/creation started all over to produce oxigen consuming life is not a necessary step: both could have evolved parallel, with the oxigen users profiting from their corbondioxide-consuming brethren's succes later on.

[germanos]

Hell, come to think about it. Couldn't it be the O2--> CO2 (a more complex molecule to begin with) organisms be responsible for the evolution of plants (CO2 --> O2) in the first place?

[Starchild]

Re: 3 Creations

Originally posted by Zkribbler
We've all been taught in science class, that life sprang from the protein soup in our oceans. --But that would have only been plant life.

Plants breathe in carbon dioxide and breathe out oxygen. After eons of our world having plants as the only life form, Earth was facing "oxygen poisoning." Then animals evolved, breathing in oxygen and breathing out carbon dixoide. --But does Darwinian Evolution permit new species to evolve with a totally different kind of metabolism?? How does a mutant specie spring from a predecessor, breathing an entirely different gas, ignoring photosynthesis, and eating other species.

And then there's the newly discovered life forms, deep in the oceans, located near hydrothermic vents. They live in the superheated water on the sulphuric minerals and poisoness gasses emitted there. That type of life form couldn't have evolved from either of the other two. It's as if God pulled off THREE separate Creations.

....I'm counting sorting this mess out as my karmic good deed for the week.

Plants weren't the first forms of life. Plants and animals, fungi, bacteria, etc etc are thought to be descended from Luca, the last universal common ancestor.

"Primitive" forms of life can breath a much wider variety of things than we limited oxygen breathers can. Bacteria and Archae can use iron, nitrogen compounds, other metals, etc in the same way we use oxygen, ie, as the end of a long chain of energy harvesting steps that work at a molecular level.

So the original forms of life could quite happily live in an oxygen less environment.

Then, a group of these creatures figure out a way to harness the energy in light and use it for their energy purposes. Eventually, they find a way to store the energy in complicated compounds of joined carbon and oxygen atoms, ie, sugars. These ancestors of the chloroplasts in plants flooded the world with their waste: oxygen. They also joined up with more complicated cells as internal symbiots to form the first simple plants.

Oxygen is the devil. Its damaging and toxic and has a tendency to burn, either quickly in fire or a slow caustic burn at a molecular level. However, if you can use it, oxygen is terribly useful at helping you get every last drop of energy from the new fancy carbon compounds also being made by those green devils.

The creatures that managed to tame oxygen also symbiotically ended up with the ancestors of plants (they breathe oxygen just like we do, they just produce more of it than they use) and non-plant eukaryotes. Blah blah blah, billion years later and the world's set to be taken over by visually pretty but biochemically dull multicellular lifeforms.

So its not three separate creations of entirely new metabolic regimes. The rough mechanics of energy production have been around for billions of years: The movement of high energy electrons (either from a chemical source or a light source) to produce a proton gradient that in turn can power the production of molecules that store that energy, like ATP. Since Luca, its most been tweeking the system, not inventing an entirely new one. And the system hasn't really been tweeked for a good 2 billion years.

/me is not entirely happy with his rough and shoddy guide to bio-energetic evolution but it will do at 10pm on a sunday night

[Zkribbler]

Still, you've taken my knowledge to a place further than it was before. I've never heard of "Luca" before. Thank you.

[Starchild]

Luca's a theory. A hypothetical organism living in the primordial soup that managed to outcompete its competition and its children inherited the Earth. I happen to like it since its a neat explanation for why all life on earth seems to be based on the same molecular machinery even if the life in question is dissimilar as humans, archae living in acid hot springs or worms living in the darkest ocean depths.

[Geronimo]

Originally posted by Starchild
Luca's a theory. A hypothetical organism living in the primordial soup that managed to outcompete its competition and its children inherited the Earth. I happen to like it since its a neat explanation for why all life on earth seems to be based on the same molecular machinery even if the life in question is dissimilar as humans, archae living in acid hot springs or worms living in the darkest ocean depths.

This assumes that LUCA (Last Universal Common Ancestor) had any competition to outcompete.

[Provost Harrison]

Bear in mind this electron transport chain and proton gradient make up the underlying principle of both photosynthesis and respiration and how you get ATP out of the other end...

[Perfection]

Originally posted by Geronimo


This assumes that LUCA (Last Universal Common Ancestor) had any competition to outcompete.

Given the sophistication of LUCA, it's fair to say there were other forms of life around.

[Starchild]

Originally posted by Geronimo


This assumes that LUCA (Last Universal Common Ancestor) had any competition to outcompete.

True. I'm open to the idea that there are other ways of organising life since in the lab, its possible to incorporate non-standard amino acids and nucleotides into proteins and genetic codes. And the right handed preference for organic molecules may be just random chance.

Maybe not entirely different forms of life but certainly different variations may have competed.

Then again, that far back in the past, beyond the reach of the fossil record, its all down to interpretation of what's survived to this day. Any non-Luca life wouldn't be evident for obvious reasons.

[Geronimo]

Originally posted by Perfection
Given the sophistication of LUCA, it's fair to say there were other forms of life around.

It's fair to speculate that there may have been other forms of life around sure.

But I don't think we can confidently assert that LUCA outcompeted organisms which it can meaningfully be thought to have competed against. We simply don't have good enough data to say this.

A big part of the problem is the possibility of a "sea" of horizontal gene transfer preceding the LUCA divergence which would mean that talk of LUCA "outcompeting" the "other" forms of life would be at best greatly misleading or at worse meaningless.

This concept of an era of mass horizontal gene transfer has been accepted as plausible at least since Carl Woese proposed it in the late 90's.