Originally posted by Krypton
I'm just thinking that if life spontaneously sprouted once, it should sprout multiple times, in locations such as Yellowstone or underwater volcano vents. I would think this would be something scientists would be trying to observe in nature. But then again, if it happens, it's on an extremely small scale...:(
One word: "Equilibrium"
Acton
quote:
Originally posted by Krypton
Hopefully this'll be an interesting discussion. So how did life start? The preeminent theory is the primordial soup of organic compounds. If that is true, shouldn't life be constantly sprouting? I don't see it happening which leads me to believe life was somehow seeded onto the planet.
Life probably isn't constantly sprouting because some other life form around would probably eat it!
I'm open to all theories, but I would say I have more belief in the primordial soup theory.
Nrg2Nfinit
quote:
Originally posted by Domesticated
4. Conditions on Earth were a lot different millions of years ago. There was more oxygen in the air and it was warmer. This was more conducive to new life: "Towards the end of the Carboniferous era (about 300 million years ago) atmospheric O2 levels reached a maximum of 35% by volume, which may have contributed to the large size of insects and amphibians at this time."
just an addition to this:
life originated in a carbon rich environment (reducing environment) in order for amino acids and essentially DNA to form.
yukii
Because you don't see it happening doesn't mean it isn't. The primordial soup theory is what i was taught in my univ. bio class. The key to everything was the creation of amino acids, they are the sole component of polypeptides, without polypeptides, cells would not even exist. Lastly, without nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), would not exist.
So, the question is not whether life should be sprouting.. The most basic life form (prokaryote) has been formed 3.5 billion years ago [if i remember correctly].. So the "basics" have already been formed, I don't think we'll be seeing a single celled organism any time soon. However, I do believe new life is sprouting. In remote, diverse and untouched by mankind areas, such as the Amazon, or as you mentioned, the deep sea water vents, there are different life forms being discovered. You won't see a new zebra pop up, however, you will see several bugs/amphibians that still have not been classified in the Amazon, or small organisms that have adapted and can live without any source of sunlight at the bottom of the ocean, and the high levels of sulfide from the vents which would be highly toxic to almost any other animal.
Over 300 new species have been discovered at hydrothermal vents, many of them "sister species" to others found in geographically separated vent areas. It has been proposed that before the North American plate overrode the mid-ocean ridge, there was a single biogeographic vent region found in the eastern Pacific.[10] The subsequent barrier to travel began the evolutionary divergence of species in different locations. The examples of convergent evolution seen between distinct hydrothermal vents is seen as major support for the theory of natural selection and evolution as a whole. http://en.wikipedia.org/wiki/Hydrot..._origin_of_life
Anyway, I'm not too interested about the creation of any new species/organisms..
What I want to know is HOW the amino acids came to be...:conf: I know our universe/earth was based off of CHON (Carbon, Hydrogen, Oxygen, Nitrogen), but imo, the structure of an amino acid is a lot more complicated, the amino group & the carboxyl group.. what I find interesting is that without the R group (side chain), the molecule is just CHON on it's own.. I doubt CHON can help create cells & metabolisms.. So unless it spontaneously {which im not refuting the theory either because it took SEVERAL years to get to that point, but still don't find it reasonable} happened, I want to know how the amino acid, apart from the CHON structure, was formed?
My teacher & i once were talking about this, and we were talking about another option.. could Earth have received the amino acid?.. As far as i know, another galaxy (or in our own) could have a planet far more developed than ours, and as our planet had still not developed, a meteorite could have hit our planet [which was very common in that time period] containing amino acids or at least the right components for creating one..
I just found this article, it's different theory but it mentions amino acids coming to Earth through meteorites..
The results, published in the March 28 Nature, suggest that some amino acids could have formed in giant clouds of icy particles and then hitched rides on comets and asteroids to planets throughout the universe, says Max Bernstein of NASA'S Ames Research Center in Mountain View, Calif. http://findarticles.com/p/articles/...61/ai_84804464/
Anyway, that's probably the most reliable theory i can think of how amino acids got here, i find it hard to believe they just formed because just putting all the components together doesn't create an amino acid. But i do want to hear other peoples' theories! :D
iTranscendence
No one has mentioned the possibility that life was transported here by celestial bodies, a theory that will hold more weight if we find life on mars that shares most of our DNA.
yukii
quote:
Originally posted by iTranscendence
No one has mentioned the possibility that life was transported here by celestial bodies, a theory that will hold more weight if we find life on mars that shares most of our DNA.
Do you mean fully-functioning organisms or amino acids being transported here? Because that's how I said amino acids (theoretically) got here [my previous post].. I don't think organisms were transported though, realistically..
iTranscendence
quote:
Originally posted by yukii
Do you mean fully-functioning organisms or amino acids being transported here? Because that's how I said amino acids (theoretically) got here [my previous post].. I don't think organisms were transported though, realistically..
If there is one organism there must be more, and it doesn't even necessarily have to be a creature as advanced as this, but until we can scientifically create a simple living organism from amino acids and electricity, this theory is more in line with Occams razor.
yukii
Okay, let me rephrase, what i meant to say is, i don't think an organism more than a single celled organism, i.e. 'water bears' would have realistically been transported to Earth, I'm not saying it's not possible.. but that organism is highly more developed than a prokaryote, hence, if you're saying that those kind of highly developed organisms were transported to Earth & the first organsms to be here, then we're skipping entire phases of evolution.. Evolution would not go backwards & the existence of a single celled organism would not be necessary.
Nrg2Nfinit
quote:
Originally posted by yukii
Okay, let me rephrase, what i meant to say is, i don't think an organism more than a single celled organism, i.e. 'water bears' would have realistically been transported to Earth, I'm not saying it's not possible.. but that organism is highly more developed than a prokaryote, hence, if you're saying that those kind of highly developed organisms were transported to Earth & the first organsms to be here, then we're skipping entire phases of evolution.. Evolution would not go backwards & the existence of a single celled organism would not be necessary.
realisticly i dont think a complex organism like a water bear could survive a collisoin into the earth atmosphere (ground impact specifically)
but its not improbable for DNA or RNA to have been transported. The theory of life from mars has some proponents.
Yeah, that's another good point, thanks for pointing that out. Anything less though, like DNA, RNA, amino acid, etc, I do find probable of having been able to land on Earth..
If amino acids were transported to Earth via collisions, meteorites, etc- I'd like to know from WHERE.
iTranscendence
I'm not saying that I'm saying if there are organism like the water bear that could feasibly survive it, then there is a possibility that single celled organisms did as well.
How would they have survived is what would be your next question. Creatures evolve more often than not to suit their environment and our single celled organisms may have been here so long that they lost capacities similar to the water bears.
This entire premise and theory is more plausible based on the evidence we currently have, it doesn't make it the correct theory and could be easily disproven by creating a simple organism.
