Origin of life

[ChaosKnight]

It's amazing how far research has gone in this area.

"Remarkably, a solution of highly poisonous cyanide in ammonia, frozen solid in a refrigerator for 25 years, produced adenine, a necessary component of life."
http://www.sciencedaily.com/releases/20 ... 114051.htm
This research implies adenine, the A in ATCG, can form spontaneously. The raw material to form adenine is cyanide, and we know cynanide compounds have been found in comets.

http://www.sciencedaily.com/releases/20 ... 121623.htm
This research indicates self-replicating chains need not be RNA or DNA. It may be something different and more primitive. Which means for life to start, you only need a simple replicating molecule, much simpler than RNA or DNA.

http://www.sciencedaily.com/releases/20 ... 091444.htm
This final is the most amazing of the 3.

The researchers basically dumped fatty acids into a solution where they spontaneously form vesicles. This happens naturally if we have chains with hydrophillic/phobic groups. Next, they injected some with replicating RNA. When the RNA replicated, the vesicles grew in size. If you read the original article published in Science, there's some indication the researchers managed to get to the extent where the vesicles divide.

Therefore the vesicle walls represent the lipid bilayer of a cell, and the RNA is the replicating material. They have essentially developed an artificial cell that is capable of replicating.

Personally i think all these indicate life is not a random event. It's something that arises spontaneously.

[kingkong]

so it seems life is even more prolific than first thought.

[Tachyon]

I always distinguish between life and intelligent life. The former may be
easy, but the latter is definitely not.

Craig Venter's new project is to make an artificial cell. Let's see how this works out.

Those who worked in Life Sciences would appreciate how complicated and intricate a Eukaryote cell can be. Even now, the role of DNA is still not fully elucidated. We have many more years to go!

[VinSnr]

why so cheem one? Tot origin of life is something that started on the bed by man and woman?

[ChaosKnight]

I always distinguish between life and intelligent life. The former may be
easy, but the latter is definitely not.

Are you saying it's easy to develop life, but difficult to develop intelligent life? If so, I have to disagree.

Simply because it took 1.2 billion years for the first cell to appear on Earth, 5 million from australopithecus to us, and only a few tens of thousand years from Java/Peking man and Cro Magnons to us.

[ChaosKnight]

so it seems life is even more prolific than first thought.

iirc, it was Michael Crichton that said "Life is a crystal."

He meant the physical world is such that order can spontaneously arise out of chaos, the way a highly ordered crystal is formed.

The process of forming life is similar. Life is not a random event, but is instead driven by molecular interactions. This is what we are seeing here.

All the talk about calculating the time scales needed for a DNA molecule, or a living cell, to assemble by chance, is likely irrelevant.

[Tachyon]

I always distinguish between life and intelligent life. The former may be
easy, but the latter is definitely not.

Are you saying it's easy to develop life, but difficult to develop intelligent life? If so, I have to disagree.

Simply because it took 1.2 billion years for the first cell to appear on Earth, 5 million from australopithecus to us, and only a few tens of thousand years from Java/Peking man and Cro Magnons to us.

My hypothesis is not based on the time needed to develop, but on the complexity of the organism itself. It is one thing to develop a single self-sustaining organism (even then, you must remember that that single organism is so complex we have not fully understood it yet), and another to create a multitude of organisms that interact and are dependent on each other.

So what is your hypothesis?

[ChaosKnight]

The way i see it, it's most difficult to get the basic unit of complex life, a cell.

But after the cell is developed, they will spontaneously get together to form multicellular organisms, and eventually intelligent organisms.

Sure, a multicellular intelligent organism is more complex than a cell, but can this complexity arise spontaneously? If so, then although a multicellular organism is complex, it is not difficult to form, at least not as we imagined.

[Tachyon]

The way i see it, it's most difficult to get the basic unit of complex life, a cell.

But after the cell is developed, they will spontaneously get together to form multicellular organisms, and eventually intelligent organisms.

Sure, a multicellular intelligent organism is more complex than a cell, but can this complexity arise spontaneously? If so, then although a multicellular organism is complex, it is not difficult to form, at least not as we imagined.

I will leave that to your judgment after you have studied a bit about biochemistry and genetics. I suggest Genes IX by Ben Lewin for a start - it's a standard textbook for most Uni students but still easy to read. If you are more adventurous, read Molecular Biology of the Cell by Bruce Alberts - another textbook.

Cheers!

[ChaosKnight]

If you are more adventurous, read Molecular Biology of the Cell by Bruce Alberts - another textbook.

Cheers!

Isn't that the big gray textbook recommended, or used, by NUS bio engineering? Yes, i read that sometime back. If i'm not wrong, the book focuses mostly on mechanisms at the cellular level and how cells interact at the tissue level, but hardly anything on the formation of your complex "intelligent" organisms.

What do i know, i never went to JC to take biology, and never took bio at sec sch. But since you asked my hypothesis, i'll tell you how i think a primitive complex organism is formed.


- Organic material have the ability to change the morphology of common NaCl into dendritic structures.
- Near coastal areas, this could have happened: a dendrite made of organic material and salt could have easily formed when drying.
- Primitive cells attached to the dendrite use the embedded organic material for food, and start reproducing.
- As they reproduced, they colonized the dendrite, forming a simple, early plant.
- Over time different cells form symbiotic relationships or diversified.
- As the organism progressed, it retains the dendritic shape, because it confers favourable properties on the organism. Things like surface area vs volume is optimised. The organism now has a simple version of a "complex" network.
- This dendritic structure is retained eventually through evolution. Now you see them in your circulatory or lymphatic systems, or in the brances of plants.

I'm not claiming this is your "intelligent" multicellular organism, but it gives a scenario on how unicellular organisms progressed to a multicellular organism more complex than your regular chunks of stromatolites. Again, it shows complexity arising spontaneously and naturally.