Discussion: Origin of life.

[iNow]

It does? Not really, the title of the thread is "Origin of life" and panspermia is just another hypotheses related to the subject. It says that life in earth was transfered from some extraterrestrial source and the other stuff that says the link.

 

TDS,

 

I think you have seriously underestimated lucaspa's understanding of the subject matter based on the tone of your response to him above, and I also completely agree with his point that the panspermia hypothesis only pushes the problem elsewhere. The thread title does not say "orgin on life on earth," it just says, "origin of life." Lucaspa's point is that, if life came from elsewhere (ala the panspermia hypothesis), then where and how did THAT life begin? Panspermia is not so much an "answer," but more a displacement of the original question.

[Obelix]

1st sorry for my english, if there are mistakes...

 

I have an idea in my mind and I would like to ask you people, who understand science more than me, what do you think of it:

 

So we separate living world and non-living world (saying non-living I mean stones, water and so etc.). The living world has one very specific thing in itself. It is, let's call it force that make it survive. In organisms this is called 'an instinct of self-preservation'. What is this force?

 

Using the term "force" can be seriously misleading. It was used by Newton in a rather loose way, in the absence of a better term, and it has been long given up in Physics.

 

Do you mean to say that the instinct of self preservation is what identifies a "living" entity as such?

 

In my oppinion this is a natural force that existed even before the life(what we understand of it) appeared.

 

If so, it must be still existing. How does it appear in what is called "non - living" matter (stones, water, etc)? What known properties are there in such matter, which, if extrapolated, can lead to an instinct of self preservasion in living matter?

 

Is it the very old idea of a vis vitalis you have in mind? But this used to be, by definition, the very thing that was absent from non - living matter, distinguishing it from the living one...

[lucaspa]

It does? Not really, the title of the thread is "Origin of life" and panspermia is just another hypotheses related to the subject.

 

iNow stated the argument very well. Below is what I wrote before I read iNow's response.

 

But "origin of life" does not say "origin of life on earth". As you say, Panspermia "says that life in earth was transfered from some extraterrestrial source and the other stuff that says the link."

 

What's the origin of life at the extraterrestrial source? See? We really don't have an origin of life in Panspermia. Panspermia just pushes the question off earth to some other location.

[Donut.Hole]

I don't know too much about it, but that's true for the rest of the world. Scientists (I'll give the short version) think that it was some freak chemical reaction of hydrogen, carbon, and oxygen, which formed complex chains of proteins, which started the first organisms.

[iNow]

I don't think your use of the general term "scientists" and the specific term "freak chemical reaction" are very helpful in a discussion such as this, but I get your point. It's just chemistry and electricity, and most people have absolutely no idea just how long a few billion years truly is and what can happen during those vast unimaginable eons.

[mihail]

I changed my idea a little bit. I meant that life appears in rocks etc. but now i changed my mind. I am wondering what makes living beings to survive. Life adapts itself ewerywhere. For example we have evidance that life on our planet that life can survive with no light, in severe temperatures, no air, water etc. I think life is a parasite itself and appears and exploit the environment, just to survive. This is led by its "will" to survive. Evolution is manifestation of its "will" to survive. The instinct for self preservation also. This is the one and biggest pursuit of life. What makes it do it. I think that when we understand this we would be closer to the truth about the origin.

[Phi for All]

I think life is a parasite itself and appears and exploit the environment, just to survive.

I would avoid this generalization. Parasites feed off a host but tend not to kill it or benefit it. Symbiosis is more what you're looking for.

 

And I wouldn't look at life as exploitation of the environment. There certainly have been some exploitative practices but there are ways to use the environment that are more sustainable and we are coming to realize how they are better. Taking advantage of natural occurrences is not necessarily exploitation.

[mihail]

the problem is there that i am not a scientist and my expression is more kind of talkative... I cannot explain my idea without making that kind of mistakes, sorry about that.

[Phi for All]

I think that when we understand this we would be closer to the truth about the origin.

Remember also that science is not as much interested in "why"; that's for the philosophers. Science wants to observe, make predictions and understand "how" things work. And even if we discover that all life started from a chemical interaction and grew from there, it still wouldn't begin to answer a question like "why".

[lucaspa]

I am wondering what makes living beings to survive. Life adapts itself ewerywhere. For example we have evidance that life on our planet that life can survive with no light, in severe temperatures, no air, water etc. I think life is a parasite itself and appears and exploit the environment, just to survive. This is led by its "will" to survive. Evolution is manifestation of its "will" to survive. The instinct for self preservation also. This is the one and biggest pursuit of life. What makes it do it. I think that when we understand this we would be closer to the truth about the origin.

 

Sigh. Another attempt to get "will" or consciousness into evolution. Mihail, there is no magical "will" to survive and no "will" coming from organisms to "exploit" the environment.

 

Instead, as I have said elsewhere, individuals are either lucky or unlucky in the alleles (forms of genes) that they get. IF and individual is lucky enough to get a set of alleles that allows it to access a new food source or environment, then it will do better in the competition for scarce resources ("struggle for existence" in natural selection) because it will have resources the other individuals do not. So that individual will produce more offspring, which will inherit the new ability. After hundreds/thousands of generations, the entire population will be able to exploit the new resources/ecological niche. No "consciousness" on the part of the individual involved.

 

In terms of what humans think of as the "instinct to survive", think about that also in terms of natural selection. Those individuals unlucky enough to be born with alleles that caused them to "give up" in the face of adversity have a greater likelihood of dying than those who are lucky to have alleles that cause them to keep living. Those with the "survival instinct" will, on average, survive longer and have more kids that those who were unlucky and had the set of alleles to "give up". Thus, our "instinct of self preservation" or "will to survive" also came from natural selection.

 

Remember also that science is not as much interested in "why"; that's for the philosophers. Science wants to observe, make predictions and understand "how" things work. And even if we discover that all life started from a chemical interaction and grew from there, it still wouldn't begin to answer a question like "why".

 

That's a stance that's often taken, but it really isn't true. Science is interested in the "why". Science does answer lots of "why" questions. In fact, so many that some scientists, like Dawkins, Atkins, and Sagan, think science can answer all the "why" questions.

 

It's not that science doesn't deal with "why" questions, it's that science cannot deal with all the "why" questions.

[mihail]

natural selection, ok. But I am still wondering what is the logic for life to manage to survive. Imagine the time when it was the beginning. I don't understand how this chemicals start "trying"(achieving or something like that) to not disappear, which is the top PRIORITY in living beings, isn't it? Why every animal's aim is to keep itself alive? Why would a chemical reaction do things like that?

P.S. I don't believe god does this things if someone thinks so.

[lucaspa]

natural selection, ok. But I am still wondering what is the logic for life to manage to survive. Imagine the time when it was the beginning. I don't understand how this chemicals start "trying"(achieving or something like that) to not disappear, which is the top PRIORITY in living beings, isn't it? Why every animal's aim is to keep itself alive? Why would a chemical reaction do things like that?

 

Those are separate topics. So let's go to the origin of life. I posted the answer to that one back on 3-21. Let's try again:

"As to how to get life from non-living chemicals, there are several possible ways to do this. The one I like best is "protein first". Heat a mixture of amino acids to have them form proteins. The proteins will then spontaneously form cells. The cells are alive. You can do this dry (as in a tidal pool) or at underwater hydrothermal vents.

 

http://www.siu.edu/~protocell/

http://www.theharbinger.org/articles/rel_sci/fox.html "

 

Read the references. If you don't understand, then ask questions about them.

 

The protocells survived because there wasn't anything that was going to kill all of them. There were no predators, no disease, and whatever natural disaster happened, there were so many protocells in so many places that nothing could kill them all. Think of bacteria today. There are lots of natural disasters that could cause humans to go extinct, but bacteria would survive them.

 

Living beings don't have a "top priority" like you are using the term -- "every animal's aim is to keep itself alive". That phrase again implies conscious decision on the organism's part -- each animal saying to itself "I must stay alive". That isn't what happens. There are only a few species that may have consciousness on the level of humans and would think in those terms. We are the only species we know for sure thinks that way. You can't extrapolate us to every other animal.

 

Instead, as I said, trying to stay alive (for multicellular animals with a brain) and struggling to survive when injured or faced with obstacles (like fighting to swim in a flood) is a product of natural selection. Any individual ancestors that did not struggle but gave up did not leave the alleles to give up to its descendents. Only those lucky few with the alleles for fighting in those circumstances survived and thus every individual is descended from them and have the alleles that cause that behavior. The animal itself doesn't have an "aim to keep itself alive", just a set of behaviors that is controlled by its genes. The animal itself is unaware of this and does the behavior because, very loosely speaking, the genes tell it to.

 

For plants and animals without a brain and a very limited set of behaviors, they are designed by natural selection to survive in their present environment. Otherwise, it's a matter of luck. A plant doesn't try to "keep itself alive" when a herbivore comes to dine on it. It's unlucky enough to get eaten. But the herbivores don't eat all the plants.

 

And let's face it, individual organisms and species do die, from a number of causes. 99.9% of all species that have ever lived on earth are extinct. They didn't survive.

[Mr Skeptic]

mihail, what you call the "will to survive" is perhaps better described as the tendency of living things to maintain homeostasis. A critter "tries" to maintain its internal environment. A lot of this is just a big complicated feedback loop. One example is how a chain of reactions driven by enzymes is inhibited (slowed down) by the presence of large quantities of the final product. So when the amount of that product is lowered, the rate of production for it goes up. All automatic, no thought involved.

[foodchain]

I changed my idea a little bit. I meant that life appears in rocks etc. but now i changed my mind. I am wondering what makes living beings to survive. Life adapts itself ewerywhere. For example we have evidance that life on our planet that life can survive with no light, in severe temperatures, no air, water etc. I think life is a parasite itself and appears and exploit the environment, just to survive. This is led by its "will" to survive. Evolution is manifestation of its "will" to survive. The instinct for self preservation also. This is the one and biggest pursuit of life. What makes it do it. I think that when we understand this we would be closer to the truth about the origin.

 

Well that could apply to fire also. Fire will spread out and react to its environment to stay alive but I don’t look at fire as having a will, its more or less a natural process like a planetary orbit. Natural selection operates on two variables primarily, which in my opinion are simply reproduction and variation. Variation seems to occur naturally, as in I doubt for a genome if conscious and fully mutalistic to desire obtaining say some form of a disease? So if you have say variation and reproduction and in that you find difference that can be selected for or against via the environment.

 

Lets look at sexual reproduction, or polyploidy. Why don’t humans have say six or more copies for a karyotype in each cell? It seems to benefit plants? Why does some life use sexual reproduction over binary fission?

 

The environment basically produces a constant fitness landscape, in which via reproduction and variation traits, or genes or alleles become selected for or against. Its why you don’t see typically terrestrial mammals as dominant figures in say a aquatic ecosystem, you find fish. Even with say avian or mammal like organisms that have found niches in say aquatic ecosystems you can find how variation/reproduction combined with selection has lead to say seals and whales or penguins.

 

Traits that express an increased fitness can come to become fixed in say a population, such as sight. Also from the reality of natural selection you have convergent evolution. In which similar traits can evolve independently of say a direct ancestral basis for the existence of such, like drip tips on leaves in the rain forest, or again the simple reality of penguins. Its just natural selection operating on variation/reproduction. If per say you had an environment in which multicellular life was selected against constantly it would not sustain any particular length of time, or for any specific traits this is true. So is say mutualism a evolutionary successful strategy? The only answer you could give to that would be dynamic, because it pertains to the environment. This is why natural selection became such a powerful descriptor for life, if you take it away nothing in biology makes any sense, and someone has already said that I just don’t remember the name. Not to mention the overwhelming support for such in terms of science stuff like evidence.

[mihail]

mihail, what you call the "will to survive" is perhaps better described as the tendency of living things to maintain homeostasis. A critter "tries" to maintain its internal environment. A lot of this is just a big complicated feedback loop. One example is how a chain of reactions driven by enzymes is inhibited (slowed down) by the presence of large quantities of the final product. So when the amount of that product is lowered, the rate of production for it goes up. All automatic, no thought involved.

 

yes, i don't think that thought is involved. I just think that there is some natural referance to the "will" to survive. So you say that this is normal in chemical reactions or something like that. I don't understand yet. There is a lot of time for me to do this. I'll think again, I am a little drunk right now, sorry... stupid me. I haven't read the other postings yet greetings.,

 

This is very interesting topic, I don't know why, mabye this is the mystery about it. i hope you are close to the truth, but agree that history remembers a lot of stories in which scientists were wrong just because they thought they knew so much. I don't say you are wrong, just keep this in mind when you are convinced in something and believe it is true.

 

sorry for disturbing you with my so called stupidity

[SkepticLance]

Mihael

 

Please do not apologise. I think it is great that someone who uses English as a second language, with a little difficulty, should persist with this forum. It is a tribute to your interest in the subject. Please continue.

[lucaspa]

yes, i don't think that thought is involved. I just think that there is some natural referance to the "will" to survive.

 

If you don't mean "thought", then what do you mean? "Will" implies thought, either on the part of the plant or animal or infused by some other thinking agent: like humans programming our smart weapons to have the "will" to hit the target.

 

So you say that this is normal in chemical reactions or something like that.

 

No, what he is saying is that living organisms have evolved feedback loops that regulate the chemical reactions in the cell. That way the cell doesn't make too much of something. It's very common for the end product of a synthetic pathway to inhibit the pathway. The more end product is made, the slower the pathway works and the less end product is made.

 

A classic example is the synthesis of the amino acid isoleucine from threonine. The pathway is threonine to alpha-ketoglutarate to alpha-acetohydroxybuyrate to dihidroxy-beta-methylvaline to alpha-ketomethylvalerate to isoleucine. Isoleucine binds to the enzyme that catalyzes that first step from threonine to alpha-ketoglutarate and stops the whole process.

 

i hope you are close to the truth, but agree that history remembers a lot of stories in which scientists were wrong just because they thought they knew so much. I don't say you are wrong, just keep this in mind when you are convinced in something and believe it is true.

 

What we are presenting to you are only very well-supported theories, so well supported that they are facts. That you said this worries me: it implies that you are going to look for a "will" beyond natural selection no matter what data we present to you. I'm afraid that there is a point in science where you really can't hide behind "a lot of stories in which scientists were wrong". You need to accept the data unless and until some new data (which we haven't been able to find and probably doesn't exist) is found.

[Similibus]

Hi

 

Can anyone tell me how energy is produced through the Krebs cycle? I get that there is a process of different molecules forming with progressively more and more potential energy in their chemical bonds. What is this energy called - the potential energy in the molecular bonds? And how is it freed and utilised? And what is it called when it is not potential energy anymore, but energy that has been freed and is being utilised?

Thanks very much for any answers,

Sim