Why does the evolutionary process exist?
- Thread starter Theoryofrelativity
- Start date
Everything requires energy. Energy is free for the taking. Sunlight. Electrical (lightning) and chemical. There are some who think life may have arisen in the complete absence of light or electricity. Deep ocean vents even now support whole ecosystems based on chemosynthesis. Sulfur compounds are apparently the energy source for this system.samcdkey said:
Did you read the wiki article I posted?
http://en.wikipedia.org/wiki/Origin_of_life
It's got descriptions of various models for how this may have happened. No one knows for sure.
Fraggle Rocker
Staff member
Good grief, that doesn't sound difficult at all.perplexity said:
Assume that we don't care about punctuation, spacing, capitalization, or interspersed numerals. The math is only slightly more complicated otherwise and the probability of course decreases dramatically. We just want the letters and spaces in the right order. Assume the monkeys hit all keys at random. Again an oversimplification for the sake of the example, but we can perform tests to determine each letter's frequency of occurrence easily enough.
What is the probability of any character the monkeys type being the correct letter or space? One in 27.
How many characters are there in Shakespeare's oeuvre? You got me and there are too many "characters" named "Count" in his plays to google it, but let's say a million. (I think it's at least ten million.)
So the probability of any string of one million characters typed by the monkeys to be the works of Shakespeare is one in 27^1,000,000. That's a number with somewhere between ten million and one billion zeroes.
That's a pretty small chance. If you had a whole planet full of monkeys and they type from now until the end of the universe in a reverse Big Bang the odds are enormous that it won't happen.
But what are the odds of a tiny live organism with the ability to replicate appearing spontaneously in the good old Primordial Ooze? That one is more difficult to calculate than the example you picked. But is it just as astronomical? Chemical reactions occur much more frequently than monkey key strokes. And there are a lot more sub-microscopic molecules to react in the Primordial Ooze than the trillion or so monkeys we could house on a planet. For comparison we're talking about the equivalent of an entire galaxy full of monkeys. Or perhaps an entire galaxy with the space between the stars packed with artificial habitats full of monkeys.
I don't know. It's a good question. But one thing I have learned is that when it comes to really, really big numbers--the kind we have to write in scientific notation instead of with commas--our intuition is no help and usually guides us in the wrong direction.
I'm sorry, I didn't mean to imply that you were. That was sloppy language on my part.Theoryofrelativity said:
There is no reason to believe that complexity cannot occur at random. This is the Shakespearean monkey problem. Given enough time, it's just a matter of probability, that that combination of characters can show up on a typewriter just as easily as one we're not looking for.
Any given combination of molecules, like any given combination of letters, is as likely as any other. (Of course I'm oversimplifying, you're not going to get molecules of argon iodide as often as water, but the math can still be done.
) Once you make peace with that, it's just a matter of a long cosmic wait for the one you want to occur, no matter how complicated it is. Complexity means a longer wait, but it doesn't mean it is impossible.It will be so fascinating to find out whether there is life on the first extrasolar planets we explore. If it turns out that life is common, that will mean that those reactions aren't all that rare. If it's not, it means we verge on unique.
Of course this will never stop the evolution/creation debate. If life is common the religionists will say that it could never pop up that frequently if it was a random chemical process. If it's rare they will say that just shows how special we all are to their god.
Tor, if you're really interested in this, I'd recommend that you read books on evolution. I can personally recommend "The Selfish Gene" by Richard Dawkins. I can guarantee you'll learn a lot more about evolution by reading books rather than talking to people on these forums, not because there aren't a lot of smart people on this board who have a lot of knowledge on the subject (there are), but because when you're reading books you're more focused on assimilating and forming ideas.
It just seems like a waste of time to discuss evolution on a science forum without basic knowledge on the subject. I'd recommend reading.
It just seems like a waste of time to discuss evolution on a science forum without basic knowledge on the subject. I'd recommend reading.
Last edited:
makeshift said:
Don't presume I know nothing of evolution, I studied animal evolution 10yrs ago (not greatly but some) the study did not go so far back as the 'origin of life' and was species related, my topic of study was bats. Re the Selfish gene, I am familiar with that book, came across it many many yrs ago. I also have 'The language of genes'. I'll dig it out and refresh my memory. Not sure it covers what I desire to know though.
Meanwhile this forum is for exchanging information, you don't like being asked then don't read and don't respond to me. Others are enjoying this exchange of information as am I.
Super, Sam and Sarkus, great posts, very intersting thanks. I am absorbing it and will get back to you.
For those of you that struggle with the origins of life, you would be well-off to not think of those first interactions from a biological standpoint, but from a chemical one.
It is easy to get confused with the first chemical interactions because of our knowledge of where those interactions led (namely, and egotistically, US).
Don't lose sight of the uniqueness of that early sea of chemical interactions. The bizarre thing about the early Earth is that there was ~no life~ back then. There were no predators. I realize that this is maddeningly simple to point out, but it has extraordinary implications that we tend to discount when we picture what was going on back then.
Early Earth was a veritable buffet of building blocks and food. And there was zero competition. Chemistry was the name of the game, with any bonds that would form, forming. There was ample energy from heat, lightening, venting, rock substrates, and crystals. And the building blocks of life form pretty spontaneously. We see methane and amonia in orbital debris. Laboratory firings of electricity into chemical soups result in an amazing collection of life-legos.
The early Earth was trillions of tons of fluid, full of these chemicals, in every combination possible, going through every temperature range imaginable, with all sorts of impacts, rock substrates, and electrical discharges. And there was none of the life-killing poison that is O2 around. With billions of these experiments occuring every second, for trillions of seconds at a stretch, I wouldn't be surprised if the thing which led to RNA (which probably led to DNA) wasn't floating around withing the first few thousand years of Earth cooling and holding an ocean of water.
This is borne out with observation. As far back as we can find rock, we can find evidence of life.
A good primer on the chemical nature of proto-life can be found in the book "Vital Dust". It has been around for years, but to my knowledge, has not been usurped from its throne where it rules this topic.
And great thread.
It is easy to get confused with the first chemical interactions because of our knowledge of where those interactions led (namely, and egotistically, US).
Don't lose sight of the uniqueness of that early sea of chemical interactions. The bizarre thing about the early Earth is that there was ~no life~ back then. There were no predators. I realize that this is maddeningly simple to point out, but it has extraordinary implications that we tend to discount when we picture what was going on back then.
Early Earth was a veritable buffet of building blocks and food. And there was zero competition. Chemistry was the name of the game, with any bonds that would form, forming. There was ample energy from heat, lightening, venting, rock substrates, and crystals. And the building blocks of life form pretty spontaneously. We see methane and amonia in orbital debris. Laboratory firings of electricity into chemical soups result in an amazing collection of life-legos.
The early Earth was trillions of tons of fluid, full of these chemicals, in every combination possible, going through every temperature range imaginable, with all sorts of impacts, rock substrates, and electrical discharges. And there was none of the life-killing poison that is O2 around. With billions of these experiments occuring every second, for trillions of seconds at a stretch, I wouldn't be surprised if the thing which led to RNA (which probably led to DNA) wasn't floating around withing the first few thousand years of Earth cooling and holding an ocean of water.
This is borne out with observation. As far back as we can find rock, we can find evidence of life.
A good primer on the chemical nature of proto-life can be found in the book "Vital Dust". It has been around for years, but to my knowledge, has not been usurped from its throne where it rules this topic.
And great thread.
swivel said:
I'm confused (permanently
)this 'no Oxygen ' thing has been mentioned before,
If the later presence of oxygen and then 'water' kick started biological evolution, did the rise of biological evolution stop dead chemical evolution?
Theoryofrelativity said:I'm confused (permanently
this 'no Oxygen ' thing has been mentioned before,
If the later presence of oxygen and then 'water' kick started biological evolution, did the rise of biological evolution stop dead chemical evolution?
The presence of oxygen had nothing to do with biological evolution getting started. The only reason we have an O2 environment is because of photosynthetic respiration. The conversion of energy in the animal kingdom (the ATP cycle and CREB process) takes place by a chemical reaction that consumes CO2, and releases O2.
The fact that we do the opposite does not imply that our process is the correct one. As a matter of fact, the other way is far superior. The only way we can get energy is by consuming the energy made by the CO2 -> O2 cycle. That can mean eating plants, where we break down the sugars and carbs that hold precious ATP, or by eating other animals that have eaten plants.
Oxygen is not a necessary ingredient for life. It is actually a toxin that is very bad for biological organisms. Overcoming the buildup of O2 in the atmo would have been a major hurdle for organisms on Earth (and anywhere else). The reason is O2's caustic electron structure. The stuff is readily combustible. Heck, look what it does to metals.
Yes. And for ToR, organisms basically were killing themselves (inadvertently of course) with their own waste products (O<sub>2</sub>). Many lifeforms adapted to use this toxic waste to their advantage. Kind of reminds me of what we are intentionally doing to the planet with industrial CO<sub>2</sub> emmissions.swivel said:
As an interesting side note, when interferometric telescopes can finally take decent spectra of extrasolar planets, the presence of a strong oxygen line will almost certainly indicate the presence of life. Why? Since oxygen is so chemically reactive, it dosen't linger long in an atmosphere before chemically combining with the other elements that make up the planet.
Of course, a strong methane line could indicate the same thing, since by no means is it a requirement that life becomes oxygen-producing at some point. As far as we know. We have so few examples of life bearing planets...1.
Of course, a strong methane line could indicate the same thing, since by no means is it a requirement that life becomes oxygen-producing at some point. As far as we know. We have so few examples of life bearing planets...1.
superluminal said:
I often wonder about this. Chemistry is such a precise field. I would think that any process which got up and running would have a huge advantage, but with chemistry, usually the best process... the one that is most "downhill" will eventually take over and surpass anything inferior.
For that reason, I would be very surprised to find a life-cycle much different from what we have on Earth.
Which is pretty on-topic, because if this is true, then the question of this thread is pretty moot. Evolution occurs because if the conditions are right, it must. It would be like questioning gravity in the presence of mass...
I tend to agree with that. My "gut" feeling is the same. I'd be really suprised to find life systems greatly different from our own. But you know, this is one of those things that may be 99% for sure, but until we have some more examples, we're sort of stuck.swivel said:
swivel said:
2 things confuse me:
1) If no oxygen then we had no water, are you saying we had 'life' before we had water?
2) the report I read re 'where did water come from?'
suggests Oxygen not just here on Earth but in universe in general
http://www.madsci.org/posts/archives/oct99/941236464.Es.r.html
"....... When the earth coalesced out of the
primordial gas cloud that surrounded the young sun, hydrogen and oxygen
were two of the chemical elements incorporated in the earth. Hydrogen is of
course by far the most common element everywhere in the universe: you can't form a planet without hydrogen. Oxygen is less abundant in the universe, but it is a common element too, if you don't consider the "biggies", hydrogen and helium. Oxygen and hydrogen are chemically quite reactive, and so they both combined with various other elements to form chemical
compounds. One of these compounds is water, and water quickly became an
important part of the earth's surficial layer, along with many other
familiar chemicals (silica - a major component of sand, calcium carbonate -
what limestone is made of, etc.).
I get the impression this confirms presence of oxygen before presence of life.
superluminal said:
well from what you say, oxygen is toxic to biological life so yes we can have life systems vastly different to our own. Imagine if our world and biological organsims continued to evolve without the prescenece and interference of oxygen, we'd have completely a different life system.
So life can exist in space without oxygen
Did the prescence of oxygen (water) have a terraforming effect on our planet?
Theoryofrelativity said:
Oxygen is a byproduct of photosynthesis. The very first organisms were not photosynthesizers. They came later. When they did come the oxygen content of the earth's atmosphere was raised to artificial levels. The presence of oxygen in the atmosphere is unrelated to the presence of water (as in direct causal relationship). This is not a secret. Usually this little fact is brought up during basic science education.
Or as wikipedia says:
Theoryofrelativity said:
Indeed. Oxygen was formed in stars long before there was an earth. If there was oxygen long before earth than there was also oxygen long before life.
Indeed:
However, this oxygen is not freely available.
Free oxygen only started to become abundant with the evolution of photosynthesizers.
Of course swivel already explained it before:
Which was ingored.
Theoryofrelativity said:
Oxygen is a by product of life. Nowadays it is used by life because it is so abundant.
Cellular respiration or oxydation still has to occur, whether there is oxygen or not.
In fact in your own body you actually do oxydation without oxygen
Usually like this (wikipedia):
Glucose ---> Lactic Acid + Energy (ATP)
In fact, the world is still full of anaerobe organisms (that do not use oxygen for respiration).
The most classic example are the organisms living around deep sea vents. A whole community of animal life is based around microorganisms that use chemosynthesis.
Life as we know it cannot life in space, because it is too cold or there are no energy sources, or there are no resources. There are specific locations in space where you can find these things. They are called planets. And maybe other cellestial bodies will do too.
I can tell this is all quite basic text book stuff. But you will probably blow a valve again.
It seems there is some confusion about Oxygen and O2. Oxygen is the element, O2 is a molecule. The fact that there was no O2 (in any amount worth mentioning) does not mean that the element of Oxygen was not present. You can have tons of water and not have any O2.
Well, oxygen is both used as element and 'O2'.
See dictionary.
See dictionary.
spuriousmonkey said:
I agree that the word "oxygen" is used to mean both, which is unfortunate. My point remains that someone else in this thread thought that by my saying there was no O2 (I was always explicit), the poster thought that there could not have been any water. That is where the confusion was, and obviously still is.
And I feel a lot of rudeness coming from your post. Is this intended? Or is it the natural way that everyone here relates to one another? I'm new, and curious if I will have to be dealing with passive agressiveness and open hostility often. Not that I mind terribly... just disappointed if this is the case.