It's basically an amazing shield around our home that protects us from harmful ultraviolet light, blocking 98% of it.

At some point there must have not been an ozone layer around our planet. It was created when large amounts of oxygen made its way into the atmosphere.

I read up on this, and apparently oxygen and ozone participate in a process known as the ozone-oxygen cycle.

Ozone molecules are created when ultraviolet light from the sun hits oxygen molecules, splitting them into 2 distinct oxygen atoms. These single oxygen atoms in turn bond with other oxygen molecules, producing ozone molecules (O+02=O3). This process is continuous, but couldn't have started without any oxygen in the atmosphere to begin with.

So how did the oxygen get there? Did plants arise before the ozone layer existed, eventually pumping a ton of oxygen into the atmosphere? This created the ozone layer, creating the shield, allowing more complex life forms to come into existence?

Is that how it happened? If so.. why oxygen? Why do plants naturally create this?

Is it just a coincidence that one of the first forms of life to appear on the planet are oxygen factories, which is what is required for more complex forms of life to develop? Why were these oxygen producing species selected for? (in evolutionary terms) Why oxygen?

Why this interesting connection, and can somebody (who knows what they're talking about, hopefully) shed a bit more light on it?

Get This To The Science Forum

So how did the oxygen get there?

Allah.

XCL

Oxygen was a natural by product of early sea living bacteria (or algae or something, I am not a biologist). These would not have been exposed too much to ultra violet light, and not been damaged too much by it.

Also, shouldn't this be in Science/Technology?

There is a science/technology subforum?

Uhmm okay, TOPIC CHANGE

What is the Christian perspective on all of this?

What is the Christian perspective on all of this?

God did it, now shaddup and stop thinkin'.

Oxygen was a natural by product of early sea living bacteria (or algae or something, I am not a biologist). These would not have been exposed too much to ultra violet light, and not been damaged too much by it.

Also, shouldn't this be in Science/Technology?

What business do they have creating oxygen? Why is it a natural byproduct?

God did it, now shaddup and stop thinkin'.

I know God did it. I want to know which God did it.

I know God did it. I want to know which God did it.

There's only one God, the Christian God!

Is it just a coincidence that one of the first forms of life to appear on the planet are oxygen factories, which is what is required for more complex forms of life to develop? Why were these oxygen producing species selected for? (in evolutionary terms) Why oxygen?

Why this interesting connection, and can somebody (who knows what they're talking about, hopefully) shed a bit more light on it?
Well, life probably developed to live off oxygen because it was, y'know, there. If it wasn't, it may have developed differently, then again, I don't know if it works that way.

Oxygen was a natural by product of early sea living bacteria (or algae or something, I am not a biologist). These would not have been exposed too much to ultra violet light, and not been damaged too much by it.

Also, shouldn't this be in Science/Technology?
What he said.
There is a science/technology subforum?

Uhmm okay, TOPIC CHANGE

What is the Christian perspective on all of this?
God is benevolent and loving, and created this system so that we, his children, may live in peace below it, but if we venture out of it, we will perish and die in our frivolous attempts to escape from God's fish bowl.


All in all, the Ozone is awesome, I love it. If I could hug it, I would.

Well, life probably developed to live off oxygen because it was, y'know, there. If it wasn't, it may have developed differently, then again, I don't know if it works that way.

Ahh, but it wasn't there, unless I'm horribly mistaken.

All oxygen on this planet is produced by green algae, cyanobacteria, and plants.

Thread moved.

The problem you are having is that you assume (I guess) that it appears to be a pretty big coincidence that plants "excrete" oxygen since we need that to live. The coincidence is that other more complex life forms could use that oxygen that was flying around unused. Had it been methane instead of oxygen and human life needed methane to exist you'd be surprised that there was something that caused methane to enter our atmosphere in the first place.

Humans and other living beings evolved with the ability to process and dependency on oxygen because given the environment they evolved in allowed (or favoured) only that possibility.

Ahh, but it wasn't there, unless I'm horribly mistaken.

All oxygen on this planet is produced by green algae, cyanobacteria, and plants.

Well, there was H2O, and had been before life, right?

What business do they have creating oxygen? Why is it a natural byproduct?

Photosynthesis.

Incidentally, oxygen is widely used in biology because it's the third most abundant abundant element in the universe, and the most abundant (by mass) in the earths' crust.

I don't know enough high level chemistry, but I'd speculate that more abundant elements, namely helium and hydrogen, are quite unsuitable for stable reactions.

That is, hydrogen is far to reactive. With only one electron it basically reacts with almost any non-metal it comes across, and a good porton of metals to. Hence the effects of acid.

Helium, on the other hand is almost completely unreactive. A noble gas, it reacts with almost nothing, evidently this would make chemical reaction in biology pretty tough.

Thus, oxygen is a healthy medium. Much like carbon really, another abundant element.

Incidentally, the importance of oxygen and ozone relies only on carbon/oxygen based life. We might not be having this arguement if we were made from silicon ;)

The problem you are having is that you assume (I guess) that it appears to be a pretty big coincidence that plants "excrete" oxygen since we need that to live.

No, that part makes perfect sense to me.. that's not the coincidence I brought up in the OP.. Did you read it?

Photosynthesis.

Incidentally, oxygen is widely used in biology because it's the third most abundant abundant element in the universe, and the most abundant (by mass) in the earths' crust.

I don't know enough high level chemistry, but I'd speculate that more abundant elements, namely helium and hydrogen, are quite unsuitable for stable reactions.

That is, hydrogen is far to reactive. With only one electron it basically reacts with almost any non-metal it comes across, and a good porton of metals to. Hence the effects of acid.

Helium, on the other hand is almost completely unreactive. A noble gas, it reacts with almost nothing, evidently this would make chemical reaction in biology pretty tough.

Thus, oxygen is a healthy medium. Much like carbon really, another abundant element.

Incidentally, the importance of oxygen and ozone relies only on carbon/oxygen based life. We might not be having this arguement if we were made from silicon ;)

But see.. say we were silicon-based... and that organisms that expunge oxygen into the atmosphere never developed either.

There would be no ozone.. right? Would it thus be harder for complex life to develop?

Are (complex) oxygen/carbon-based lifeforms almost an inevitability, because you need oxygen for ozone, and without an ozone layer complex life forms would never arise?

No, that part makes perfect sense to me.. that's not the coincidence I brought up in the OP.. Did you read it?


Yes, I misunderstood. I had a similar chat with a friend the other day and I was, apparently, thinking about that
.



But see.. say we were silicon-based... and that organisms that expunge oxygen into the atmosphere never developed either.

There would be no ozone.. right? Would it thus be harder for complex life to develop?

Are (complex) oxygen/carbon-based lifeforms almost an inevitability, because you need oxygen for ozone, and without an ozone layer complex life forms would never arise?

Maybe life that was more resistant to cosmic radiation would have developed. Life on earth doesn't have that because it didn't need to, it has not been a favourable trait. Just a guess.

The first life forms on Earth would not have been photosynthetic, but chemosyntetic. this article gives a breife discription of what a chemosynthetic organisim is and what it lives in.


http://www.gomr.mms.gov/homepg/regulate/environ/chemo/chemo.html
In most respects, the deep-sea biology of the GOM is similar to that in other subtropical and temperate basins. For the most part, benthic (bottom-dwelling) deep-sea animals live under conditions of perpetual darkness and low temperature. Typically, the bottom consists of nearly featureless silt, ooze, and mud. Here, there are very sparse food resources. Devoid of living plant material, the ultimate source of food for life is the energy-poor remains of organic materials that rain slowly from above. Most deep-sea animals tend to be generally small and fragile and they display low densities and overall biomass. All have developed anatomical characteristics, and physiological and biochemical adaptations to cope with these conditions.

In contrast to the deepsea, surface waters, especially those closer to shore, tend to be rich in life; it is near the surface and in the presence of sufficient sunlight, that small drifting plants called phytoplankton, and larger algae and seagrasses (with their green pigment, chlorophyll), convert dissolved carbon dioxide gas and water into simple sugar through the chemical process called photosynthesis:

6CO2
(carbon dioxide) + 12H2O
(water) + light
(energy) → C6H12O6
(a sugar) + 6O2
(oxygen) + 6H2O
(water)

Photosynthesis is a process resulting in biochemical food production that ultimately drives and supports the ecosystem, up to and including the largest predators at the top of the food chain, such as seals, sharks and killer whales. It is called primary productivity because it is at the very bottom of the food chain. Animals that eat other animals or plants are termed consumers. Photosynthesis also recharges much of the world's oxygen supply. This singular process, the one supporting the whole biosphere of the planet, has been recognized for centuries.

plants do not just produce oxygen, but they will also consume it the same way we do. A few plants actualy consume more CO2 then the amount of O2 they produce.

This lecture could probably answer about 70% of this
http://rainbow.ldgo.columbia.edu/courses/v1001/7.html

IV. However, the crust finally solidified by about 3.7 billion years ago. Gasses pouring out of volcanoes and fissures, along with lava, began to accumulate, perhaps added to by the impact of a few giant comets (which are mostly gas).
The gases that accumulated were those we still find coming out of volcanoes:
Water vapor (H2O)
Hydrogen chloride (HCl)
Carbon Monoxide (CO)
Carbon Dioxide (CO2)
Nitrogen (N2)
These gases combined to form:
Methane (CH4)
Ammonia (NH4)
Hydrogen Cyanide (HCN)

Evidently, photosynthesis must have started nearly at the beginning. At once that changed the world because of the release of free oxygen.

Photosynthesis is a process resulting in biochemical food production that ultimately drives and supports the ecosystem, up to and including the largest predators at the top of the food chain, such as seals, sharks and killer whales. It is called primary productivity because it is at the very bottom of the food chain. Animals that eat other animals or plants are termed consumers. Photosynthesis also recharges much of the world's oxygen supply. This singular process, the one supporting the whole biosphere of the planet, has been recognized for centuries.

Alright, so I get that oxygen is one of the best suited elements for such a thing.

But what's the relation to the ozone layer? Is that just a coincidence?

early life would of survived just fine without the ozone layer, the edit i made to my previous post has a link to a lecture that could explain it better then i could.

The answer you are probably looking for has more to do with the properties of Ozone

which would deal with
bond length
electronegativety
intermolecular forces
etc. etc.

If that is the information you are seeking I know i can't enlighten you, and i doubt this forum has the capacity to go that in depth into this with out ending up in a debate about Hitler.


But what's the relation to the ozone layer? Is that just a coincidence Warpus

I know that all the reasons can be explained, i just can not find an article online that describe why.(I will keep looking and hopefuly i can find something more specific)


I would assume the reason why plants evolved was because there was plenty of co2 in the enviroment.

O2 + energy -> O3 (ozone).

The energy can be in the form of lightning, or it can be something else. This means that if there is oxygen in the air, there will be ozone in the atmosphere.

Like most things, it starts in the stars. He, H, C, N, and O are so abundant in nature because they are products of the two major nuclear fusion cycles to occur in stars, the p-p cycle and the CNO cycle. It's little wonder that life developed using chiefly C, H and O, when those are three major products of the two most important cycles in stellar nucleosynthesis.

http://en.wikipedia.org/wiki/CNO_cycle

http://en.wikipedia.org/wiki/Stellar_nucleosynthesis

We can thank gravity some as well.

Like most things, it starts in the stars. He, H, C, N, and O are so abundant in nature because they are products of the two major nuclear fusion cycles to occur in stars, the p-p cycle and the CNO cycle. It's little wonder that life developed using chiefly C, H and O, when those are three major products of the two most important cycles in stellar nucleosynthesis.

http://en.wikipedia.org/wiki/CNO_cycle

http://en.wikipedia.org/wiki/Stellar_nucleosynthesis

What makes ozone such a good radioactive blocker anyway?

What makes ozone such a good radioactive blocker anyway?

It absorbs the ultraviolet light coming from the sun.

Ozone just WANTS to react with anything it can get its hands on, and so reduces (wrong chemisty term? oxidises perhaps?) the rays

Ozone just WANTS to react with anything it can get its hands on, and so reduces (wrong chemisty term? oxidises perhaps?) the rays

<winces> Neither oxidation or reduction is anything like the right term. They are when an atom or molecule loses or gains an electron respectively.

Basically different molecules (or atoms) absorb photons of specific frequencies. Which ones depend on the spacing between the possible energy levels of the atom or molecule. For ozone, these frequencies happen to cover the most damaging part of the UV spectrum, which is good from our point of view. They therefore absorb UV photons, are raised to an excited state, and then relax back by a variety of mechanisms (vibrational, photochemical reaction, etc.)

But isn't O3 so reactive because it as one spare electron? (or is 1 from being "complete")

Im sorry, my chemisty (which i detested) is 5 years old an i forget..

QUESTION: WHAT IS OZONE?
ANSWER: Ozone is a molecule that consists of three oxygen atoms (O3), with a delta negative and a delta positive electric charge. The ozone molecule is very unstable and has a short half-life. Therefore, it will decay after some time into its original form: oxygen (O2, according reaction presented below)

2O3 ⇋ 3O2

In essence ozone is nothing more than oxygen (O2), with an extra oxygen atom, formed by an electric high charge an extra oxygen atom. In nature ozone is produced by some chemical reactions. The most familiar example is of course the ozone layer, where ozone is produced from the sun’s ultra-violet (UV) rays. But ozone is also produced at thunderstorms and waterfalls. The extreme high voltages attended with thunderstorms produce ozone from oxygen. The special “fresh, clean, spring rain” smell is a result from nature-produced ozone. Ozone derives from the Greek word ozein, which means to smell.

Ozone is only produced under extreme circumstances. This can also be created by ozone generators. Ozone generators produce ozone with extreme high voltages or with UV-light.

http://www.lenntech.com/faqozone.htm

Oxidation is not the wrong term, you only used it in wrong context.

O2 molecules are excited and absorb another O atom, then O3 is formed. O3 is not able to stay excited for very long and soon the bonds break (realy it just has a short half-life, which means it will 'devolve', back into O2. basicly the cycle just keeps on going. The sun's radiation is absorbed by 02 atoms, etc...O2 forms O3

But isn't O3 so reactive because it as one spare electron? (or is 1 from being "complete")

Im sorry, my chemisty (which i detested) is 5 years old an i forget.. abbandon

O3 is just very unstable, also it has a very short half-life duration.

aha, thanks :D

But isn't O3 so reactive because it as one spare electron? (or is 1 from being "complete")

O3 is very unstable with respect to O2, largely due to the uneven distribution of charge, and weak O-O bond. That makes it a very good oxidising agent.

That's nothing to do with how it blocks UV though. That's just absorbing photons. Oxidation is loss of electrons, which is only applicable to atoms and molecules - not photons.

Meh, you can try but I dropped chemisty a long time ago for a reason sorry ;)

O3 has two forms, where the double bond is on opposite sides in each for each form.

As for why it absorbs UV so well: It absorbs the energy posessed by UV radiation, and then decomposes into Oxygen gas because of its exited state. At least, this is how I remember it ( gonna have to ask chem teacher tmrw in class)

<winces> Neither oxidation or reduction is anything like the right term. They are when an atom or molecule loses or gains an electron respectively.

Basically different molecules (or atoms) absorb photons of specific frequencies. Which ones depend on the spacing between the possible energy levels of the atom or molecule. For ozone, these frequencies happen to cover the most damaging part of the UV spectrum, which is good from our point of view. They therefore absorb UV photons, are raised to an excited state, and then relax back by a variety of mechanisms (vibrational, photochemical reaction, etc.)

Any other gas that would work as well, or better?

N2, and O2 will absorb photons with wavelengths samler then 230 nm, Ozone will absorb photons with wavelenths from 240 nm to 310 nm.

here is a good article that offers some more insight into ozone.

http://scifun.chem.wisc.edu/chemweek/ozone/ozone.html

be sure you check the nasa link at the bottom of the page.

Well, this thread certainly didn't go anywhere near where I wanted it to go.

Thanks a lot mods, for dumping it here to die in the Technology subforum.

So how did the oxygen get there? Did plants arise before the ozone layer existed, eventually pumping a ton of oxygen into the atmosphere? This created the ozone layer, creating the shield, allowing more complex life forms to come into existence?

Did plants arise before the ozone layer? - as other posters have said, yes. simple plants, particularly protected by water, are not that vulnerable to UV.

This created the ozone layer, creating the shield, allowing more complex life forms to come into existence?

Careful on the logic here. The complex life forms currently on Earth rely on the ozone layer. That does not however mean that no complex life could not appear on a planet without an ozone layer. Life might have had to take a very different route, but it might have found a way round the problem of UV. On this world, the ozone layer did form due to the oxygen produced by early plants. Therefore there was no need for life to find an alternative protection from UV, and so complex life on Earth relies on the ozone layer.

As to whether there are other gases that would shield better or as well a ozone, I don't know. I'd have to check through a library of possible atmospheric gases, look at the wavelengths they absorb at, and compare that to the absorption spectrum of ozone, and also how the molecule would relax back to ground state - I don't have that information ready to hand.

Careful on the logic here. The complex life forms currently on Earth rely on the ozone layer. That does not however mean that no complex life could not appear on a planet without an ozone layer. Life might have had to take a very different route, but it might have found a way round the problem of UV.

It seems to me as though removing the problem of UV radiation (as the ozone layer does) gives complex life an easier time and a better chance of arising & flourishing.

I suppose that was my initial point when I thought up this thread: Early life on this planet produced oxygen in abundance, which lead to the creation of the ozone layer, which lead to an environment which made complex life more sustainable..

Isn't that kinda.. neat? :)

All those oxygen-producing plants that first arose created a perfect environment for us - Oxygen to breathe & and a protective ozone layer above... as well as the foundation for the entire eco-system, without which, we wouldn't be here.

It all seems so.. planned.. doesn't it? ;)