If all the CO2 now locked up in limestone formations was in the atmosphere how did life ever begin?

Question

If all the CO2 now locked up in limestone formations was in the atmosphere how did life ever begin?

Answer 1

Some plant had to evolve to produce oxygen so the animals could live.CO2 is a heavy gas and will smother us very quickly if it increases enough to lower the oxygen below 19.5%.

Answer 2

CO2 is constantly being produced through different ways.  Volcanoes, for instance, produce CO2 so there has been a lot around since the beginning of our Earth.

CO2 we can't survive with too much CO2 so we rely upon CO2 being stored in various manners such as in limestone.  If CO2 were not stored away perhaps we'd have a planet similar to Venus; very, very hot with evaporated oceans.

Don't know what you mean about life beginning, though.  Without life CO2 could not be stored in limestone, or coal, or oil.

Life began about 4 billion years ago and lived without oxygen.  About 2 billion years ago a blue-green algae came about and began producing oxygen.  Oxygen, at the time was a heavy pollutant and there were massive extinctions.  Survivors withstood the oxygen pollutant and our atmosphere gradually build up a lot of oxygen about 20% now.

Plants and animals evolved to use oxygen.  Plants do use oxygen but they produce more than they use.

Answer 3

Although all the CO2 locked up in limestone was once in the atmosphere, that doesn't mean that all the CO2 that was in our atmosphere at the time was locked up in limestone.

When life began, there was no oxygen in the atmosphere. It was mostly CO2 and Nitrogen. All the Oxygen was trapped in the CO2. Oxygen only appears in our atmosphere as a by-product of plant respiration.

Answer 4

i guess life used photosynthesis first and later oxygen breathing creatures evolved once the atmosphere was oxygenated.

Answer 5

I wasn't here when life began, so its really hard to know how actuate the various theories are.

Answer 6

Well now, this is an age old question. However, what makes you believe that all CO2 was once locked away in limestone?

Answer 7

They call it Green Algae now:

http://answers.yahoo.com/question/index;...

Actually the better question is where did the water on our planet come from.

Answer 8

http://www.globalchange.umich.edu/global...

says the early planet had almost no atmosphere.  

Any CO2 would have helped keep the planet warm, especially at night.  

Early life forms (like anerobic bacteria) do fine without oxygen.

Answer 9

Co2 is a byproduct of breathing. I don't understand your question. CO2 has always been in the atmosphere..... Maybe you can ask a clearer question?

Answer 10

I guess life just evolved for the different conditions.  I'm wagering that we can still do that.