Geologic evidence indicates that the atmosphere of the early Earth was free of oxygen. What constraints might that have had on early life? I don't understand what the answer could be. My teacher told me to just search "ozone layer" on Google. The ozone protects us from the radiation of the sun, so what am I missing here?
I'm not entirely sure but the air we breathe has like 4% of oxygen, so I guess when it didn't have any oxygen at all it would have been because there was no plant life? Since plants take carbon dioxide and create oxygen.
It could be a bit of this, but it might also involve the fact that Ozone is a special type of oxygen and, without it, we wouldn't be protected from the UV rays of the sun and such. You just had to look up what the ozone layer was made up of (that's what I did).
Well I said..."Can you explain this question more to me and where I can find it? My guess would be that there would be no carbon dioxide?" And that's when she said "no - it has to do with uv radiation. a simple search in google under 'ozone layer' will give you more details."
I thought that the early Earth had tons more oxygen, which allowed for larger organisms to live such as the dinosaurs? Then again, I sucked at science in school.
Somewhere around 21% actually. It's O3, right? (Trioxygen? Trioxide? XD) ...I was sure that there was more CO2 back then, which lead to bigger everything...I think. I used to care more about this stuff but I haven't studied any Geology-related stuff in a long time. I'm better at other sciences. >>
Is this right then? Oxygen depends on our plants and crops. Without them, there woudln't be oxygen. Without carbon dioxide, there wouldn't be plants and crops. If oxygen and carbon dioxide didn't exist, there wouldn't be humans or plants. There wouldn't be life at all. The ozone layer is a special type of oxygen which creates life for Earth's life and protects us from the sun and radiation.
Not really. "Extremophiles" are an example that not all life requires CO2 or Oxygen. Some survive in sulfur-filled environments. ...In either case, just do some more research. I don't recall any members being an expert in this area. If there are any, they should show themselves! D8
How many marks is this question? Or is it an essay or something? Because I don't know how much detail to give you. This is actually what they've just covered at school in science. So I know bits and pieces. Let's make a general Sum up of what I think you're educator was hinting at: The Ozone layer is made up of oxygen in order to absorbs or some of the harmful radiation given off by the sun, mainly UV, however it doesn't stop all UV radiation from coming in. Without oxygen the temperature of the Earth would have likely been substantially higher in average temperature then it is today.
The Ozone layer contains somewhere from 97% to 99% O3. Since the Ozone layer keeps away the harmful Ultraviolet light/radiation, there would only be a minor possibility something could live, due to the excess UV lights. With no Oxygen, you have no Ozone, which means the UV light has basically nothing hindering it from hitting the earth, and you know that when you've been out in the sun too long, your skin changes. This is with ozone. You can imagine how it would be without. I think that's what he's getting at.
Have you ever heard of Green House effect? Even though it can be bad, It also makes us able to live. As the O3 in the ozone layer gets in touch with the UV light it absorbs it and come back to earth as O2, the "Hole in the ozone layer" Was made because some pollutants like CFC would prevent the O2 to become O3 again and more UV would enter the earth (and you know too much UV kills) and it would be bouncing back from the clouds of pollutants and the earth. Even though the O2 was not so abundante at the start of earth early life didn't use it, and how @machinna said, the "extremophiles" are probably the organisms that are closest to the bacterias from that time. These bacteria would do chemosynthesis before photosynthesis ever existed and would produce some O2... by chance some bacteria acquired the ability to use the sun light as energy source for the production of energy and release of O2,and then the photosynthesis made it possible for all the biosphere to be filled mostly of O2 and the aerobic organisms to develop further. Oparin made some experiments of how some inorganic elements believed to exist on the beginning of earth made organic elements, and than life.
you know, I could explain what my chemistry book said to me, but that might not be fair. But maybe I can try to explain to you why oxygen is important and how it protects us from the UV radiation and all that. Now bear in mind, I suck at explaining, so this might come out weird. Ok, so if you look at the Elements table, you see that Oxygen is in the 6A column. And the 8A column is full of what people call Noble Gases. Now each element on the table tries to get 8 electrons to be like these noble gases. Since Oxygen has 6 Electrons because it is in 6A, that means it wants to find 2 more electrons to become like the Noble Gases. Now this is where the whole Purely Ionic Bonding and Polar Ionic Bonding comes into play. Polar is when a gas takes electrons from another element. But Pure Ionic Bonding is when they share these electrons. Ozone is made up of 3 Oxygens. And there's a reason for this too. Because there are 3 harmful rays that come from the sun. The Ozone is made of triple bonds, which protect us from the UV Radiation, and the Nitrogen has double bonds, which protect us from whatever, and Oxygen, or O2(2 is subscript) is that last layer. The O3 is the only thing strong enough to protect us from UV Radiation because of that triple bond. Nitrogen and Oxygen don't have strong enough bonds to protect us from the UV Radiation. So I don'tk now if that helps, but at least you got a little bit of a science lesson out of it. I might have completely forgotten what I wrote this for though XD.
