C13.1 - History of our atmosphere Flashcards
When do scientists think the Earth was formed?
Scientists think that the Earth was formed 4.6 billon years ago
What do scientists think the Earth was, to begin with?
To begin with, scientists think that the Earth was a molten ball of:
- Rock
- Minerals
What was the Earth for its 1st billion years?
The Earth for its 1st billion years was a very hot, turbulent place
Scientists think that the Earth was formed 4.6 billon years ago.
To begin with, scientists think that the Earth was a molten ball of rock and minerals.
The Earth for its 1st billion years was a very hot, turbulent place.
What was the Earth’s surface covered with?
The Earth’s surface was covered with volcanoes that erupted
Scientists think that the Earth was formed 4.6 billon years ago.
To begin with, scientists think that the Earth was a molten ball of rock and minerals.
The Earth for its 1st billion years was a very hot, turbulent place.
The Earth’s surface was covered with volcanoes that erupted, releasing fire and gases into the atmosphere.
What did the volcanoes do?
The volcanoes moved chemicals from inside the Earth to the:
- Surface
- Newly forming atmosphere
Atmosphere
The atmosphere is the relatively thin layer of gases that surround planet Earth
What are there several theories about?
There are several theories about the Earth’s early atmosphere
There are several theories about the Earth’s early atmosphere, but what is there?
There are several theories about the Earth’s early atmosphere, but there is little direct evidence to draw on from billions of years ago
There are several theories about the Earth’s early atmosphere, although there is little direct evidence to draw on from billions of years ago.
However, what have scientists done?
Scientists have reconstructed what they think the atmosphere must have been like
There are several theories about the Earth’s early atmosphere, although there is little direct evidence to draw on from billions of years ago.
However, scientists have reconstructed what they think the atmosphere must have been like.
What have scientists reconstructed what they think the atmosphere must have been like based on?
Scientists have reconstructed what they think the atmosphere must have been like, based on:
- Evidence from gas bubbles trapped in ancient rocks
- Data gathered from the atmospheres of other planets and their moons in the solar system
How can scientists get information about what the Earth’s atmosphere was like in the past based on evidence from gas bubbles trapped in ancient rocks?
Scientists can get information about what the Earth’s atmosphere was like in the past based on evidence from gas bubbles trapped in ancient rocks from Antarctic ice cores
What does one theory about the atmosphere suggest?
One theory about the atmosphere suggests that volcanoes released:
1. Carbon dioxide
2. Water vapour
2. Nitrogen
and that these gases formed the early atmosphere
How did the first oceans form?
The first oceans formed as water vapour in the atmosphere:
- Condensed as the Earth gradually cooled down
- Fell as rain
The first oceans formed as water vapour in the atmosphere condensed as the Earth gradually cooled down and fell as rain.
Water collected in hollows in the crust as the rock solidified.
Another theory speculates that what could also have brought water to the Earth?
Another theory speculates that comets could also have brought water to the Earth
As the Earth began to stabilise, what was the early atmosphere probably mainly?
As the Earth began to stabilise, the early atmosphere was probably mainly carbon dioxide
Chemical formula for carbon dioxide
The chemical formula for carbon dioxide is CO2
Chemical formula for water vapour
The chemical formula for water vapour is H20
Chemical formula for nitrogen gas
The chemical formula for nitrogen gas is N2
Chemical formula for methane
The chemical formula for methane is CH4
Chemical formula for ammonia
The chemical formula for ammonia is NH3
What does an atmosphere mostly made up of carbon dioxide, with possibly some water vapour, nitrogen gas, traces of methane and ammonia and virtually no oxygen resemble?
An atmosphere mostly made up of carbon dioxide, with possibly some water vapour, nitrogen gas, traces of methane and ammonia and virtually no oxygen resembles the atmospheres that are known to exist today on the planets:
- Mars
- Venus
After the initial violent years of the history of the Earth, how did the atmosphere remain?
After the initial violent years of the history of the Earth, the atmosphere remained quite stable
After the initial violent years of the history of the Earth the atmosphere remained quite stable.
When was this until?
This was until life first appeared on Earth
What are there also many theories about?
There are also many theories as to how life was formed on Earth
When do scientists think that life began?
Scientists think that life began 3.4 billion years ago
Scientists think that life began 3.4 billion years ago, when the first simple organisms, similar to bacteria, appeared.
What could these simple organisms use as a source of energy?
These simple organisms could use the breakdown of chemicals as a source of energy
Scientists think that life began 3.4 billion years ago, when the first simple organisms, similar to bacteria, appeared.
Then, about 2.7 billion years ago, what evolved?
Then, about 2.7 billion years ago:
1. Bacteria
2. Other simple organisms
evolved
Scientists think that life began 3.4 billion years ago, when the first simple organisms, similar to bacteria, appeared.
These simple organisms could use the breakdown of chemicals as a source of energy.
Then, about 2.7 billion years ago, bacteria and other simple organisms, such as algae, evolved.
What could algae use to make their own food by photosynthesis?
Algae could use the energy from the Sun to make their own food by photosynthesis
Algae could use the energy from the Sun to make their own food by photosynthesis.
What did this produce as a waste product?
This produced oxygen gas as a waste product
About 2.7 billion years ago, bacteria and other simple organisms, such as algae, evolved.
Algae could use the energy from the Sun to make their own food by photosynthesis.
This produced oxygen gas as a waste product.
What happened over the next billions years or so?
Over the next billion years or so, the levels of oxygen rose steadily
About 2.7 billion years ago, bacteria and other simple organisms, such as algae, evolved.
Algae could use the energy from the Sun to make their own food by photosynthesis.
This produced oxygen gas as a waste product.
Over the next billion years or so, the levels of oxygen rose steadily.
Over the next billion years or so, the levels of oxygen rose steadily, as what?
Over the next billion years or so, the levels of oxygen rose steadily, as the:
1. Algae
2. Bacteria
thrived in the seas
About 2.7 billion years ago, bacteria and other simple organisms, such as algae, evolved.
Algae could use the energy from the Sun to make their own food by photosynthesis.
This produced oxygen gas as a waste product.
Over the next billion years or so, the levels of oxygen rose steadily, as the algae and bacteria thrived in the seas.
Then, what happened?
Then:
1. More
2. More
plants evolved
About 2.7 billion years ago, bacteria and other simple organisms, such as algae, evolved.
Algae could use the energy from the Sun to make their own food by photosynthesis.
This produced oxygen gas as a waste product.
Over the next billion years or so, the levels of oxygen rose steadily, as the algae and bacteria thrived in the seas.
Then, more and more plants evolved.
What were all of them doing?
All of them were photosynthesising
The chemical formula for photosynthesis
The chemical formula for photosynthesis is:
(energy from sunlight)
6CO2 + 6H20 —> C6H12O6 + 6O2
What did plants do, as they evolved?
As they evolved, plants successfully colonised most of the surface of the Earth
As they evolved, plants successfully colonised most of the surface of the Earth, so what?
As they evolved, plants successfully colonised most of the surface of the Earth, so the atmosphere became richer in oxygen
As they evolved, plants successfully colonised most of the surface of the Earth, so the atmosphere became richer in oxygen.
What did this make possible?
This made it possible for the first animal forms to evolve
As they evolved, plants successfully colonised most of the surface of the Earth, so the atmosphere became richer in oxygen.
This made it possible for the first animal forms to evolve.
What could these animals do?
These animals could not make their own food like the:
1. Algae
2. Plants
could
As they evolved, plants successfully colonised most of the surface of the Earth, so the atmosphere became richer in oxygen.
This made it possible for the first animal forms to evolve.
These animals could not make their own food like the algae and plants could.
What did they rely on?
These animals relied on:
- The algae and plants for their food
- Oxygen to respire
Where did some of the first photosynthesising bacteria probably live?
Some of the first photosynthesising bacteria probably lived in colonies like stromatolites
Many of the earliest living microorganisms could not do what?
Many of the earliest living microorganisms could not tolerate a high oxygen concentration
Why could many of the earliest living microorganisms not tolerate a high oxygen concentration?
Many of the earliest living microorganisms could not tolerate a high oxygen concentration, because they had evolved without it
Many of the earliest living microorganisms could not tolerate a high oxygen concentration, because they had evolved without it.
What happened as a result?
As a result, they largely died out
Some bacteria do not need what?
Some bacteria do not need oxygen
Some bacteria do not need oxygen and they will die if they are exposed to it.
However, where can they survive and breed?
They can survive and breed in:
- Rotting tissue
- Other places where there is no oxygen
Scientists think that the Earth was formed 4.6 billon years ago.
To begin with, scientists think that the Earth was a molten ball of rock and minerals.
The Earth for its 1st billion years was a very hot, turbulent place.
The Earth’s surface was covered with volcanoes that erupted, releasing what into the atmosphere?
The Earth’s surface was covered with volcanoes that erupted, releasing:
1. Fire
2. Gases
into the atmosphere
Scientists can get information about what the Earth’s atmosphere was like in the past based on evidence from gas bubbles trapped in ancient rocks from Antarctic ice cores.
Each year what forms with tiny bubbles of air trapped in it?
Each year a layer of ice forms with tiny bubbles of air trapped in it
Scientists can get information about what the Earth’s atmosphere was like in the past based on evidence from gas bubbles trapped in ancient rocks from Antarctic ice cores.
Each year a layer of ice forms with tiny bubbles of air trapped in it.
What happens the deeper you go in the ice?
The deeper you go in the ice, the older the air
Scientists can get information about what the Earth’s atmosphere was like in the past based on evidence from gas bubbles trapped in ancient rocks from Antarctic ice cores.
Each year a layer of ice forms with tiny bubbles of air trapped in it.
The deeper you go in the ice, the older the air.
So analysing bubbles from different layers shows you what?
Analysing bubbles from different layers shows you how the atmosphere has changed
The first oceans formed as water vapour in the atmosphere condensed as the Earth gradually cooled down and fell as rain.
Water did what as the rock solidified?
Water collected in hollows in the crust as the rock solidified
The first oceans formed as water vapour in the atmosphere condensed as the Earth gradually cooled down and fell as rain.
Water collected in hollows in the crust as the rock solidified.
Another theory speculates that comets could also have brought water to the Earth.
What happened as icy comets rained down on the surface of the Earth?
As icy comets rained down on the surface of the Earth, they melted
The first oceans formed as water vapour in the atmosphere condensed as the Earth gradually cooled down and fell as rain.
Water collected in hollows in the crust as the rock solidified.
Another theory speculates that comets could also have brought water to the Earth.
As icy comets rained down on the surface of the Earth, they melted, doing what?
As icy comets rained down on the surface of the Earth, they melted, adding to its water supplies
As the Earth began to stabilise, the early atmosphere was probably mainly carbon dioxide.
There could also have been some what?
There could also have been some:
- Water vapour
- Nitrogen gas
- Traces of methane
- Ammonia
As the Earth began to stabilise, the early atmosphere was probably mainly carbon dioxide.
There could also have been some water vapour, nitrogen gas, traces of methane and ammonia.
There would have been very little or no what at that time?
There would have been: 1. Very little Or, 2. No oxygen at that time
Scientists think that life began 3.4 billion years ago, when what?
Scientists think that life began 3.4 billion years ago, when the first simple organisms, similar to bacteria, appeared
Scientists think that life began 3.4 billion years ago, when the first simple organisms, similar to bacteria, appeared.
Then, about 2.7 billion years ago, bacteria and other simple organisms, such as what, evolved?
Scientists think that life began 3.4 billion years ago, when the first simple organisms, similar to bacteria, appeared. Then, about 2.7 billion years ago: 1. Bacteria 2. Other simple organisms, such as algae ,evolved
About 2.7 billion years ago, bacteria and other simple organisms, such as algae, evolved.
Algae could use the energy from the Sun to make their own food by photosynthesis.
This produced oxygen gas as a waste product.
Over the next billion years or so, the levels of oxygen rose steadily, as the algae and bacteria thrived in the seas.
Then, more and more plants evolved.
All of them were photosynthesising, doing what?
All of them were photosynthesising:
- Removing carbon dioxide
- Making oxygen
Some of the first photosynthesising bacteria probably lived in colonies like stromatolites.
They grew in what?
They grew in water
Some of the first photosynthesising bacteria probably lived in colonies like stromatolites.
They grew in water and did what?
They:
- Grew in water
- Released oxygen into the early atmosphere
Many of the earliest living microorganisms could not tolerate a high oxygen concentration, because they had evolved without it.
As a result, why did they largely die out?
As a result, they largely died out, because there were fewer places where they could survive
Some bacteria do not need oxygen and they will what if they are what?
Some bacteria:
- Do not need oxygen
- Will die if they are exposed to it
