Basics of Ocean System Flashcards
1
Q
When was the oldest known evidence of life (hetertrophs)
A
3.86 billion years ago
2
Q
When did eukaryotes appear?
A
1800 million years ago
3
Q
How did photosynthesis change the atmosphere?
A
Atmosphere became polluted by oxygen
Altered the carbon dioxide content
4
Q
When was the first sexual reproduction?
A
900 million years ago
5
Q
When was the atmosphere fully oxygenated?
A
600 million years ago
6
Q
When did diatoms evolve?
A
200 million years ago
7
Q
When did the first marine mammals in the fossil record appear?
A
30 million years ago
8
Q
How much of the earth is covered in oceans?
A
70%
9
Q
How much water is in oceans?
A
97%
Other 3 comprised of atmospheric, terrestrial water
10
Q
How much of the sea floor has been explored?
A
10%
