History Of Life Flashcards
1
Q
How old do scientists estimate the earth to be?
A
4,6 billion years old
2
Q
How many millions are in a billion?
A
1000
3
Q
When do scientists estimate life to have begun?
A
3,8 billion years ago
4
Q
What was the first organism?
A
Unicellular
Prokaryotic
Similar to a bacterial cell
5
Q
How do scientists try to make sense of the history of life on Earth?
A
By relating it to other important events
6
Q
What are the four main important events that scientists relate history to?
A
Increase in oxygen levels in the earth’s atmosphere
Climate change
Geological events
Fossil evidence
