Lec 4 Flashcards
1
Q
ocean appeared during
A
Haden era (4.4 bya)
2
Q
first life
A
3.5-4bya (precambrian)
3
Q
life originated either hot or cold
A
hot (deep marine hydrothermal vents)
cold (adenine & guanine require freezing conditions)
4
Q
oldest fossils dated
A
3.26 bya
5
Q
origin of oxygen
A
stromatolites (prod by cyanobac)
6
Q
4 main periods of life
A
precambrian
paleozoic
mesozoic
cenozoic
7
Q
precambrian
A
life appeared on earth, cyanobac, O2 conc changed
8
Q
venetian period
A
earliest multicellular organisms
9
Q
Paleozoic period
A
(543 to 248 mya) Cambrian explosion then mass extinction
