Ch 24 (Exm 2) Flashcards
1
Q
Fossils
A
preserved remains
- tell us about morphology
2
Q
relative dating
A
determine the age of rocks relative to each other
3
Q
strata
A
layers
4
Q
steno’s observations
A
- fossils of similar organisms are found in widely separated places
5
Q
radiometric dating
A
decay in predictable patters
6
Q
half life
A
time it takes a substance to half
7
Q
carbon dating
A
can be used on less than 50,000 years old
8
Q
earth’s crust
A
- solid plates make up the lithosphere
- plates float on molten rock
- ## plates move as the magma rises
9
Q
continental drift
A
movement of lithospheric plates and the continents
10
Q
how did O2 increase
A
- 2.4 B years, bacteria began using water to split, generating O2 as waste_ cyanobacteria made enough O2 to evolve organisms to use O2
- prokaryotes: evolved ability to use O2 and gained advantages
- about 1 B, large eukaryotic cells developed
- more O2 allowed multicellularity
11
Q
earth’s climate
A
shifts between ice age and normal, and is correlated with the oxygen levels.
12
Q
what can change climate
A
volcanoes- ash can block sun
extraterrestrial events- meteorites cause mass extinction
13
Q
precambrian life
A
small and aquatic, mostly prokaryotes but some unicellular eukaryotes and multicell
14
Q
paleozoic era
A
- Cambrian period marks the beginning of the paleozoic Era
- O2 was almost like now
- Gondwana existed
- Cambrian explosion occurred, with lots of new animals
15
Q
order of eras
A
paleozoic, mesosoic, cenozoic
