Flashcards in Lecture 17 - History of the Earth Deck (39)
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1
The history of the earth is recorded in its __________
strata
2
What is the principle of superposition?
"In a sequence of layered rocks, any layer is older than the layer next above it."
3
Who is Nicholas Steno?
Principle of Superposition
4
What are 2 exceptions to superposition?
-intrusions
-overturned rock
5
What are plate tectonics?
movements of the earth
6
Layers are originally deposited _________
horizontally
7
What alters the the orientation of the layers?
plate tectonics
8
What is uniformitarianism?
-processes that alter the Earth are uniform through time
9
Who was Charles Lyell?
-believed in uniformitarianism
-earth was transformed not by unimaginable catastrophes by slow changes
10
What are 4 processes that result in the production of sediment particles?
1. erosion
2. volcanic eruption
3. organisms
4. mineral precipitation
11
What are 4 conditions that make it more likely that an organism will have fossil record?
1. has hard parts
2. is abundant and widespread
3. exists for a long time
4. lives in a habitat conducive deposition
12
How are rocks and fossils dated?
biostratigraphy
13
Sedimentary strata only reveals __________ ages
relative
14
how can absolute dating in igneous strata be determined?
radiometric dating
15
a "parent" isotope decays into a "daughter isotope at _________
a constant rate
16
What is a half-life?
time required for half the parent isotope to decay
17
What is the believed age of the earth?
4.6 billion years ago
18
What is most atmospheric origin?
biological origin
19
What produced this biological origin?
photosynthesis in bacteria similar to modern cyanobacteria
20
What did O2 reacted with?
dissolve iron
21
What did the O2 and dissolved iron do?
precipitated out to form banded iron formations
22
What did the O2 revolution cause?
-enormous die-off of many organisms
-anaerobic organisms had to either hide or adapt
23
What are 3 qualities of the earliest eukaryotes?
-from about 2.1 BYA
-probably spherical algal protists
-probably formed by endosymbiosis
24
What are 3 qualities of terrestrial plants?
1. primitive vascular system
2. waterproof coating
3. mycorrhizal fungi
25
What are 2 qualities of earliest terrestrial animals?
1. possibly arthropods
2. included organisms similar to modern millipedes etc.
26
What is the Principle of Superposition?
in a sequence of layered rocks, any layer is older than the layer next/above it
27
What happened 3.8 BYA?
oldest rocks on earth's surface
28
What happened 3.7 BYA?
oldest fossils of cells appear (stromatolites)
29
What are stromatolites composed of?
-bacteria
-sediment biofilm
30
