Flashcards in Lecture 17 - History of the Earth Deck (39):
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
What happened 2.7 BYA?
concentration of atmospheric oxygen
31
What happened 2.1 BYA?
oldest fossils of eukaryotic cells apear
32
How were the oldest fossils of eukaryotic cells formed? What were they?
endosymbiosis
spherical algal protists
33
What is the Theory of Serial Endosymbiosis?
-large host cell and ingest bacteria could easily become dependent on one another for survival
-permanent relationship
34
What happened 635 MYA?
Ediacaran
35
What was the Ediacaran age?
-diverse algae
-soft body invertebrate animals appear
36
What happened 540 MYA?
Cambrian Explosion
37
What was the Cambrian Explosion?
-resulted in modern body plans
-hardbody forms
-movement from seafloor to new niches
38
What was the reason for the explosion in diversity? Theories?
-unknown
-theories: increase O2 availability, mineral availability, evolutionary innovation
39