Lecture 17 - History of the Earth Flashcards Preview

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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

What happened 488 MYA?

marine algae abundant
-colonization of land by diverse fungi, plants, animals