Sept 2 Lecture (intro)

Question 1

list 4 risks on earth related to environmental geology

Answer 1

1. earthquakes
2. volcanoes
3. floods
4. landslides

Question 2

How do humans add to the risks on earth? (list 4-7)

Answer 2

• soil erosion
• pollution
• shortage of clean water
• storage of toxic wastes
• fracking (man-made eq)
• oil/mineral extraction
• climate change

Question 3

geology was an ____ science and now it’s an ____ science

Answer 3

observational –> analytical

Question 4

list 3 problems with studying geology

Answer 4

1. size (volcano is massive, river can’t be contained in a lab, etc)
2. time (geological processes take millions of years, we’re limited to human time)
3. resolution of data
   - public wants predictions w/ exact time etc

Question 5

define Anthropocene

Answer 5

humans now influence the earth, not the other way around (because there are so many people; exponentially growing)

Question 6

did the solar system form before or after the universe?

Answer 6

after

Question 7

the earth is at ___ degree tilt from vertical, which is why _________

Answer 7

23.5

days aren’t always the same length

Question 8

list the planets of our solar system in order

Answer 8

mercury, venus, earth, mars, jupiter, saturn, uranus, neptune, pluto

• 4 rocky/ metallic, hot inner planets
• 4 gaseous, cold outer planets

Question 9

the density/ composition of planets is correlated with how close they are to the ____

Answer 9

sun (temp they formed at)

Question 10

describe how a gaseous planet could form

Answer 10

when a young star is surrounded by the dense disk of gas and dust, gaseous planets like Saturn can form. Once the gas has been ejected from the system, gaseous planets can no longer form

Question 11

define panspermia

Answer 11

the theory that life on earth originated from microorganisms or chemical precursors of life present in outer space and able to initiate life upon reaching a suitable enviro like earth

Question 12

earth earth was barren and lacked ___ and ____

Answer 12

oceans and atmosphere

Question 13

earth was the target of many impacts. list 3

Answer 13

1. asteroids (origin of moon!)
2. meteorites
3. comets (panspermia?)

Question 14

differentiation of the earth developed _______ zones

Answer 14

compositional

Question 15

list the 3 compositional zones of earth

Answer 15

• central core
• mantle
• crust

Question 16

define the central core

Answer 16

dense and hot (made of nickel and iron)

Question 17

define the mantle

Answer 17

thick zone that surrounds the core. composed of ultramafic and mafic rocks and magma (heat from core escapes by convective circulation)

Question 18

crust of earth…

Answer 18

chemically different from core or mantle!

- 2 types= oceanic (mafic) and crustal (felsic)

Question 19

how old is the earth predicted to be (right now)?

Answer 19

4.5-4.6 billion years old

Question 20

how old did ussher predict the earth to be?

Answer 20

6000 years (in 1650)
- predicted by counting the generations in the bible

Question 21

how old did buffon predict the earth to be?

Answer 21

75000 years old (in ~1750)

- looked at mountain building rates

Question 22

How old did Lyell predict the earth to be?

Answer 22

several hundred million years old (in ~1850)
- looked at uniformitarian- the forces molding the planet today have operated continuously throughout history; cooling rates)

Question 23

How old did Kelvin predict the earth to be?

Answer 23

24-400 million yrs old (in ~1900)

- based off of thermal gradient calculations

Question 24

how old did Joly predict the earth to be?

Answer 24

100 million years old in ~1900

- salt content of oceans

Question 25

current method of dating the earth?

Answer 25

radioactive dating

Question 26

earth’s early atmosphere was composed of _, _, and/ or __.

There was lots of ____, and lacked free __

Answer 26

N2, CO2, methane (CH4)
water- early ocean
lacked O2

Question 27

why did first life likely flourish at hot springs deep in oceans/ volcanic rock?

Answer 27

because the early atmosphere had no oxygen and hot oceans; life had to evolve in extreme conditions!

Question 28

O2 first accumulated in atmosphere ~___ years ago

- enough to support breathing organisms ___ yeas ago

Answer 28

2.4 billion

500 million

Question 29

photosynthetic algae evolved 3-3.5 billion years ago, producing ___.
Describe how

Answer 29

oxygen

1. sunlight energized a chemical rxn in algae
2. food was produced from co2
3. oxygen given off as byproduct

Question 30

give a timeline (in order, no dates) of life exploding on earth in the past 500million years

Answer 30

• vertebrates
• land plants
• insects
• dinos
• birds
• mammals
• primitive humans
• homo sapiens