GEOL 1110 – EXAM 2 STUDY
GUIDE – AURBURN QUESTIONS
AND ANSWERS
What does this tell us about the Archean geosphere? (lecture 16) - Answer- - there was
land
- there was oceanic crust
- there were continents
- there was some type of volcanic activity
What's the MAIN WAY earth's atmosphere was different from today's atmosphere?
(lecture 16) - Answer- - the modern atmosphere is made up of 78% Nitrogen and 21%
oxygen
- the early atmosphere had no oxygen - but the volcanoes emit nitrogen and carbon
dioxide into the atmosphere and water into the oceans
How do we know that there were large bodies of water during the Archean eon? (lecture
16) - Answer- - sedimentary rocks need water to form
1st marine sedimentary rocks = in Isua Belt, Greenland = water was present
has life on Earth always been abundant and complex? (lecture 17) - Answer- Earth
began with no life (Haden eon) - it was a "ball of molten lava" with no life
was it possible to create the "building blocks" of life out of non-living
materials/processes? (lecture 17) - Answer- yes - scientists had to create a "simulated
Archean atmosphere" with gases, water, heat, and electricity to make chemical
reactions
- it was discovered that the ancient oceans could have possibly held molecules that are
necessary to life were formed by non-living processes in the atmosphere
about how old are the earliest fossils we've found? are these trace or body fossils or
both? (lecture 17) - Answer- - around 3.5 billion years old
- both body (remains of living things) and trace (a mark left by a living thing i.e. footprint)
fossils were found
- some Archean rocks hold microscopic fossils (bacteria) which are the oldest forms of
life
- splitting Archean rocks open allows access to trace fossils/evidence of past life
what do we consider to be the oldest form of life? (lecture 17) - Answer- bacteria
, what is a stromatolites? (lecture 17) - Answer- bacterial trace fossils - a solid form of
sand put together by bacteria
how do stromatolites form? do we have stromatolites today? (lecture 17) - Answer- -
bacteria gets thrown together by a wave, they stick together, and are buried alive by
oncoming sand
- the process of bacteria moving upwards to avoid being buried occurs in a cycle until a
sand structure is formed - leaving behind a huge stromatolite which becomes a fossil to
study
how do heterotrophs get energy? (lecture 17) - Answer- they eat other things and gain
energy from the food (humans and animals)
how do autotrophs get energy? (lecture 17) - Answer- they do not eat other things (like
ancient bacteria, since they were the only living things at the time) make their own food
- nonliving chemical reactions (like in volcanoes) supply heat from inside the earth and
ultimately provide energy for life to use (some other living things capture sunlight to use
for energy ie. plants)
what are humans? (lecture 17) - Answer- heterotrophs
what 3 "ingredients" are needed for photosynthesis? (lecture 17) - Answer- sunlight
(energy), carbon dioxide, and water (to make sugar) (stores energy), and oxygen
what does photosynthesis produce? (lecture 17) - Answer- oxygen (the plants don't
need it)
what reacts with iron oxides to create red-looking rocks? (lecture 18) - Answer- - the red
color comes from the mixture of iron and oxygen
- there wasn't oxygen in the early atmosphere (Archean) until later periods
- ie. Chert = banded iron formations due to lots of iron oxide mixed into it
what is the Great Oxygenation Event? (lecture 18) - Answer- this was the time when
oxygen was brought into the atmosphere in abundance
why was it important? (lecture 18) - Answer- - occurred when bacteria started making
more and more oxygen = creating new life
- this marks the end of the Archean eon
When did the Proterozoic eon begin? (lecture 18) - Answer- - after the Great
Oxygenation Event
- "azoic" = zoo // "Proterozoic" = before
- "before animals"
GUIDE – AURBURN QUESTIONS
AND ANSWERS
What does this tell us about the Archean geosphere? (lecture 16) - Answer- - there was
land
- there was oceanic crust
- there were continents
- there was some type of volcanic activity
What's the MAIN WAY earth's atmosphere was different from today's atmosphere?
(lecture 16) - Answer- - the modern atmosphere is made up of 78% Nitrogen and 21%
oxygen
- the early atmosphere had no oxygen - but the volcanoes emit nitrogen and carbon
dioxide into the atmosphere and water into the oceans
How do we know that there were large bodies of water during the Archean eon? (lecture
16) - Answer- - sedimentary rocks need water to form
1st marine sedimentary rocks = in Isua Belt, Greenland = water was present
has life on Earth always been abundant and complex? (lecture 17) - Answer- Earth
began with no life (Haden eon) - it was a "ball of molten lava" with no life
was it possible to create the "building blocks" of life out of non-living
materials/processes? (lecture 17) - Answer- yes - scientists had to create a "simulated
Archean atmosphere" with gases, water, heat, and electricity to make chemical
reactions
- it was discovered that the ancient oceans could have possibly held molecules that are
necessary to life were formed by non-living processes in the atmosphere
about how old are the earliest fossils we've found? are these trace or body fossils or
both? (lecture 17) - Answer- - around 3.5 billion years old
- both body (remains of living things) and trace (a mark left by a living thing i.e. footprint)
fossils were found
- some Archean rocks hold microscopic fossils (bacteria) which are the oldest forms of
life
- splitting Archean rocks open allows access to trace fossils/evidence of past life
what do we consider to be the oldest form of life? (lecture 17) - Answer- bacteria
, what is a stromatolites? (lecture 17) - Answer- bacterial trace fossils - a solid form of
sand put together by bacteria
how do stromatolites form? do we have stromatolites today? (lecture 17) - Answer- -
bacteria gets thrown together by a wave, they stick together, and are buried alive by
oncoming sand
- the process of bacteria moving upwards to avoid being buried occurs in a cycle until a
sand structure is formed - leaving behind a huge stromatolite which becomes a fossil to
study
how do heterotrophs get energy? (lecture 17) - Answer- they eat other things and gain
energy from the food (humans and animals)
how do autotrophs get energy? (lecture 17) - Answer- they do not eat other things (like
ancient bacteria, since they were the only living things at the time) make their own food
- nonliving chemical reactions (like in volcanoes) supply heat from inside the earth and
ultimately provide energy for life to use (some other living things capture sunlight to use
for energy ie. plants)
what are humans? (lecture 17) - Answer- heterotrophs
what 3 "ingredients" are needed for photosynthesis? (lecture 17) - Answer- sunlight
(energy), carbon dioxide, and water (to make sugar) (stores energy), and oxygen
what does photosynthesis produce? (lecture 17) - Answer- oxygen (the plants don't
need it)
what reacts with iron oxides to create red-looking rocks? (lecture 18) - Answer- - the red
color comes from the mixture of iron and oxygen
- there wasn't oxygen in the early atmosphere (Archean) until later periods
- ie. Chert = banded iron formations due to lots of iron oxide mixed into it
what is the Great Oxygenation Event? (lecture 18) - Answer- this was the time when
oxygen was brought into the atmosphere in abundance
why was it important? (lecture 18) - Answer- - occurred when bacteria started making
more and more oxygen = creating new life
- this marks the end of the Archean eon
When did the Proterozoic eon begin? (lecture 18) - Answer- - after the Great
Oxygenation Event
- "azoic" = zoo // "Proterozoic" = before
- "before animals"
