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1. Science 20 > C: Geology = the Changing Earth 1.2 Early Life > Flashcards

C: Geology = the Changing Earth 1.2 Early Life Flashcards

1
Q

What is Cameron Falls known for?

A

A popular sightseeing spot in Waterton Lakes National Park featuring ancient sedimentary rock

Cameron Falls is located in southwestern Alberta.

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2
Q

What type of rock is highlighted at Cameron Falls?

A

Alberta’s oldest sedimentary rock

The rock shows layers of sediment compressed into solid rock.

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3
Q

What do the properties of sediments and fossils in sedimentary rock reveal?

A

Evidence about the type of environment that existed when they were deposited 1.5 billion years ago.

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4
Q

Where did the sediments that formed the layers at Cameron Falls likely originate?

A

At the mouth of a river flowing into an ancient ocean.

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5
Q

What do similar Precambrian sedimentary rock formations indicate?

A

That several large rivers deposited sand, clay, and silt into an ancient ocean.

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6
Q

What is sedimentary rock?

A

Rock formed from compressed layers of pre-existing rock or organic matter.

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7
Q

Define ‘fossil’.

A

The evidence or remains of ancient life preserved in Earth’s crust.

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8
Q

What are ‘strata’?

A

The layered bands within sedimentary rock.

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9
Q

Fill in the blank: A sandwich of sedimentary rock at Cameron Falls is currently _______ km thick.

A

1

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10
Q

What was the early Earth environment like?

A

Hostile with frequent volcanic eruptions, poisonous gases, and extremely hot oceans over 100°C

The atmosphere contained little oxygen.

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11
Q

What did scientists initially believe about life in extreme conditions?

A

Life under extreme conditions would have been impossible

This belief was based on the harsh environment of early Earth.

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12
Q

What recent discoveries have changed the perception of life in extreme conditions?

A

Discovery of a group of extreme bacteria-like organisms that tolerate heat and live on poisonous gases

These organisms are known as Archaea.

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13
Q

Where was one of the first discoveries of Archaea made?

A

In the boiling waters of hot springs in Yellowstone National Park

This discovery indicated that life can thrive in extreme environments.

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14
Q

At what temperature were similar creatures found near deep-sea thermal vents?

A

150°C

This highlights the adaptability of life in extreme heat.

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15
Q

Fill in the blank: The oceans on early Earth were extremely _______.

A

hot

More than 100°C.

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16
Q

True or False: The early Earth’s atmosphere had a high concentration of oxygen.

A

False

The atmosphere contained little oxygen.

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17
Q

What gases were prevalent in the early Earth’s atmosphere?

A

Methane and hydrogen sulfide

These gases contributed to the hostile conditions.

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18
Q

What is the world’s oldest evidence of life?

A

3.8 billion years ago

This evidence includes fossilized remains that suggest life existed during this time.

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19
Q

What type of organisms are considered the earliest life forms?

A

Single-celled bacteria

These organisms are believed to have appeared approximately 3.8 billion years ago.

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20
Q

What is a stromatolite?

A

A layered structure formed by microbial mats

Stromatolites are often associated with ancient microbial life.

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21
Q

What are cyanobacteria?

A

Microscopic, photosynthetic, single-celled bacteria

Cyanobacteria are significant for their role in producing oxygen and contributing to the Earth’s atmosphere.

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22
Q

Fill in the blank: Life may have existed before _______ years ago, but there is no fossil evidence to support this.

A

3.8 billion

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23
Q

True or False: There is a consensus in the scientific community about how and when life began on Earth.

A

False

There is still plenty of debate among scientists regarding the origins of life.

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24
Q

What is the world’s oldest evidence of life?

A

3.8 billion years ago

This evidence includes fossilized remains that suggest life existed during this time.

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25
Q

What type of organisms are considered the earliest life forms?

A

Single-celled bacteria

These organisms are believed to have appeared approximately 3.8 billion years ago.

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26
Q

What is a stromatolite?

A

A layered structure formed by microbial mats

Stromatolites are often associated with ancient microbial life.

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27
Q

What are cyanobacteria?

A

Microscopic, photosynthetic, single-celled bacteria

Cyanobacteria are significant for their role in producing oxygen and contributing to the Earth’s atmosphere.

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28
Q

Fill in the blank: Life may have existed before _______ years ago, but there is no fossil evidence to support this.

A

3.8 billion

29
Q

True or False: There is a consensus in the scientific community about how and when life began on Earth.

A

False

There is still plenty of debate among scientists regarding the origins of life.

30
Q

What are deep-sea thermal vents?

A

Locations that release intense volcanic heat and hydrogen sulfide gas

31
Q

Which organisms thrive near deep-sea thermal vents?

A

Archaea organisms

32
Q

What gas do Archaea feed on near thermal vents?

A

Hydrogen sulfide

33
Q

True or False: Hydrogen sulfide is safe for humans.

A

False

34
Q

What may Archaea organisms represent in terms of Earth’s history?

A

The closest living relatives of Earth’s earliest life

35
Q

How long ago did the layers of rock at Cameron Falls start to form?

A

15 billion years ago

36
Q

What type of environment surrounded Cameron Falls during its formation?

A

A large shallow mud flat

37
Q

What type of fossil evidence indicates the presence of cyanobacteria?

A

Stromatolites

38
Q

Where did cyanobacteria live in ancient times?

A

In the tropically warm shallow waters along the coast of ancient landmasses

39
Q

Fill in the blank: The organisms living near deep-sea thermal vents are known as _______.

A

Archaea

40
Q

What are cyanobacteria?

A

Microscopic, photosynthetic single-celled bacteria

They are among Earth’s first photosynthetic organisms.

41
Q

How do cyanobacteria contribute to the formation of limestone?

A

By growing and dying one layer on top of the other, depositing layers of calcium carbonate

Calcium carbonate is the main ingredient of limestone and our bones.

42
Q

What are stromatolites?

A

Large mounds formed by layers of calcium carbonate from cyanobacteria

Stromatolites can be 10 to 30 cm tall and are remnants of ancient cyanobacterial activity.

43
Q

What type of fossil are stromatolites an example of?

A

Trace fossil

They are not the actual cyanobacteria but represent evidence of their existence.

44
Q

What impact does the atmosphere have on the evolution of life?

A

It affects the evolution of future life and has spinoff effects on the planet’s geology

This relationship is explored in investigations regarding Earth’s oxygen-rich atmosphere.

45
Q

Fill in the blank: Stromatolites are the remains of _______.

A

calcium carbonate layers

46
Q

True or False: Cyanobacteria are multicellular organisms.

A

False

Cyanobacteria are single-celled organisms.

47
Q

What geological phenomena will the next investigation explore?

A

The impact of Earth’s oxygen-rich atmosphere

This will include its effects on geological processes.

48
Q

What does the presence of banded iron formations indicate about Earth’s early atmosphere?

A

It suggests the presence of oxygen in Earth’s atmosphere during the Precambrian Era

49
Q

What role did cyanobacteria play in making Earth livable?

A

Cyanobacteria were one of the only early producers of oxygen

They significantly contributed to the development of an oxygen-rich atmosphere, essential for other forms of life.

50
Q

Where is the earliest direct evidence of cyanobacteria found?

A

Isua Rock in Greenland

This evidence dates back 3.7 billion years.

51
Q

What complex molecule did cyanobacteria use to trap the Sun’s energy?

A

Chlorophyll

Chlorophyll is essential for photosynthesis, allowing organisms to convert sunlight into energy.

52
Q

What process uses the Sun’s energy to make glucose from carbon dioxide and water?

A

Photosynthesis

This process is crucial for the production of energy in plants and cyanobacteria.

53
Q

What is the by-product of photosynthesis?

A

Oxygen

Oxygen is released into the atmosphere as a result of the photosynthesis process.

54
Q

For how long were cyanobacteria the dominant form of life on Earth?

A

Two billion years

Despite their microscopic size, they had a significant impact on Earth’s atmosphere and ecosystems.

55
Q

How did cyanobacteria impact Earth’s atmosphere?

A

They are largely responsible for creating Earth’s atmospheric oxygen

This transformation was critical for the evolution of aerobic life forms.

56
Q

True or False: Cyanobacteria were the first organisms to use chlorophyll.

A

True

This adaptation allowed them to harness solar energy for photosynthesis.

57
Q

What significant ice age is referred to as ‘Snowball Earth’?

A

A time period late in the Precambrian Era when icecaps covered most of the planet for nearly ten million years

58
Q

What happened to the oceans during ‘Snowball Earth’?

A

The oceans froze solid except for small pockets of water that remained liquid due to heat escaping from Earth’s mantle

59
Q

What evidence of glacial activity is found in late Precambrian rocks?

A

Evidence of glaciers advancing and retreating

60
Q

Where can evidence of Precambrian glacial activity be found?

A

In rocks all over the world, including Alberta’s Rocky Mountains

61
Q

What do some scientists believe was the result of the stresses placed on organisms during the deep freeze of ‘Snowball Earth’?

A

An explosion in species diversity leading to the first complex creatures

62
Q

By the end of the Precambrian Era, what percentage of Earth’s history had passed?

A

Nearly 90%

63
Q

What were the first producers that transformed the atmosphere?

A

Cyanobacteria

64
Q

What indirect evidence of cyanobacteria’s existence is found in the geological record?

A

Stromatolite mounds and banded iron deposits

65
Q

What direct evidence of early life is found in the Rocky Mountains?

A

Fossil imprints

66
Q

What types of features shared the shallow waters with stromatolites?

A

Multicellular creatures like small jellyfish, worm-shaped animals, and ferns

67
Q

What major section of geological time was initiated by an explosion of new and bizarre creatures?

A

The Paleozoic Era

68
Q

Fill in the blank: The first producers, ________, transformed the atmosphere.

A

cyanobacteria

1. Science 20 (52 decks)

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