chapter10 Flashcards

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1
Q

a scientist that studies fossils is called what?

A

paleontologist

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2
Q

gradual change in living things over long periods of time is called

A

evolution

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3
Q

radioactive dating is used to do what

A

determine the absolute age of rocks

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4
Q

what happens during radioactive decay

A

atoms of one element break down to form atoms of another element

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5
Q

the half life of a radioactive element is what

A

time it takes for half of the radioactive atoms to decay

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6
Q

when all the atoms of a particular type of matter are all the same it is called

A

element

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7
Q

what is the law of superposisition used for

A

determine the realtive age of rocks

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8
Q

in a horizontal sedimentary rock what is at the bottom

A

the oldest layer

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9
Q

magma that forces its way into rocks and hardens is called what

A

intrusion

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10
Q

what is intrusion

A

a hardened layer of magam beneath Earths surface

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11
Q

what is extrusion

A

hardened layer of lave on Earths surface

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12
Q

what do fossils provide us

A

evidence of changes in Earths surface, how environments on Earth have changed over time and how groups of organisms have changed over time

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13
Q

when do most fossils form

A

when organisms die and are buried in sediment

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14
Q

mold,cast,petrified fossil, carbon film trace are all types of what

A

fossils

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15
Q

is a cast a solid copy of the shape of an organisms?

A

yes

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16
Q

true or false: a mold is a hollow are in sediment in the shape of an organism

A

true

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17
Q

true or false: molds and cast are the least common types of fossils

A

false: the are the most common

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18
Q

true or false: carbon film consists of an extremenly thick film of carbon on rock

A

false: thin film

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19
Q

trace fossils provide evidence of what

A

activities of ancient organisms

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20
Q

when does a petrified fossil form

A

when minerals replace all or part of an organism

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21
Q

where are fossils almost always found

A

sedimentary rock

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22
Q

the relative age of a rock is what

A

the age of the rock compared to ages of other rocks

23
Q

why are index fossils useful

A

they tell the Relative ages of rock layers

24
Q

the absolute age of a rocks is what

A

number or years since the rock formed

25
Q

index fossils are used to what

A

determine relative age of rocks and are widely distributed throughout the world

26
Q

what are ammonities

A

group of hard shelled animals the evolved in shallow seas more that 50,000 years ago. used as index fossils

27
Q

geologist often use carbon-14 to do what

A

date materials that lived up to about 50,000 years ago

28
Q

geologist use potassium-40 to do what

A

date rocks that are older than 50,000 years

29
Q

the record of life forms and geologic events in Earths history is called what

A

geologic time scale

30
Q

geologic time between precambrian time and today is divided into what

A

3ears

31
Q

each era is also divided into what

A

periods

32
Q

when did the earliest forms of life appear

A

precambrian time. similiar to bacteria of our time

33
Q

in the cambrian explosion a great number of ___________evolved

A

organisms

34
Q

when did plants and animals first reach land

A

paleozoic era

35
Q

most fossilo fuels (primary coal) formed during which period

A

carboniferous

36
Q

what formed during the permian period

A

pangaea

37
Q

when did vertebrates arise

A

during ordovician & silurian periods

38
Q

animals without backbones are called invertebrates. what are animals called with backbones

A

vertebrates

39
Q

when did dinosaurs rule the Earth

A

mesozoic era. often called the age of reptiles

40
Q

reptiles eveolved from what

A

amphibians

41
Q

a gap in the geologic record is called what

A

unconformity

42
Q

name all 4 eras:

A

cenozoic,mesozoic,paleozoic and precambrian time

43
Q

in quaternary how many years ago and duration (millions of years)

A

1.8 million years ago and 1.8 to present is duration

44
Q

tertiary what is its duration

A

65

45
Q

cretaceous years and duration

A

66.4 and 78 is duration

46
Q

jurassic years and duration

A

144 and 64 is duration

47
Q

triassic years and duration

A

208 and 37 is duration

48
Q

permian years and duration

A

245 and 41 is duration

49
Q

carboniferous years and duration

A

285 and 74 is duration

50
Q

devonian years and duration

A

360 and 48 is duration

51
Q

silurian years and duration

A

408 and 30 is duration

52
Q

ordovician years and duration

A

438 and 67 is duration

53
Q

cambrian years and duration

A

544 and 544 million to 4.6 billion years ago