chapter10

Question 1

a scientist that studies fossils is called what?

Answer 1

paleontologist

Question 2

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

Answer 2

evolution

Question 3

radioactive dating is used to do what

Answer 3

determine the absolute age of rocks

Question 4

what happens during radioactive decay

Answer 4

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

Question 5

the half life of a radioactive element is what

Answer 5

time it takes for half of the radioactive atoms to decay

Question 6

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

Answer 6

element

Question 7

what is the law of superposisition used for

Answer 7

determine the realtive age of rocks

Question 8

in a horizontal sedimentary rock what is at the bottom

Answer 8

the oldest layer

Question 9

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

Answer 9

intrusion

Question 10

what is intrusion

Answer 10

a hardened layer of magam beneath Earths surface

Question 11

what is extrusion

Answer 11

hardened layer of lave on Earths surface

Question 12

what do fossils provide us

Answer 12

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

Question 13

when do most fossils form

Answer 13

when organisms die and are buried in sediment

Question 14

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

Answer 14

fossils

Question 15

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

Answer 15

yes

Question 16

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

Answer 16

true

Question 17

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

Answer 17

false: the are the most common

Question 18

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

Answer 18

false: thin film

Question 19

trace fossils provide evidence of what

Answer 19

activities of ancient organisms

Question 20

when does a petrified fossil form

Answer 20

when minerals replace all or part of an organism

Question 21

where are fossils almost always found

Answer 21

sedimentary rock

Question 22

the relative age of a rock is what

Answer 22

the age of the rock compared to ages of other rocks

Question 23

why are index fossils useful

Answer 23

they tell the Relative ages of rock layers

Question 24

the absolute age of a rocks is what

Answer 24

number or years since the rock formed

Question 25

index fossils are used to what

Answer 25

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

Question 26

what are ammonities

Answer 26

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

Question 27

geologist often use carbon-14 to do what

Answer 27

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

Question 28

geologist use potassium-40 to do what

Answer 28

date rocks that are older than 50,000 years

Question 29

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

Answer 29

geologic time scale

Question 30

geologic time between precambrian time and today is divided into what

Answer 30

3ears

Question 31

each era is also divided into what

Answer 31

periods

Question 32

when did the earliest forms of life appear

Answer 32

precambrian time. similiar to bacteria of our time

Question 33

in the cambrian explosion a great number of ___________evolved

Answer 33

organisms

Question 34

when did plants and animals first reach land

Answer 34

paleozoic era

Question 35

most fossilo fuels (primary coal) formed during which period

Answer 35

carboniferous

Question 36

what formed during the permian period

Answer 36

pangaea

Question 37

when did vertebrates arise

Answer 37

during ordovician & silurian periods

Question 38

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

Answer 38

vertebrates

Question 39

when did dinosaurs rule the Earth

Answer 39

mesozoic era. often called the age of reptiles

Question 40

reptiles eveolved from what

Answer 40

amphibians

Question 41

a gap in the geologic record is called what

Answer 41

unconformity

Question 42

name all 4 eras:

Answer 42

cenozoic,mesozoic,paleozoic and precambrian time

Question 43

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

Answer 43

1.8 million years ago and 1.8 to present is duration

Question 44

tertiary what is its duration

Answer 44

65

Question 45

cretaceous years and duration

Answer 45

66.4 and 78 is duration

Question 46

jurassic years and duration

Answer 46

144 and 64 is duration

Question 47

triassic years and duration

Answer 47

208 and 37 is duration

Question 48

permian years and duration

Answer 48

245 and 41 is duration

Question 49

carboniferous years and duration

Answer 49

285 and 74 is duration

Question 50

devonian years and duration

Answer 50

360 and 48 is duration

Question 51

silurian years and duration

Answer 51

408 and 30 is duration

Question 52

ordovician years and duration

Answer 52

438 and 67 is duration

Question 53

cambrian years and duration

Answer 53

544 and 544 million to 4.6 billion years ago