Lesson 5- The Fossil Record

Question 1

The (blank) (blank) provides evidence about the history of life on Earth. It also shows how different groups of organisms, including species, have changed over time.

Answer 1

fossil record

Question 2

The fossil record provides incomplete information about the history of life.

Over 99% of all species that have lived on Earth have become (blank), which means that the species has died out.

Those species that still exist are referred to as being (blank).

Answer 2

extinct, extant

Question 3

Most fossils form in sedimentary rock.

(Blank) (blank) forms when exposure to the elements breaks down existing rock into small particles of sand, silt, and clay.

Answer 3

Sedimentary rock

Question 4

(Blank) carries small rock -particles to lakes and seas.

Answer 4

Water

Question 5

(Blank) (blank) are buried by layers of sediment, which forms new rock

Answer 5

Dead organisms

Question 6

Paleontologists determine the age of fossils using (blank) (blank) or (blank) (blank)

Answer 6

relative dating or radioactive dating

Question 7

In (blank) (blank), the age of a fossil is determined

by comparing its placement with that of fossils in other layers of rock.

(Blank) (blank) form in order by age-the oldest on the bottom, with more recent layers on top

Answer 7

relative dating, Rock layers

Question 8

(Blank) (blank) are used to compare the relative ages of fossils.

An (blank) is a species that is recognizable and that existed for a (sentence blank)

Answer 8

Index fossils, short period but had a wide geographic range.

Question 9

Scientists use (blank) (blank) to assign an absolute age to rocks.

(Blank) (blank) is the use of half-lives to determine the age of a sample.

A (blank) is the length of time required for half of the radioactive atoms in a sample to decay.

Answer 9

radioactive decay, Radioactive dating, half-life

Question 10

The basic divisions of the geologic time scale are (blank) and (blank).

Answer 10

eras and periods.

Question 11

Geologic time begins with (blank) (blank), which covers about 88% of Earth’s history.

Answer 11

Precambrian Time

Question 12

Eras

Geologists divide the time between Precambrian time and the present into three eras:

Answer 12

• Paleozoic Era
• Mesozoic Era
• Cenozoic Era

Question 13

Geologic Time Scale
Era: Paleozoic
Periods:

Answer 13

Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian

Question 14

Geologic Time Scale
Era: Paleozoic
Periods: Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian

Time (millions of years ago)

Answer 14

Permian- 290-245
Carboniferous- 360-290
Devonian- 410-360
Silurian- 440-410
Ordovician- 505-440
Cambrian- 544-505

Question 15

Geologic Time Scale
Era: Mesozoic
Period:

Answer 15

Cretaceous
Jurassic
Triassic

Question 16

Geologic Time Scale
Era: Mesozoic
Period: Cretaceous
Jurassic
Triassic
Time (million years ago)

Answer 16

Cretaceous- 145-65
Jurassic- 208-145
Triassic- 245-208

Question 17

Geologic Time Scale
Era: Cenozoic
Period:

Answer 17

Quaternary
Tertiary

Question 18

Geologic Time Scale
Era: Cenozoic
Period: Quaternary
Tertiary
Time (millions of years ago)

Answer 18

Quaternary- 1.8-present
Tertiary- 65-1.8