Download 14 The History of Life

14 The History of Life
1 Fossil Evidence of Change
7(B)
MAINIDEA
Write the Main Idea for this lesson.
REVIEW VOCABULARY
Recall the definition of the Review Vocabulary term.
extinction
extinction
NEW VOCABULARY
Use the terms in the left column to complete the paragraph below.
Cambrian explosion
eon
Scientists measure Earth’s geological and biological events
using the
epoch
era
fossil
geologic time scale
, which is divided into
,
,
The
, and
.
was a period of rapid change during
which the ancestors of most animal groups emerged. A layer of
soot found between rock layers worldwide, known as the
, might indicate that a large meteorite
K-T boundary
law of superposition
paleontologist
collided with Earth.
The theory of
describes Earth’s surface as
period
large plates that move over Earth’s thick, liquid interior. These plates
plate tectonics
are made up of rocks.
radiometric dating
study
relative dating
using
are scientists who
. They determine the relative age of rocks
, which compares the sequence of rock
layers. The
states that younger rock
layers are deposited on top of older rock layers. Another method of
determining the age of rocks is
, which
measures the decay of radioactive isotopes. The rate of decay is
measured using
, the amount of time required for
half of a radioactive isotope to decay.
Science Notebook • The History of Life
196
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
half-life
1 Fossil Evidence of Change (continued)
Student Edition, pp. 392–400
Reading Essentials,
pp. 157–163
Sequence the organizer below by listing the order of events that led to
the formation of Earth’s early atmosphere. The last step has been done
for you.
Volcanoes erupted, giving off gases and forming the early
atmosphere.
Identify three types of materials in which fossils are found.
1.
Copyright © McGraw-Hill Education. Permission is granted to reproduce for classroom use.
2.
3.
Compare relative and radiometric dating using the table below.
Provide three facts for each type of dating.
Relative Dating
Radiometric Dating
1.
1.
2.
2.
3.
3.
Science Notebook • The History of Life
197