Transcript Activity 92: Time for Change

Activity 92: Time for Change
 Challenge How long have organisms
been living on Earth?
Key Vocabulary:
 Geologic Time Scale
 Radiometric Dating
 Mass Extinction
Geologic Time Scale
 ON the first day of school, how do you know when to go to
each of your classes??
 Scientists have broken Earth’s history into distinct sections
of time, with each section defined by different
characteristics
 Geologic Time Scale  categorizes and divides the history
of Earth into a series of consecutive sections that are
organized by periods of time
 Radiometric Dating  the analysis of certain
minerals that contain radioactive elements, which
over time decay into different elements. (This gives
us ages of rocks/fossils)
 Mass Extinction  High rates of extinction for many
species in a relatively short geologic time span.
Reasons for Mass Extinction:



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Volcanic eruptions
Tectonic activity
Global cooling/warming
Meteor strikes
 The Earth has had 5 major mass Extinctions!!!
How old is the Earth??
 We estimate the Earth to be about 4.5 billion years
old
 That is a lot of time!! Think about how much has
changed in the last decade!
Glue in Student Sheet 92.1
 We are going to investigate your own history and
construct a personal time scale.
 Begin Part One of the Procedure (page F-17) and stop
at Step 6
Part 2
 Put your 6 Fossil Cards in order. Follow Procedure
Steps 7-10
 Glue in Student Sheet 92.2
 Use the chart to construct your Geologic Timeline:
 Follow Step 11
Mass Extinctions
 Geologic Event Time Cards – Follow Steps 14 and 15
 When you are finished, Answer Analysis Question 4
with your group and record your answers in your
notebook.