2. Objectives:
1)To describe and explain how fossils are
records of organisms and events in the
Earth’s history.
2)To explain the evidence of evolution from
a variety of sources of scientific data.
3. Explorations Through Time
• This site has it all
including 2 different
learning levels!
Click on the dinosaur
to tour the History of
Time.
http://www.ucmp.berkeley.edu/education/explotime.html
4. Sum it all up!
• Fossils are preserved plants and animals
and all of the traces that they have left
behind.
• The Law of Superposition states that each
layer is older than the one above it and
younger than the one below it.
• Absolute dating determines a fossil’s age
in years. Radioisotope dating is the most
widely used method for dating a fossil.
5. Sum it up (cont’d)
• Relative dating is an estimate based on
the known age of the sediment layer in
which the fossil is found.
• The geologic time scale is a calendar
scientists use to outline the history of
Earth and life on Earth.
• Many species existed for a few million
years and then became extinct. Mass
extinctions have occurred several times in
Earth’s history.
6. The Geological Time Scale
• What is a Geological Time Scale?
This graph is in correct proportion referencing time!
It is a calendar
scientists use to
outline the
history of life on
Earth. It is
broken down into
important events
that have
occurred in
history.
Click on the Time Scale and take a drive (in a
Porsche) along the outline of time. Click on the
Shockwave Flash version for the ride of your life!
7. Precambrian Time
• Began 4.6 billion years
ago and ended 540
million years ago.
• It is the longest length
of time period.
• The oldest known
fossils (3.5 Billion) are
of bacteria.
• ARCHEABACTERIA!
8. Paleozoic Era
Holds the two most
important events.
1. Diversity of Life
blossoms quickly
2. Mass extinction of
marine organisms
10. Cenozoic Era
The Age of Mammals
Birds are
considered to be
‘today’s’
dinosaurs!
Ray – finned fish
now appear.
Flowering plants begin in
this era.
This era marks the
dominance of
mammals and finally –
people!
Insects also
dominate this
era!
