PowerPoint Storyboard
Nancy Stearns and Annwesa
Dasgupta
Evidence of Ancient Life: Fossils
• What are fossils?
Naturally preserved remains or traces of animals or plants
that lived in the geologic past. Fossils include the remains of
organisms that were once living or can be the signs left
behind by organisms like footprints, tracks, trails, and
burrows.
• What do we learn from them?
The fossil record can tell a lot of evolution as it has occurred
over the past million years.
How are fossils formed?
• In several ways:
– Tiny air spaces in buried bone and shell
can let water seep in and minerals are
deposited as a result which reinforce
the bone and shell.
– Preserved in amber or ice tombs.
– A sudden natural disaster can lead to
fossilization of trapped living things.
• Watch the videos to learn more about
how fossils are formed:
http://www.classzone.com/books/earth
_science/terc/content/visualizations/es
2901/es2901page01.cfm?chapter_no=vi
sualization
http://www.pbs.org/wgbh/evolution/lib
rary/04/3/quicktime/l_043_01.html
http://www.pbs.org/wgbh/evolution/library/04/3/l_043_01.html
The Fossil Records:
Let’s do an activity to learn about the ‘The fossil bearing unit: The
Burgess Shale’
http://www.ucmp.berkeley.edu/cambrian/burgess.html
Teacher-lesson plan:
http://www.discoveryeducation.com/teachers/free-lessonplans/the-fossil-record.cfm#que
How can fossils show evolution?
• Transitional fossils: Fossils or
organisms that show the
intermediate states between an
ancestral form and that of its
descendants are referred to as
transitional forms.
• Numerous examples of transitional
forms in the fossil record, provide
an abundance of evidence for
change over time.
• Example: Transitional fossils of
whales -evolution from land to
water.
Source: Zimmer, C. (2006). Evolution: The
Triumph of an Idea. New York, NY:
HarperCollins.
Whales in Transition:
• Read the following material with a focus on ‘evidence’ that
elaborates the fossil sequence from terrestrial mammals through
more and more whale-like forms until the appearance of modern
whales
http://www.indiana.edu/~ensiweb/lessons/wh.or.11.pdf
• Divide in groups of three and fill out the various characteristics that
you come across as you read. After completing the worksheet, take a
note of the various similarities and differences during the course of
whale evolution
http://www.indiana.edu/~ensiweb/lessons/wh.ev.dt.pdf
Explore from the activity :
Why aren’t there more of these transitional fossils?
Why do gaps exists these fossil finds?
http://www.indiana.edu/~ensiweb/lessons/whale.ev.html
Discussion
• Why are fossils so rare and difficult to find
ancestral fossil species to show evolution from
a common ancestor?
• Any there any questions that fossil records
might not be able to answer?