Lab Activity: Mystery of the Far-Flung Fossils

Problem: Use fossil evidence to infer when and how Pangaea drifted apart.

Introduction: Imagine that the five continents of South America, Africa, Antarctica, Australia, and India are each represented by a stack of sedimentary rocks on five lab tables. The continents are in their natural geographical shape and their sizes are proportional. The blue, top layer, represents modern times, and the pictures of the modern animals you see are native to the continent. The three lower layers depict sedimentary rocks of three past ages:

·  Green rock samples—100 million years ago

·  Yellow rock samples—200 million years ago

·  Red rock samples—300 million years ago

Materials

1.  Sedimentary rock samples from South America, Africa, Antarctica, Australia and India

2.  Fossil Catalog

Procedure

1.  In your group, proceed to the station designated by your teacher.

2.  On your data sheet, record the names of the fossils you find in the rock on the continent at your station.

3.  Also, record the names of the animals now living on the present day continents.

4.  At the teacher’s signal, rotate to the next station and repeat data collection.

OVER

Data: Create the following table in your lab notebook.

South America / Africa / India / Australia / Antarctica
Present Day (blue)
100 million years ago (green)
200 million years ago
(yellow)
300 million years ago (red)

Analysis and Conclusions

1.  For each of the rock samples (red, yellow and green) list the continents that had similar fossils.

2.  With this evidence in mind, what inference might you make?

3.  On your fossil expedition you also found glacial grooves (scratches in the bedrock made by glaciers) in southern Africa. What might you infer about this evidence?

4.  How was the theory of continental drift strengthened by discoveries of closely related earthworms of widely separated continents?

5.  List as many pieces of evidence as you can to support the theory of continental drift.

6.  Why do you think it is so difficult for some people to accept the idea of continental drift?