Fig 7.19. Some of the landmasses of the ancient supercontinent Gondwanaland show selected geological and fossil evidence.
Image by US Geological Survey and US Department of Interior modified by Byron Inuoye
Title
Activity: Continental Movement over Long Time Scales
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts
NGSS Disciplinary Core Ideas
Table of Contents
Materials
- Table 7.5.
- Fig. 7.19
- Scissors
- Colored pencils or crayons
- Construction paper
- Glue or gluestick
- World map (optional)
Procedure
A. Evaluate and interpret the available evidence.
- Carefully read each piece of evidence listed in Table 7.5.
- Discuss each piece of evidence with your group.
- Evaluate the quality of the evidence by ranking each statement on a scale of 1–5 in the “quality” column of Table 7.5:
- 1 = “low quality” evidence that does not support the idea of continental drift
- 5 = “high quality” evidence that is very supportive of the idea of continental drift.
- Explain the reasoning for your ranking in the “interpretation” column of Table 7.5.
- Evaluate the quality of the evidence by ranking each statement on a scale of 1–5 in the “quality” column of Table 7.5:
B. Map the evidence.
- Use scissors to cut out all continent pieces from Fig. 7.19.
- Place the continent pieces in their modern day relative positions. You may lay these continent pieces over a modern world map if needed.
- Glacial striations are deep grooves gouged into rock formations by moving or spreading glaciers or ice sheets.
- Find regions where ancient glacial striations have been discovered, as indicated on Fig. 7.19 with the symbol “=”.
- Color these regions yellow.
- Fossils of the fern plant Glossopteris can be found within the distinct Gondwana rock sequence (Table 7.5; Fig. 7.20 C).
- Find regions where Glossopteris plant fossils have been discovered, as indicated on Fig. 7.19 with symbol G.
- Color these regions green.
- Fossils of the aquatic reptile Mesosaurus can be found within the distinct Gondwana rock sequence (Table 7.5; Fig. 7.20 A).
- Find regions where Mesosaurus fossils have been discovered, as indicated on Fig. 7.19 with symbol M.
- Color these regions blue.
- Fossils of the aquatic reptile Cynognathus can be found within the distinct Gondwana rock sequence (Table 7.5; Fig. 7.20 B).
- Find regions where Cynognathus fossils have been discovered, as indicated on Fig. 7.19 with symbol C.
- Color these regions orange.
- Fossils of the aquatic reptile Lystrosaurus can be found within the distinct Gondwana rock sequence (Table 7.5; Fig. 7.20 D).
- Find regions where Lystrosaurus fossils have been discovered, as indicated on Fig. 7.19 with symbol L.
- Color these regions brown.
- Present-day earthworm species within the family Megascolecidae have a limited geographic distribution (Table 7.5).
- Find regions where present-day megascolecid earthworms occur, as indicated on Fig. 7.19 with symbol E.
- Color these regions red.
Image
Fig. 7.20. (A) Fossil skeleton of Mesosaurus sp.
Image courtesy of Tommy, Flickr
Fig. 7.20. (B) Fossil skull of Cynognathus sp.
Image courtesy of Ghedoghedo, Wikimedia Commons
Fig. 7.20. (C) Fossil of Glossopteris sp. plant leaves
Image courtesy of Daderot, Wikimedia Commons
Fig. 7.20. (D) Fossil skeleton of Lystrosaurus sp.
Image courtesy of Ghedoghedo, Wikimedia Commons
- Try to fit all the continent pieces together so that the continental edges match. Try to also make the colored evidence regions match.
- Compare your arrangement of matched continents to that of your classmates.
- Discuss the role of each piece of evidence in the arrangement of your supercontinent.
- After coming to an agreement on the arrangement of your single supercontinent, glue the pieces to a sheet of construction paper.
Activity Questions
- The following questions are about evaluating the quality of evidence in Table 7.5.
- a. Which pieces of evidence did you consider to be strongly in support of the idea that the continents have moved over a long time scale (continental drift)?
- b. Which pieces of evidence did you consider to refute the concept of continental movement over time?
- c. How did you assess the quality of scientific evidence in Table 7.5?
- d. Provide an example of poor quality evidence (from Table 7.5) and your reasons for considering it low quality.
- e. What makes a piece of evidence strong quality compared to poor quality?
- Develop your own explanation for the observed evidence listed in Table 7.5. Swap explanations with a classmate. Evaluate each other’s work based on how they address and explain the observed evidence.
- One shortfall of Alfred Wegener’s theory of continental drift in 1912 was that it lacked an explanation for how the continents could have moved over time. Can you suggest a possible mechanism driving the movement of entire continents?
- Glossopteris is a genus of fern plants known to have thrived in humid tropical and temperate climates. What does this information tell you about the climate of ancient Antarctica?
- Lystrosaurus fossils have been discovered in present-day China and Southeast Asia (part of Laurasia, not part of ancient Gondwanaland). Scientists are still working on an explanation for this observation. Suggest your own explanation for this phenomenon.
- Alfred Wegener’s theory of continental drift was first proposed in 1912. However, the concept of moving continents was not widely accepted by scientists until the 1960s. Why do you think the idea of moving continents took so long for the scientific community to accept?
- Which modern day landmasses are represented by in Fig. 7.18? Label them on your map.
- Are all of the current landmasses represented in Fig. 7.18? Which ones are missing?
