The Pangea Puzzle
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Texas A&M University *
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Course
207
Subject
Geology
Date
Apr 3, 2024
Type
docx
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11
Uploaded by KidWrenMaster1290
The Pangea Puzzle
Introduction One of the most fundamental questions we can ask in geology is how the continents that we see today got to be in their current configurations. Data on the distributions of organisms in the fossil record make
it possible to identify where they lived in the past, and that data can be used to help identify past continental positions. To do this, paleontologists track the occurrence of fossil organisms, in other words where a species occurs in space (geographically) and when a species occurs in time (stratigraphically). The Paleobiology Database (PBDB, https://paleobiodb.org/navigator/
) is a huge online database that seeks to catalogue all fossil occurrences, across all geologic time, and across the whole tree of life. It’s the standard tool used by paleobiologists to track where fossil organisms lived and when. Delving into the Database Open the PBDB Navigator and spend some time getting comfortable with how it works: https://paleobiodb.org/navigator/
The Navigator consists of three parts: 1.
Map
(CENTER) showing continents with dots representing fossil occurrences. The color of these dots represents their geologic age. If you click on the dots, you can see all of the information on each site and the fossil species that occur there.
2.
Geologic time scale
(BOTTOM) showing the major eras, periods, and stages. If you click on the timescale, the map will show you the location of all fossil occurrences from that time interval. 3.
Tool bar
(LEFT) showing the tools you can use to explore the database. These include:
zoom in/out on the map
reconstructs plate tectonic configurations for time interval you are exploring narrow down which taxonomic group is plotted on map
create a diversity curve for the occurrences currently plotted on map
download the data (lat/long, geologic age, etc.) for the occurrences plotted on map
Need help? Here’s a YouTube video to help you get started: https://www.youtube.com/watch?
v=db2He3p-Jco
Goal:
Use fossil distributions to test the hypothesis that the modern continents were joined in Pangaea during the Late Paleozoic but largely separated in Mesozoic.
Step 1: Construct maps of fossil distributions
Lystrosaurus
is not a dinosaur. It is a genus of synapsid, and thus more closely related to mammals than to dinosaurs, that lived in the Late Permian to early Triassic. Reconstruction of
Lystrosaurus murrayi.
Image by Dmitry Bogdanov CC BY-SA 3.0
via Wikimedia Commons
1.
Enter Lystrosaurus
in the search field and click enter. 2.
The dots on the map show where in the modern world paleontologists have discovered fossils of
Lystrosaurus
. At this point, stop and consider your map. a.
Describe the locations of the fossil finds in terms of the continents and/or countries in which the fossil were found. (1 pt)
They are mostly found in South Africa with some being found throughout Asia.
3.
The color of the dots on the map match those of the geologic time scale below, indicating the age of the fossils. You may need to zoom in a bit to get the dots to change to a specific color. a.
Based on this matching, during which geologic period did the majority of the Lystrosaurus
found live? (1 pt)
Triassic 4.
Now, reconstruct the map at that time period by clicking on the name of the time period in the geologic time scale followed by the tool bar icon showing the continents on the left. Note that the map changes, moving the continents to their positions during the time period that you clicked. a.
Describe how the position of the fossil finds changed. Are they now closer together or further apart? (1 pt)
They are closer with some outliers being even further.
b.
Save a copy of your map for Lystrosaurus
and paste it on the fifth page of this lab (1 pts)
. Repeat this process for Mesosaurus
and Glossopteris
. Mesosaurus
is also not a dinosaur. It is an extinct genus of aquatic reptile from the early Permian.
Reconstruction of
Mesosaurus
.
Image by Nobu Tamura CC
BY-SA 3.0
via Wikimedia Commons
5.
Enter Mesosaurus
in the search field and click enter. (Be sure to clear out the information about Lystrosaurus
.)
6.
Look at the distribution for these fossils. a.
Describe the locations of the fossil finds in terms of the continents and/or countries in which the fossil were found. (1 pt)
They are found in South America, in Brazil, and in the South Africa region.
b.
In what ways is the distribution of Mesosaurus
different from Lystrosaurus
? (1 pt)
Some of them were found in South America, none of the Lystosaurus were found in South America, they were found in Asia.
c.
Given the different ecologies of Mesosaurus and
Lystrosaurus, provide a well-reasoned explanation for why their distributions are different. (1 pt)
Since this dinosaur is more closely related to reptiles than mammals, it is probably more cold blooded and needs to stay in areas that have lots of heat. The Lystrosaurus is more closely related to mammals which would allow it to stay in places with colder temperatures.
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d.
How do you think this animal might have gotten distributed in this pattern? (1 pt)
I think this animal lived near a tectonic plate and when they shifted some stayed
on one side and others stayed on the other causing them to be found in both South America and South Africa.
7.
Click on the time period on the geological time scale that represents when the majority of Mesosaurus fossils were found.
e.
Describe how the position of the fossil finds changed. Are they now closer together or further apart? (1 pt)
They are closer together. I believe my hypothesis in the previous question is correct.
8.
Save a copy of your map for Mesosaurus
and paste it on the fifth page of this lab (1 pts)
. Glossopteris
is a genus of seed ferns, and extinct group of plants that lived in Permian period. Image from OSU QM 270-16-B, Orton Geology Museum, Ohio State University, Columbus, Ohio, USA CC BY-SA 3.0
via Wikimedia Commons
. 9.
Enter Glossopteris
in the search field and click enter. (Be sure to clear out the information about
Lystrosaurus
.)
10.
Look at the distribution for these fossils. f.
Describe the locations of the fossil finds in terms of the continents and/or countries in which the fossil were found. (1 pt)
The location of the fossil is found all over the southern hemisphere. There are some but very few in the northern hemisphere.
g.
In what ways is the distribution of Glossopteris
different from Lystrosaurus
? (1 pt)
It is much more abundant and are found in many more places than the Lystrosaurus.
h.
Provide a well-reasoned explanation for there are so many more fossil occurrences of Glossopteris than Lystrosaurus
. (1 pt)
The reason could be as simple as the species is way more abundant than the Lystrosaurus. Since this is a plant, there could have been a significant more number of plants than Lystrosaurus. The sheer numbers of this plant could have allowed it to reach fossilizing conditions more times than the other species.
11.
Using the data on the distribution of these three organisms from the Permian and Triassic as evidence, provide a well-reasoned argument for the claim that continents that are distant today where once consolidated into a supercontinent. (4 pts)
Fossil findings throughout the world argue for the idea that there was once a super continent. This is because many fossils of the same species are found in different parts of the world. How could this be possible without the idea of a supercontinent? The dinosaurs cannot just swim across the ocean or build a boat to do so. The only explanation is that a super continent must have occurred at one point and species of the same kind were separated when the tectonic plates shifted. This could have happened before they were fossilized or during the time they were alive.
Paste your maps of Lystrosaurus
, Mesosaurus, and Glossopteris here.
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Part 3: Dinosauria after Pangea
Let’s examine the distribution of some dinosaur genera that originated after the breakup of Pangea. For each genus, individually examine the modern maps check off the modern continents where fossils from each are found using the table. (2 pts)
12.
Describe the similarities and differences in the distribution of these genera using names of modern continents or countries. (2 pts)
None of the genera were found in Australia or Antarctica. Tyrannosaurus and Hadrosaurus were found in North America. Spinosaurus and Carcharodontosaurus were found in Africa together. Hadrosaurus is the only genera that was found in Europe.
13.
Examine each genus individually on the Cretaceous paleogeographic map. How might the position of the continents explain the distribution of each these genera? (2 pts)
For all the genera, the places that they were found in the modern world were where they used to live in the Cretaceous period. The continents shifted since then explaining why they are found where they are. They lived in what becomes
the modern map, not the modern map.
14.
Paste the Cretaceous maps for each genus on the next page of this lab. (2 pts)
15.
Does the data you collected in the lab support or refute the hypothesis that that the modern continents were joined in Pangaea during the Late Paleozoic but largely separated in Mesozoic? Provide clear evidence and reasoning to support your claim. (5 pts)
I think the data supports this hypothesis. We studied closely within the Permian,
Triassic, and Cretaceous periods. I think the data showing that fossils of the same species being found all over the world proves this theory. The genera we studied closer to the Late Paleozoic era are more scattered throughout the Genus
N. America
S. America
Asia
Europe
Africa
Australia
Antarctica
Tyrannosaurs YES
YES
Hadrosaurus
YES
YES
Spinosaurus
YES
Carcharodontosaurus
YES
YES
world than those we studied in the Mesozoic era. I believe this shows that the continents were once together in the late Paleozoic and split apart in the Mesozoic. The reason why the genera in the Cretaceous periods are not found all over the world as much is because the continents were already beginning to separate at that time Paste your Cretaceous Dinosaur
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maps here