Lab2_The Pangea Puzzle
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School
Texas A&M University *
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Course
207
Subject
Geology
Date
Dec 6, 2023
Type
Pages
9
Uploaded by ChancellorThunder4984
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)
-
Some in Russia, China, Antarctica, and India, but mostly in South Africa 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)
-
Early 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 a lot closer with only a few far off into the north. 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)
-
Brazil and southern Africa b.
In what ways is the distribution of Mesosaurus
different from Lystrosaurus
? (1 pt)
-
They are not as spread out and near the coast. c.
Given the different ecologies of Mesosaurus and
Lystrosaurus, provide a well-reasoned explanation for why their distributions are different. (1 pt) -
The Mesosaurus is a more aquatic animal than the lystrosaurus so it would make sense that they would gather more towards bodies of water. d.
How do you think this animal might have gotten distributed in this pattern? (1 pt)
-
They probably all gathered in that location when Pangea was still one and then got separated when the continents split apart. 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 now all centralized in the central/left side of the super continent. 8.
Save a copy of your map for Mesosaurus
and paste it on the fifth page of this lab (1 pts)
.
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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)
-
Antarctica, South America, Africa, India, Australia, and some in China/Middle East. g.
In what ways is the distribution of Glossopteris
different from Lystrosaurus
? (1 pt)
-
It is way more spread out then either and in many more locations. h.
Provide a well-reasoned explanation for there are so many more fossil occurrences of Glossopteris than Lystrosaurus
. (1 pt) -
Because it’s a
plant and plants have many ways to spread and pollinate and grow faster and potentially have less lethal predators.
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 were once consolidated into a supercontinent. (4 pts)
-
The locations that they were discovered at might seem far apart, however, when the continents are brought back together it shows that the past animals and plants habituated an area much more reasonable and understandable. As well as being in much more sensible area that a living animal would find comfortable and sustainable and corresponds with the land mass to ocean distribution.
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) -
The last two where similarly located in Africa and South America while the first two were also similarly located in N. America and the Asian/European area. 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) -
Most of the dinosaurs stayed in one location, but the continents were still close/connected enough that if a dinosaur wanted to travel to a new location they could. 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) -
Yes, as most of the fossils from the Late Paleozoic would be together and not separated by vast oceans as they are today which would be impossible for them to traverse and that most of the fossils from the Mesozoic were gathered together but with some not too distant back then as the continents were still close or connected with smaller seas/bodies of water separating them but are now far apart today would be the only explanation as how they did move to another continent but with only a few doing so.
Genus N. America S. America Asia Europe Africa Australia Antarctica Tyrannosaurs x x x Hadrosaurus x x Spinosaurus x x Carcharodontosaurus x x
Paste your Cretaceous Dinosaur maps here
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