Lab2_The Pangea Puzzle
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School
Texas A&M University *
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Course
207
Subject
Geology
Date
Feb 20, 2024
Type
Pages
8
Uploaded by MegaSealPerson992
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)
The continents the Lystrosaurus was found were Asia, Africa, and Antarctica. 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)
The majority lived in the Triassic period, specifically the Early Triassic period. 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 together in terms of being on the same land mass since there isn’t really countries or at least a clear divide, but relatively they’re still a bit far apart.
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)
The continents the Mesosaurus was found in were South America and Africa. b.
In what ways is the distribution of Mesosaurus
different from Lystrosaurus
? (1 pt)
The Mesosaurus fossils are distributed not all in the same place, but still in bunches. The Lystrosaurus tended to be scattered alone. c.
Given the different ecologies of Mesosaurus and
Lystrosaurus, provide a well-reasoned explanation for why their distributions are different. (1 pt) The distributions for the Mesosaurus and Lystrosaurus are different because of their adaptations and the geological changes occurring during their time periods. A difference in time period means the distributions could have also been affected by continental drift, and changes in climate and sea level. d.
How do you think this animal might have gotten distributed in this pattern? (1 pt)
They might have gotten distributed in this pattern when Pangea broke up due to continental drift. 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)
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In the Permian period, the Mesosaurus is a lot closer together, spread out but concentrated around the same spot. 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)
There were fossil finds of the Glossopteris nearly everywhere, such as South America, Africa, India, Australia, and Antarctica. Countries include South Africa, India, and China. g.
In what ways is the distribution of Glossopteris
different from Lystrosaurus
? (1 pt)
The distribution of Glossopteris and Lystrosaurus because the Glossopteris was during the Permian period while the Lystrosaurus was both the Permian and Triassic periods. The Lystrosaurus is also distributed a lot less and not as close together as the Glossopteris. h.
Provide a well-reasoned explanation for there are so many more fossil occurrences of Glossopteris than Lystrosaurus
. (1 pt)
There are more fossil occurrences of Glossopteris than Lystrosaurus because Glossopteris is a group of plants, which could reproduce in large numbers and cover extensive areas such forests and wetlands unlike the Lystrosaurus, which is a reptile who could have been seen as prey, died naturally, been endangered and/or gone extinct or been a victim of natural selection. Plants also naturally have a better preservation rate. 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)
Paste your maps of Lystrosaurus
, Mesosaurus, and Glossopteris here.
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) Tyrannosaurus and Hadrosaurus fossils have been found in North America, specifically in the western United States and Canada as well as Asia. Spinosaurus and Carcharodontosaurus fossils have been found in North Africa and Egypt. 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) The position of the continents might explain the distribution of each genus since as the environment changes, different animals are better or worse adapted and then eventually fossilized there. 14.
Paste the Cretaceous maps for each genus on the next page of this lab. (2 pts)
Genus N. America S. America Asia Europe Africa Australia Antarctica Tyrannosaurs X X Hadrosaurus X X Spinosaurus X X Carcharodontosaurus X
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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) The distribution of these dinosaur genera supports the hypothesis that the modern continents were joined in Pangaea during the Late Paleozoic but largely separated in the Mesozoic. The presence of these genera on continents that are now widely separated supports the idea of continental drift. For example, fossils of Tyrannosaurs were found in North America which suggests that this region was part of a larger landmass, as it was connected to other continents within Pangaea during the Late Paleozoic.
Paste your Cretaceous Dinosaur maps here