Lab2_The Pangea Puzzle
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Texas A&M University *
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Course
207
Subject
Geology
Date
Apr 3, 2024
Type
Pages
11
Uploaded by ConstableFrog4162
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 fossils were found on various continents of both Asia and Africa. The specific modern-day countries the fossils were found in are India, China, Russia, and 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)
Majority of the Lystrosaurus were found to live during the 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)
The position of the fossil finds are now closer together. There is no water separating the continents and instead the Lystrosaurus appear to inhabited a region further south with a few slightly north eastern.
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 fossils are found on two continents: South America and Africa. In terms of countries, they are found in modern day South Africa and Brazil/Uruguay. b.
In what ways is the distribution of Mesosaurus
different from Lystrosaurus
? (1 pt)
The distribution of the Mesosaurus is different from that of the Lystrosaurus because the Mesosaurus have limited geographical distribution. Fossil of the Mesosaurus were mainly found and concentrated within two regions. Those being present day South-Africa and Brazil and Uruguay. In contrast the Lystrosaurus was found within an extensive regions (or various parts of the world) on the map. Fossils were discovered in various parts of the world such as South Africa, China, India, and Russia. c.
Given the different ecologies of Mesosaurus and
Lystrosaurus, provide a well-reasoned explanation for why their distributions are different. (1 pt) There distributions are different since the Mesosaurus and the Lystrosaurus lived during different periods and because of this there are millions of years of both geological and environmental change separating them. An explanation for how their distributions differs could be due to the breakup of Pangea. The geological context of each species’ given time period would have influenced the availability of habitats and resources leading to different distributions. d.
How do you think this animal might have gotten distributed in this pattern? (1 pt)
I think this animal might have gotten distributed in this pattern because during the time period in which the Mesosaurus lived the continent was part of Pangea. Pangea was considered a supercontinent and was a large piece of land that make up most of today’s continents. During the lifetime of the Mesosaurus they likely would have lived in the shallow waters of Pangea, which includes modern day
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South America and western Africa. As continental drift began to take place, Pangea began to break up and landmasses started to drift away from one another. Due to this the fossils of the Mesosaurus have been found in both regions because at one point in time, those regions were a part of the same landmass. 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)
The time period that represents when the majority of Mesosaurus fossils were found is the Permian period. During this time modern day continents South America and Africa were a part of a supercontinents called Pangea. Over time as Pangea split this resulted in the change of the positions of the fossils causing them to be further apart from one another. 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 Glossopteris fossils are found on multiple different continents. Specifically, continents such as Africa, Australia, Antarctica, and South America. Some specific countries in which the fossils were found include South Africa, Madagascar, Zimbabwe, Mozambique, Argentina, Brazil, Uruguay, China and India. g.
In what ways is the distribution of Glossopteris
different from Lystrosaurus
? (1 pt)
One of the ways that the distribution of Glossopteris differs from that of Lystrosaurus is that the Glossopteris was a seed fern that existed during the Permian and Triassic periods. Due to this the distribution pattern reflects the widespread presence of Glossopteris as it dominated across its landmasses during those times. While the Lystrosaurus lived during the early Triassic period. In this time they would have primarily been found in regions that were a part of Pangaea, because of that when Pangaea broke up due to tectonic movement, this can explain the distribution. h.
Provide a well-reasoned explanation for there are so many more fossil occurrences of Glossopteris than Lystrosaurus
. (1 pt) An explanation for why there are so many more fossil occurrences of Glossopteris than Lystrosaurus could be explained by the fact that it is much easier for a plant to reproduce and spread compared to a reptile. Plants tend to reproduce in larger numbers and cover a widespread area such as wetlands and forests. In contrast, the reproduction of reptiles is dependent on a lot more. Such as, the amount of food available and the ability to find and maintain a habitat. 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)
The distribution of these three organisms from the Permian and Triassic period periods provide compelling evidence that supports the hypothesis that continents that are distant in modern day, were once consolidated into a supercontinent called Pangea. The distribution for the Lystrosaurus fossil shows it was found in regions that are now geographically distant and widely separated by oceans. This can also similarly be said for the Mesosaurus as its fossils have been found in regions that are now separated by large expanses of water. The distribution of these fossil patterns may suggest that these organisms were once able to inhabit areas that now are currently separated by vast distances. Regarding the distribution of the glossopteris, evidence indicates that it was widespread across the southern continents of Gondwana, including South America, Africa, Antarctica, India, and Australia, during the Permian and Triassic periods. The similarity of Glossopteris across these distant regions also strongly suggest that at one point in time these landmasses were connected together.
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 Tyrannosaurus and the Hadrosaurus fossils are distributed within the same areas being found in North America and Asia. Specifically, what is now the western part of the United States and Canada. While the Spinosaurus and the Carcharodontosaurus are primarily found in Africa, but also in South America. They are found within the modern-day countries of Morocco, Tunisia, Algeria, 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 during the Cretaceous period may explain the distribution of each these genera and plays a significant role in it. During the Cretaceous period geographic barriers and geographic distance between landmasses as seen in the images, influenced the distribution patterns of each genus. Another way the position of the continents may explain the distribution is the presence of suitable habitats and favorable environmental conditions in the western interior of North America. 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 **** **** Hadrosaurus **** **** Spinosaurus **** **** Carcharodontosaurus **** ****
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 data I collected during the lab regarding the Tyrannosaurs, Hadrosaurus, Spinosaurus, and Carcharodontosaurus does support the hypothesis that the modern continents were joined in Pangaea during the Late Paleozoic but largely separated in Mesozoic. There are multiple examples of clear evidence within this lab to support this hypothesis. To begin with both the fossils of the Tyrannosaurus and the Hadrosaurus have been discovered in North America. The presence of both of these fossils in North America during the Cretaceous implies that this region was once part of a larger landmass and would have connected to other continents within Pangea forming this supercontinent during the Late Paleozoic. Another large piece of evidence is that the fossils of the Spinosaurus were found in North Africa and some fossils on South America. The distribution of these fossils also supports the idea that the continents were once a part of a super continent during the Late Paleozoic. With that, fossils of the Carcharodontosaurus were also found on the continent of modern-day Africa and South America. This implies that during the Late Paleozoic this region was connected to one another to form a large land mass, that being Pangaea. The finding of the fossils of the same genera on different modern-day continents supports the idea of continental drift. Therefore distribution of all of these genera supports the hypothesis that the modern day continents were joined in Pangaea during the Late Paleozoic. Paste your Cretaceous Dinosaur maps here
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