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 GrandProton748
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 catalog 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)
These fossils were found in India, China, South Africa, & Russia.
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 Lystrosaurus mostly lived 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)
Now the fossils are a lot closer to each other, most of them are in the south with a few
in the north. There is no water separating the continents in Pangea.
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 were found in south western Africa and south eastern part of South
America.
b.
In what ways is the distribution of
Mesosaurus
different from
Lystrosaurus
?
(1 pt)
Mesosaurus was found in only a few places, mainly in what's now southern/eastern
South America and western/southern Africa. On the other hand, Lystrosaurus was
found in more places around the world, like South Africa, Russia, India, and China. This
shows that Lystrosaurus lived in more areas globally than Mesosaurus.
c.
Given the different ecologies of
Mesosaurus
and
Lystrosaurus,
provide a well-reasoned
explanation for why their distributions are different.
(1 pt)
The reason Mesosaurus and Lystrosaurus lived in different places is because they
adapted to different environments. Mesosaurus adapted to water and the lystoaurus
adapted to land. Also, the geological changes during their time periods and the
movement of continents played a role, along with changes in climate and sea levels.
d.
How do you think this animal might have gotten distributed in this pattern?
(1 pt)
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)
Mesosaurus likely lived in the shallow waters of Pangea, which today includes parts of
South America and western Africa. As Pangea started to break apart because of
continental drift, the landmasses moved away from each other. This split what's now
South America and western Africa. Fossils of Mesosaurus have been found in both
regions because they were once joined together before continental drift separated
them.
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)
The fossils of the Glossopteris were found in various continents/countries such as
South America, India, Australia, and Antarctica.
g.
In what ways is the distribution of
Glossopteris
different from
Lystrosaurus
?
(1 pt)
The distribution of these two organisms differ a lot because one is a plant genus and
one is a reptile genus. The plant lived in the Permian period and the reptile lived through both
the permian and triassic periods.
h.
Provide a well-reasoned explanation for there are so many more fossil occurrences of
Glossopteris than
Lystrosaurus
.
(1 pt)
A plant such as the Glossopteris could have spread easily and more plentiful through
forests and other land while a reptile like the Lystrosaurus’s ability to reproduce was
more limited by the availability of food and a suitable environment.
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 fact that Glossopteris, Lystrosaurus, and Mesosaurus are found on continents that are now
far apart supports the theory of continental drift and the existence of a large combination of
continents called Pangaea. This suggests that these continents were once connected as larger
landmasses before separating over a lot of time.
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 are mostly found in North America, especially in the
western United States and Canada, as well as in Asia. Meanwhile, fossils of Spinosaurus and
Carcharodontosaurus are primarily discovered in North Africa, specifically in what is now
Morocco, Tunisia, Algeria, and Egypt. These species are exclusive to North Africa and haven't
been found in any other regions.
13.
Examine each genus individually on the Cretaceous paleogeographic map. How might the
position of the continents explain the distribution of each of these genera?
(2 pts)
The positions of the continents during the cretaceous period definitely influenced how these
species were distributed. Factors such as geographic barriers, availability of suitable habitats,
and the distances between landmasses affected where these genera could be found.
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)
The evidence about Tyrannosaurs, Hadrosaurus, Spinosaurus, and Carcharodontosaurus supports the
idea that today's continents were once part of Pangaea during the Later part of the Paleozoic era but
split apart during the Mesozoic era. This is because the Tyrannosaur fossils were mainly found in North
America, meaning it might have been part of a larger landmass connected to other continents in
Pangaea. Hadrosaurus fossils in the United States and Canada also suggest North America was part of
Pangaea. Spinosaurus and Carcharodontosaurus fossils in North Africa show it was connected to other
landmasses in Pangaea too. The distribution of these fossils on now-separated continents supports the
theory of continental drift.
Genus
N.
America
S.
America
Asia
Europe
Africa
Australia
Antarctica
Tyrannosaurs
X
X
Hadrosaurus
X
X
Spinosaurus
X
Carcharodontosaurus
X
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Paste your Cretaceous Dinosaur maps here