Unit E Lesson E15 Figuring Out Fossils
Completion requirements
Lesson E15: Figuring Out Fossils
Video Lesson
Fossils are incredibly important. They help us learn about Earth in the past, and they allow us to understand better what is happening now and what might happen in the future. Working with fossils requires much patience, but the rewards of diligence can
be amazing.
Lesson E15: Figuring Out Fossils
Fossil Puzzles
Every fossil presents a challenge for recovery and display. Many fossils are found by accident or by sheer luck. The hard work begins when the paleontologists begin the recovery process, and it continues as they and their teams work to assemble the fossil and understand how it represented the organism, the time, and the location.
Every fossil presents a challenge for recovery and display. Many fossils are found by accident or by sheer luck. The hard work begins when the paleontologists begin the recovery process, and it continues as they and their teams work to assemble the fossil and understand how it represented the organism, the time, and the location.
Reading and Materials for This Lesson
Science in Action 7
Materials:
Science in Action 7
Reading: Pages 415-418
Materials:
scissors
Figure E.4.15.1 – Some very delicate work is required to free some fossils from the rock in which they are found. Sometimes even more work is required to stabilize the fossil.
Figure E.4.15.2 – The study of fossils includes making inferences about how the organisms lived and how the fossils can be displayed to reflect the lives of the organisms.
Fossil Reconstruction
Perhaps you have put together big jigsaw puzzles. Try mixing the pieces of two puzzles and then constructing the pictures. That would be difficult!
Imagine you have the task of putting together the pieces of 10 000 jigsaw puzzles that have been scattered and hidden all over the world – and you do not know how many pieces are in each puzzle! Often, the pieces are buried deeply, and they may be broken or incomplete when you find them. This is what it is like when paleontologists find fossils and try to make sense of what they have found. Their secret weapon, however, is that they all work together. These fossil scientists share their findings and write about their theories, allowing others to read, comment, and learn.
The first step when a fossil has been transported safely to a technician in a paleontology lab is to free it safely from the rock in which it is found. If the rock is soft such as sandstone, it can be chipped carefully from the fossil. Rock such as limestone, however, may require chemicals to separate it from the fossil. Before, during, and after the removal process, the technician may use glues and cements to try to hold the fossil together. Sometimes, the rock around the fossil is the only thing holding the fossil together.
Every fossil found is measured, catalogued, and photographed very carefully. All this information is added to the fossil record so that it can be compared to other fossils. When a technician starts working on a new fossil, his or her main goal is to try to identify the organism. This is done with the help of the fossil record. If the technician’s observations match those of a previous fossil find, the technician can identify the organism. If the fossil does not match anything found before, this may be an exciting new discovery!
Imagine you have the task of putting together the pieces of 10 000 jigsaw puzzles that have been scattered and hidden all over the world – and you do not know how many pieces are in each puzzle! Often, the pieces are buried deeply, and they may be broken or incomplete when you find them. This is what it is like when paleontologists find fossils and try to make sense of what they have found. Their secret weapon, however, is that they all work together. These fossil scientists share their findings and write about their theories, allowing others to read, comment, and learn.
The first step when a fossil has been transported safely to a technician in a paleontology lab is to free it safely from the rock in which it is found. If the rock is soft such as sandstone, it can be chipped carefully from the fossil. Rock such as limestone, however, may require chemicals to separate it from the fossil. Before, during, and after the removal process, the technician may use glues and cements to try to hold the fossil together. Sometimes, the rock around the fossil is the only thing holding the fossil together.
Every fossil found is measured, catalogued, and photographed very carefully. All this information is added to the fossil record so that it can be compared to other fossils. When a technician starts working on a new fossil, his or her main goal is to try to identify the organism. This is done with the help of the fossil record. If the technician’s observations match those of a previous fossil find, the technician can identify the organism. If the fossil does not match anything found before, this may be an exciting new discovery!
Figure E.4.15.3 – Very rarely do fossils show a relationship between two organisms. This fossil shows an ancient fish capturing a flying reptile. Image by
Eberhard Frey and Helmut Tischlinger.
Figure E.4.15.4 – As paleontologists learn more and share their knowledge, they can make some incredible models of ancient life.
When the fossil has been identified and catalogued for scientific purposes, it may be prepared for display. This is true especially for fossils such as those found at the Royal Tyrrell Museum in Drumheller or the Philip J. Currie Dinosaur Museum near
Grande Prairie. The fossil may be displayed as it was found, perhaps embedded in a sedimentary rock such as with many sea fossils such as trilobites. But, if the fossil is to be presented in a lifelike display, it must be prepared to represent what
it looked like when it was alive. Because we know very little about the soft parts of many organisms, this can be tricky.
This is where the very important link between paleontology and biology occurs. There are many similarities between fossilized organisms and those alive today. Most animals with backbones, for example, always have a basic design of how their bodies are put together. Biologists learn the relationships between bones and muscles and animal movement.. The same rules can be applied to fossilized animals because their skeletons follow the same basic rules.
This is where the very important link between paleontology and biology occurs. There are many similarities between fossilized organisms and those alive today. Most animals with backbones, for example, always have a basic design of how their bodies are put together. Biologists learn the relationships between bones and muscles and animal movement.. The same rules can be applied to fossilized animals because their skeletons follow the same basic rules.
All this information is used in the finished model of the fossilized organism. Many displays are modelled first on a computer so that materials are not wasted when the museum piece is made. Often, the model is placed beside other fossils that have lived
in the same place and time as the fossil. All these parts are put together in ways to show an ancient ecosystem from Earth’s past. This includes the amazing displays of fossils in our excellent Alberta museums.
Try It!
Fossil Reconstruction
Try this simple model of fossil reconstruction. What seems to be an impossible puzzle at first becomes easier if you have access to helpful information and the work of other paleontologists.
In 1812, Samuel Thomas von Soemmering was the first paleontologist to reconstruct successfully a certain type of fossilized creature. You will follow in his footsteps and attempt to discover the type of organism his work helped to understand better.
Materials:
Try this simple model of fossil reconstruction. What seems to be an impossible puzzle at first becomes easier if you have access to helpful information and the work of other paleontologists.
In 1812, Samuel Thomas von Soemmering was the first paleontologist to reconstruct successfully a certain type of fossilized creature. You will follow in his footsteps and attempt to discover the type of organism his work helped to understand better.
Materials:
-
DOWNLOAD this document. Worksheet #1 – Random Fossilized Remains
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Scissors
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DOWNLOAD this document. Worksheet #2 – Fossil Reconstruction (worksheet #2 is at the end of this document)
Safety Warning
Take care with scissors; don't cut yourself or anyone else!
Instructions:
1. Print Worksheet #1 - Random Fossilized Remains. Cut out the fossil pieces on the page carefully.
2. Try placing together as many of the pieces as you can without using any hints or doing any further research. Note which pieces you work with the most.
3. When you have tried your best to put the pieces together, flip to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences about the fossils and the organism to which they belong.
5. Go back to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences based on your first hint.
7. Return to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences based on this second hint.
9. Return to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences based on this third hint.
10. Consider Hint 4. Your team discovers some trace fossils near the original site of your fossil. The tracks match your fossil’s front and back feet; the creature seems to have walked on all fours. Make additional notes or sketches on your previous guess.
1. Print Worksheet #1 - Random Fossilized Remains. Cut out the fossil pieces on the page carefully.
2. Try placing together as many of the pieces as you can without using any hints or doing any further research. Note which pieces you work with the most.
3. When you have tried your best to put the pieces together, flip to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences about the fossils and the organism to which they belong.
5. Go back to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences based on your first hint.
7. Return to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences based on this second hint.
9. Return to Worksheet #2 - Observations and Inferences. Make a short list of observations and inferences based on this third hint.
10. Consider Hint 4. Your team discovers some trace fossils near the original site of your fossil. The tracks match your fossil’s front and back feet; the creature seems to have walked on all fours. Make additional notes or sketches on your previous guess.
Questions:
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
Think about the following questions very carefully. Then, type or write your answers. After you have your answers, click the questions for feedback.
The most difficult step probably was the first. There was no way to know where many of the body part fossils belonged.
Seeing a complete specimen that was similar probably helped the most. When you can see how the parts fit together, you can make inferences about what the creature was actually like.
This is a fossil of a Pterosaur, a huge flying reptile that ran along the ground when necessary.
Figure E.4.15.6 – Information about where a fossil is found can be vital to understanding as much as possible about its past. This is a photo from Kangaroo Island, Australia. Photo by
UNE Photos.
Figure E.4.15.8 – The white layer of rock at the top of the ridge was discovered to hold some excellent fossils.
Figure E.4.15.8 – Many fossils were found, including skeletons that were almost completely intact.. Photo by
Carl Malamud.
Fossil Interpretation
If treated with a careful scientific approach, every fossil found can help us learn something new or help support current ideas. Therefore it is very important to take note of the rock layer the fossil is found in. Its precise location must be recorded. If the fossil has been moved by erosion or some other means, that must be noted as well. Fossil reconstruction involves similar techniques to criminal investigation and the forensics tests used to help understand the who, what, where, when, and how of crime scenes.
How paleontologists piece together the clues they find in the fossils has no particular order, but following is a possible list of steps.
Figure E.4.15.8 – The light-coloured sedimentary rock turned out to be an ashfall from the eruption of a nearby volcano.
1. Where was the fossil found?
The location of the fossil can tell a paleontologist what the organism probably was or was not. For example, if a fossilized fern frond is found near Rocky Mountain House, it would likely not be closely related to fern fronds found in Africa. However, it might be related to fern fossils from British Columbia. Studying fossils for nearest relations in different locations helped form the idea of continental drift.
2. In which layer of rock was the fossil found?
This is a very important aspect of finding fossils. Paleontologists and geologists are experts at identifying, aging, and matching layers of sedimentary rock all over the world. When a fossil is found still encased in rock, the rock layer often reveals the age of the fossil. Geological columns are recognizable collections of sedimentary layers located throughout a large area. Alberta consists of many layers of sedimentary rock similar to a layer cake that extend across most of the province. Glaciers and rivers have eroded channels in the layers and the Rocky Mountains have pushed up one side of the layers, but most of the same layers are found throughout the province.
The location of the fossil can tell a paleontologist what the organism probably was or was not. For example, if a fossilized fern frond is found near Rocky Mountain House, it would likely not be closely related to fern fronds found in Africa. However, it might be related to fern fossils from British Columbia. Studying fossils for nearest relations in different locations helped form the idea of continental drift.
2. In which layer of rock was the fossil found?
This is a very important aspect of finding fossils. Paleontologists and geologists are experts at identifying, aging, and matching layers of sedimentary rock all over the world. When a fossil is found still encased in rock, the rock layer often reveals the age of the fossil. Geological columns are recognizable collections of sedimentary layers located throughout a large area. Alberta consists of many layers of sedimentary rock similar to a layer cake that extend across most of the province. Glaciers and rivers have eroded channels in the layers and the Rocky Mountains have pushed up one side of the layers, but most of the same layers are found throughout the province.
Figure E.4.15.9 – When a fossil was uncovered enough it would be identified to help the scientists freeing it from its rocky covering.
If two fossils are found in the same layer of the same geological column, they must be similar age. In places such as
Horseshoe
Canyon near Drumheller, many layers of the geological column are exposed in one place.
3. From whom does the fossil come?
Paleontologists keep track of their work. They can identify an unknown fossil by comparing it to other fossils. They can determine how closely related two fossils are by how similar they appear. Such information is used when the fossils are put together to resemble the organism. Many inferences are made from what is observed, but very strong evidence must be available before decisions are made about the evidence. Surprise can occur! For example, recent discoveries in China have led paleontologists to conclude that many dinosaurs had feathers. When this was agreed upon, many other dinosaurs related to those that were found with feathers had to be reviewed to decide if they would have had feathers, also.
3. From whom does the fossil come?
Paleontologists keep track of their work. They can identify an unknown fossil by comparing it to other fossils. They can determine how closely related two fossils are by how similar they appear. Such information is used when the fossils are put together to resemble the organism. Many inferences are made from what is observed, but very strong evidence must be available before decisions are made about the evidence. Surprise can occur! For example, recent discoveries in China have led paleontologists to conclude that many dinosaurs had feathers. When this was agreed upon, many other dinosaurs related to those that were found with feathers had to be reviewed to decide if they would have had feathers, also.
Figure E.4.15.10 – The baby rhino fossil, labeled #1 in the photo, was found right beside the fossil of a 3-toed horse, labeled #2.
4. What happened to the organism from which the fossil came?
We have learned about many major events in Earth’s past by comparing fossils with the materials found in the layers of rock in which the fossils are found. This is true especially of events such as major extinctions and mountain building events.
5. What did the organism look like?
This can be very tricky because usually only the hard parts of the organism appear as fossils. Skin, feathers, fur, muscles, and other soft parts very rarely are found as fossils. Trace fossils and the rare feather, skin, or fur sample can help, but paleontologists compare their fossil finds to living things on Earth today because characteristics are passed from one generation to the next. For example, dinosaur fossils that show the presence of feathers are understood better when they are compared to modern birds that show feathers are used.
We have learned about many major events in Earth’s past by comparing fossils with the materials found in the layers of rock in which the fossils are found. This is true especially of events such as major extinctions and mountain building events.
5. What did the organism look like?
This can be very tricky because usually only the hard parts of the organism appear as fossils. Skin, feathers, fur, muscles, and other soft parts very rarely are found as fossils. Trace fossils and the rare feather, skin, or fur sample can help, but paleontologists compare their fossil finds to living things on Earth today because characteristics are passed from one generation to the next. For example, dinosaur fossils that show the presence of feathers are understood better when they are compared to modern birds that show feathers are used.
Figure E.4.15.11 – If the fossil preservation and recovery go well, a museum, gallery, or collector might assemble an anatomical representation. Photo by
Dallas Krentzel.
Figure E.4.15.11 – The baby rhino can be drawn from its reassembled skeleton, as well as knowledge of the other plants and animals that likely lived in the area at that time.
Watch More
Fossil Stories - Leptoceratops
Sometimes, the fit of the puzzle pieces makes fossil reconstruction difficult.
Jaw muscles attach directly to skulls for chewing, but the same is not true for legs and arms. To make things even more complicated, dinosaurs such as Leptoceratops had arms and legs quite similar to today’s crocodiles and alligators. Those animals move very awkwardly on land.
Did Leptoceratops move like this as well? Now that you know more about fossil reconstruction, watch the following two videos, and make your own decision about how you think Leptoceratops walked.
Sometimes, the fit of the puzzle pieces makes fossil reconstruction difficult.
Jaw muscles attach directly to skulls for chewing, but the same is not true for legs and arms. To make things even more complicated, dinosaurs such as Leptoceratops had arms and legs quite similar to today’s crocodiles and alligators. Those animals move very awkwardly on land.
Did Leptoceratops move like this as well? Now that you know more about fossil reconstruction, watch the following two videos, and make your own decision about how you think Leptoceratops walked.
Figure E.4.15.13 – Tyrannosaurus rex is probably the most famous dinosaur ever discovered.
Figure E.4.15.14 – Giganotosaurus was a huge carnivorous dinosaur that lived in South America.
Fossil Stories - Tyrannosaurus vs. Giganotosaurus
If you looked at the fossils of Tyrannosaurus and Giganotosaurus side by side, you might think they were from the same species of dinosaur, or at least a very close relative. Both dinosaurs were about 3 metres tall, had large heads, and walked on their hind legs.
However, when paleontologists looked more closely at both sets of fossils, some clear differences could be seen. Giganotosaurus had very different teeth than Tyrannosaurus had. Based on where the Giganotosaurus jaw muscles attached to the skull, Giganotosaurus appears to have had a much weaker bite than Tyrannosaurus had. After having watched the video above, do you agree that Giganotosaurus had a weaker bite than Tyrannosaurus?
If you looked at the fossils of Tyrannosaurus and Giganotosaurus side by side, you might think they were from the same species of dinosaur, or at least a very close relative. Both dinosaurs were about 3 metres tall, had large heads, and walked on their hind legs.
However, when paleontologists looked more closely at both sets of fossils, some clear differences could be seen. Giganotosaurus had very different teeth than Tyrannosaurus had. Based on where the Giganotosaurus jaw muscles attached to the skull, Giganotosaurus appears to have had a much weaker bite than Tyrannosaurus had. After having watched the video above, do you agree that Giganotosaurus had a weaker bite than Tyrannosaurus?
Fossil Stories - Gar Pike
Paleontologists get very excited when the can match ancient fossils to currently living species.. Species such as this are referred to as ‘living fossils’. This is the case with gar pike, a group of long-nosed fish that are alive today throughout western North America, and whose 60 million-year-old fossils have been found in the same area!
Gar pike scales have been found as artifacts used by some First Nations as arrowheads. When paleontologists find ancient fossils such as the gar pike, they have a convenient model that they can study in the wild right now. Watch the following video about an amazing gar pike fossil find and ask yourself, what special things can ‘living fossils’ teach us?
Paleontologists get very excited when the can match ancient fossils to currently living species.. Species such as this are referred to as ‘living fossils’. This is the case with gar pike, a group of long-nosed fish that are alive today throughout western North America, and whose 60 million-year-old fossils have been found in the same area!
Gar pike scales have been found as artifacts used by some First Nations as arrowheads. When paleontologists find ancient fossils such as the gar pike, they have a convenient model that they can study in the wild right now. Watch the following video about an amazing gar pike fossil find and ask yourself, what special things can ‘living fossils’ teach us?
Figure E.4.15.15 – The Gar Pike is a living fossil.
Make sure you have understood everything in this lesson. Use the Self-Check below, and the Self-Check & Lesson Review Tips to
guide your learning.
Unit E Lesson 15 Self-Check
Instructions
Complete the following 6 steps.
Don't skip steps – if you do them in order, you will confirm your
understanding of this lesson and create a study bank for the future.
- DOWNLOAD the self-check quiz by clicking here.
- ANSWER all the questions on the downloaded quiz in the spaces provided. Think carefully before typing your answers. Review this lesson if you need to. Save your quiz when you are done.
- COMPARE your answers with the suggested "Self-Check Quiz Answers" below. WAIT! You didn't skip step 2, did you? It's very important to carefully write out your own answers before checking the suggested answers.
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REVISE your quiz answers if you need to. If you answered all the questions correctly, you can skip this step. Revise means to change, fix, and add extra notes if you need to. This quiz is NOT FOR MARKS, so it is perfectly OK to correct
any mistakes you made. This will make your self-check quiz an excellent study tool you can use later.
- SAVE your quiz to a folder on your computer, or to your Private Files. That way you will know where it is for later studying.
- CHECK with your teacher if you need to. If after completing all these steps you are still not sure about the questions or your answers, you should ask for more feedback from your teacher. To do this, post in the Course Questions Forum, or send your teacher an email. In either case, attach your completed quiz and ask; "Can you look at this quiz and give me some feedback please?" They will be happy to help you!
Self-Check Time!
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Self-Check Quiz Answers
Click each of the suggested answers below, and carefully compare your answers to the suggested answers.
If you have not done the quiz yet – STOP – and go back to step 1 above. Do not look at the answers without first trying the questions.
This is a fossil of a bat. Bats are not very large and tend to live in warm, humid areas that have many insects. Because they do not normally live (and die) near shallow bodies of water, their fossils are quite rare.
The femur is actually from a Megalosaurus, a large carnivorous dinosaur that lived in southern England 165 million years ago. Scientists of 400 years ago had no idea that life had existed for so long or that huge animals had roamed
Earth before humans lived here. When they found the huge Megalosaurus femur, they compared it to a type of femur that it resembled -- that of a human being.
Anomalocaris lived on Earth 500 million years ago. It was a very confusing fossil find because it has very distinct body parts that rarely are found together as a whole fossilized animal. The Burgess Shale is a unique fossil location because
it is very old and has many fossils that include soft body parts. This helps paleontologists better observe what ancient forms of life looked like.
‘Living fossils’ are species alive on Earth today that have apparently been on Earth for a very long time because they are the only close relations to some ancient species discovered by their fossils. A species such as the aardvark has no other
closely related species on Earth, and the few relatives it does have appear as 30-million-year-old fossils.
The closest living relatives of birds today are the crocodile and alligator. Their common link is the dinosaurs, to which both are related directly. The only dinosaurs to survive the great extinction of 65 million years ago were the crocodiles
and the birds. Fascinating!