Unit E Section 4 Introduction Fossil Evidence Provides Clues to Changes in the Earth
Completion requirements
Section 4: Fossil evidence provides many clues about how the Earth has changed.
Unit E: Section 4 - Introduction
Figure E.S.4.1 – The erosion of sedimentary rock, such as seen in the Badlands, reveals fossils and layers of sediment deposited over long periods.
Figure E.S.4.2 – Fossils and the rocks in which they are found can help paleontologists learn about Earth’s history and what life was like at that time.
The Geologic History of Earth and the Fossil Record
Imagine the amazingly complicated puzzle that is Earth’s history. Not only is that history billions of years of change, but the clues and evidence that are necessary to complete the puzzle are, at best, difficult to find and tricky to interpret.
Scientists are eager to learn about the past, because it helps to explain what exists today. For example, you can learn about an animal by observing it in the wild, but much more can be learned if you understands how the ancestors of the animal lived.
The study of Earth’s geologic history overlaps with the study of ancient forms of life. Scientists have developed a timeline of Earth’s history called the Geologic Time Scale that places Earth’s geologic changes and the changing forms of life on one convenient scale. How life has changed over thousands and millions of years is closely connected with changes to Earth’s geology. Fossil clues often are found in rocks. Extinctions often are tied to geologic events. Earth and the forms of life found on our planet always will be related closely to each other.
Scientists are eager to learn about the past, because it helps to explain what exists today. For example, you can learn about an animal by observing it in the wild, but much more can be learned if you understands how the ancestors of the animal lived.
The study of Earth’s geologic history overlaps with the study of ancient forms of life. Scientists have developed a timeline of Earth’s history called the Geologic Time Scale that places Earth’s geologic changes and the changing forms of life on one convenient scale. How life has changed over thousands and millions of years is closely connected with changes to Earth’s geology. Fossil clues often are found in rocks. Extinctions often are tied to geologic events. Earth and the forms of life found on our planet always will be related closely to each other.
Figure E.S.4.3 – The more we learn about Earth’s past, the more accurately we can predict what life was like then and conditions that existed before, during, and after that time.
Words to Think About:
Check out the word cloud below. It pictures the important words that you are going to learn in this section. Watch for these words, and combinations of these words, as you read. When you see them highlighted, you can click on them to learn more about
what the word means.
You can also visit the course glossary and read definitions for all of these words.
Lessons in This Section
Lesson E14: How does paleontology help to understand geologic change?
Key Question – What is the relationship between ancient life and changes to Earth’s surface?
Lesson E15: Understanding Fossils
Key Question – How do paleontologists find, isolate, and study fossils?
Lesson E16: Case Study: Amazing Alberta Fossils
Key Question – What are some of the amazing fossils found in Alberta, and what do they tell us about the past?
Lesson E17: The Geologic Time Scale
Key Question – How have scientists organized events in Earth’s past?
Lesson E18: How do we know how old something is?
Key Question – What methods do scientists use to determine the age of something?
Reading and Materials for This Section
Science in Action 7
Reading: Pages 410-431
Materials Lists for Unit:
Think • Interpret • Decide
Observations and Inferences
Figure E.S.4.4 – In this illustration a ferocious Camptosaurus appears to have just noticed a Stegosaurus quietly grazing on plants near a watering hole.
Download:
DOWNLOAD this document. It provides spaces for you to write answers to the questions found later in this activity.
Instructions:
Science involves making observations and inferences. Observations are sights you see and make note of for later reference. Inferences are reasons, connections, and explanations based on your observations. Gravity is an excellent example. Things fall to the ground when you let go of them. This is an observation. Scientists make note of this, and they make inferences that explain what they saw. The theory of gravity is a very complicated explanation of why things fall to the ground.
Earth’s distant past is much more difficult to observe than gravity is. The challenge becomes even greater to make inferences that explain the observations we make when we find a fossil, or we use radioactive dating to determine the age of a rock, or we discover similar fossils on different continents.
Look at the image above of ancient swampland and the organisms that lived there. Examine each statement below, and in the blanks place O if the statement is an observation or I if it is an inference.
DOWNLOAD this document. It provides spaces for you to write answers to the questions found later in this activity.
Instructions:
Science involves making observations and inferences. Observations are sights you see and make note of for later reference. Inferences are reasons, connections, and explanations based on your observations. Gravity is an excellent example. Things fall to the ground when you let go of them. This is an observation. Scientists make note of this, and they make inferences that explain what they saw. The theory of gravity is a very complicated explanation of why things fall to the ground.
Earth’s distant past is much more difficult to observe than gravity is. The challenge becomes even greater to make inferences that explain the observations we make when we find a fossil, or we use radioactive dating to determine the age of a rock, or we discover similar fossils on different continents.
Look at the image above of ancient swampland and the organisms that lived there. Examine each statement below, and in the blanks place O if the statement is an observation or I if it is an inference.
_____ 1. The volcano is erupting.
_____ 2. The Camptosaurus is going to eat the Stegosaurus.
_____ 3. The Stegosaurus will run into the water to escape.
_____ 4. The Camptosaurus is leaving tracks.
_____ 5. The ground where the Camptosaurus is walking is wet.
_____ 6. Plants are growing in the water.
_____ 7. The Camptosaurus is going into the water to eat the plants.
_____ 8. A tree is growing next to the river.
_____ 9. The tree looks like a palm tree.
_____ 10. The climate is warm.
_____ 11. The Stegosaurus is eating the plant.
_____ 12. The Stegosaurus is a herbivore.
_____ 13. Bones from a dead animal are by the shore.
_____ 14. The Camptosaurus killed the animal.
_____ 15. Some more bones are in the water.
_____ 16. The Camptosaurus cannot swim and will drown.
_____ 17. Lava is flowing down the sides of the volcano.
_____ 18. The Camptosaurus has sharp teeth for eating meat.
After you have completed the blanks, ask yourself the following questions.
You see and experience observations. You make inferences based on what you see and experience.
Observations are certain; they have been observed and can be measured. Inferences, on the other hand, are ideas that help observations make sense, and connect observations and inferences.
Since there is no way to travel back in time to make observations of the past we have to make inferences based on the evidence that we find. Fossils, rocks, and other pieces of evidence are observed in order to make inferences about the past. It is also
very important to make observations about what is happening today. Inferences can then be made about similar processes that happened in the past.
__O__ 1. The volcano is erupting.
__ I __ 2. The camptosaurus is going to eat the stegosaurus.
__ I __ 3. The stegosaurus will run into the water to escape.
__O__ 4. The camptosaurus is leaving tracks.
__ I __ 5. The ground where the camptosaurus is walking is wet.
__O__ 6. Plants are growing in the water.
__ I __ 7. The camptosaurus is going into the water to eat the plants.
__O__ 8. A tree is growing next to the river.
__O__ 9. The tree looks like a palm tree.
__ I __ 10. The climate is warm.
__O__ 11. The stegosaurus is eating the plant.
__ I __ 12. The stegosaurus is an herbivore.
__O__ 13. Bones from a dead animal are by the shore.
__ I __ 14. The camptosaurus killed the animal.
__O__ 15. Some more bones are in the water.
__ I __ 16. The camptosaurus cannot swim and will drown.
__O__ 17. Lava is flowing down the sides of the volcano.
__O__ 18. The camptosaurus has sharp teeth for eating meat.
__ I __ 2. The camptosaurus is going to eat the stegosaurus.
__ I __ 3. The stegosaurus will run into the water to escape.
__O__ 4. The camptosaurus is leaving tracks.
__ I __ 5. The ground where the camptosaurus is walking is wet.
__O__ 6. Plants are growing in the water.
__ I __ 7. The camptosaurus is going into the water to eat the plants.
__O__ 8. A tree is growing next to the river.
__O__ 9. The tree looks like a palm tree.
__ I __ 10. The climate is warm.
__O__ 11. The stegosaurus is eating the plant.
__ I __ 12. The stegosaurus is an herbivore.
__O__ 13. Bones from a dead animal are by the shore.
__ I __ 14. The camptosaurus killed the animal.
__O__ 15. Some more bones are in the water.
__ I __ 16. The camptosaurus cannot swim and will drown.
__O__ 17. Lava is flowing down the sides of the volcano.
__O__ 18. The camptosaurus has sharp teeth for eating meat.
Do the answers match what you decided? If they don’t, you shouldn't worry about it! You will be learning much more about observations and inferences in this section.