Index Fossils: Clues to Earth's Past
Explore index fossils, their characteristics, and how scientists use them to understand Earth's geological history and relative dating.
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Index Fossils: Clues to Earth's Past
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Read each question carefully and answer to the best of your ability. Use complete sentences for short answer questions.
1. What is the primary characteristic of an index fossil?
It is very large and easy to find.
It lived for a long period of Earth's history.
It existed for a short period and was widespread geographically.
It is always found in deep ocean sediments.
2. Why are index fossils important for relative dating?
They tell us the exact age of a rock.
They help compare the ages of different rock layers.
They are only found in igneous rocks.
They are always perfectly preserved.
3. An index fossil must have lived for a period of time and been geographically .
4. The process of determining whether one event or object is older or younger than another is called dating.
5. A fossil that is found in only one small area of the world can be a good index fossil.
True
False
6. Scientists use index fossils to match the ages of rock layers from different locations.
True
False
7. Look at the image below. Imagine this fossil was found in a rock layer. What information might this fossil provide about the age of the rock layer?
8. Name two examples of organisms that are often considered good index fossils and explain why.