Identifying Index Fossils Activity PDF by The Common Core and More - Free Printable
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Step-by-step solution for: Identifying Index Fossils Activity PDF by The Common Core and More
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Show Answer Key & Explanations
Step-by-step solution for: Identifying Index Fossils Activity PDF by The Common Core and More
To solve the problem of determining which fossil would be a good index fossil, we need to analyze the provided diagram and answer the questions step by step. Let's break it down:
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An index fossil is a fossil that is used to identify and date the rock layers (strata) in which it is found. To qualify as an index fossil, a fossil must meet the following criteria:
1. Widespread: The organism must have been distributed over a large geographic area.
2. Short-lived: The organism must have existed for a relatively short period of geological time.
3. Abundant: The fossil should be easily identifiable and abundant in the rock record.
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The diagram shows four columns (Samples A, B, C, D) and four rows (Row 1, Row 2, Row 3, Row 4). Each cell contains a symbol representing a fossil or its absence. We need to evaluate the fossils based on the criteria mentioned above.
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#### a. Which fossils are widespread?
A fossil is considered widespread if it appears in multiple samples (columns) across the same row. Let's examine each row:
- Row 1: The symbol appears in all four samples (A, B, C, D). This indicates it is widespread.
- Row 2: The symbol appears only in Samples A and B. This is not widespread.
- Row 3: The symbol appears only in Samples B and C. This is not widespread.
- Row 4: The symbol appears only in Sample D. This is not widespread.
Answer: Circle the fossils in Row 1.
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#### b. Which fossils are short-lived?
A fossil is considered short-lived if it appears in only one row. Let's check each sample:
- Sample A: The symbol appears in Rows 1 and 2. Not short-lived.
- Sample B: The symbol appears in Rows 1, 2, and 3. Not short-lived.
- Sample C: The symbol appears in Rows 1 and 3. Not short-lived.
- Sample D: The symbol appears in Rows 1 and 4. Not short-lived.
None of the fossils appear in only one row. However, the question asks us to mark them with an "X." Since none fit this criterion perfectly, we can infer that the fossils in Row 4 (appearing only in Sample D) are the closest to being short-lived.
Answer: Place an "X" on the fossils in Row 4.
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#### c. Which fossil(s) are seen in only one row in each sample?
We need to identify fossils that appear in only one row within each sample. Let's check each sample:
- Sample A: The symbol appears in Rows 1 and 2. Not unique to one row.
- Sample B: The symbol appears in Rows 1, 2, and 3. Not unique to one row.
- Sample C: The symbol appears in Rows 1 and 3. Not unique to one row.
- Sample D: The symbol appears in Rows 1 and 4. Not unique to one row.
None of the fossils meet this exact criterion. However, the fossils in Row 4 (appearing only in Sample D) are the closest to being unique to one row.
Answer: Highlight the fossils in Row 4.
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#### d. Which fossil (s) is a good index fossil? Explain why.
To determine the best index fossil, we need to find a fossil that is both widespread and short-lived. Based on our analysis:
- Row 1: Widespread (appears in all samples) but not short-lived (appears in multiple rows).
- Row 4: Short-lived (appears in only one sample) but not widespread (appears in only one sample).
Neither row perfectly fits all criteria, but Row 1 is the closest to being a good index fossil because it is widespread. While it is not short-lived, it is the most geographically extensive fossil shown.
Answer: The fossils in Row 1 are the best candidates for index fossils because they are widespread. However, no fossil in the diagram perfectly meets all the criteria for an ideal index fossil.
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\[
\boxed{\text{Row 1}}
\]
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Step 1: Understand the Concept of Index Fossils
An index fossil is a fossil that is used to identify and date the rock layers (strata) in which it is found. To qualify as an index fossil, a fossil must meet the following criteria:
1. Widespread: The organism must have been distributed over a large geographic area.
2. Short-lived: The organism must have existed for a relatively short period of geological time.
3. Abundant: The fossil should be easily identifiable and abundant in the rock record.
---
Step 2: Analyze the Diagram
The diagram shows four columns (Samples A, B, C, D) and four rows (Row 1, Row 2, Row 3, Row 4). Each cell contains a symbol representing a fossil or its absence. We need to evaluate the fossils based on the criteria mentioned above.
---
Step 3: Answer the Questions
#### a. Which fossils are widespread?
A fossil is considered widespread if it appears in multiple samples (columns) across the same row. Let's examine each row:
- Row 1: The symbol appears in all four samples (A, B, C, D). This indicates it is widespread.
- Row 2: The symbol appears only in Samples A and B. This is not widespread.
- Row 3: The symbol appears only in Samples B and C. This is not widespread.
- Row 4: The symbol appears only in Sample D. This is not widespread.
Answer: Circle the fossils in Row 1.
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#### b. Which fossils are short-lived?
A fossil is considered short-lived if it appears in only one row. Let's check each sample:
- Sample A: The symbol appears in Rows 1 and 2. Not short-lived.
- Sample B: The symbol appears in Rows 1, 2, and 3. Not short-lived.
- Sample C: The symbol appears in Rows 1 and 3. Not short-lived.
- Sample D: The symbol appears in Rows 1 and 4. Not short-lived.
None of the fossils appear in only one row. However, the question asks us to mark them with an "X." Since none fit this criterion perfectly, we can infer that the fossils in Row 4 (appearing only in Sample D) are the closest to being short-lived.
Answer: Place an "X" on the fossils in Row 4.
---
#### c. Which fossil(s) are seen in only one row in each sample?
We need to identify fossils that appear in only one row within each sample. Let's check each sample:
- Sample A: The symbol appears in Rows 1 and 2. Not unique to one row.
- Sample B: The symbol appears in Rows 1, 2, and 3. Not unique to one row.
- Sample C: The symbol appears in Rows 1 and 3. Not unique to one row.
- Sample D: The symbol appears in Rows 1 and 4. Not unique to one row.
None of the fossils meet this exact criterion. However, the fossils in Row 4 (appearing only in Sample D) are the closest to being unique to one row.
Answer: Highlight the fossils in Row 4.
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#### d. Which fossil (s) is a good index fossil? Explain why.
To determine the best index fossil, we need to find a fossil that is both widespread and short-lived. Based on our analysis:
- Row 1: Widespread (appears in all samples) but not short-lived (appears in multiple rows).
- Row 4: Short-lived (appears in only one sample) but not widespread (appears in only one sample).
Neither row perfectly fits all criteria, but Row 1 is the closest to being a good index fossil because it is widespread. While it is not short-lived, it is the most geographically extensive fossil shown.
Answer: The fossils in Row 1 are the best candidates for index fossils because they are widespread. However, no fossil in the diagram perfectly meets all the criteria for an ideal index fossil.
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Final Answer
\[
\boxed{\text{Row 1}}
\]
Parent Tip: Review the logic above to help your child master the concept of index fossils worksheet.
