Educational worksheet on fossil dating methods and horse evolution.
Fossils: Evidence for Evolution Worksheet showing a diagram of rock layers with fossils and a section on horse evolution.
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Step-by-step solution for: Fossil Evidence Of Evolution Worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Fossil Evidence Of Evolution Worksheet
Let's solve each question from the "Fossils: Evidence for Evolution Worksheet" step by step, using the information provided in the text and the diagram.
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Answer:
The two ways of finding the age of a fossil are:
- Relative dating
- Absolute dating
> *Explanation:* As stated in the passage, scientists use both relative and absolute dating methods to determine the age of fossils.
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Answer:
Relative dating determines the age of a fossil by its location in rock layers. Fossils found deeper in the ground are usually older than those found higher up. So, if a fossil is in layer 1, it is older than one in layer 6. This method helps scientists determine the sequence of events but not the exact age.
> *Explanation:* The diagram shows layers labeled 1 through 6, with layer 1 at the bottom (oldest) and layer 6 at the top (youngest). Relative dating uses this principle of superposition — that lower layers are older than upper ones.
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Answer:
Absolute dating determines the actual age of a fossil by measuring the amount of a radioactive element, such as carbon-14, in the fossil. Scientists use mathematical formulas to calculate how much time has passed based on the decay rate of the element.
> *Explanation:* The passage explains that by measuring carbon-14 levels and applying a formula, scientists can determine an actual number of years since the organism died.
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Answer:
Carbon-14 is important because it is a radioactive isotope that decays at a known rate. By measuring how much carbon-14 remains in a fossil, paleontologists can calculate how long ago the organism died. This allows them to determine the actual age of the fossil.
> *Explanation:* Carbon-14 dating is effective for organic materials up to about 50,000 years old. It’s crucial for determining precise ages in more recent fossil records.
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Answer:
Layer 1 is the oldest.
> *Explanation:* In the diagram, layer 1 is at the bottom of the rock strata. According to the principle of superposition used in relative dating, the lowest layer is the oldest.
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#### Claim:
Horses have evolved over time to become larger, with longer legs and fewer toes.
#### Evidence:
From the diagrams of horse evolution:
1. Early horses (like *Hyracotherium*) were small, had multiple toes (four on the front, three on the back), and lived in forests.
2. Modern horses (*Equus*) are much larger, have only one toe per foot (a single hoof), and are adapted for running on open grasslands.
#### Reasoning:
These changes show adaptations to environmental shifts — as grasslands expanded, horses evolved longer legs and single toes for faster running across open terrain. This gradual change supports the idea of evolution over millions of years.
> *Note:* The CER (Claim-Evidence-Reasoning) format requires you to make a claim, support it with evidence from the diagram, and explain why the evidence supports the claim.
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1. Relative dating and absolute dating
2. Relative dating uses the position of fossils in rock layers — deeper = older.
3. Absolute dating gives the actual age by measuring radioactive elements like carbon-14.
4. Carbon-14 decays at a predictable rate, allowing scientists to calculate the fossil's age.
5. Layer 1 is the oldest.
CER Response:
- Claim: Horses have evolved to be larger and have fewer toes over time.
- Evidence: Early horses had multiple toes and were small; modern horses have one toe and are large.
- Reasoning: These changes reflect adaptation to open grasslands, enabling faster movement and survival.
Let me know if you'd like this formatted for printing or submission!
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1. What are the two ways of finding the age of a fossil?
Answer:
The two ways of finding the age of a fossil are:
- Relative dating
- Absolute dating
> *Explanation:* As stated in the passage, scientists use both relative and absolute dating methods to determine the age of fossils.
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2. Describe how relative dating works.
Answer:
Relative dating determines the age of a fossil by its location in rock layers. Fossils found deeper in the ground are usually older than those found higher up. So, if a fossil is in layer 1, it is older than one in layer 6. This method helps scientists determine the sequence of events but not the exact age.
> *Explanation:* The diagram shows layers labeled 1 through 6, with layer 1 at the bottom (oldest) and layer 6 at the top (youngest). Relative dating uses this principle of superposition — that lower layers are older than upper ones.
---
3. What does absolute dating do?
Answer:
Absolute dating determines the actual age of a fossil by measuring the amount of a radioactive element, such as carbon-14, in the fossil. Scientists use mathematical formulas to calculate how much time has passed based on the decay rate of the element.
> *Explanation:* The passage explains that by measuring carbon-14 levels and applying a formula, scientists can determine an actual number of years since the organism died.
---
4. Why is the element carbon-14 important for paleontologists?
Answer:
Carbon-14 is important because it is a radioactive isotope that decays at a known rate. By measuring how much carbon-14 remains in a fossil, paleontologists can calculate how long ago the organism died. This allows them to determine the actual age of the fossil.
> *Explanation:* Carbon-14 dating is effective for organic materials up to about 50,000 years old. It’s crucial for determining precise ages in more recent fossil records.
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5. Which layer is the oldest?
Answer:
Layer 1 is the oldest.
> *Explanation:* In the diagram, layer 1 is at the bottom of the rock strata. According to the principle of superposition used in relative dating, the lowest layer is the oldest.
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CER: How has the horse evolved over time?
#### Claim:
Horses have evolved over time to become larger, with longer legs and fewer toes.
#### Evidence:
From the diagrams of horse evolution:
1. Early horses (like *Hyracotherium*) were small, had multiple toes (four on the front, three on the back), and lived in forests.
2. Modern horses (*Equus*) are much larger, have only one toe per foot (a single hoof), and are adapted for running on open grasslands.
#### Reasoning:
These changes show adaptations to environmental shifts — as grasslands expanded, horses evolved longer legs and single toes for faster running across open terrain. This gradual change supports the idea of evolution over millions of years.
> *Note:* The CER (Claim-Evidence-Reasoning) format requires you to make a claim, support it with evidence from the diagram, and explain why the evidence supports the claim.
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✔ Final Answers Summary:
1. Relative dating and absolute dating
2. Relative dating uses the position of fossils in rock layers — deeper = older.
3. Absolute dating gives the actual age by measuring radioactive elements like carbon-14.
4. Carbon-14 decays at a predictable rate, allowing scientists to calculate the fossil's age.
5. Layer 1 is the oldest.
CER Response:
- Claim: Horses have evolved to be larger and have fewer toes over time.
- Evidence: Early horses had multiple toes and were small; modern horses have one toe and are large.
- Reasoning: These changes reflect adaptation to open grasslands, enabling faster movement and survival.
Let me know if you'd like this formatted for printing or submission!
Parent Tip: Review the logic above to help your child master the concept of fossil record worksheet.
