Item CA042002: Similar skeletal features (in dogs and fish) indicate a common ancestor. (Identify claim, evidence, and reasoning.)
A class of students is visiting a natural history museum. Students are looking at the skeleton of a dog, after which they walk over to an exhibit showing the skeleton of a fish.
As a homework assignment the teacher asks the students to think about the following question:
“Do dogs and fish share a common ancestor?”
Students are asked to write an argument to justify their answer. One student writes:
Common ancestors are a topic in evolution. Similar skeletal features likely indicate a common ancestor. Dogs and fish have similar anatomical features. For example, they both have a backbone, a bony skull, and their ribcages are similar. Dogs and fish may have a common ancestor.
Identify the claim, evidence, and reasoning statement in the student’s argument.
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Claim: Similar skeletal features likely indicate a common ancestor.
Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar.
Reasoning: Dogs and fish have similar anatomical features.
 - 
    
Claim: Similar skeletal features likely indicate a common ancestor.
Evidence: Dogs and fish have similar anatomical features.
Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar.
 - 
    
Claim: Fish and dogs may have a common ancestor.
Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar.
Reasoning: Similar skeletal features likely indicate a common ancestor.
 - 
    
Claim: Fish and dogs may have a common ancestor.
Evidence: Similar skeletal features likely indicate a common ancestor.
Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar
 
Pre-Test
Answer Choice  | 
					Overall  | 
					Grades  | 
					Gender  | 
					Primary Language  | 
				||||
|---|---|---|---|---|---|---|---|---|
|   n = 559  | 
								6–8 n = 23  | 
				9–12 n = 499  | 
				Male n = 221  | 
				Female n = 300  | 
				English n = 516  | 
				Other n = 13  | 
			||
| A. | 
     Claim: Similar skeletal features likely indicate a common ancestor. Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar. Reasoning: Dogs and fish have similar anatomical features.  | 
							20% | 30% | 19% | 21% | 19% | 20% | 15% | 
| B. | 
     Claim: Similar skeletal features likely indicate a common ancestor. Evidence: Dogs and fish have similar anatomical features. Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar.  | 
							17% | 4% | 18% | 17% | 17% | 17% | 8% | 
| C. | 
     Claim: Fish and dogs may have a common ancestor. Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar. Reasoning: Similar skeletal features likely indicate a common ancestor.  | 
							47% | 43% | 46% | 43% | 49% | 46% | 38% | 
| D. | 
     Claim: Fish and dogs may have a common ancestor. Evidence: Similar skeletal features likely indicate a common ancestor. Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar  | 
							17% | 22% | 17% | 19% | 16% | 16% | 38% | 
Post-Test (Control)
Answer Choice  | 
					Overall  | 
					Grades  | 
					Gender  | 
					Primary Language  | 
				||||
|---|---|---|---|---|---|---|---|---|
|   n = 281  | 
								6–8 n = 18  | 
				9–12 n = 229  | 
				Male n = 109  | 
				Female n = 135  | 
				English n = 243  | 
				Other n = 9  | 
			||
| A. | 
     Claim: Similar skeletal features likely indicate a common ancestor. Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar. Reasoning: Dogs and fish have similar anatomical features.  | 
							22% | 39% | 20% | 19% | 21% | 21% | 11% | 
| B. | 
     Claim: Similar skeletal features likely indicate a common ancestor. Evidence: Dogs and fish have similar anatomical features. Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar.  | 
							18% | 28% | 17% | 17% | 18% | 18% | 11% | 
| C. | 
     Claim: Fish and dogs may have a common ancestor. Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar. Reasoning: Similar skeletal features likely indicate a common ancestor.  | 
							41% | 17% | 45% | 42% | 46% | 43% | 44% | 
| D. | 
     Claim: Fish and dogs may have a common ancestor. Evidence: Similar skeletal features likely indicate a common ancestor. Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar  | 
							19% | 17% | 19% | 22% | 16% | 18% | 33% | 
Post-Test (Treatment)
Answer Choice  | 
					Overall  | 
					Grades  | 
					Gender  | 
					Primary Language  | 
				||||
|---|---|---|---|---|---|---|---|---|
|   n = 305  | 
								6–8 n = 3  | 
				9–12 n = 280  | 
				Male n = 139  | 
				Female n = 150  | 
				English n = 276  | 
				Other n = 8  | 
			||
| A. | 
     Claim: Similar skeletal features likely indicate a common ancestor. Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar. Reasoning: Dogs and fish have similar anatomical features.  | 
							23% | 0% | 22% | 22% | 21% | 22% | 38% | 
| B. | 
     Claim: Similar skeletal features likely indicate a common ancestor. Evidence: Dogs and fish have similar anatomical features. Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar.  | 
							17% | 33% | 18% | 17% | 19% | 18% | 25% | 
| C. | 
     Claim: Fish and dogs may have a common ancestor. Evidence: For example, they both have a backbone, a bony skull, and their ribcages are similar. Reasoning: Similar skeletal features likely indicate a common ancestor.  | 
							43% | 33% | 43% | 40% | 46% | 43% | 25% | 
| D. | 
     Claim: Fish and dogs may have a common ancestor. Evidence: Similar skeletal features likely indicate a common ancestor. Reasoning: For example, they both have a backbone, a bony skull, and their ribcages are similar  | 
							17% | 33% | 17% | 21% | 14% | 17% | 13% | 

