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Item CA043004: Recognize a valid argument that supports the claim that chimpanzees and gorillas have a more recent common ancestry than chimpanzees and orangutans because their average genetic similarity is greater.

Scientists studying evolution compared the DNA of several primate species. They looked for genetic similarities.

The scientists summarized their data in the following table:

Pair of Species Compared

Average Genetic Similarity

Chimpanzee and Gorilla

98%

Chimpanzee and Orangutan

97%

Gorilla and Orangutan

97%

 

When the scientists published their findings, they wrote:

"We studied the DNA of several ape species by sequencing their DNA. Genetic similarities can be used to measure how closely related two species are. Gorillas and chimpanzees have 98% genetic similarity and gorillas and orangutans have 97% genetic similarity. Gorillas and chimpanzees have a more recent common ancestor than do gorillas and orangutans."

Which of the following describes a valid argument that the scientists are making?

  1. Claim: Gorillas and chimpanzees have a more recent common ancestor than gorillas and orangutans.

    Evidence: The genetic similarity between gorillas and chimpanzees was 98% and the genetic similarity between gorillas and orangutans is 97%.

    Reasoning: When comparing multiple species the species with the greater genetic similarity have a more recent common ancestor.

  2. Claim: Gorillas and chimpanzees have a more recent common ancestor than gorillas and orangutans.

    Evidence: When comparing multiple species the species with the greater genetic similarity have a more recent common ancestor.

    Reasoning: The genetic similarity between gorillas and chimpanzees was 98% and the genetic similarity between gorillas and orangutans is 97%.

  3. Claim: Gorillas and chimpanzees have more genetic similarity than gorillas and orangutans.

    Evidence: The genetic similarity between gorillas and chimpanzees was 98% and the genetic similarity between gorillas and orangutans is 97%.

    Reasoning: Genetic similarities can be used to measure how closely related two species are.

  4. Claim: When comparing multiple species the species with the greater genetic similarity have a more recent common ancestor.

    Evidence: Genetic similarity is a measure of how similar the DNA from two organisms is.

    Reasoning: The genetic similarity between gorillas and chimpanzees was 98% and the genetic similarity between gorillas and orangutans is 97%.

Distribution of Responses
Chart showing distrubtion of responses for Item EN043004
Points Earned
Group Correct Total Percent
Overall 275 572 48%
Grades
  6–8 6 18 33%
  9–12 239 502 48%
Gender
  Male12324550%
  Female12528344%
Primary Language
  English23951147%
  Other121867%

View data table

Distribution of Responses
Chart showing distrubtion of responses for Item EN043004
Points Earned
Group Correct Total Percent
Overall 152 274 55%
Grades
  6–8 4 14 29%
  9–12 132 230 57%
Gender
  Male6411954%
  Female7513058%
Primary Language
  English13423757%
  Other4944%

View data table

Distribution of Responses
Chart showing distrubtion of responses for Item EN043004
Points Earned
Group Correct Total Percent
Overall 170 278 61%
Grades
  6–8 1 4 25%
  9–12 150 248 60%
Gender
  Male7513058%
  Female8413164%
Primary Language
  English15025160%
  Other4580%

View data table

Science and Engineering Practices
SEP7 Evaluate the claims, evidence, and/or reasoning behind currently accepted explanations or solutions to determine the merits of arguments.
Notes
Although there is no statement in NGSS that aligns precisely to the idea in this test item, it is reasonable to assume that if students are expected to evaluate claims, evidence, and/or reasoning in arguments, they would also be expected to recognize the difference between claim, evidence, and reasoning statements.