QUESTION TEXT: Loggerhead turtles live and breed in distinct…
QUESTION TYPE: Weaken
CONCLUSION: It’s likely that young Baja peninsula loggerhead turtles hatched 10,000 kilometers away, in Japanese waters.
REASONING: Loggerhead turtles in the Baja peninsula have DNA that is 95% similar to that of loggerhead turtles near Japan.
ANALYSIS: This argument sounds persuasive. But it hasn’t told us how similar we should expect loggerhead DNA to be. Maybe all loggerheads have similar DNA, including those in the Atlantic.
___________
- This would just show the pacific group is widespread. It strengthens the argument.
- This tells us Atlantic turtles behave differently than Pacific turtles. It somewhat strengthens the argument.
- This just tells us a fact about loggerhead population. It doesn’t show that the two populations aren’t different.
- CORRECT. This shows that Atlantic loggerheads have DNA similar to that of pacific loggerheads. This weakens the argument that the populations are distinct.
- The argument didn’t say that the loggerheads couldn’t interbreed. It just said that they generally didn’t breed.
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Memberjj says
I’m not sure with your answer of A. How does this not weaken argument? If there was a nesting site was found off the north of Baja peninsula, I believe it would weaken the argument because then it does not mean that Pacific jouvenile turtles hatch in Japanese water, instead it was hatch on the north of Baja Peninsula.
FounderGraeme Blake says
First, the answer doesn’t say the nesting happens in the Baja peninsula. It says it happens “several thousand kilometres north of the Baja peninsula”.
Second, “have been found” is very weak. It’s equivalent to “some”. This could be a handful of nesting sites. We’re concerned with what happens to the vast majority of turtles, and A doesn’t weaken the idea that almost all turtles hatch in Japan. There will always be exceptions to most rules, but that doesn’t mean the exceptions are significant.