Q8 - The giant Chicxulub crater in Mexico

[ohthatpatrick]

Question Type:
Weaken

Stimulus Breakdown:
Conclusion: Asteroid probably didn't cause most of the dinosaur extinctions.
Evidence: There have been craters that size (or bigger) before that didn't seem to cause extinctions. Asteroid strikes definitely kill stuff in the region of impact, but it's doubtful an asteroid could affect stuff worldwide.

Answer Anticipation:
Given that asteroid impacts seem to only kill locally, and that similar sized impacts at other times haven't caused extinctions, how can we argue that THIS asteroid DID cause a bunch of dinosaur extinctions?

Correct Answer:
E

Answer Choice Analysis:
(A) This doesn't matter. We know that many dinosaur species became extinct around the time of the asteroid, and we're only analyzing whether the asteroid could have caused most of THOSE extinctions.

(B) Well, sure. How would this wishy-washy answer choice help us argue that Chicxulub asteroid killed a bunch of dinosaurs?

(C) Maybe, but the author acknowledges that SOME dinosaurs (near the impact zone) would have been killed. This answer doesn't help us argue that the asteroid caused most of the dino extinctions around that time period.

(D) This doesn't do anything. The author wasn't thinking that there were multiple simultaneous asteroids. Whether there was another asteroid at the same time is irrelevant to judging whether the Chicxulub asteroid killed a bunch of dinos.

(E) Yes! This allows us to argue that THIS asteroid DID cause a bunch of dinosaur extinctions. If "MOST remaining dinos" were near the impact zone, then it's easy to argue that the asteroid impact may have killed most of them.

Takeaway/Pattern: The author shot down the asteroid hypothesis because an asteroid would only have local deaths, not global ones. What the author was assuming (and never mentioned) was that there were dinosaurs spread out all over the globe. The correct answer goes against this assumption and allows us to argue the opposite of the author's conclusion.

#officialexplanation

[carly.applebaum]

For this question, are we trying to weaken the statement that an impact could not have had a world wide effect? Or are we trying to weaken the fact that the asteroid didn't cause the extinction of dinosaurs?

I easily eliminated A B and D, and chose C. Now looking over it, I am thinking maybe C just attacks the premise? And also, the stimulus talks about extinction, whereas this answer choice just talks about a number of dinosaurs dying. Is this reasoning correct?

In looking at E, I don't see how it really weakens. What if most dinosaurs lived in the region where the asteroid hit, but then migrated elsewhere before they would have been wiped out? It doesn't tell us anything about them becoming extinct as a result of the asteroid.

HELP!

Thanks!!

[jolieyang]

For this question, you want to weaken the argument that the huge asteroid that created the crater was responsible for many of the last dinosaurs species becoming extinct. The reason the stimulus gives is that a major asteroid strike kills organisms in or near the region of impact and little evidence of worldwide effect. You can therefore infer that the argument suggests that many of the dinosaurs were not near the region of impact.

C) is incorrect because it says that a number of dinosaurs died as a result but the stimulus is not talking about a number of dinosaurs, but the extinction of dinosaur species. Therefore, it could have been true that a number of dinosaurs died and it would not weaken the stimulus. Also, "a number" does not necessarily mean "most" dinosaurs.

E) is the correct answer because it states that MOST dinosaurs lived in or near the region of the impending impact. Since the stimulus implies that dinosaurs were not near the region of the impact (hence the reason why it states that a strike probably could not have a worldwide effect) this answer would weaken that assumption.

In regards to your questions about dinosaurs migrating, that would not be a concern because the stimulus states that many organisms would be killed if they live in or near the region of the impact. E weakens the argument a little bit by stating that most dinosaurs actually did live near or in the region so by saying that they didn't and that being a reason why the asteroid did not cause their extinction is questionable.

Does that make sense?

[shirando21]

do you mean a number of = some

[andrew-burtlow]

I got this wrong when taking the pt, but I think I can make sense of this. The first sentence of the stimulus says that "many" dinosaurs were becoming extinct when the asteroid hit. The next sentence states that the asteroid was "PROBABLY not responsible for MOST of the dinosaur extinctions." This should alone rule out c, because we can infer that the author would have no issue with this because of his concessions in his first two sentences. The next sentence says that the impact of the asteroid only could have had a local effect. Look at E. If most dinosaurs lived in the locality if the asteroid strike, perhaps the asteroid caused their extinction. E plays with the stimulus' author's own words and leaves the author dumbfounded.

[ganbayou]

What is the assumption here?

[VickX462]

The assumption:
If the impact of the asteroid strike is not worldwide and if other craters larger than the one we have here did not cause extinction, the strike that engendered crater C is probably not responsible for most of the extinctions.

We want to find an answer choice that helps us prove that the asteroid strike that created crater C IS responsible for most of the extinctions of dinos mentioned in the stimulus.

(A) In any way it would strengthen the argument instead of weakening it. The impact of this answer choice is unclear if you notice that the argument limits the extinction of dinos to "many of the last dinosaur species" in the stimulus.

(B) Size of the crater is irrelevant here. We want to know if the creation of this crater caused the extinction of dinos.

(C) Unclear bearing. How many is "a number of", which is the equivalent of "some"? 2 dino fossils? 10? I am always wary of quantifiers such as "some", "a number of", and "many", since they typically have no power in S&W questions.

(D) Unclear bearing. What about a million of smaller asteroids striking Earth at the same time as the asteroid that produced crater C? That would perhaps exempt the latter from killing most of the dinos.

(E) BOOM! Yes if most of the dinos are struck and killed by the asteroid directly the asteroid is likely to be held responsible.