Self-study
Foster: Many species of extremely large North American mammals became extinct during the last ice age, which was also the time of the first human migration to North America. █████ ███████ █████ ███ ███████ ███ ████████ ███████ ███████ ██ ████ █████ ██████████
██████ █████ ███████████ ████ ██████ ██ ███ ████████ █████ ██ █ ███████ ████████ ███ ███████ ███████ ██ ███████ ████ ███ ███████ █████ ███ ██████
Summarize Argument: Phenomenon-Hypothesis
Fisch's hypothesis is that the extinctions were caused by a dramatic shift to a harsh climate. Fisch's premise is that this shift happened too fast for the species to adapt.
Notable Assumptions
Fisch assumes that if a species can’t adapt to dramatic climatic changes, those species will go extinct. In other words, Fisch assumes that these species couldn't survive in both climates without adaptation, which doesn't necessarily have to be true.
18.
Which one of the following, ██ █████ ████ ███████████ ███████ █████████
a
Similar species living ██ █████ ██ ███ █████ █████ █████ ████ ████████ ███████ ██ ███████ ███ ███ ██████ ████████
This weakens Fisch’s argument. This tells us that similar species, which also wouldn't have had time to adapt, didn't go extinct just because of the drastic change in climate. This suggests that climate change alone doesn't explain the extinction of these species.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
b
Most of the ███████ ████ ████████ ██ █████ ███████ ████████ ████ ████ ██ ███ ████ ████ ██ ███ ██████ █████████
This is more relevant to Foster's argument than to Fisch's. But for both arguments, we're not interested in the animals that survived. We're interested in the animals that went extinct, and why.
Failed alternate explanation
Failed alternate explanation
Weaken Qs: Answers that try to introduce an alternate explanation, but fall short, or try to explain a different phenomenon.
Strengthen Qs: Answers that try to eliminate an alternate explanation, but fall short, or try to eliminate an explanation for a different phenomenon.
c
Human migration to █████ ██████████ ████████ █████ ███ ████████ ██ ██████ ███████ ████████ ████████
This supports Foster's argument, not Fisch's.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
d
Archaeological evidence reveals ████ ███ █████ ████████ ███ █ ██████ ██ █████████ █████ ██ █████ ████████
This is potentially useful evidence for Foster's argument, not Fisch's.
e
The huge size ██ ███ ███████ ████ ██ █████████ ███ ████ ██ ███████ ███ █████ █████████ ██ ██████ █████████████
This strengthens Fisch's argument. This answer choice cuts off the possibility that even if the animals couldn't adapt to the new climate, they could have migrated somewhere else. Since we know that these species couldn't migrate to a milder environment, and that they couldn't adapt to the harsher climate, Fischer's argument that climate change caused these species' extinction seems more likely.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.