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Extinction

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Extinction

by aj5105 » Fri Jun 12, 2009 3:10 am
Extinction is a process that can depend on a variety of ecological, geographical, and physiological variables. These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions. However, the fossil record shows that extinction occurs in a surprisingly definite pattern, with many species vanishing at the same time.

Which of the following, if true, forms the best basis for at least a partial explanation of the patterned extinctions revealed by the fossil record?

(A) Major episodes of extinction can result from widespread environmental disturbances that affect numerous different species.

(B) Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species.

(C) Some species become extinct because of accumulated gradual changes in their local environments.

(D) In geologically recent times, for which there is no fossil record, human intervention has changed the pattern of extinctions.

(E) Species that are widely dispersed are the least likely to become extinct.
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Source: — Critical Reasoning |
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by scoobydooby » Fri Jun 12, 2009 3:22 am
would go for B.

B explains why there may definite patterns in extinction, as it selectively affects species with particular characteristics
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by tohellandback » Fri Jun 12, 2009 7:17 am
IMO B,
same explanation as above
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by Osirus@VeritasPrep » Fri Jun 12, 2009 7:50 am
what's the OA?
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by vinaynp » Fri Jun 12, 2009 8:21 am
C), D), E) are out of scope.

A0 talks about environmental disturbances. Hence, eliminated.

IMO B)
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by schumi_gmat » Fri Jun 12, 2009 8:24 am
IMO A.

conclusion : fossil records show definite pattern of extinction

A. env changes affect NUMEROUS different species

B Certain extinction episodes selectively affect organisms with particular sets of characteristics unique to their species.

particular - limits the scope also does not reinforces the relationship in the conclusion.
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by Osirus@VeritasPrep » Fri Jun 12, 2009 8:30 am
IMO A. B doesn't offer an explanation other than certain characteristics. I don't see how that adds anything to the argument, while A gives you a pretty good reason why "many species" would vanish at the same time. With B those characteristics wouldn't explain why many species would vanish at the same time, but a large environmental shift would.
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by hk » Fri Jun 12, 2009 12:15 pm
I go with A.

The reasoning given for the argument's conclusion states "These variables affect different species of organisms in different ways, and should, therefore, yield a random pattern of extinctions"

But the conclusion says that fossils indicate that this is actually not true as there is infact a definite pattern.
Statement A explains that pattern and thus explains the patterned extinctions revealed by the fossil record.

Would like to know the OA.
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by ssmiles08 » Fri Jun 12, 2009 12:54 pm
IMO A as well.
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by turbo jet » Fri Jun 12, 2009 7:11 pm
IMO:A

Conclusion 1: Extinction occurs in definite pattern
Premise 1: Diff factors affecting extinction affect diff species differently


Conclusion 2: Extinction DOES NOT occur in definite pattern
Premise 2: Fossil records

Tip: This is a paradox/contradictory situation where we need to pick the answer that resolves the paradox in a manner that it allows both the contradictory statements/ both conclusions to exist.


A: Provides a suitable explanation
B: "Certain" phrase has been used. However we are talking about many species. Hence eliminated.
C: Eliminated bec it is talking about some species. On some grounds as B, eliminated
D: Neutral
E: Refutes conclusion 2

OA please.


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by mehravikas » Fri Jun 12, 2009 7:32 pm
IMO - A

OA please
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by aj5105 » Fri Jun 12, 2009 8:03 pm
Well done! OA (A)
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by khanshainur » Sun May 15, 2016 10:35 pm
Answer is clearly A here
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