Extinctions

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Extinctions

by goelmohit2002 » Thu Jul 09, 2009 1:48 pm
Hi All,

In the below question, OA is B.

Can someone please tell what is the problem with E.....why E is not weakening the Krech objection ? If E is true, then isn't the whole basis of Krech objection(i.e. climate change occured at the plaeistone era that caused the exintiction) weakened ?

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According to a theory advanced by researcher Paul Martin, the wave of species extinctions that occurred Line in North America about 11,000 years ago, at the end of the Pleistocene era, can be directly attributed to the arrival of humans, i.e., the Paleoindians, who were ancestors of modern Native Americans. However, anthropologist Shepard Krech points out that large animal species vanished even in areas where there is no evidence to demon-strate that Paleoindians hunted them.Nor were extinctions confined to large animals: small animals, plants, and insects disappeared, presumably not all through human consumption. Krech also contradicts Martin’s exclusion of climatic change as an explanation by asserting that widespread climatic change did indeed occur at the end of the Pleistocene. Still, Krech attributes secondary if not primary responsibility for the extinctions to the Paleoindians, arguing that humans have produced local extinctions elsewhere.

Which of the following, if true, would most weaken Krech’s objections to Martin’s theory?

A. Further studies showing that the climatic change that occurred at the end of the Pleistocene era was even more severe and widespread than was previously believed
B. New discoveries indicating that Paleoindians made use of the small animals, plants, and insects that became extinct
C. Additional evidence indicating that widespread climatic change occurred not only at the end of the Pleistocene era but also in previous and subsequent eras
D. Researchers’ discoveries that many more species became extinct in North America at the end of the Pleistocene era than was previously believed
E. New discoveries establishing that both the arrival of humans in North America and the wave of Pleistocene extinctions took place much earlier than 11,000 years ago[/spoiler]
Source: — Critical Reasoning |

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by crackgmat007 » Thu Jul 09, 2009 3:24 pm
In order to weaken Krech's objection, we need something which confirms that humans were in fact responsible for extinctions.

A. Further studies showing that the climatic change that occurred at the end of the Pleistocene era was even more severe and widespread than was previously believed

Severity of climate change doesnt help weaken

B. New discoveries indicating that Paleoindians made use of the small animals, plants, and insects that became extinct

Choose B - this provides info that humans were responsible for extinctions



C. Additional evidence indicating that widespread climatic change occurred not only at the end of the Pleistocene era but also in previous and subsequent eras


Widespread climatic change in other eras doesnt help weaken

D. Researchers’ discoveries that many more species became extinct in North America at the end of the Pleistocene era than was previously believed

This choice states that there is an increase in the number of species that were exinct but doesnt not provide what were the causes for extinction.

E. New discoveries establishing that both the arrival of humans in North America and the wave of Pleistocene extinctions took place much earlier than 11,000 years ago

Objection that was raised by Krech is that humans were not responsible for the extinction. This choice just states that extinctions and arrival occured earlier than 11000 years ago, but doesnt not give any info of what were the causes of extinction.

HTH

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by goelmohit2002 » Thu Jul 09, 2009 9:03 pm
crackgmat007 wrote:
E. New discoveries establishing that both the arrival of humans in North America and the wave of Pleistocene extinctions took place much earlier than 11,000 years ago

Objection that was raised by Krech is that humans were not responsible for the extinction. This choice just states that extinctions and arrival occured earlier than 11000 years ago, but doesnt not give any info of what were the causes of extinction.

HTH
The basis for Krech objection is climate change that occured at the end of Pleistocene age....

As you too mentioned that both extinctions and human arrivals happened earlier than 11000 years ago...so surely the Pleistocene age climate change was not the reason(since the same happend later then extinctions as E states)....

So whole basis of Krech objection is weakened....isn't it....

i.e. there is something else then climate change at the end of Pleistocene era that caused the extinctions....

thus weakening argument...

Kindly tell what is the flaw in the above reasoning....or there is any extra assumption that I am taking in the above reasoning ?

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by ketkoag » Fri Jul 10, 2009 3:00 am
Except B all are either out of scope or strengthen the argument.
IMO B..

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by goelmohit2002 » Fri Jul 10, 2009 5:36 am
ketkoag wrote:Except B all are either out of scope or strengthen the argument.
IMO B..
Thanks Ketkoag.

But can you please tell the flaw in the reasoning that I wrote in the above post for E....

Probably I am missing something here....

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by bignasty666 » Fri Jul 10, 2009 8:33 am
E negates even martin's argument that the plati extinctions occured 11000 yrs ago which will be incorrect as it becomes out of scope.. B is more direct a choice where it mentions that humans might have hunted smaller animals for other uses...

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by goelmohit2002 » Fri Jul 10, 2009 8:46 am
bignasty666 wrote:E negates even martin's argument that the plati extinctions occured 11000 yrs ago which will be incorrect as it becomes out of scope.. B is more direct a choice where it mentions that humans might have hunted smaller animals for other uses...
Thanks. Surely B is a good answer...But I am confused why E is not the correct answer....

How does E negates the martin argument too.... ? Both humans and extinctions have moved to earlier time period....i.e. say both occured at say 35,000 years ago, then Martin theory IMO is still valid...

Both extinctions and humans happend 35,000 years ago....

But Krech argument is on thing that is still 11,000 old(climate change at 11,000) years ago...

Please tell what I am missing here...so based on the above analysis didn't E also makes sense....

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by dumb.doofus » Fri Jul 10, 2009 10:04 am
Well, my two cents..

We all agree that its either B or E. So there's no need to explain the other choices. I believe few frens have very well explained all choices above. Below is just my take on B and E.

Keep few things in mind:
1. Critical reasoning requires you to limit your thinking to what the passage is saying. The passage is the truth and the ONLY truth.

This passage gives us certain FACTS among which the most important one is:
the wave of species extinctions that occurred Line in North America about 11,000 years ago, at the end of the Pleistocene era

This is a fact and there's no disputing this fact and this is exactly what choice E is doing. It is disputing the very fact. Weakening the argument means to find the assumption on which the argument lies and to negate the assumption. Any weakening the argument question does not introduce a new fact to weaken. It only introduces an assumption, which if were to be true weakens the argument.

That's the reason why we call such options "out of scope". You have to restrict your scope to the passage.

Moreover, B is the contrary of the assumption that the passage makes. It clearly says in the passage that there is no evidence. Choice B negates the assumption

Hope this clarifies the reason for B to be the right answer.
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by james33 » Sun May 15, 2016 8:25 pm
In my opinion E is the most logical one.