Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 06 May 2016, 09:07

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Some species of dolphins find their prey by echolocation

Author Message
TAGS:

### Hide Tags

Manager
Joined: 15 Apr 2013
Posts: 86
Location: India
Concentration: Finance, General Management
Schools: ISB '15
WE: Account Management (Other)
Followers: 1

Kudos [?]: 64 [0], given: 61

Some species of dolphins find their prey by echolocation [#permalink]

### Show Tags

18 Aug 2013, 05:31
3
This post was
BOOKMARKED
00:00

Difficulty:

75% (hard)

Question Stats:

55% (03:01) correct 45% (02:29) wrong based on 210 sessions

### HideShow timer Statictics

Some species of dolphins find their prey by echolocation; they emit clicking sounds and listen
for echoes returning from distant objects in the water. Marine biologists have speculated that
those same clicking sounds might have a second function: particularly loud clicks might be used by
the dolphins to stun their prey at close range through sensory overload. Other toothed whales
can produce high pitched clicks. When these clicks hit an object, some of the sound will echo
back to the 'sender'. By listening to the echo and interpreting the time it took before the echo came
back, the dolphin estimate the distance of the object.

Which of the following, if discovered to be true, would cast the most serious doubt on the
correctness of the speculation described above?
A. Dolphins that use echolocation to locate distant prey also emit frequent clicks at intermediate distances as they close in on their prey.
B. The usefulness of echolocation as a means of locating prey depends on the clicking sounds being of a type that the prey is incapable of perceiving, regardless of volume.
C. If dolphins stun their prey, the effect is bound to be so temporary that stunning from far away even if possible, would be ineffective.
D. Echolocation appears to give dolphins information about the richness of a source of food as well as about its direction.
E. The more distant a dolphin's prey, the louder the echolocation clicks must be if they are to reveal the prey's presence to the hunting dolphin.
[Reveal] Spoiler: OA
Princeton Review Representative
Joined: 17 Jun 2013
Posts: 163
Followers: 134

Kudos [?]: 259 [1] , given: 0

Re: Some species of dolphins find their prey by echolocation [#permalink]

### Show Tags

18 Aug 2013, 06:38
1
KUDOS
Expert's post
1
This post was
BOOKMARKED
this is a weaken question so we have to determine the conclusion and premises first.

the conclusion of this argument is named as the speculation - that the clicking sounds might stun prey through sensory overload.
the premise is that other toothed whales stun their prey with clicks.

To weaken an argument, you generally bring in new, relevant information, that shows that the conclusion is not necessarily true. So here we need to show that the clicking sounds are not used to stun. so an answer choice has to provide information that would mean this.
pavan2185 wrote:

A. Dolphins that use echolocation to locate distant prey also emit frequent clicks at intermediate distances as they close in on their prey.[color=#ff0000]The fact that they emit clicks as intermediate distances does not give us information about the ability to stun prey[/color]
B. The usefulness of echolocation as a means of locating prey depends on the clicking sounds being of a type that the prey is incapable of perceiving, regardless of volume.This is the correct answer because if the clicks can only be useful if the prey cannot perceive them then this means that the prey could not be stunned by sensory overload by them - making it unlikely that they use the clicks for both echolocation and to stun their prey
C. If dolphins stun their prey, the effect is bound to be so temporary that stunning from far away even if possible, would be ineffective.the conclusion does not depend on how long the prey is stunned, only that they are stunned by the clicks so this is irrelevant
D. Echolocation appears to give dolphins information about the richness of a source of food as well as about its direction.the fact that the clicks can give more information does not mean that they cannot also stun their prey so this does not weaken the argument
E. The more distant a dolphin's prey, the louder the echolocation clicks must be if they are to reveal the prey's presence to the hunting dolphin.The volume of the clicks is not mentioned in relation to stunning a prey, only in revealing it and no information is given that they could not use these loud clicks to stun as well so this does not weaken.

_________________

Special offer! Save $250 on GMAT Ultimate Classroom, GMAT Small Group Instruction, or GMAT Liveonline when you use the promo code GCVERBAL250. Or, save$150 on GMAT Self-Prep when you use the code GCVERBAL150. Enroll at www.princetonreview.com

Manager
Status: Persevering
Joined: 15 May 2013
Posts: 225
Location: India
GMAT Date: 08-02-2013
GPA: 3.7
WE: Consulting (Consulting)
Followers: 1

Kudos [?]: 74 [0], given: 34

Re: Some species of dolphins find their prey by echolocation [#permalink]

### Show Tags

18 Aug 2013, 06:56
B it is, as the speculation by marine biologist is "particularly loud clicks might be used by
the dolphins to stun their prey at close range through sensory overload";

B says "The usefulness of echolocation as a means of locating prey depends on the clicking sounds being of a type that the prey is incapable of perceiving, regardless of volume." if prey cannot perceive it how can the sensory overload take place ?
_________________

--It's one thing to get defeated, but another to accept it.

Manager
Joined: 15 Apr 2013
Posts: 86
Location: India
Concentration: Finance, General Management
Schools: ISB '15
WE: Account Management (Other)
Followers: 1

Kudos [?]: 64 [0], given: 61

Re: Some species of dolphins find their prey by echolocation [#permalink]

### Show Tags

18 Aug 2013, 10:44
BeckyRobinsonTPR wrote:
this is a weaken question so we have to determine the conclusion and premises first.

the conclusion of this argument is named as the speculation - that the clicking sounds might stun prey through sensory overload.
the premise is that other toothed whales stun their prey with clicks.

To weaken an argument, you generally bring in new, relevant information, that shows that the conclusion is not necessarily true. So here we need to show that the clicking sounds are not used to stun. so an answer choice has to provide information that would mean this.
pavan2185 wrote:

A. Dolphins that use echolocation to locate distant prey also emit frequent clicks at intermediate distances as they close in on their prey.[color=#ff0000]The fact that they emit clicks as intermediate distances does not give us information about the ability to stun prey[/color]
B. The usefulness of echolocation as a means of locating prey depends on the clicking sounds being of a type that the prey is incapable of perceiving, regardless of volume.This is the correct answer because if the clicks can only be useful if the prey cannot perceive them then this means that the prey could not be stunned by sensory overload by them - making it unlikely that they use the clicks for both echolocation and to stun their prey
C. If dolphins stun their prey, the effect is bound to be so temporary that stunning from far away even if possible, would be ineffective.the conclusion does not depend on how long the prey is stunned, only that they are stunned by the clicks so this is irrelevant
D. Echolocation appears to give dolphins information about the richness of a source of food as well as about its direction.the fact that the clicks can give more information does not mean that they cannot also stun their prey so this does not weaken the argument
E. The more distant a dolphin's prey, the louder the echolocation clicks must be if they are to reveal the prey's presence to the hunting dolphin.The volume of the clicks is not mentioned in relation to stunning a prey, only in revealing it and no information is given that they could not use these loud clicks to stun as well so this does not weaken.

What is the level of this question, according to your estimation?
GMAT Club Legend
Joined: 01 Oct 2013
Posts: 7435
Followers: 701

Kudos [?]: 140 [0], given: 0

Re: Some species of dolphins find their prey by echolocation [#permalink]

### Show Tags

15 Feb 2016, 18:44
Hello from the GMAT Club VerbalBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Re: Some species of dolphins find their prey by echolocation   [#permalink] 15 Feb 2016, 18:44
Similar topics Replies Last post
Similar
Topics:
1 Some anthropologists argue that the human species.. 6 27 Nov 2012, 06:53
Some paleontologists believe that certain species of 7 25 Nov 2011, 09:42
14 Some animals, such as dolphins, dogs, and African grey 20 11 Mar 2009, 11:02
Some animals, such as dolphins, dogs, and African grey 14 17 Apr 2007, 00:47
Some species of dolphins find their prey by echolocation; 7 25 Jun 2006, 01:55
Display posts from previous: Sort by