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

It is currently 23 Jul 2014, 02:39

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Although numbers of animals in a given region may

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
SVP
SVP
User avatar
Joined: 06 Sep 2013
Posts: 1629
Location: United States
Concentration: Finance
GMAT 1: 710 Q48 V39
WE: Corporate Finance (Investment Banking)
Followers: 10

Kudos [?]: 132 [0], given: 254

GMAT ToolKit User
Although numbers of animals in a given region may [#permalink] New post 25 Sep 2013, 15:12
Although numbers of animals in a given region may ...

Although numbers of animals in a given region may fluctuate from year to year, the fluctuations are often temporary and, over long periods, trivial. Scientists have advanced three theories of population control to account for this relative constancy.The first theory attributes a relatively constant population to periodic climatic catastrophes that decimate populations with such frequency as to prevent them from exceeding some particular limit. In the case of small organisms with short life cycles, climatic changes need not be catastrophic: normal seasonal changes in photoperiod (daily amount of sunlight), for example, can govern population growth. This theory---the density-independent view---asserts that climatic factors exert the same regulatory effect on population regardless of the number of individuals in a region.

A second theory argues that population growth is primarily density-dependent---that is, the rate of growth of a population in a region decreases as the number of animals increases. The mechanisms that manage regulation may vary. For example, as numbers increase, the food supply would probably diminish, which would increase mortality. In addition, as Lotka and Volterra have shown, predators can find prey more easily in high-density populations. Other regulators
include physiological control mechanisms: for example. Christian and Davis have demonstrated how the crowding that results from a rise in numbers may bring
about hormonal changes in the pituitary and adrenal glands that in turn may regulate population by lowering sexual activity and inhibiting sexual maturation. There is evidence that these effects may persist for three generations in the absence of the original provocation. One challenge for density-dependent theorists is to develop models that would allow the precise prediction of the effects of crowding.

A third theory, proposed by Wynne-Edwards and termed “epideictic,” argues that organisms have evolved a “code”in the form of social or epideictic behavior displays, such as winter-roosting aggregations or group vocalizing; such codes provide organisms with information on population size in a region so that they can,
if necessary, exercise reproductive restraint. However, wynne-Edwards’ theory, linking animal social behavior and population control, has been challenged, with some justification, by several studies
1. The primary purpose of the passage is to:
(A) argue against those scientists who maintain that animal populations tend to fluctuate
(B) compare and contrast the density-dependent and epideictic theories of population control
(C) provide example of some of the ways in which animals exercise reproductive restraint to control their own numbers
(D) suggests that theories of population control that concentrate on the social behavior of animals are more open to debate than are theories that do not
(E) summarize a number of scientific theories that attempt to explain why animal populations do not exceed certain limits
[Reveal] Spoiler:
E


2. It can be inferred from the passage that proponents of the density-dependent theory of population control have not yet been able to

(A) use their theory to explain the population growth of organisms with short life cycles
(B) reproduce the results of the study of Christian and Davis
(C) explain adequately why the numbers of a population can increase as the population’s rate of growth
decreases
(D) make sufficiently accurate predictions about the effects of crowding
(E) demonstrate how predator populations are themselves regulated

[Reveal] Spoiler:
D


3. Which of the following, if true, would best support the density-dependent theory of population control as it is
described in the passage?

(A) As the number of foxes in Minnesota decrease, the growth rate of this population of foxes begins of increase.
(B) As the number of woodpeckers in Vermont decreases, the growth rate of this population of woodpeckers also begins to decrease.
(C) As the number of prairie dogs in Oklahoma increases, the growth rate of this population of prairie dogs also begins to increase.
(D) After the number of beavers in Tennessee decreases, the number of predators of these beavers begins to increase.
(E) After the number of eagles in Montana decreases, the food supply of this population of eagles also
begins to decrease.

[Reveal] Spoiler:
A


4. According to the Wynne-Edwards theory as it is described in the passage, epideictic behavior displays serve the function of

(A) determining roosting aggregations
(B) locating food
(C) attracting predators
(D) regulating sexual activity
(E) triggering hormonal changes

[Reveal] Spoiler:
D


5. The challenge posed to the Wynne-Edwards-theory by several studies is regarded by the author with

(A) complete indifference
(B) qualified acceptance
(C) skeptical amusement
(D) perplexed astonishment
(E) agitated dismay

[Reveal] Spoiler:
B


6. Which of the following statements would provide the most of logical continuation of the final paragraph of the passage?

(A) Thus wynne-Edwards’ theory raises serious questions about the constancy of animal population in a region.
(B) Because Wynne-Edwards’ theory is able to explain more kinds of animal behavior than is the densitydependent theory, epideictic explanations of population regulation are now widely accepted.
(C) The results of one study, for instance, have suggested that group vocalizing is more often used to defend territory than to provide information about
population density.
(D) Some of these studies have, in fact, worked out a systematic and complex code of social behavior that can regulate population size.
(E) One study, for example, has demonstrated that birds are more likely to use winter-roosting aggregations than group vocalizing in order to provide information on population size.
[Reveal] Spoiler:
C


Last edited by jlgdr on 27 Sep 2013, 06:28, edited 14 times in total.
Intern
Intern
avatar
Joined: 10 Sep 2013
Posts: 41
Location: United States
Concentration: Strategy, Operations
GMAT Date: 12-10-2013
GPA: 3.5
WE: Operations (Manufacturing)
Followers: 0

Kudos [?]: 13 [0], given: 15

Re: Although numbers of animals in a given region may [#permalink] New post 26 Sep 2013, 04:29
OA Please....
My answers are : 1-E,2-D,3-A,4-D,5-B,6-D
For 5th question, I m nt vry sure...
Director
Director
avatar
Joined: 24 Aug 2009
Posts: 510
Schools: Harvard, Columbia, Stern, Booth, LSB,
Followers: 8

Kudos [?]: 354 [0], given: 241

Re: Although numbers of animals in a given region may [#permalink] New post 26 Sep 2013, 04:43
Hey jlgdr
Follow RC rules or else the post will remain locked.

_________________

If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS.
Kudos always maximizes GMATCLUB worth
-Game Theory

If you have any question regarding my post, kindly pm me or else I won't be able to reply

Manager
Manager
User avatar
Joined: 29 Apr 2013
Posts: 101
Location: India
Concentration: General Management, Strategy
GMAT Date: 11-06-2013
WE: Programming (Telecommunications)
Followers: 1

Kudos [?]: 60 [0], given: 50

Re: Although numbers of animals in a given region may [#permalink] New post 27 Sep 2013, 21:56
Can anyone explain why A is the correct answer in question #3 ?

_________________

Do not forget to hit the Kudos button on your left if you find my post helpful 8-)

Collection of some good questions on Number System

Manager
Manager
User avatar
Joined: 09 Jun 2013
Posts: 54
GMAT 1: 680 Q49 V33
GMAT 2: 690 Q49 V34
GPA: 3.86
WE: Analyst (Advertising and PR)
Followers: 1

Kudos [?]: 27 [0], given: 3

Re: Although numbers of animals in a given region may [#permalink] New post 28 Sep 2013, 01:23
We need information from paragraph 2 to answer question 3.
Relevant information from the text:
1) the rate of growth of a population in a region decreases as the number of animals increases.
2) as numbers increase, the food supply would probably diminish, which would increase mortality.
3) predators can find prey more easily in high-density populations.
4) a rise in numbers may bring about hormonal changes in the pituitary and adrenal glands that in turn may regulate population by lowering sexual activity and inhibiting sexual maturation.

Now the answer choices:

(A) As the number of foxes in Minnesota decrease, the growth rate of this population of foxes begins of increase. This matches information (1).
(B) As the number of woodpeckers in Vermont decreases, the growth rate of this population of woodpeckers also begins to decrease. This contradicts information (1)
(C) As the number of prairie dogs in Oklahoma increases, the growth rate of this population of prairie dogs also begins to increase. Same problem as choice (B)
(D) After the number of beavers in Tennessee decreases, the number of predators of these beavers begins to increase. This contradicts information (3).
(E) After the number of eagles in Montana decreases, the food supply of this population of eagles also begins to decrease. This contradicts information (2).

_________________

Don't be afraid to fail, but be afraid not to try

Re: Although numbers of animals in a given region may   [#permalink] 28 Sep 2013, 01:23
    Similar topics Author Replies Last post
Similar
Topics:
5 find number, given median dreambeliever 5 18 Sep 2011, 19:02
Total Number of factors for a given number ? njvenkatesh 2 20 Oct 2006, 09:32
Zoologists warn of an imminent surge in the number of animal zoom612 11 24 Jul 2006, 12:03
Zoologists warn of an imminent surge in the number of animal X & Y 23 15 Jun 2006, 09:47
The number of plants and animal species that humans are shailu22 13 25 Mar 2006, 18:08
Display posts from previous: Sort by

Although numbers of animals in a given region may

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.