The Laysan Rail, an insectivore bird once present on several of the

Question

The Laysan Rail, an insectivore bird once present on several of the Hawaiian Islands, can no longer be found and is thought to be extinct. Scientists originally thought that a decrease in the amount of ground vegetation available for nesting was responsible for the decline of the bird. However, they now believe that increased competition for food was ultimately responsible for the Laysan Rail's inability to survive.

Which of the following would best help to account for the change in the accepted explanation for the Laysan Rail's extinction?

A. The vegetation on the Laysan Rail's home island was decimated when rabbits were introduced to the island in the 1910s.

B. When attempts were made to relocate the Laysan Rail to other islands, the birds lost the geographical cues that they relied on for finding mating sites.

C. The Laysan Rail builds nests under dense ground cover to protect the eggs.

D. An increase in the use of pesticides resulted in a decrease in the numbers of flies and moths present in the Laysan Rails territory.

E. Many species nested.in the same types of vegetation as the Laysan Rail.

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Rucha.Shukla · Answer

IMO E

E. Many species nested.in the same types of vegetation as the Laysan Rail.

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neilacesthegmat · Answer

We need to account for the change in the explanation for the Laysan Rail's extinction from a decrease in ground vegetation for nesting to increased competition for food. Therefore we need to find evidence that impacts the availability of food and not the nesting environment.

Option A - addresses the destruction of vegetation and not competition for food.
Option B - This concerns the birds mating behavior and not competition for food.
Option C - Supports the importance of vegetation for nesting but does not relate to competition for food.
 Option D - This option addresses a reduction in the Laysan Rail's food supply (flies and moths), which aligns with increased competition for food. 
Option E - This option addresses competition for nesting and not competition for food.

Given the shift in the argument that food availability rather than nesting is the cause of extinction, option D is the most relevant as it explains how the decline in food sources due to pesticide use likely led to increased competition for the remaining food.

Shwarma · Answer

Option D
Bird extinct in Hawaii thought originally coz of vegetation, Now scientists say it may be coz of higher competition for food (so more predators or less food)

Strengthen the new explanation
A- does not, support the older idea
B- Not relevant
C- Not related to the new idea
E- Maybe many species were there, but how did it impact the food.. were they all insectivores..? no idea

HarishD · Answer

"they now believe that increased competition for food was ultimately responsible for the Laysan Rail's inability to survive."

Pre-thinking: Either new species are introduced (Who eats the same kind of food). OR somehow there is a shortage of food in the island

only  Option D  can increase the competition for food.

Bunuel · Answer

KAPLAN OFFICIAL EXPLANATION:

D

Scientists first attributed the bird's extinction to a loss of ground vegetation, which the birds used for nesting, but they now believe that a lack of food (insects) was actually responsible. Let's examine the choices to find one that explains why scientists changed their opinion.

(A) provides evidence that a decrease in vegetation did in fact occur. If anything, that would have strengthened the hypothesis that loss of vegetation led to the birds' extinction, rather than causing the scientists to find a new explanation. (B) is out of scope. The passage doesn't concern relocation to other islands, and neither extinction hypothesis has anything to do with mating habits. (C) would strengthen the vegetation hypothesis, by providing evidence of how important the vegetation was to the birds' survival. (E) focuses on other species. Moreover, it supports the vegetation theory, not the food theory. (D) might explain the shift. Since the birds eat insects (Sentence 1), a decrease in the insect population would increase competition for food and could lead to extinction if the birds were not able to compete effectively.

Rishmadhu · Answer

What if introduction of Rabbit increased the competition of food. Rabbit also eat vegetation food along with Rail birds. Earlier it was only Rail birds. Can anyone please explain ?

VerbalBot · Answer

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The Laysan Rail, an insectivore bird once present on several of the

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