While researching a topic, a student has taken the following notes:Wolf populations in Yellowstone National Park were eliminated by hunting...
GMAT Expression of Ideas : (Expression) Questions
While researching a topic, a student has taken the following notes:
- Wolf populations in Yellowstone National Park were eliminated by hunting in the 1920s.
- In 1995, wildlife biologists reintroduced gray wolves to the ecosystem.
- The Lamar Valley was one of the first areas to receive reintroduced wolf packs.
- Scientists documented changes in elk behavior and grazing patterns following wolf reintroduction.
- Vegetation along riverbanks began recovering as elk avoided those areas.
- The return of wolves correlated with increased biodiversity throughout the valley.
The student wants to establish a relationship between species reintroduction and ecosystem changes. Which choice most effectively uses relevant information from the notes to accomplish this goal?
Gray wolves were reintroduced to Yellowstone in 1995, with the Lamar Valley receiving some of the first wolf packs.
Reintroducing wolves can trigger cascading ecological changes, as evidenced in Lamar Valley where wolf presence altered elk behavior, allowing vegetation recovery and supporting increased biodiversity.
The Lamar Valley experienced increased biodiversity after wolves were reintroduced in 1995.
After wolves were eliminated in the 1920s, wildlife biologists reintroduced gray wolves to Yellowstone, including the Lamar Valley, in 1995.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Wolf populations in Yellowstone National Park were eliminated by hunting in the 1920s." |
|
| "In 1995, wildlife biologists reintroduced gray wolves to the ecosystem." |
|
| "The Lamar Valley was one of the first areas to receive reintroduced wolf packs." |
|
| "Scientists documented changes in elk behavior and grazing patterns following wolf reintroduction." |
|
| "Vegetation along riverbanks began recovering as elk avoided those areas." |
|
| "The return of wolves correlated with increased biodiversity throughout the valley." |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: The reintroduction of wolves to Yellowstone created a cascade of ecological changes that ultimately increased biodiversity throughout the ecosystem.
Argument Flow: The notes present a clear cause-and-effect sequence: wolves were eliminated, then reintroduced in specific areas like Lamar Valley. This reintroduction triggered behavioral changes in elk, which led to vegetation recovery, which contributed to increased biodiversity across the entire valley.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- The correct choice needs to show the connection between species reintroduction and ecosystem changes
- It should demonstrate how bringing wolves back didn't just add wolves to the park—it set off a chain reaction of changes throughout the ecosystem
- The best answer will show this cascading effect: wolves return → immediate changes (like elk behavior) → broader changes (like vegetation recovery) → system-wide impacts (like increased biodiversity)
Gray wolves were reintroduced to Yellowstone in 1995, with the Lamar Valley receiving some of the first wolf packs.
✗ Incorrect
- Simply states when and where wolves were reintroduced
- Provides factual information but shows no relationship to ecosystem changes
Reintroducing wolves can trigger cascading ecological changes, as evidenced in Lamar Valley where wolf presence altered elk behavior, allowing vegetation recovery and supporting increased biodiversity.
✓ Correct
- Shows the complete causal relationship the student wants to establish
- Demonstrates cascading ecological changes and connects wolf reintroduction to elk behavior changes to vegetation recovery to increased biodiversity
The Lamar Valley experienced increased biodiversity after wolves were reintroduced in 1995.
✗ Incorrect
- Only mentions the end result (increased biodiversity) without showing the connection
- Lacks the causal relationship between reintroduction and changes
After wolves were eliminated in the 1920s, wildlife biologists reintroduced gray wolves to Yellowstone, including the Lamar Valley, in 1995.
✗ Incorrect
- Focuses entirely on timeline and locations
- Makes no mention of ecosystem changes or their relationship to wolf reintroduction