SpeciesMean bill surface area (cm²)Mean maximum temperature of warmest month (°C)Mean minimum temperature of coldest month (°C)Brown thrasher1.8630.40...
GMAT Information and Ideas : (Ideas) Questions
| Species | Mean bill surface area (cm²) | Mean maximum temperature of warmest month (°C) | Mean minimum temperature of coldest month (°C) |
|---|---|---|---|
| Brown thrasher | 1.86 | 30.40 | −4.29 |
| Bendire's thrasher | 1.98 | 36.57 | 0.24 |
| Long-billed thrasher | 2.24 | 35.27 | 8.82 |
| Cozumel thrasher | 2.28 | 33.27 | 18.21 |
| Ocellated thrasher | 3.26 | 27.56 | 5.45 |
It has been hypothesized that since birds can dissipate excess heat through their bills, bill size should increase with habitat temperature. To evaluate this hypothesis for a 2021 study, Charlotte Probst and colleagues gathered data on mean bill surface area of species of North American thrashers (genus: Toxostoma) as well as on climate conditions of the birds' native habitats. Based on their data, Probst and colleagues concluded that the hypothesis was not fully supported.
Which choice most effectively uses data from the table to support Probst and colleagues' conclusion?
Although the Bendire's thrasher has one of the smallest mean bill surface areas of the birds included in the table, its habitat has one of the lowest mean maximum temperatures in the warmest month and one of the lowest mean minimum temperatures in the coldest month.
Although the Cozumel thrasher has the second greatest mean bill surface area of the birds included in the table, its habitat's mean temperature in the warmest month is significantly higher than that of the other birds' habitats.
Of the birds included in the table, the brown thrasher has the smallest mean bill surface area and the habitat with the lowest mean minimum temperature in the coldest month, while the long-billed thrasher has the second-largest mean bill surface area and the habitat with the second-highest mean minimum temperature in the coldest month.
Of the birds included in the table, the ocellated thrasher has the largest mean bill surface area and the habitat with the lowest mean maximum temperature in the warmest month, while the Bendire's thrasher has the second smallest mean bill surface area and the habitat with the highest mean maximum temperature in the warmest month.
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| Table showing 5 thrasher species with bill surface area and temperature data |
|
| It has been hypothesized that since birds can dissipate excess heat through their bills, bill size should increase with habitat temperature. |
|
| To evaluate this hypothesis for a 2021 study, Charlotte Probst and colleagues gathered data on mean bill surface area of species of North American thrashers (genus: Toxostoma) as well as on climate conditions of the birds' native habitats. |
|
| Based on their data, Probst and colleagues concluded that the hypothesis was not fully supported. |
|
Part B: Passage Architecture & Core Elements
Main Point: Probst and colleagues found that their data on thrasher birds did not fully support the hypothesis that bill size increases with habitat temperature.
Argument Flow: The passage presents a scientific hypothesis about bird bill size correlating with temperature, describes a study that tested this hypothesis using thrasher data, and concludes that the data did not fully support the expected relationship.
Step 2: Interpret the Question Precisely
- What's being asked? Which answer choice uses table data to support the researchers' conclusion
- What type of answer do we need? Specific data points that show the hypothesis is NOT fully supported
- Any limiting keywords? "most effectively" and "from the table" - must use actual numbers/data
Step 3: Prethink the Answer
- If the hypothesis (bigger bills in hotter places) was NOT fully supported, we need examples where:
- Large-billed birds live in cooler places, OR
- Small-billed birds live in hot places, OR
- The relationship is inconsistent
- Looking at the data quickly:
- Bill sizes range from 1.86 (Brown) to 3.26 (Ocellated)
- Max temperatures range from 27.56 (Ocellated) to 36.57 (Bendire's)
- The most striking contradiction: Ocellated thrasher has the LARGEST bill (3.26) but the LOWEST max temperature (27.56), while Bendire's has the second SMALLEST bill (1.98) but the HIGHEST max temperature (36.57).
- So the right answer should point out these contradictory examples that go against the hypothesis.
Although the Bendire's thrasher has one of the smallest mean bill surface areas of the birds included in the table, its habitat has one of the lowest mean maximum temperatures in the warmest month and one of the lowest mean minimum temperatures in the coldest month.
✗ Incorrect
- Claims Bendire's thrasher has "one of the lowest" maximum temperatures
- Actually, Bendire's has the HIGHEST max temperature at \(36.57°\mathrm{C}\)
- This choice contains factually incorrect data
Although the Cozumel thrasher has the second greatest mean bill surface area of the birds included in the table, its habitat's mean temperature in the warmest month is significantly higher than that of the other birds' habitats.
✗ Incorrect
- Says Cozumel thrasher has second largest bill and higher temperature than others
- This would actually SUPPORT the hypothesis, not contradict it
- We need data that shows the hypothesis isn't supported
Of the birds included in the table, the brown thrasher has the smallest mean bill surface area and the habitat with the lowest mean minimum temperature in the coldest month, while the long-billed thrasher has the second-largest mean bill surface area and the habitat with the second-highest mean minimum temperature in the coldest month.
✗ Incorrect
- Brown thrasher: smallest bill + lowest min temp; Long-billed: second largest bill + second highest min temp
- This pattern would actually SUPPORT the hypothesis (smaller bills with colder temps, larger bills with warmer temps)
- Doesn't help prove the hypothesis is wrong
Of the birds included in the table, the ocellated thrasher has the largest mean bill surface area and the habitat with the lowest mean maximum temperature in the warmest month, while the Bendire's thrasher has the second smallest mean bill surface area and the habitat with the highest mean maximum temperature in the warmest month.
✓ Correct
- Ocellated thrasher: largest bill \(3.26\) + lowest max temp \(27.56\) - contradicts hypothesis
- Bendire's thrasher: second smallest bill \(1.98\) + highest max temp \(36.57\) - contradicts hypothesis
- These are perfect examples of why the hypothesis isn't fully supported - the data goes in the opposite direction of what was predicted