Amphibian species (common name)Percentage of eggs eatenNative to AustraliaProduces bufadienolideLittle red tree frog1%yesnoCane toad90%noyesShort-foot...
GMAT Information and Ideas : (Ideas) Questions
| Amphibian species (common name) | Percentage of eggs eaten | Native to Australia | Produces bufadienolide |
|---|---|---|---|
| Little red tree frog | 1% | yes | no |
| Cane toad | 90% | no | yes |
| Short-footed frog | 7% | yes | no |
| Striped burrowing frog | 10% | yes | no |
| Dainty green tree frog | 1% | yes | no |
Native to Latin America, the cane toad was introduced to Australia in the 1930s. In recent decades, tadpoles in the Australian population have been shown to consume eggs of their own species. A 2022 study showed that when presented with cane toad eggs as well as eggs of native Australian amphibians, cane toad tadpoles disproportionately consumed eggs of their own species. This behavior results from their attraction to bufadienolide, a chemical produced by the eggs of cane toads but not by the eggs of native amphibians. However, using data from this study, a student wishes to argue that the presence of bufadienolide doesn't entirely explain the cane toad tadpoles' preference for certain eggs over others.
Which choice best describes data from the table that support the student's argument?
The tadpoles consumed a higher percentage of the striped burrowing frog eggs than they did of the eggs of the dainty green tree frog.
The tadpoles left a certain percentage of the eggs of each of the five species unharmed, thus ultimately allowing them to hatch.
The tadpoles consumed a lower percentage of the short-footed frog eggs than they did of the eggs of their own species.
The tadpoles consumed the same percentage of the dainty green tree frog eggs as they did of the little red tree frog eggs.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Native to Latin America, the cane toad was introduced to Australia in the 1930s.' |
|
| 'In recent decades, tadpoles in the Australian population have been shown to consume eggs of their own species.' |
|
| 'A 2022 study showed that when presented with cane toad eggs as well as eggs of native Australian amphibians, cane toad tadpoles disproportionately consumed eggs of their own species.' |
|
| 'This behavior results from their attraction to bufadienolide, a chemical produced by the eggs of cane toads but not by the eggs of native amphibians.' |
|
| 'However, using data from this study, a student wishes to argue that the presence of bufadienolide doesn't entirely explain the cane toad tadpoles' preference for certain eggs over others.' |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: While bufadienolide chemical attraction explains why cane toad tadpoles prefer their own species' eggs, a student wants to demonstrate this explanation is incomplete.
Argument Flow: The passage establishes the scientific understanding that cane toad tadpoles' egg preferences are driven by bufadienolide attraction, then introduces a student's challenge to this explanation's completeness using data from the same study.
Step 2: Interpret the Question Precisely
What's being asked? We need to find data from the table that supports the student's argument that bufadienolide doesn't entirely explain tadpole preferences.
What type of answer do we need? Evidence showing the tadpoles have preferences that cannot be explained by bufadienolide presence alone.
Any limiting keywords? The evidence must come from 'data from this study' and support an argument about incompleteness of the bufadienolide explanation.
Step 3: Prethink the Answer
- If bufadienolide were the complete explanation, we'd expect the tadpoles to show strong preference only for cane toad eggs (which have bufadienolide) and treat all native Australian eggs equally (since none have bufadienolide)
- However, looking at the native species data, we see variation in consumption rates: 1%, 7%, 10%, and 1% for different native species
- This suggests other factors beyond bufadienolide influence preferences
The tadpoles consumed a higher percentage of the striped burrowing frog eggs than they did of the eggs of the dainty green tree frog.
✓ Correct
- Shows striped burrowing frog (10% eaten) vs. dainty green tree frog (1% eaten)
- Both species are native Australian amphibians that don't produce bufadienolide
- The significant difference in consumption rates (10% vs. 1%) among non-bufadienolide eggs proves other factors influence preferences
- This directly supports the student's argument that bufadienolide alone doesn't explain all preferences
The tadpoles left a certain percentage of the eggs of each of the five species unharmed, thus ultimately allowing them to hatch.
✗ Incorrect
- Points out that some percentage of each species' eggs remained uneaten
- This observation doesn't address differences in preference patterns and doesn't show preference variation
The tadpoles consumed a lower percentage of the short-footed frog eggs than they did of the eggs of their own species.
✗ Incorrect
- Compares short-footed frog (7%) to cane toad (90%) consumption rates
- This actually supports the bufadienolide explanation since the species with bufadienolide was consumed much more heavily
The tadpoles consumed the same percentage of the dainty green tree frog eggs as they did of the little red tree frog eggs.
✗ Incorrect
- Notes that dainty green tree frog and little red tree frog both had 1% consumption
- Equal consumption rates among non-bufadienolide species would actually support the bufadienolide explanation rather than challenge it