The variety of species with adaptations to produce toxins is matched by the variety of uses of those toxins: northern...
GMAT Information and Ideas : (Ideas) Questions
The variety of species with adaptations to produce toxins is matched by the variety of uses of those toxins: northern stargazers, for example, use toxins for defense, whereas tiger snakes use toxins for predation and skeleton shrimp use toxins for intraspecific competition. In fact, a species may have adaptations enabling it to produce a toxin with multiple uses. Finding that the venom used by the Panamanian scorpion Centruroides granosus to subdue prey also inhibits growth of the pathogenic bacteria Escherichia coli, Dumas Gálvez and colleagues conclude that the particular form of venom production observed in C. granosus may have propagated through the species because it mitigates risk during feeding in addition to enhancing predation success.
Which finding, if true, would most directly support Gálvez and colleagues' conclusion?
E. coli does not appear to be virulent for C. granosus even when transmitted from prey captured without the use of venom.
E. coli is frequently found in species preyed on by C. granosus and can survive exposure to the digestive juices of C. granosus.
C. granosus appears to be chemically sensitive to prey infected with E. coli and tends to favor uninfected individuals.
Exposure to C. granosus venom also inhibits the growth of nonpathogenic bacteria species common in the native environment of C. granosus.
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'The variety of species with adaptations to produce toxins is matched by the variety of uses of those toxins:' |
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| 'northern stargazers, for example, use toxins for defense, whereas tiger snakes use toxins for predation and skeleton shrimp use toxins for intraspecific competition.' |
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| 'In fact, a species may have adaptations enabling it to produce a toxin with multiple uses.' |
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| 'Finding that the venom used by the Panamanian scorpion Centruroides granosus to subdue prey also inhibits growth of the pathogenic bacteria Escherichia coli,' |
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| 'Dumas Gálvez and colleagues conclude that the particular form of venom production observed in C. granosus may have propagated through the species because it mitigates risk during feeding in addition to enhancing predation success.' |
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Part B: Provide Passage Architecture & Core Elements
- Main Point: Researchers conclude that C. granosus scorpion venom evolved to serve dual purposes - both enhancing hunting success and reducing feeding risks by inhibiting harmful bacteria.
- Argument Flow: The passage moves from general (toxins have varied uses) to specific (some toxins serve multiple purposes) to a particular research finding (C. granosus venom both kills prey and stops E. coli) to the researchers' evolutionary explanation for this dual functionality.
Step 2: Interpret the Question Precisely
What's being asked? Which finding would most directly support Gálvez and colleagues' conclusion.
What type of answer do we need? Evidence that would strengthen their argument that the venom evolved because it provides both hunting advantages AND feeding safety.
Any limiting keywords? most directly support
Step 3: Prethink the Answer
- The researchers conclude that C. granosus venom evolved because it serves two purposes: enhances predation AND reduces feeding risk
- For this conclusion to be well-supported, we'd need evidence showing that E. coli actually poses a real threat during feeding for these scorpions and that the antibacterial properties would provide meaningful protection
E. coli does not appear to be virulent for C. granosus even when transmitted from prey captured without the use of venom.
✗ Incorrect
- States that E. coli isn't harmful to C. granosus even without venom
- This would actually weaken the researchers' conclusion by suggesting there's no real feeding risk to mitigate
E. coli is frequently found in species preyed on by C. granosus and can survive exposure to the digestive juices of C. granosus.
✓ Correct
- Shows that E. coli is frequently present in the scorpion's prey AND can survive the scorpion's digestive system
- This establishes that E. coli poses a real, ongoing threat during feeding that the venom's antibacterial properties could help address
- Directly supports both parts of the researchers' conclusion
C. granosus appears to be chemically sensitive to prey infected with E. coli and tends to favor uninfected individuals.
✗ Incorrect
- Suggests scorpions actively avoid E. coli-infected prey
- If they can simply avoid infected prey, the venom's antibacterial properties wouldn't provide much evolutionary advantage
Exposure to C. granosus venom also inhibits the growth of nonpathogenic bacteria species common in the native environment of C. granosus.
✗ Incorrect
- Mentions nonpathogenic (harmless) bacteria rather than the pathogenic E. coli
- Since nonpathogenic bacteria don't pose a feeding risk, this doesn't support the risk mitigation aspect of the researchers' conclusion