sat suite question viewer
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?
Explanation
Choice B is the best answer because it presents a finding that, if true, would most directly support Dumas Gálvez and colleagues’ conclusion that the venom produced by the scorpion species Centruroides granosus helps mitigate, or reduce, risk during feeding in addition to enhancing predation success. According to the text, Gálvez and colleagues found that the venom used by C. granosus both subdues prey and inhibits the growth of Escherichia coli, a pathogen that, if ingested by C. granosus, would presumably cause disease unless neutralized in some way. If it were true that E. coli is commonly found in species preyed on by C. granosus and, moreover, can withstand C. granosus’s digestive juices after ingestion, this would suggest that C. granosus likely relies on another mechanism to neutralize E. coli to make E. coli-infected prey safe for consumption by the scorpion species. Given that, as the text states, C. granosus’s venom was found to inhibit the pathogen’s growth, it therefore follows that the venom provides protection for C. granosus against E. coli that its digestive system wouldn’t otherwise provide, making it reasonable to conclude that the trait may have spread through the species because it mitigates risk during feeding.
Choice A is incorrect because a finding that E. coli doesn’t appear to be virulent, or dangerous, for C. granosus even when venom isn’t used would weaken rather than strengthen Gálvez and colleagues’ conclusion that a particular form of venom production spread in C. granosus in part because it helps reduce risk during feeing, since this finding would suggest that E. coli isn’t actually a risk to C. granosus when consuming prey. Choice C is incorrect because a finding that C. granosus can detect and avoid consuming E. coli-infected prey in the first place would suggest that an ability other than venom production is the primary factor that reduces C. granosus’s risk when feeding, which would suggest there has been less evolutionary pressure to develop venom that provides protection; thus, this finding wouldn’t clearly support the conclusion that C. granosus’s form of venom production spread in the species in part because it helps reduce risk during feeding. Choice D is incorrect because Gálvez and colleagues’ conclusion focuses on C. granosus venom in relation to the risk of E. coli, and a finding that the venom also inhibits nonpathogenic (not disease-causing) bacteria species, which presumably don’t pose a risk if consumed, wouldn’t be relevant to the conclusion that C. granosus’s particular form of venom production spread in the species in part because it helps reduce risk during feeding.