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Pesticide Residues in Urine To carry the USDA’s organic label (right), food must be produced without synthetic pesticides that farmers often use on conventionally grown, fruits, vegetables, and many grains.
Chensheng Lu of Emory University used urine testing to see whether eating organic food has a significant effect on the levels of pesticides in children's bodies (FIGURE 40.11). Over the course of 15 days, Lu and his colleagues collected the urine of 23 children (aged 3 to 11) and tested it for breakdown products of two synthetic pesticides. The children ate their normal diet of conventionally grown foods for three days, switched to organic versions of the same foods and drinks for five days, then returned to their convention.al diet for a week
FIGURE 40.11 Concentrations of metabolites of two pesticides (malathion and chlorpyrifos) in children’s urine during the three different phases of the study. The difference in the mean level of metabolites between the organic and conventional phases of the study was statistically significant.
During which phase of the experiment was the maximum level of the chlorpyrifos metabolite detected?
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Chapter 40 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
- What are biofertilizers and mention the significancearrow_forwardPCBs and River Otters: Otters in Washington State’s Green-Duwamish River have high levels of polychlorinated biphenyls (PCBs) in their livers. PCBs can bind to the estrogen receptors in animals and disrupt the endocrine system of these otters. The PCBs seem to increase the estrogen to androgen ratio, skewing the ratio toward too much estrogen. How would increased estrogen affect the river otter population? Based on your reading of the materials in this unit, what factors can affect fertility in humans? Explain how each of the factors affecting human fertility that you described can disrupt the human endocrine system to affect reproduction.arrow_forwardOther than oil and alcohol, are there other liquids you could compare to water (that are liquid at room temperature)? How is water unique compared to these other liquids? What follow-up experiment would you like to do, and how would you relate it to your life?arrow_forward
- Selection of Traits What adaptations do scavengers have for locating and feeding on prey? What adaptations do predators have for capturing and consuming prey?arrow_forwardCompetition Between Species What natural processes limit populations from growing too large? What are some resources organisms can compete over in their natural habitat?arrow_forwardSpecies Interactions Explain how predators, prey and scavengers interact. Explain whether predators and scavengers are necessary or beneficial for an ecosystem.arrow_forward
- magine that you are conducting research on fruit type and seed dispersal. You submitted a paper to a peer-reviewed journal that addresses the factors that impact fruit type and seed dispersal mechanisms in plants of Central America. The editor of the journal communicates that your paper may be published if you make ‘minor revisions’ to the document. Describe two characteristics that you would expect in seeds that are dispersed by the wind. Contrast this with what you would expect for seeds that are gathered, buried or eaten by animals, and explain why they are different. (Editor’s note: Providing this information in your discussion will help readers to consider the significance of the research).arrow_forwardWhat is the difference between Uniporters, Symporters and Antiporters? Which of these are examples of active transport?arrow_forwardWhat are coupled transporters?arrow_forward
