AP Biology: Donor Source Pathogen Resistance Validation Practice Questions
Practice evaluating whether donor populations can persist under disease pressure after movement among climate refugia. These original questions distinguish resistance and tolerance, test genotype-by-pathogen interaction under local pathogen pressure, examine fitness cost, and connect multi-strain common-garden evidence to post-release validation.
Free original practice questions for study purposes. Open Exam Prep is an independent study resource and is not affiliated with, endorsed by, or sponsored by the makers of AP Exams.
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Answer the questions below — you get instant feedback and a full explanation for each.
1. Which statement best distinguishes pathogen resistance from pathogen tolerance in a donor plant population?
Explanation. Resistance and tolerance are different host strategies. Resistance reduces infection or pathogen load, while tolerance preserves survival or reproduction despite a measured pathogen load.
2. Which experiment most directly tests for a genotype-by-pathogen interaction among three donor populations?
Explanation. A factorial design can reveal a genotype-by-pathogen interaction when the relative performance of donor genotypes changes across pathogen strains. Replication and common conditions reduce environmental confounding.
3. Why should local pathogen pressure be included when selecting a donor source for a climate refugium?
Explanation. Local pathogen pressure reflects the strains and exposure levels a released population is likely to encounter. Resistance measured against unrelated strains may not predict performance at the recipient site.
4. A donor genotype resists infection but produces fewer seeds than other genotypes when no pathogen is present. What does this pattern suggest?
Explanation. A fitness cost occurs when a trait that is beneficial under one condition reduces survival or reproduction under another. Such trade-offs matter when disease pressure varies through space or time.
5. Which multi-strain common-garden design provides the strongest comparison of donor performance?
Explanation. A multi-strain common-garden experiment crosses donor sources with pathogen treatments while holding the environment similar. Randomization, replication, and controls support causal comparisons.
6. In a common-garden experiment, donor A has the highest survival with strain 1 but the lowest survival with strain 2. Which conclusion is best supported?
Explanation. A ranking reversal means donor performance depends on pathogen identity. This interaction cautions against choosing a source from results obtained with only one strain.
7. Which pair of measurements best separates resistance from tolerance after controlled inoculation?
Explanation. Pathogen load provides evidence about resistance. The relationship between load and host fitness provides evidence about tolerance, so both pathogen burden and fitness are needed.
8. A field survey finds that one donor population has low disease prevalence. Why does this observation alone not validate genetic resistance?
Explanation. Observational prevalence combines host traits, pathogen exposure, and environmental effects. A controlled comparison is needed to separate inherited resistance from differences in exposure.
9. Why might managers retain several validated donor genotypes instead of selecting only the genotype with the strongest response to one pathogen strain?
Explanation. Different genotypes may perform best against different strains or conditions. Maintaining diversity can reduce reliance on one response, although it does not guarantee protection.
10. A resistance allele increases survival during outbreaks but reduces annual seed production by 15% without disease. What is the most testable prediction?
Explanation. Selection depends on fitness across the environments a population experiences. Benefits during frequent outbreaks can offset a fitness cost, whereas rare outbreaks may not.
11. Which post-release validation plan most directly tests whether experimental resistance predicts field performance?
Explanation. Post-release validation links controlled predictions to repeated field outcomes. Genotype identity, pathogen load, and fitness measures show whether resistance or tolerance persists under realistic exposure.
12. Field monitoring shows that a selected donor has low pathogen load but unexpectedly low reproduction. What is the most defensible adaptive-management response?
Explanation. Low pathogen load supports resistance but does not establish overall fitness. Comparing reproduction and reference genotypes can identify a fitness cost or another limiting factor before a larger release.
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FAQ
Are pathogen resistance and tolerance the same trait?
No. Resistance reduces infection or pathogen burden, while tolerance reduces the loss of survival or reproduction caused by a given burden. A donor population can show one, both, or neither.
Why test donor populations against multiple pathogen strains?
Donor performance can depend on strain identity. A multi-strain common-garden design can detect genotype-by-pathogen interactions that a single-strain test would miss.
Why is post-release validation still needed after a controlled experiment?
Controlled experiments isolate mechanisms, but field conditions add variable exposure, competitors, climate, and resource limits. Repeated field measurements test whether predicted resistance, tolerance, and fitness hold after release.