The chapter “Organisms and Populations” links individual-level biology to population-level patterns (growth, survival, reproduction, and stability). It is crucial for board and competitive exams because key results like exponential/logistic growth, age-structured reproduction ( , generation time , intrinsic rate ), and metapopulation concepts frequently appear in application-based MCQs and numericals.
15
Minutes
10
Questions
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Marking
Q1. A bacterial population grows according to . If and , how many hours will it take to reach ?
Q2. A population follows logistic growth given by . For , and initial , how many years until the population first reaches ? (Use with .)
Q3. A species has age classes with survivorship and fecundity: . Find the value of adult fecundity that gives a stable population ().
Q4. Consider the following statements about metapopulations and habitat fragmentation.
I. A metapopulation can persist regionally even if local populations undergo frequent extinctions because empty patches can be recolonized.
II. Increasing isolation among habitat patches reduces recolonization rate and therefore increases the probability of regional extinction.
Both I and II are true, and II explains I.
Both I and II are true, but II does not explain I.
I is true, II is false.
I is false, II is true.
Q5. A population has age classes with . Using , mean generation time and , estimate the doubling time . Choose the closest value.
Q6. In a closed pond a capture–recapture study used the Lincoln–Petersen estimator . Researchers first marked and released fish. Later they captured fish, of which were marked. What is the best estimate of the total fish population ?
Q7. A population follows continuous logistic growth with , where . For , and initial , estimate the time (in years) required for to reach (90% of ).
Q8. Given age-specific data with survivorship and fecundity , compute , generation time and approximate intrinsic rate . Which value is closest to (per time unit)?
Q9. A harvested population follows with , and constant harvest individuals per year. Equilibria satisfy . If the starting population is , what is the long-term outcome?
Population will decline to extinction ()
Settle to the low unstable equilibrium near
Settle to the high stable equilibrium near
Exhibit sustained oscillations around
Q10. Field observations give: when , ; when , ; when , . Assuming discrete logistic dynamics approximated by per capita growth
, use these data to estimate the carrying capacity (nearest whole number).