Define net reproductive rate R0 and its ecological interpretation.

• A. R0 is the expected number of daughters produced by a newborn female over her lifetime; R0>1 implies population growth.
• B. R0 is the current population size; if R0>1 population declines.
• C. R0 is the mutation rate per generation; R0>1 increases diversity.
• D. R0 is the carrying capacity; R0<1 indicates overcrowding.

Answer: (D)

Net reproductive rate is the average number of daughters a newborn female would produce over her lifetime, given the current survival and fertility patterns at each age. It’s calculated by combining age-specific survival and fecundity across all reproductive ages. Ecologically, this tells you about potential population growth per generation: if R0 is greater than 1, the population is expected to grow; if R0 is less than 1, it will decline; if R0 equals 1, it remains stable. It’s not about current population size, mutation rate, or carrying capacity—the environment’s limit on population size. Carrying capacity relates to available resources, while R0 focuses on how many offspring are produced and how that translates into future population change.