Final answer:
In polygynous mating systems, one would expect the effective population size to be smaller than the actual population size due to a few males mating with many females, resulting in reduced genetic diversity.
Step-by-step explanation:
In a polygynous mating system, where one male mates with multiple females, we would expect the effective population size to be smaller than the actual population size. This is because only a few males contribute genetically to the next generation. The females establish territories and attract males to the resources they control, leading to a few dominant males mating with many females. The genetic contribution of the population is thus skewed, with less genetic diversity being passed on to offspring compared to a population with equal mate contribution from both sexes.
Polygyny often results in a reduced effective population size due to the unequal reproductive success among males, as dominant males monopolize mating opportunities. This system contrasts with polyandry, where one female mates with multiple males, which is less common. Effective population size is an important concept in population genetics as it influences the rate of inbreeding and genetic drift in a population.