A viable population is a population capable of maintaining itself, without significant manipulation. How the population is regulated.
Small populations are fragile because of chance events, or stochasticity.
Variation in birth and death rates 2. Variation in size of reproducing population 3. B. Genetic Uncertainty - Genetic diversity is necessary for populations to adapt to environmental change. Loss of genetic diversity reduces future evolutionary options. Structured populations lose genetic variation over time more quickly than panmictic ones of the same total size.