1. Conservation biology.  Conservation biology is the study of biodiversity, its rate of loss, and methods for sustaining it.
2. Species-area relationship.  The observation that greater sizes of habitat will support greater numbers of species is called the species-area relationship. Its converse, smaller areas will support smaller numbers of species, has been used to estimate the effects if habitat loss.
3. Endemism.  Endemic species have evolved in, and are restricted to, only one geographic area.
4. Minimum viable population (MVP).  The approximate number or density of individuals necessary for the continuation and growth of a population, or the minimum viable population, is often estimated to determine a population's risk of extinction.
5. Population viability analysis (PVA).  Conservation biologists conduct a population viability analysis to determine how the population size is influenced by random variations in birth rates, death rates, and genetic variability.