Final answer:
Compensatory mortality occurs when mortality in one age group is balanced by higher survival rates in another age group, resulting in a stable population. Additive mortality occurs when mortality is added to a population and the overall death rate increases.
Step-by-step explanation:
Compensatory mortality and additive mortality are two different ways of measuring death in a population.
Compensatory mortality occurs when mortality in one age group is balanced by higher survival rates in another age group, resulting in a stable population. For example, if a population experiences high mortality in younger individuals but lower mortality in older individuals, the older age group compensates for the loss by surviving longer.
Additive mortality occurs when mortality is added to a population and the overall death rate increases. This can happen when mortality affects all age groups equally, leading to a decline in the population size. For example, if a population experiences higher mortality rates across all age groups due to a disease outbreak or some other factor, the overall death rate will increase and lead to a decrease in population size.