Life-History Parameters

Life History

The sequence, timing, and nature of events in an organism’s life, from birth to reproduction to death.

Life History Strategies

A pattern of life-history traits that determines some aspect of life history for an organism or species, such as age and size at maturity, number and size of offspring produced, or longevity.

Successful Life History Strategy

A strategy that results in a growing or stable population estimated growth rate (r-value).

Unsuccessful Life History Strategy

A strategy that results in a contracting or shrinking population estimated growth rate (r-value).

Birth Rate (b)

The number of individuals born per individual in a population per unit of time.

Death Rate (d)

The number of individuals that die per individual in a population per unit of time.

Estimated Growth Rate (r)

The net change in population size per unit of time. A positive r-value indicates a growing population, a r-value close to zero indicates a stable population, and a negative r-value indicates a contracting or shrinking population.

Fecundity

The average number of offspring per reproductive female per unit of time.

Population Age Structure

The distribution of individuals across ages within a population, from birth to the species' maximum life span.

Age/Population Pyramids

Graphical representations of a population's age structure, which can indicate whether the population size is growing, shrinking, or stable.