21 terms

Chapter 19: Population Ecology

Population density
number of individuals per unit area
Age structure
proportion of people in different age groups in a population
Life tables
age-specific summaries of the survival pattern of a population
Survivorship curve
Graph showing the number of survivors in different age groups for a particular species.
Life history
the traits that affect an organism's schedule of reproduction and survival
opportunistic life history
• Take immediate advantage of favorable conditions
• Typically exhibit a Type III survivorship curve
equilibrial life history
the pattern of reproducing when mature and producing few offspring but caring for the young (larger - bodied species)
Exponential population growth
The geometric increase of a population as it grows in an ideal, unlimited environment.
Limiting factors
environmental factors that restrict population growth
carrying capacity
largest number of individuals of a population that a environment can support
logistic population growth
A model describing population growth that levels off as population size approaches carrying capacity
Intraspecific competition
competition between individuals for the same species for limited resources
density-dependent factor
a population limiting factor whose effects intensify as the population increases in density
density-independent factor
a population limiting factor whose intensity is unrelated to population density
Biological control
the intentional release of a natural enemy to attack a pest population
the process in which species exert selective pressure on each other and gradually evolve new features or behaviors as a result of those pressures
Population momentum
the potential for future increases or decreases in a population based on the present age structure
Ecological footprint
An estimate of the amount of land required to provide the raw materials an individual or a population consumes.
Endangered species
one that is in danger of extinction through out all or a significant portion of its range
Threatened species
defined as those that are likely to become endangered in the foreseeable future
invasive species
a non-native species that has spread far beyond the original point of introduction and causes environmental or economic damage.