APES Unit Three Vocabulary

age-structure pyramids

show the relative number of individuals of each age in a population and can be used to predict and explain many demographic patterns

biotic potential

Maximum rate at which the population of a given species can increase when there are no limits on its rate of growth.

birth rate (crude birth rate)

the number of births in a year for every 1,000 people in a population

carrying capacity

Largest number of individuals of a population that a environment can support

death rate (crude death rate)

is equal to the number of deaths per 1,000 members of the population in a year.

demographic transition model

A sequence of demographic changes in which a country moves from high birth and death rates to low birth and death rates through time.

Emigration

movement of individuals out of an area

Developed Country (MDC)

a modern, industrialized country in which people are generally better educated and healthier and live longer than people in developing countries do

Developing Country (LDC)

Country identified as those that have not achieved significant industrial growth relative to increase in population. Their GDP remains relatively low and as a result, their standard of living is low. Their structures such as governments and education systems are often unstable.

exponential population growth

Growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time.

Gross National Product (GNP)

The total value of goods and services, including income received from abroad, produced by the residents of a country within a specific time period, usually one year.

K-selected species

Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age.

r-selected species

Species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period.

logistic population growth

A model describing population growth that levels off as population size approaches carrying capacity; represented by an S shaped curve

Overshoot

The extent to which a population exceeds the carrying capacity of its environment

population density

A measurement of the number of people per given unit of land

population momentum

The propensity for a growing population to continue growing even through fertility is declining because of their young age distribution

replacement birth rate

refers to the number of children a couple must have in order to replace themselves in a population; usually greater than two due to infant and child mortality

Total Fertility Rate (TFR)

The average number of children a woman will have throughout her childbearing years.

generalist species

Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. Examples are flies, cockroaches, mice, rats, and human beings.

specialist species

Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food.

Type I survivorship curve

A survivorship curve in which newborns, juveniles, and young adults all have high survival rates and death rates do not begin to increase greatly until old age.

Type II survivorship curve

a constant death rate over the organism's life span

Type III survivorship

Experience the greatest mortality early on in life, with relatively low rates of death for those surviving

keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

invasive species

species that enter new ecosystems and multiply, harming native species and their habitats

crude growth rate

crude birth rate - crude death rate

Population Dieback

a rapid decrease in numbers experienced by a population of organisms that has temporarily exceeded, or overshot, its carrying capacity

density dependent factors

A limiting factor of a population wherein large, dense populations are more strongly affected than small, less crowded ones.

density independent factors

limiting factor that affects all populations in similar ways, regardless of population size

Percent Change

((New-Old)/Old)*100

infant mortality rate

A figure that describes the number of babies that die within the first year of their lives in a given population.

Rule of 70

Doubling time (in years) = 70/(percentage growth rate)

Gross Domestic Product (GDP)

The total output of all economic activity in the nation, including goods and services.