AP Environmental Science: Population Ecology, Dynamics, and Demographics

Comprehensive vocabulary review flashcards covering population ecology, growth models, carrying capacity, human demography, and the demographic transition model from AP Environmental Science Units 3.1 through 3.4.

Generalist Species

Species that live in many environments and eat a variety of foods, allowing them to adapt easily when environmental conditions change (e.g., kangaroos, stickleback fish, and white pine trees).

Specialist Species

Species that live in specific environments and eat specific foods, thriving in stable habitats but vulnerable to extinction if their habitat or food supply changes (e.g., koalas and leaf beetles).

K-selected Species

Species characterized by long lifespans, few offspring per event, high parental care, and stable populations that remain near carrying capacity ($K$) (e.g., elephants, humans, and birds).

r-selected Species

Species characterized by short lifespans, many offspring per event, low or no parental care, and populations that bounce up and down (e.g., mice, mosquitoes, and dandelions).

Type I Survivorship Curve

A survivorship curve characterized by high survival rates throughout life, in which most individuals survive until old age (typical of K-selected species like humans and elephants).

Type II Survivorship Curve

A survivorship curve characterized by a constant risk of dying and an equal chance of mortality at any age (e.g., squirrels and birds of prey).

Type III Survivorship Curve

A survivorship curve characterized by high mortality among the young and low survival early in life, with very few individuals reaching adulthood (typical of r-selected species like frogs, mosquitoes, and dandelions).

Density-Dependent Factors

Factors whose influence on an individual's probability of survival and reproduction depends on population size, such as food supply, competition for space or nesting sites, clean water, and disease transmission.

Density-Independent Factors

Factors that exert the exact same effect on an individual's probability of survival and reproduction regardless of population size or density, such as tornadoes, hurricanes, floods, volcanic eruptions, fires, extreme cold spells, and habitat clearing.

Biotic Potential

The maximum reproductive capacity of a population under ideal environmental conditions.

Exponential Growth Model

A growth model that estimates a population's future size over time based on its biotic potential and current reproducing individuals under conditions of unlimited resources, producing a J-shaped curve.

Logistic Growth Model

A growth model describing a population whose expansion begins exponentially but slows as the population approaches the carrying capacity ($K$) of its environment, generating an S-shaped curve.

Carrying Capacity ($K$)

The maximum number of individuals of a given species that an environment can sustainably support over time.

Inflection Point

The point on a logistic growth curve (occurring around $K/2$, or half the carrying capacity) where the population growth rate begins to decelerate due to resource scarcity.

Limiting Resource

A resource that a population requires to survive and grow, but which exists in quantities lower than what the population needs to expand (e.g., water, nitrogen, phosphorus, sunlight, food, clean water, shelter, or nesting cavities).

Lag Time

The delay between the time resources become available (such as during fall/winter mating seasons) and when offspring are actually born (spring/summer).

Overshoot

The phenomenon occurring when a population briefly exceeds the environment's actual carrying capacity ($K$) because reproduction depends on past resource levels rather than current ones.

Dieback (Crash)

A severe and rapid drop in population size far below carrying capacity caused by starvation and mortality when an overshot population rapidly exhausts available resources.

Crude Birth Rate (CBR)

The number of live births per $1{,}000$ individuals per year.

Crude Death Rate (CDR)

The number of deaths per $1{,}000$ individuals per year.

Net Migration Rate

The difference between immigration and emigration per $1{,}000$ individuals in a given year.

$(\text{CBR} - \text{CDR}) / 10$.

Global Population Growth Rate Formula

$((\text{CBR} + \text{Immigration}) - (\text{CDR} + \text{Emigration})) / 10$.

National Population Growth Rate Formula

Life Expectancy

The average number of years an infant born in a specific year and country can be expected to live.

Infant Mortality Rate

The number of deaths of children under $1\text{ year}$ of age per $1{,}000$ live births.

Child Mortality Rate

The number of deaths of children under age $5$ per $1{,}000$ live births.

Environmental Justice

The study of disproportionate exposure to environmental hazards experienced by people of color, recent immigrants, or individuals of lower socioeconomic status.

Total Fertility Rate (TFR)

The estimated average number of children a woman will bear during her childbearing years, defined as ages $15\text{–}49$.

Replacement-Level Fertility

The total fertility rate needed to offset deaths in a population to maintain a stable population size without net migration (approximately $2.0$ or $2.1$ in developed nations, and greater than $2.1$ in developing nations).

$70 / \text{growth rate (\%)}$.

Rule of 70

Stage 1 (Preindustrial)

The phase of the Demographic Transition Model characterized by slow population growth where high birth rates and high death rates cancel each other out.

Stage 2 (Industrializing)

The phase of the Demographic Transition Model characterized by rapid population growth where death rates drop due to better sanitation and healthcare, but birth rates remain high.

Stage 3 (Industrialized)

The phase of the Demographic Transition Model characterized by stable population growth where birth rates drop as income, education, and urbanization increase.

Stage 4 (Declining)

The phase of the Demographic Transition Model where birth rates drop below death rates, resulting in declining population growth and an aging population (e.g., Japan and Italy).

IPAT Equation

A conceptual formula used to estimate the environmental impact of human lifestyles and populations: $\text{Impact} = \text{Population} \times \text{Affluence} \times \text{Technology}$.