APES UNIT 3

Specialist species

Species with a narrow ecological niche and small tolerance range, making them highly vulnerable to environmental change and extinction

Generalist species

Species with a broad ecological niche and wide tolerance range, making them adaptable and less prone to extinction

Ecological niche

The role a species plays in its environment, including how it uses resources and interacts with other organisms

K

selected species

r

selected species

Biotic potential

The maximum rate at which a population can grow under ideal conditions with unlimited resources

Population dynamics

Changes in population size and structure over time

Survivorship curve

A graph showing the proportion of individuals in a cohort that survive at each age

Type I survivorship

High survival in early and middle life with most mortality occurring at old age

Type II survivorship

A constant mortality rate throughout the lifespan

Type III survivorship

High mortality early in life with greater survival for individuals that reach adulthood

Carrying capacity (K)

The maximum number of individuals an environment can sustainably support

Overshoot

When a population temporarily exceeds its carrying capacity

Die

off

Predator–prey cycle

A population cycle in which predator numbers rise and fall in response to changes in prey population size

Population size (N)

The total number of individuals in a population at a given time

Population density

The number of individuals per unit area

Population distribution

The pattern of spacing among individuals within a population

Random distribution

A population distribution in which individuals are spaced unpredictably

Uniform distribution

A population distribution in which individuals are evenly spaced due to territorial behavior

Clumped distribution

A population distribution in which individuals are grouped together in clusters

Sex ratio

The proportion of males to females in a population

Density

dependent factors

Density

independent factors

Age structure diagram

A graph showing the number of individuals in each age group of a population, usually separated by sex

Population pyramid

An age structure diagram with a wide base, indicating high birth rates and rapid population growth

Pre

reproductive age group

Reproductive age group

Individuals ages 15–44 who are capable of reproduction

Post

reproductive age group

Population momentum

Continued population growth after birth rates decline due to a large proportion of individuals in reproductive age

Pyramid

shaped age structure

Column

shaped age structure

Inverted pyramid age structure

An age structure indicating population decline

Total Fertility Rate (TFR)

The average number of children a woman is expected to have during her lifetime

Replacement

level fertility

Infant Mortality Rate (IMR)

The number of deaths of infants under age one per 1,000 live births

Exponential growth

Rapid population growth under unlimited resources, producing a J

Logistic growth

Population growth that slows as it approaches carrying capacity, producing an S

Malthusian theory

The idea that population growth will eventually exceed food supply, resulting in population decline

Crude Birth Rate (CBR)

The number of births per 1,000 people per year

Crude Death Rate (CDR)

The number of deaths per 1,000 people per year

Growth rate (r)

The percent change in population size per year

Demography

The scientific study of human populations and population trends

Affluence

The level of wealth and consumption per person in a population

Ecological footprint

The amount of land and resources required to support an individual or population

IPAT equation

A formula estimating environmental impact as the product of population, affluence, and technology

Technology (IPAT)

The environmental impact per unit of consumption, which can increase or decrease total impact

Doubling time

The number of years required for a population to double in size

Rule of 70

A method for estimating doubling time by dividing 70 by the growth rate percentag