population

Baby Boom

A period of significantly higher birth rates, especially in the U.S. from 1946 to 1964, following World War II.

Birth rate

The number of live births in a specific population over a set period, usually per 1,000 people per year.

Carrying Capacity

The maximum number of individuals an environment can support without damaging the ecosystem.

Crude Birth Rate

The number of live births per 1,000 people in a population per year.

Crude Death Rate

The number of deaths per 1,000 people in a population per year.

Demographic Transition Model

A theory that describes how birth and death rates change over time as a country develops, typically moving through four stages: high birth and death rates, declining death rates, declining birth rates, and low birth and death rates.

Demography

The study of populations, including their size, structure, distribution, and changes over time.

Density-dependent Factors

Environmental factors, like food and disease, that affect a population more strongly as its density increases.

Density-independent Factors

Environmental factors, like weather or natural disasters, that affect a population regardless of its size.

Doubling Time

The time it takes for a population to double in size at a constant growth rate.

Emigration

The movement of individuals out of a population or area.

Exponential Growth

A population growth pattern where the size increases rapidly due to a constant growth rate.

Family Planning

Practices and methods used to control the number and timing of children born.

Growth Rate

The rate at which a population increases or decreases over time.

Immigration

The movement of individuals into a population or area.

Infant Mortality Rate

The number of infants who die before reaching one year old, per 1,000 live births.

IPAT model

A formula (Impact = Population × Affluence × Technology) used to estimate environmental impact based on population, affluence, and technology.

Replacement Level Fertility

The fertility rate needed for a population to replace itself without growing or shrinking, usually about 2.1 children per woman.

Survivorship Curves

Graphs showing the number or proportion of individuals surviving at each age for a species.

The Rule of 70

A formula used to estimate the doubling time of a population: 70 ÷ growth rate.

Total Fertility Rate (TFR)

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

Type I - Survivorship Curve

A curve showing high survival rates for most of the population until old age, common in species with few offspring (e.g., humans).

Type II - Survivorship Curve

A curve showing a constant death rate throughout the life of the organism, often seen in some birds and reptiles.

Type III - Survivorship Curve

A curve showing high mortality early in life, with a few individuals surviving to old age, common in species with many offspring (e.g., fish).