The Human Population

Flashcards covering key vocabulary related to human population dynamics, limiting factors, reproductive patterns, survivorship, and ways to influence population growth, based on lecture notes.

Range of tolerance

The variation in physical and chemical environment under which a population can survive.

Limiting factors

Variables that constrain population size, such as precipitation on land or water temperature, depth, and clarity in aquatic environments.

Population density

A measure of how crowded a population is, influencing density-dependent factors that can limit its size.

J-shaped curve of growth

A visual representation of exponential population growth, characteristic of species that reproduce quickly with many offspring.

Environmental resistance

The sum of all factors (e.g., limited resources, predation, disease) that collectively limit the growth of a population.

Carrying capacity

The maximum population size of a given species that a particular habitat can sustain indefinitely without degradation.

Overshoot

When a population temporarily exceeds its habitat's carrying capacity, often leading to a population crash.

r-Selected species

Species characterized by a high capacity for population growth, often having many small offspring, reproducing early, and having short life spans (e.g., bacteria, insects).

K-Selected species

Species characterized by reproducing later in life, having few, larger offspring, and long life spans, typically existing near their carrying capacity (e.g., large mammals, humans).

Survivorship curve

A graph illustrating the percentage of a population's members surviving at different ages.

Late loss (Type I survivorship)

A pattern where most individuals survive to old age, typical of K-selected species with high parental care.

Early loss (Type III survivorship)

A pattern where most individuals die at young ages, common in r-selected species with many offspring and little parental care.

Constant loss (Type II survivorship)

A pattern where the mortality rate is relatively constant across all ages, seen in species like many songbirds.

Cultural carrying capacity

The maximum number of people who could live in reasonable freedom and comfort indefinitely without decreasing the earth's ability to sustain future generations.

Total fertility rate (TFR)

The average number of children born to women of childbearing age in a population.

Replacement-level fertility rate

The average number of children a couple must bear to replace themselves in the population, typically around 2.1 in more-developed countries.

Life expectancy

An indicator representing the average number of years a person is expected to live in a given population, reflecting overall health.

Infant mortality rate

The number of babies out of every 1,000 live births who die before reaching their first birthday, often linked to insufficient food, poor nutrition, and disease.

Migration

The movement of people into (immigration) and out of (emigration) specific geographic areas.

Age structure

The distribution of individuals in a population by age groups: pre-reproductive (0-14), reproductive (15-44), and post-reproductive (45 and older).

Demographic momentum

The tendency for a population to continue growing for decades, even after fertility rates have declined, due to a large proportion of young people.

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.

American Baby Boom

A period between 1946–1964 in the U.S. when approximately 79 million people were born, significantly impacting subsequent demographic trends.

Demographic transition

A model illustrating generalized population change as countries become industrialized, characterized by declining poverty and slower population growth.

Family planning

Practices and services that enable individuals to decide freely and responsibly the number and spacing of their children, often involving contraception and related health care.

China's One-Child Policy

A strict government program implemented in China in 1978 to curb population growth, which reduced fertility rates but also led to negative social and demographic consequences.