Population

Population Size

The total number of individuals in a population at a specific time.

Population Density

The number of individuals per unit area or volume.

Sex Ratio

The proportion of males to females in a population.

Age Structure

The distribution of individuals across different age groups in a population.

Distribution

The spatial arrangement of individuals in a population across a given area or habitat.

Density Dependent Factors

Factors that exert more influence as population density increases, such as competition for resources, predation, disease, and parasitism.

Density Independent Factors

Factors that affect populations regardless of their density, including natural disasters, temperature extremes, and habitat destruction.

Exponential Population Growth

A growth pattern where a population reproduces constantly, resulting in a J-shaped curve on a graph.

Logistic Growth Model

A population growth model that initially shows exponential growth, then levels off as the population reaches its carrying capacity.

Carrying Capacity

The maximum population size an environment can sustainably support with available resources.

r-selected species

Species that produce numerous offspring, invest little parental care, and thrive in unpredictable environments.

K-selected species

Species that produce fewer offspring but invest significantly in their care, aiming for their survival in stable environments.

Survivorship Curves

Graphs that depict the number of individuals in a population that survive at different ages.

Type I Curve

Survivorship curve characterized by low early mortality and increased mortality with age, common in K-selected species.

Type II Curve

Survivorship curve with constant mortality rates across all ages, indicating intermediate survival chances throughout life stages.

Type III Curve

Survivorship curve showing high mortality rates in early life stages, typical of r-selected species.

Metapopulation

A group of interconnected subpopulations of the same species occupying fragmented habitats.

Crude Birth Rate

The number of live births per 1,000 people in a population within a given time.

Crude Death Rate

The number of deaths per 1,000 people in a population within a given time.

Total Fertility Rate (TFR)

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

Replacement Level Fertility (RLF)

The fertility rate at which each generation exactly replaces itself without increasing or decreasing the population.

IPAT Equation

Impact = Population x Affluence x Technology; a model used to estimate environmental impact.

Urbanization

The increase in the proportion of people living in cities.

Urban Sprawl

The uncontrolled expansion of urban areas leading to environmental degradation and loss of habitats.

Smart Growth

An urban planning approach aiming for sustainable development and efficient land use.