Unit 3 Populations APES

Generalist species

Species with broad niches, able to tolerate a wide range of conditions and use varied resources.

Specialist species

Species with narrow niches, adapted to specific conditions or resources.

K-strategists (k-selected)

Species that produce few offspring, invest heavily in parental care, and have populations near carrying capacity.

R-strategists (r-selected)

Species that produce many offspring, provide little parental care, and have populations that fluctuate widely.

Survivorship curve

A graph showing the proportion of individuals surviving at each age.

Type I Survivorship

High survival in early and middle life, with most deaths occurring in older age.

Type II Survivorship

Constant death rate at all ages.

Type III Survivorship

High death rates early in life, with survivors living much longer.

Carrying capacity

The maximum population size an environment can sustain long term.

Age Structure Diagrams

Graphs showing the distribution of a population by age and sex.

Total Fertility Rate

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

Biotic potential

The maximum reproductive capacity of a species under ideal conditions.

Fecundity

The biological ability to reproduce and produce offspring.

Population overshoot

When a population exceeds the carrying capacity, often followed by a die-off.

Malthusian theory

The idea that population growth will outpace food supply, leading to resource shortages.

Rule of 70

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

Demographic Transition

The model showing how birth and death rates change as a country develops economically.

Density-independent factors

Factors that affect populations regardless of density (e.g., natural disasters, climate).

Density-dependent factors

Factors that limit population size more strongly as population density increases (e.g., disease, competition).

Developed Countries/More Developed

Nations with high income, industrialization, and low population growth.

Developing Countries/Less Developed

Nations with lower income, less industrialization, and higher population growth.