Chapter 56- Ecology and Ecosystems

Population

A group of individuals of a single species that occupy the same general area.

Density

The number of individuals of a species per unit area or volume, influenced by abiotic and biotic factors.

Dispersion Patterns

The way individuals are spatially arranged within a population; includes clumped, uniform, and random distribution.

Survivorship Curves

Graphs that plot the proportion of individuals alive at each age from an initial population.

Type I Survivorship Curve

High survival rates during early and middle life, with a steep decline in old age (e.g., humans).

Type II Survivorship Curve

A constant death rate throughout life (e.g., some birds).

Type III Survivorship Curve

High mortality early in life, but those that survive tend to live long (e.g., fish, many insects).

Exponential Growth Model

A model representing unlimited growth, where a population grows at a constant rate, forming a J-shaped curve.

Logistic Growth Model

A growth model considering environmental limitations, leading to a carrying capacity (K) and an S-shaped curve.

Carrying Capacity (K)

The maximum population size that the environment can support based on available resources.

Intraspecific Competition

Competition within the same species for limited resources, regulating population size.

Density-Dependent Factors

Factors that increase in effect as population density increases, such as competition, predation, and disease.

Density-Independent Factors

Factors affecting the population regardless of density, including natural disasters and human activities.

Boom and Bust Cycles

Population cycles where populations grow rapidly (boom) before crashing (bust) due to resource scarcity or increased predation.

J-shaped Curve

Represents unlimited growth, typically observed with abundant resources and no significant limitations.

S-shaped Curve

Reflects growth that slows as it approaches the carrying capacity, where growth stabilizes.