Unit 8: Ecology

30 vocabulary flashcards covering key ecological concepts, experimental procedures, and analytical tools emphasized in AP Biology Unit 8.

Food Chain

A linear sequence that shows how energy and matter pass from producers through successive levels of consumers.

Food Web

An interconnected network of food chains that illustrates multiple feeding relationships and energy flow within an ecosystem.

Trophic Pyramid (Energy Pyramid)

A diagram that depicts the amount of energy or biomass present at each trophic level in an ecosystem.

Biodiversity

The variety of life in an area, including species diversity, genetic variation, and ecosystem diversity.

Keystone Species

A species whose impact on community structure is disproportionately large relative to its abundance; its removal can cause ecosystem collapse.

Autotroph

An organism that captures energy from physical or chemical sources (e.g., sunlight) to produce its own organic molecules.

Heterotroph

An organism that obtains energy by consuming organic carbon compounds produced by other organisms.

Endotherm

An animal that maintains a constant internal body temperature using metabolic heat.

Ectotherm

An animal that relies primarily on external environmental heat sources to regulate body temperature.

Metabolic Rate

The amount of energy used by an organism per unit time; generally higher per gram in smaller organisms.

Exponential Growth

Population increase under ideal conditions where the growth rate is proportional to current population size (dN/dt = rₘₐₓN).

Logistic Growth

Population growth that slows as it approaches carrying capacity, producing an S-shaped curve (dN/dt = rₘₐₓN(1−N/K)).

Carrying Capacity (K)

The maximum population size that a particular environment can sustain over time.

Density-dependent Factor

A limiting factor whose influence on population size varies with population density (e.g., competition, disease).

Density-independent Factor

A limiting factor that affects populations regardless of their density (e.g., natural disasters, temperature extremes).

Simpson's Diversity Index

A quantitative measure of species diversity that accounts for both richness and relative abundance (D = 1 − Σ(n/N)²).

Trophic Cascade

A series of indirect interactions that start at the top of the food chain and ripple down to affect multiple trophic levels.

Niche Partitioning

The process by which competing species use the environment differently, reducing competition and allowing coexistence.

Invasive Species

A non-native species that enters an ecosystem and disrupts community dynamics by outcompeting native species for resources.

Pack Behavior

Cooperative group interactions in animals that can improve hunting success, defense, and reproductive fitness.

Photoperiodism

A physiological response to the length of day or night, such as timing of flowering or breeding.

Taxis

A directed movement toward or away from a specific stimulus, such as light (phototaxis) or chemicals (chemotaxis).

Fight-or-Flight Response

A rapid physiological reaction to a perceived threat that prepares an organism for immediate action.