Populations

Environment

All factors, living and nonliving, that affect an organism during its life.

Ecology

Study of the interaction between organisms and their environment.

Ecological hierarchy

Arranging ecological approaches step-wise.

Organismal ecology

Focuses on organisms' response to environmental factors.

Population

Group of same-species individuals in the same place.

Community

Interacting populations forming an identifiable group.

Ecosystem

All species on a site with physical factors.

Landscape

Adjacent ecosystems covering large areas.

Biome

Large ecological unit composed of landscapes.

Biosphere

Total life on earth with the physical environment.

Basic ecology

Study of natural organism interactions under natural conditions not impacted by humans

Applied ecology

Focuses on human impact on the environment.

Environmental science

Applying scientific principles to solve human-induced disturbances.

Environmentalism

Concerned with human effects on nature.

Ethology

Study of animal behavior.

Ethologist

Biologist specializing in ethology.

Instinct

Behavior controlled by genetics.

Learning

Developing behavioral responses based on experience.

Abiotic Resources

Environmental factors directly incorporated into an animal's body.

Abiotic Regulators

Environmental factors that are not consumed directly, but which influence the survival of the animal

Law of limiting resources

Survival limited by the scarcest resource.

Tolerance range

Range for species survival under environmental variables.

Generalists

Species thriving in various conditions.

Specialists

Species surviving in narrow conditions.

Environmental variability

Fluctuations in environmental conditions.

Biological clocks

Mechanism perceiving time lapse.

Biorhythms

Behaviors in response to biological clocks.

Navigation

Directional sense for animal movement.

Territoriality

Behaviors protecting an area against others.

Migration

Seasonal movement of species.

Navigational cues

Environmental stimuli for animal navigation.

Communication

Actions influencing other animals.

Habitat

Where an animal lives.

Niche

The sum of an organism's utilization of and interaction with its environment; an organism's “place” or “role” in the environment

Fundamental niche

Species interaction under ideal conditions.

Realized niche

Actual interactions between organism and environment.

Principle of competitive exclusion

One species out-competing another for resources.

Indicator species

Species indicating environmental conditions.

Dispersion

Distribution of individuals in a habitat.

Intrinsic rate of growth

Maximum population growth rate.

Environmental resistance

Conditions inhibiting population growth.

Carrying capacity

Maximum sustainable population size.

Demography

Study of species life history.

Life history

Phases from birth to death.

Survivorship

Lifespan of an individual in a population.

Fecundity

Offspring production per unit time.

Cohort

Group born around the same time.

Survivorship curve

Graph of survivors at different ages.

Mortality rate

Proportion of individuals dying in a time interval.

Natality rate

Proportion of individuals born in a time interval.

Reproductive strategy

Means to maximize reproductive success.

Density-dependent factors

Factors lowering population with density.

Density-independent factors

Factors lowering population regardless of density.