AP Biology Unit 8: Ecology and Energy Dynamics

Endotherms

Organisms that use thermal energy generated by metabolism to maintain homeostatic body temperatures.

Ectotherms

Organisms that lack internal mechanisms to regulate body temperature, relying on external behaviors instead.

Thermoregulation

The process by which organisms regulate their body temperature.

Metabolic rate

The rate at which an organism converts energy and matter.

Innate Behavior

Genetically hardwired actions performed by all members of a species without prior experience.

Learned Behavior

Modification of behavior based on specific experiences.

Fixed Action Pattern (FAP)

A sequence of unlearned acts linked to a simple stimulus.

Imprinting

A long-lasting behavioral response to a particular individual or object during a critical period.

Habituation

A loss of responsiveness to stimuli that convey little or no new information.

Associative Learning

Learning to associate one environmental feature with another.

Pheromones

Chemical signals transmitted between animals, often used for communication.

Agonistic Behavior

Threats or combat used to settle disputes over resources.

Altruism

Behaviors that reduce an individual's fitness but increase the fitness of others.

Photoperiodism

A physiological response to the length of day/night affecting flowering in plants.

Tropisms

Directional growth responses of a plant toward or away from stimuli.

Producers (Autotrophs)

Organisms that capture energy from physical or chemical sources.

Consumers (Heterotrophs)

Organisms that capture energy present in carbon compounds from other organisms.

Decomposers

Organisms that recycle nutrients back into the soil.

10% Rule

Only about 10% of energy at one trophic level is passed to the next level.

Gross Primary Productivity (GPP)

Total amount of solar energy converted to chemical energy by photosynthesis.

Net Primary Productivity (NPP)

Energy stored as biomass that is available to consumers.

Exponential Growth

Population growth that occurs under ideal conditions with unlimited resources.

Logistic Growth

Population growth that occurs when resources are limited.

Carrying Capacity (K)

The maximum population size that the environment can sustain.

Density-Independent Factors

Abiotic factors that affect birth/death rates regardless of population size.

Density-Dependent Factors

Biotic factors whose impact increases as population density increases.

r-selected species

Species that produce many offspring with little parental care.

K-selected species

Species that produce few offspring with high parental care.

Simpson's Diversity Index

A formula to measure the diversity of a community.

Ecological Niche

The sum of a species' use of biotic and abiotic resources.

Keystone Species

A species that has a disproportionately large effect on its ecosystem.

Primary Succession

Occurs in a lifeless area where soil has not yet formed.

Secondary Succession

Occurs where an existing community has been disturbed but soil remains intact.

Invasive Species

Non-native species that disrupt local ecosystems by outcompeting native species.

Eutrophication

An excess of nutrients causing algal blooms and subsequent die-offs of aquatic life.

Biomagnification

The accumulation of toxins in successive trophic levels.

Climate Change

Long-term changes in temperature and typical weather patterns.

Density

The number of individuals per unit area.

Dispersion

The pattern of spacing among individuals in a population.

J-shaped curve

The characteristic growth pattern of exponential growth.

S-shaped curve

The characteristic growth pattern of logistic growth.

Fundamental Niche

The niche potentially occupied by a species.

Realized Niche

The actual niche occupied by a species.

Competitive Exclusion

When one species outcompetes another, leading to extinction of the latter.

Resource Partitioning

Species evolve to use different resources to avoid competition.

Mutualism

A symbiotic relationship where both species benefit.

Commensalism

A symbiotic relationship where one species benefits and the other is unaffected.

Parasitism

A symbiotic relationship where one organism benefits at the expense of the other.