AP BIO Unit 8 ALL

Ecosystem

The sum of all the organisms living in a given area and the abiotic factors they interact with.

Biotic factors

Living, or once living, components of an environment.

Abiotic factors

Nonliving physical and chemical properties of the environment.

First law of thermodynamics

Energy can neither be created nor destroyed, only transferred.

Second law of thermodynamics

Exchanges of energy increase the entropy of the universe.

Metabolic rate

The total amount of energy an animal uses in a unit of time.

Endotherms

Organisms that use thermal energy from metabolism to maintain body temperatures.

Ectotherms

Organisms that use external sources to regulate their body temperature.

Primary producers

Autotrophs that use light energy to synthesize organic compounds.

Heterotrophs

Organisms that cannot make their own food and rely on autotrophs for energy.

Gross primary production (GPP)

Total primary production in an ecosystem.

Net primary production (NPP)

The GPP minus the energy used by primary producers for respiration.

Secondary production

The amount of chemical energy in a consumer’s food that is converted to new biomass.

Biogeochemical cycles

Nutrient cycles that contain both biotic and abiotic factors.

Water Cycle

A cycle that is essential for all life and influences the rate of ecosystem processes.

Carbon Cycle

A cycle that is essential for life and required in the formation of organic compounds.

Nitrogen Cycle

A cycle important for the formation of amino acids, proteins, and nucleic acids.

Phosphorus Cycle

A cycle important for the formation of nucleic acids, phospholipids, and ATP.

Community

A group of populations of different species living closely and capable of interacting.

Niche

The role and position a species has in its environment.

Fundamental niche

The niche potentially occupied by the species if there were no limiting factors.

Realized niche

The portion of the fundamental niche the species actually occupies.

Interspecific interactions

Interactions of individuals from one species with individuals of another species.

Competition

A -/- relationship where individuals of different species compete for limited resources.

Competitive exclusion principle

Two species competing for the same resource cannot coexist permanently.

Niche partitioning

Natural selection drives competing species into different patterns of resource use.

Predation

A +/- relationship where one species kills and eats the other species.

Cryptic coloration

Camouflage that helps prey avoid detection by predators.

Batesian mimicry

A harmless species mimics a harmful one to avoid predation.

Mullerian mimicry

Two or more bad-tasting species resemble each other.

Herbivory

A +/- relationship where one organism eats part of a plant or alga.

Symbiosis

When 2 or more species live in direct contact with one another.

Parasitism

A (+/-) relationship where one organism derives nourishment from another.

Mutualism

A (+/+) relationship where both organisms benefit from the interaction.

Commensalism

A (+/0) relationship where one organism benefits and the other is neither harmed nor benefited.

Facilitation

A (+/+ or 0/+) relationship where one species positively affects another's survival without direct contact.

Species diversity

The variety of different organisms within a community.

Species richness

The number of different species in a community.

Relative abundance

The proportion each species represents of all individuals in the community.

Simpson's diversity index

A measure of diversity based on species richness and relative abundance.

Keystone species

Species that play a more pivotal role in their ecosystem, often not abundant.

Disturbance

An event that changes a community by removing organisms or altering resource availability.

Ecological succession

The gradual process by which species composition of a community changes over time after a disturbance.

Primary succession

Changes occurring on an entirely new habitat that has not been colonized.

Secondary succession

Changes that clear an existing community but leave the soil intact.

Human disturbances

Human activities that significantly disrupt ecosystems, leading to biodiversity loss.

Habitat loss

The single greatest threat to biodiversity, often due to agricultural development and urbanization.

Invasive species

Nonnative species that can competitively exclude native species from habitats.

Overharvesting

Harvesting organisms faster than their populations can rebound.

Global change

Alterations to climate, atmospheric chemistry, and ecological systems reducing Earth's capacity to sustain life.

Biogeographical factors

Large scale factors contributing to species diversity variations across different regions.

Pathogens

Disease-causing organisms and viruses that significantly affect biodiversity.

Population Ecology

The branch of ecology that studies populations of organisms, especially the regulation of population size, life history traits, and interactions between species.

Population Density

The number of individuals of a species per unit area, which helps understand the relationship between a population and its resources.

Dispersion

The pattern of spacing among individuals within a population, which can be clumped, uniform, or random.

Demography

The statistical study of populations, including the structure, distribution, and trends in population size and dynamics.

Life Table

An age-specific summary of the survival patterns of a population.

Type I Survivorship Curve

A survivorship curve characterized by low death rates during early and middle life, with a higher death rate in older age groups.

Type II Survivorship Curve

A survivorship curve that shows a constant death rate throughout the organism's life.

Type III Survivorship Curve

A survivorship curve characterized by high death rates early in life, with lower death rates for those that survive.

Exponential Growth

A model of population growth in ideal conditions where the population grows rapidly and exponentially, producing a J-shaped curve.

Logistic Growth

A model of population growth where the per capita rate of increase decreases as the population size approaches carrying capacity.

Carrying Capacity (K)

The maximum population size that an environment can sustain indefinitely without being degraded.

K-selection

Selection for life history traits that are sensitive to population density, typically seen in high-density populations near carrying capacity.

R-selection

Selection for traits that maximize reproductive success, often seen in low-density populations with minimal competition.

Density-dependent Regulation

Factors that regulate population growth based on population density, affecting birth and death rates.

Density-independent Regulation

Factors that affect population size but do not depend on the population density, such as weather and natural disasters.

Ethology

The study of how evolutionary processes shape inherited behaviors and the ways that animals respond to specific stimuli.

Proximate Cause

How a behavior occurs or how it is modified; it includes the stimulus that causes the behavior.

Ultimate Cause

Why a behavior occurs, particularly in the context of natural selection and its contribution to survival and reproduction.

Innate Behaviors

Developmentally fixed behaviors that are hereditary and instinctive; do not require learning.

Learned Behaviors

Behaviors that depend on environmental influence; they are shaped by experience.

Fixed Action Patterns (FAPs)

A sequence of unlearned acts directly linked to a stimulus, carried out to completion.

Kinesis

A change in the rate of movement in response to a stimulus that is nondirectional.

Taxis

Directional movement towards or away from a stimulus.

Imprinting

A long-lasting behavioral response to an individual that occurs during a sensitive period of development.

Natural Selection

The process that favors behaviors (innate or learned) which increase survival and reproduction.

Altruism

Selfless behavior that reduces an individual's fitness but increases the fitness of others in the population.

Phototropism

A directional response in plants that allows them to grow towards a source of light.

Photoperiodism

The response of plants to the length of day, which affects their flowering time.

Chemical Defenses

Production of toxic or distasteful compounds by plants to deter herbivory.

Spatial Learning

Establishing memories based upon the spatial structure of an animal’s surroundings.

Social Learning

Learning through observations and imitations of others' behaviors.

Signal

A stimulus generated and transmitted from one animal to another for communication.

Pheromones

Chemical signals emitted by members of a species affecting other members of the same species.