BIO 11 EXAM: Ecology

BIO 11 EXAM

Individual / Organism

A single, distinct living entity of a specific species.

Species

A group of organisms that are genetically similar and can interbreed to produce fertile offspring.

Population

A group of individuals of the same species living in the same geographic area at the same time.

Community

All the different populations of different species that live and interact in the same area.

Ecosystem

A community of living organisms (biotic) interacting with their non-living environment (abiotic).

Biome

A large geographic region characterized by a specific climate, vegetation, and adapted animal communities.

Biosphere

The global ecological system integrating all living beings and their relationships; the zone of life on Earth.

Habitat

The specific physical place or environment where an organism naturally lives and grows.

Biotic factors

The living or once-living parts of an ecosystem that affect other organisms (e.g., predators, plants, bacteria).

Abiotic factors

The non-living physical and chemical components of an ecosystem (e.g., sunlight, temperature, water, soil).

Biodiversity

The variety and variability of life forms within a given ecosystem, biome, or the entire planet.

Species Diversity

The number of different species and the abundance of each species within a specific community.

Ecological Diversity

The variety of different ecosystems, habitats, and communities present within an entire region.

Producers (autotrophs)

Organisms that make their own food using energy from sunlight (photosynthesis) or chemicals (chemosynthesis).

Primary productivity

The rate at which solar energy is captured and converted into organic compounds (biomass) by producers.

Primary Consumer (heterotrophs)

Organisms that eat producers to obtain energy; also known as herbivores.

Secondary consumer

Organisms that eat primary consumers for energy; can be carnivores or omnivores.

Tertiary consumer

Apex predators that eat secondary consumers for energy.

Herbivore

A consumer that eats exclusively plants/producers.

Carnivore

A consumer that eats exclusively other animals (meat).

Omnivore

A consumer that eats both plants (producers) and animals.

Detritivore

An organism that physically feeds on dead organic matter and debris (e.g., earthworms, crabs).

Decomposer

An organism that chemically breaks down dead organic material and returns nutrients to the soil (e.g., fungi, bacteria).

Biomass

The total mass of living organic matter within a given trophic level or ecosystem area.

Food chain

A single, linear pathway showing the flow of energy from one organism to the next as they eat and are eaten.

Food web

A complex network of interconnected food chains showing all the feeding relationships in an ecosystem.

Energy pyramid / Food pyramid

A diagram that shows the total amount of energy or biomass available at each trophic level.

Trophic levels

The hierarchical levels or steps in an ecosystem's food chain/pyramid (e.g., producers, primary consumers).

Ten Percent Rule (10% Law)

Only about 10% of the energy at one trophic level is passed on to the next; the other 90% is lost as metabolic heat.

Keystone species

A species that has an unusually large, critical impact on maintaining the structure and balance of its ecosystem.

Photosynthesis (Ecology context)

Consumes carbon dioxide and water using sunlight to produce glucose (chemical energy) and oxygen gas.

Cellular respiration (Ecology context)

Breaks down glucose in the presence of oxygen to yield usable cellular energy (ATP), water, and carbon dioxide.

How do energy transformations connect Photosynthesis and Respiration?

Producers use photosynthesis to store solar energy as glucose. All organisms use respiration to break that glucose down to release ATP.

Niche

The specific role, position, and resources an organism utilizes within its environment.

Fundamental niche

The full, theoretical range of environmental conditions and resources an organism could occupy without competition.

Realized niche

The actual, narrower range of environmental conditions and resources an organism actually occupies due to competition.

Predation

An interaction where one organism (predator) kills and consumes another organism (prey).

Competition

An interaction where individuals struggle for the same limited resources (e.g., food, water, mates, territory).

Symbiosis

A close, long-term ecological relationship between two different species living together.

Mutualism

A type of symbiosis where both species benefit from the interaction (+/+).

Commensalism

A type of symbiosis where one species benefits and the other is unaffected/neither helped nor harmed (+/0).

Parasitism

A type of symbiosis where one species benefits (parasite) while harming, but usually not killing, the host (+/-).

Population size

The total number of individual organisms in a specific population.

Population density

The number of individuals of a population per unit of area or volume.

Exponential growth

Rapid, J-shaped population growth that occurs when resources are unlimited.

Logistic growth

S-shaped population growth that slows and levels off as resources become limited.

Carrying capacity (K)

The maximum population size of a species that an ecosystem can sustainably support over time.

Steady state / Stable growth

The phase where a population hovers near its carrying capacity, fluctuating slightly but remaining relatively stable.

Cyclic growth

Population fluctuations characterized by regular, predictable rises and falls (often seen in predator-prey cycles).

Limiting factors

Environmental resources or conditions that restrict the growth, abundance, or distribution of a population.

Density-dependent factors

Limiting factors whose impact changes based on population density (e.g., competition, disease, predation, food shortage).

Density-independent factors

Limiting factors that affect a population regardless of its density (e.g., natural disasters, weather, human activity).

Ecological Succession

The gradual process by which the structure of a biological community changes and develops over time.

Primary succession

Ecological succession that begins in a completely barren area with no soil (e.g., bare rock after a volcanic eruption).

Pioneer species

The first, hardy species to colonize a barren area during primary succession, helping to build soil (e.g., lichens, mosses).

Secondary succession

Ecological succession that occurs in an area where an existing community was disrupted, but soil remains (e.g., after a wildfire).

Climax community

The stable, mature, and balanced community that marks the final stage of ecological succession.

Bioaccumulation

The build-up of a toxic chemical or pollutant inside the tissues of a single individual organism over its lifespan.

Biomagnification

The increasing concentration of a toxin as it moves up successive levels of a food chain, hitting apex predators hardest.