productivity test

Autotroph

An organism that produces its own food using sunlight (photosynthesis) or chemicals (chemosynthesis).

Heterotroph

An organism that consumes other organisms for energy.

Trophic Level

A step in a food chain or food web, representing an organism’s feeding position.

Trophic Cascade

When a change in one trophic level affects multiple levels in an ecosystem.

Abiotic

Non-living factors in an ecosystem.

Biotic

Living organisms in an ecosystem.

Salinity

The amount of salt in water.

Water Clarity

How clear or murky water is, often affected by sediments, algae, and pollution.

Limiting Resource

A resource that limits population growth due to its scarcity.

Decomposition

The breakdown of dead organisms into nutrients by decomposers.

Detritivore

An organism that feeds on dead organic material (detritus).

Nutrient Regeneration

The recycling of nutrients back into the ecosystem through decomposition.

Ecological Niche

The role an organism plays in an ecosystem, including its habitat, diet, and interactions.

Gross Productivity

The total amount of energy produced by autotrophs in an ecosystem.

Net Productivity

The energy left over after autotrophs use some for their own growth and metabolism.

Standing Stock

The total biomass (living material) in a given area at a certain time.

Nitrogen Fixation

The process where bacteria convert nitrogen gas (N₂) into a usable form (like ammonia) for plants.

Denitrification

The process where bacteria convert nitrogen compounds back into nitrogen gas (N₂), returning it to the atmosphere.

Competition

When two or more organisms fight for the same resource (food, space, mates).

Predation

When one organism hunts and eats another.

Symbiosis

A close relationship between two different species.

Commensalism

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

Parasitism

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

Mutualism

A symbiotic relationship where both species benefit.

Exponential Growth

Population growth that keeps increasing rapidly, with no limits.

Logistic Growth

Population growth that slows and levels off when it reaches the environment’s carrying capacity.

Biomass

The total mass of living organisms in a specific area.

Stabilizing Selection

A type of natural selection where average traits are favored over extreme ones.

Directional Selection

A type of natural selection where one extreme trait is favored over the average.