Ecology: Matter and Energy in Ecosystems

Practice vocabulary flashcards defining key ecological terms, matter cycles, energy flow concepts, and environmental interactions.

Population

A group of individuals of the same species living in the same area.

Community

Multiple populations of different species living together in a defined area.

Ecosystem

All the living (biotic) and nonliving (abiotic) components interacting in a given area.

Biome

A major regional or global distribution of organisms adapted to a particular environment.

Biosphere

All life on Earth and all regions across the globe where life exists.

Biodiversity

The measurement of the number of different species living within a specific area.

Biotic Factors

The living components of an ecosystem, such as plants, animals, bacteria, and fungi.

Abiotic Factors

The nonliving components of an ecosystem, such as sunlight, water, temperature, soil, air, and rocks.

Metabolism

All the chemical processes that build up or break down materials in an organism's body.

Matter (in Ecosystems)

Substances that cycle continuously through ecosystems, can be reused, and move between living organisms and the environment.

Energy (in Ecosystems)

A resource that flows in one direction through trophic levels, typically entering as sunlight and dispersing into the environment as heat.

Food Chain

A linear sequence linking species through their feeding relationships, showing how energy transfers from one organism to another.

Producer

An autotrophic organism that makes its own food (usually using photosynthesis) and forms the base of ecological food chains.

Consumer

An organism that obtains energy and nutrients by eating other organisms.

Herbivore

A consumer that feeds exclusively on plants.

Carnivore

A consumer that feeds exclusively on other animals.

Omnivore

A consumer that feeds on both plants and animals.

Primary Consumer

An organism occupying the second trophic level that feeds directly on producers.

Secondary Consumer

An organism occupying the third trophic level that feeds on primary consumers.

Tertiary Consumer

An organism occupying the fourth trophic level that feeds on secondary consumers.

Quaternary Consumer

An organism occupying the fifth trophic level that feeds on tertiary consumers.

Trophic Level

The specific feeding position or rank of an organism in a food chain or food web.

Food Web

A complex network of interconnected feeding relationships and energy pathways between multiple trophic levels in an ecosystem.

Biomass

The total mass of living biological material in a particular area or trophic level.

Energy Pyramid

An ecological model that illustrates the distribution and transfer of available energy across successive trophic levels.

10% Rule

An ecological principle stating that approximately $10\%$ of energy is transferred from one trophic level to the next, while about $90\%$ is lost as heat, waste, or used for metabolism.

Biomass Pyramid

An ecological diagram comparing the total dry mass of living tissue present at each trophic level.

Pyramid of Numbers

An ecological diagram displaying the total count of individual organisms supported at each trophic level.

Open System

A system, such as Earth with respect to energy, that continuously receives inputs from an outside source (the Sun).

Closed System

A system, such as Earth with respect to matter, where substances are confined within boundaries and cycled without net gain or loss.

Earth System

All matter, energy, processes, and interconnected cycles contained within Earth's boundary with space.

Biogeochemical Cycle

The pathways by which a specific chemical substance moves through both biotic (living) and abiotic (nonliving) components of Earth.

Photosynthesis

The biological process wherein plants take in carbon dioxide, water, and solar energy to synthesize sugars and release oxygen.

Cellular Respiration

The process by which organisms use oxygen and sugar to release usable energy, giving off carbon dioxide and water.

Nitrogen Fixation

The chemical conversion of atmospheric nitrogen gas into usable compounds for plants, carried out by specialized bacteria such as Rhizobium.

Fossilization

The geological process whereby organic carbon becomes buried in Earth's crust and transforms over millions of years into fossil fuels.

Eutrophication

The over-enrichment of an aquatic ecosystem with excess nutrients (nitrogen and phosphorus), triggering explosive algal blooms and subsequent oxygen depletion.

Decomposers

Organisms such as bacteria and fungi that break down dead organic matter and waste, releasing and recycling vital nutrients back into the environment.

Phytoplankton

Microscopic photosynthetic organisms inhabiting aquatic ecosystems that serve as primary producers and absorb large quantities of carbon dioxide.

Evaporation

The phase change in the water cycle where solar energy heats liquid water and converts it into water vapor.

Transpiration

The process within the water cycle where plants release absorbed water vapor into the atmosphere through their tissues.

Condensation

The process in the water cycle where cooling water vapor changes into liquid water droplets to form clouds.

Precipitation

The stage of the water cycle where condensed atmospheric water falls back to Earth's surface as rain, snow, sleet, or hail.

Runoff

Water from precipitation that flows over land surfaces driven by gravity into streams, rivers, lakes, and oceans.