Ecology and Ecosystem Dynamics Vocabulary

Vocabulary flashcards based on key terms in ecology, trophic dynamics, biogeochemical cycles, and ecosystem disturbances.

Biosphere

The region of Earth where life exists, encompassing all ecosystems.

Producer

An organism that uses solar energy or chemical energy to manufacture organic compounds from inorganic materials; also known as an autotroph.

Autotroph

An organism that is capable of manufacturing its own organic nutrients from inorganic molecules using light or chemical energy.

Photosynthesis

The process by which producers convert solar energy, carbon dioxide ($\text{CO}_2$), and water ($\text{H}_2\text{O}$) into glucose ($\text{C}_6\text{H}_{12}\text{O}_6$) and oxygen ($\text{O}_2$).

Cellular respiration

The metabolic process by which cells unlock energy bound in organic molecules such as glucose.

Aerobic respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water ($\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{energy}$).

Anaerobic respiration

The cellular process of converting glucose into energy in the absence of oxygen.

Consumer

An organism that obtains energy and nutrients by consuming other organisms; also known as a heterotroph.

Heterotroph

An organism that cannot produce its own energy and must consume other organisms for nutrients.

Herbivore

A consumer that feeds exclusively on producers (plants or algae); also known as a primary consumer.

Primary consumer

A consumer that feeds directly on producers.

Carnivore

A consumer that feeds on other animals.

Secondary consumer

A carnivore or omnivore that consumes primary consumers.

Tertiary consumer

A carnivore that eats secondary consumers.

Trophic levels

The successive levels of organisms consuming one another in a food chain or food web.

Food chain

A linear sequence of consumption from producers through various levels of consumers.

Food web

A complex, interconnected network of food chains showing the flow of energy and nutrients in an ecosystem.

Scavenger

An organism that consumes dead animals.

Detritivore

An organism that specializes in breaking down dead tissues and waste products into smaller particles.

Decomposers

Fungi and bacteria that complete the breakdown process by recycling nutrients from dead organic matter back into the ecosystem.

Gross primary productivity (GPP)

The total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given amount of time.

Net primary productivity (NPP)

The energy captured by producers in an ecosystem minus the energy producers lose through cellular respiration ($\text{NPP} = \text{GPP} - \text{Respiration}$).

Biomass

The total mass of all living matter in a specific area at a given time.

Standing crop

The total amount of biomass present in an ecosystem at a particular point in time.

Ecological efficiency

The proportion of consumed energy that can be passed from one trophic level to the next higher level.

Trophic pyramid

A graphical representation showing the distribution of biomass, numbers, or energy among trophic levels in an ecosystem.

Biogeochemical cycle

The movement of matter within and between ecosystems involving biological, geological, and chemical processes.

Hydrologic cycle

The continuous movement of water through the biosphere, atmosphere, land, and oceans.

Transpiration

The release of water vapor from plant leaves into the atmosphere during photosynthesis.

Evapotranspiration

The combined amount of evaporation from soil and water bodies plus transpiration from plants.

Runoff

Water that moves across the land surface into streams, rivers, lakes, and oceans rather than infiltrating the soil.

Carbon cycle

The biogeochemical movement of carbon through the biosphere, atmosphere, hydrosphere, and geosphere.

Macronutrient

One of the key chemical elements required in relatively large amounts by living organisms, such as nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

Limiting nutrient

A nutrient required for organism growth that is available in the shortest supply relative to demand.

Nitrogen cycle

The biogeochemical cycle by which nitrogen is converted into various chemical forms as it circulates through terrestrial, marine, and atmospheric ecosystems.

Nitrogen fixation

The process that converts atmospheric nitrogen gas ($\text{N}_2$) into biologically available forms such as ammonia ($\text{NH}_3$) or nitrate ($\text{NO}_3^-$).

Nitrification

The conversion of ammonium ($\text{NH}_4^+$) into nitrite ($\text{NO}_2^-$) and then into nitrate ($\text{NO}_3^-$) by specialized bacteria.

Assimilation

The process by which plants and animals incorporate nitrate and ammonium into organic compounds like proteins and nucleic acids.

Mineralization

The process by which decomposers break down organic nitrogen compounds back into inorganic compounds.

Ammonification

The process by which decomposers convert organic nitrogen from dead organic matter into ammonia ($\text{NH}_3$) or ammonium ($\text{NH}_4^+$).

Denitrification

The conversion of nitrate ($\text{NO}_3^-$) into nitrogen gas ($\text{N}_2$) by specialized anaerobic bacteria, releasing nitrogen back into the atmosphere.

Leaching

The process in which dissolved nutrients or chemicals are transported through soil by percolating water.

Phosphorus cycle

The biogeochemical cycle describing the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

Algal bloom

A rapid increase in the population of algae in an aquatic system, often caused by nutrient enrichment like excess nitrogen or phosphorus.

Hypoxic

Characterized by extremely low dissolved oxygen concentrations in water, which can be harmful or lethal to aquatic organisms.

Dead zone

An area in a body of water with extremely low oxygen levels (hypoxia) where few aquatic organisms can survive.

Sulfur cycle

The biogeochemical movement of sulfur through the geosphere, atmosphere, and biosphere.

Disturbance

An event caused by physical, chemical, or biological agents that results in changes in population size or community composition in an ecosystem.

Resistance

A measure of how much an ecosystem resists change, remaining essentially unchanged following a disturbance.

Resilience

The rate at which an ecosystem returns to its original state following a disturbance.

Restoration ecology

The scientific study and practice of renewing and restoring degraded, damaged, or destroyed ecosystems.

Watershed

An area of land that drains all of the water that flows through or under it into a common outlet or body of water.

Intermediate disturbance hypothesis

The hypothesis that ecosystems experiencing intermediate levels of disturbance will foster higher species diversity than those with high or low disturbance levels.