Ecosystems: Structure, Function, and Human Impacts

Vocabulary flashcards covering key ecosystem concepts, cycles, dynamics, human impacts, and management topics from the notes.

Ecosystems

Complex networks of living organisms interacting with their physical environment, including biotic and abiotic components.

Biotic factors

Living components of an ecosystem (plants, animals, microorganisms).

Abiotic factors

Non-living components (temperature, light, water, soil, nutrients).

Biodiversity

The variety of life forms within an ecosystem or across ecosystems.

Trophic levels

Organization of organisms by position in the food chain (producers, primary, secondary, tertiary consumers).

Ecological niche

The role and position of a species in an ecosystem (habitat, food sources, interactions).

Carrying capacity

Maximum population size an ecosystem can sustain given resources.

Producers (autotrophs)

Organisms that convert light or chemical energy into organic compounds via photosynthesis or chemosynthesis.

Photosynthesis

Process by which producers convert light energy into chemical energy (organic matter).

Chemosynthesis

Process by which some organisms convert chemical energy into organic compounds (no light required).

Consumers (heterotrophs)

Organisms that obtain energy by feeding on other organisms.

Primary consumers

Herbivores that feed on producers (e.g., rabbits, zooplankton).

Secondary consumers

Carnivores that feed on primary consumers (e.g., snakes, small fish).

Tertiary consumers

Top predators that feed on secondary consumers (e.g., hawks, sharks).

Decomposers

Organisms that break down dead organic matter, releasing nutrients (fungi, bacteria).

Food chains

Linear pathways of energy transfer from producers to consumers.

Food webs

Complex interconnections among multiple food chains in an ecosystem.

Energy flow

Transfer of energy through trophic levels as organisms feed.

10% rule

Only about 10% of energy is transferred to the next trophic level; ~90% lost as heat or used for metabolism.

Gross primary productivity (GPP)

Total energy captured by producers through photosynthesis.

Net primary productivity (NPP)

Energy remaining after respiration; NPP = GPP − Respiration.

Respiration

Process by which organisms use energy, reducing energy available for growth.

Secondary productivity

Energy captured by consumers (biomass produced by consumers over time).

Biomass

Total mass of living organisms in an ecosystem.

Biomass pyramids

Depict the decrease in biomass at successive trophic levels.

Hydrologic cycle (water cycle)

Movement of water through evaporation, transpiration, condensation, precipitation, and runoff.

Carbon cycle

Movement of carbon among atmosphere, oceans, and organisms via photosynthesis, respiration, and decomposition; CO2 is a key component.

CO2

Carbon dioxide, a major component of the carbon cycle and a greenhouse gas.

Nitrogen cycle

Conversion of atmospheric nitrogen (N2) into usable forms through nitrogen fixation, nitrification, and denitrification.

Nitrogen fixation

Conversion of N2 to ammonia/nitrates by bacteria; makes nitrogen available to living organisms.

Nitrification

Oxidation of ammonia to nitrite and nitrate by bacteria.

Denitrification

Conversion of nitrates to N2 gas by bacteria, returning nitrogen to the atmosphere.

Phosphorus cycle

Movement of phosphorus through weathering, uptake by organisms, and decomposition.

Primary succession

Gradual changes in species composition in newly formed or bare environments; pioneer species arrive first.

Pioneer species

First colonizers in primary succession.

Intermediate species

Mid-stage species in ecological succession between pioneers and climax.

Climax community

Final, relatively stable stage of succession.

Secondary succession

Recovery and changes in previously inhabited areas after disturbances.

Disturbances

Events like fires, hurricanes, and human activities that disrupt ecosystems.

Resilience

The ability of an ecosystem to recover after a disturbance.

Habitat destruction

Loss of habitat due to human activities (deforestation, urbanization, agriculture).

Habitat fragmentation

Division of habitats into smaller, isolated patches.

Habitat degradation

Decline in habitat quality and suitability.

Overexploitation

Unsustainable harvesting of resources (overfishing, overhunting).

Pollution

Introduction of contaminants that harm ecosystems (air, water, soil).