Communities & Ecosystems Lecture CH 31

Vocabulary flashcards covering key terms and concepts from the Communities & Ecosystems lecture, including ecosystem structure, energy flow, biomes, climate influences, and biogeochemical cycles.

Ecosystem

A community of living organisms plus the non-living components with which they interact.

Biotic Environment (Community)

All living organisms within an ecosystem.

Abiotic Environment (Habitat)

The non-living physical and chemical conditions of an ecosystem.

Biome

One of Earth’s major ecological communities, defined primarily by characteristic temperature, precipitation, and vegetation patterns.

Terrestrial Biome

A land-based biome; nine chief types are recognized by climate and seasonal variation.

Aquatic Biome

A water-based biome categorized by salinity, water movement, and depth (e.g., lakes, rivers, coral reefs).

Primary Productivity

The amount of organic matter produced—usually via photosynthesis—in an ecosystem.

Net Primary Production (NPP)

Grams of carbon fixed per square meter per year; gross photosynthesis minus plant respiration.

Trophic Level

A step in the flow of energy from the sun through an ecosystem’s food relationships.

Producer (Autotroph)

An organism that converts solar energy to chemical energy through photosynthesis.

Primary Consumer

The first animal level in a food chain; eats producers.

Herbivore

An animal that feeds primarily on plants or algae.

Secondary Consumer

An organism that eats primary consumers; often a carnivore.

Carnivore

An animal that eats other animals.

Tertiary Consumer

A top-level predator feeding on secondary consumers.

Omnivore

An animal that routinely eats both plant and animal material.

Detritivore

An animal that feeds on dead organic matter (detritus) but is not a microbe.

Decomposer

Bacteria, fungi, or detritivores that chemically break down dead organisms, recycling nutrients.

Parasite

An organism that lives on or in a host organism and harms it while deriving nutrients.

Food Chain

A linear pathway showing energy flow from producers through successive consumers.

Food Web

An interconnected diagram of multiple food chains, depicting all energy pathways in a community.

Energy Pyramid (10 % Rule)

Graphic showing that only about 10 % of biomass/energy at one trophic level is converted to biomass at the next.

Biomass

The total mass of living organisms in a given area or trophic level.

Chemical Reservoir

A non-living storage pool (atmosphere, water, soil) that holds essential elements.

Carbon Cycle

Movement of carbon among reservoirs, driven largely by photosynthesis and respiration.

Nitrogen Cycle

Conversion of atmospheric N₂ into usable forms and its movement through ecosystems; includes fixation and decomposition.

Phosphorus Cycle

The movement of phosphate from rock and soil to organisms and back, crucial for ATP and DNA.

Eutrophication

Nutrient enrichment of water bodies causing algal blooms and oxygen depletion.

Hypoxic Zone (Dead Zone)

Area of severely reduced dissolved oxygen, often due to eutrophication, leading to ecosystem collapse.

Solar Energy Distribution

Uneven heating of Earth, with more direct sunlight at the equator than at the poles, driving climate patterns.

Rain Shadow

Dry region on the leeward side of mountains where descending air warms and absorbs moisture.

Urban Heat Island

City area where buildings and pavement increase absorption of solar energy, raising local temperatures.

El Niño

Periodic weakening of Pacific trade winds, causing warm water to pile up near South America and altering global weather.

Ocean Currents

Large-scale water movements that redistribute heat and influence regional climates.

Topography

Physical features of an area, including elevation and landforms, that affect local climate.

Rubisco

The enzyme that fixes CO₂ in the Calvin cycle, initiating photosynthetic sugar production.

30° Latitude Desert Belt

Global zones where descending dry air creates many of Earth’s major deserts.

Desiccation Adaptation

Traits enabling organisms to avoid or withstand water loss in dry environments.