AP Environmental Science - Ecosystems and Biogeochemical Cycles

Comprehensive vocabulary flashcards covering Earth's life-support systems, ecosystem structure, trophic dynamics, productivity, and biogeochemical cycles from APES Chapters 3 and 4.

Tropical Rain Forests

Ecosystems that cover only 2% of the Earth's land surface but contain 50% of the world's known plant and animal species.

Troposphere

The innermost atmospheric layer extending 0 to 10 km above Earth's surface where weather occurs.

Stratosphere

The atmospheric layer extending 10 to 50 km above Earth's surface that contains the protective ozone layer.

Hydrosphere

All liquid, frozen, and gaseous water found on or near Earth's surface.

Geosphere

The solid part of Earth, consisting of the intensely hot core, thick mantle, and thin outer crust.

Biosphere

The parts of Earth's air, water, and soil where living organisms exist and interact.

Ecology

The science of organisms' interactions with each other and with their nonliving environment.

Population

A group of individuals of the same species living in a particular place and potentially interacting with each other.

Community

Populations of different species living in a particular place and interacting with one another.

Ecosystem

A community of different species interacting with one another and with their nonliving environment of matter and energy.

Autotrophs

Also known as primary producers; organisms that produce the organic nutrients they need from solar energy and inorganic compounds.

Heterotrophs

Also known as consumers; organisms that obtain their energy and nutrients by consuming other organisms.

Detritus

Dead organic material, including debris, fallen leaves, and animal waste products.

Decomposers

Organisms (such as bacteria and fungi) that digest dead organic matter externally and absorb the resulting nutrients.

Detritivores

Also known as detritus feeders; organisms that feed directly on dead organic bodies or wastes of other organisms.

Aerobic Respiration

The process that uses oxygen to convert glucose back into carbon dioxide and water to produce usable cellular energy.

Anaerobic Respiration

Also known as fermentation; cellular respiration carried out without oxygen that produces compounds such as methane and acetic acid.

Food Chain

A sequence showing the movement of energy and chemical nutrients from one trophic feeding level to the next.

Food Web

A complex network of interconnected food chains representing the flow of energy through organisms.

Biomass

The dry weight of all organic matter contained in organisms at a specific trophic level in a food chain or web.

10% Rule

The principle that chemical energy decreases with each transfer up trophic levels, resulting in an average $90\%$ loss of energy at each step.

Gross Primary Productivity (GPP)

The rate at which an ecosystem's primary producers convert solar energy into chemical energy and biomass, measured in $\text{kcal/m}^2/\text{year}$.

Net Primary Productivity (NPP)

The rate at which producers store chemical energy as biomass minus the rate at which they use energy for aerobic respiration ($\text{NPP} = \text{GPP} - R$).

Transpiration

The process by which water is absorbed by plant roots and evaporates as water vapor into the atmosphere from plant leaves.

Adhesion and Cohesion

Unique properties of water driven by hydrogen bonding where water molecules stick to other surfaces (adhesion) and stick to each other (cohesion).

Carbonic Acid

A weak acid ($\text{H}_2\text{CO}_3$) formed when atmospheric carbon dioxide ($\text{CO}_2$) dissolves in water.

Nitrogen Fixation

The process where specialized soil bacteria or lightning combine nitrogen gas ($\text{N}_2$) with hydrogen to form ammonia ($\text{NH}_3$) and ammonium ions ($\text{NH}_4^+$).

Nitrification

The conversion of ammonia ($\text{NH}_3$) and ammonium ions ($\text{NH}_4^+$) in the soil to nitrate ions ($\text{NO}_3^-$) by specialized soil bacteria.

Assimilation

The process by which plants and other organisms absorb inorganic nitrogen compounds to build organic nitrogen molecules.

Denitrification

The process by which anaerobic bacteria convert nitrate ions ($\text{NO}_3^-$) back into atmospheric nitrogen gas ($\text{N}_2$).

Phosphorus Cycle

The slow biogeochemical cycle that lacks an atmospheric gas component and moves phosphorus through water, Earth's crust, and living organisms.