APES - Chapter 3

Biosphere

The life-supporting layer of the atmosphere extending from the depths of the ocean to a few kilometers into the atmosphere.

Producer

An organism that obtains energy via autotrophic processes.

Autotroph

An organism that photosynthesizes.

Photosynthesis

A chemical process converting water, sunlight, and carbon dioxide into chemical energy and oxygen.

Photosynthesis Equation

Solar E + 6H₂O + 6CO₂ → C₆H₁₂O₆ + 6O₂

Cellular Respiration

The chemical process converting oxygen and chemical energy into water, energy, and carbon dioxide.

Cellular Respiration Equation

6O₂ + C₆H₁₂O₆ → 6CO₂ + 6H₂O + Energy

Aerobic Respiration

Cellular respiration done in the presence of oxygen.

Anaerobic Respiration

Cellular respiration done without the presence of oxygen; done by very specific bacteria in denitrification.

Consumer

An organism that obtains energy as a heterotroph.

Heterotroph

An organism that obtains energy by consuming producers or other organisms.

Herbivore

An organism that consumes only plants.

Primary Consumer

An organism that consumes primary producers for energy.

Carnivore

An organism that predates over other organisms.

Secondary Consumer

A consumer that eats primary consumers and the levels below it.

Tertiary Consumer

A consumer that eats secondary consumers and the levels below it.

Trophic Levels

The levels of a food web that decrease in the amount of energy available by increasing in levels.

Food Chain

A diagram that shows the trophic levels of an ecosystem.

Food Web

A diagram that shows all the energy exchanges within an ecosystem.

Scavenger

An organism that consumes the dead matter of other organisms for energy.

Detritivore

An organism that consumes and decomposes the fecal and waste matter of other organisms.

Decomposers

An organism that breaks down dead organic material into usable nutrients.

Gross Primary Productivity

The total amount of photosynthesis done by producers in an area.

Net Primary Productivity

The GPP of an area subtracted by the amount of energy used by producers in respiration.

Biomass

The total quantity of all species in a community by unit area.

Standing Crop

The total biomass of living organisms present in a given environment.

Ecological Efficiency

The efficiency with which energy is transferred from one trophic level to the next.

Trophic Pyramid

The structure of trophic levels in an ecosystem, with 10% of energy in a previous layer moving up to the next.

Biogeochemical Cycle

The chemical, physical, and biological recycling processes of an ecosystem.

Hydrologic Cycle

The recycling of water through evapotranspiration, condensation, precipitation, runoff, and percolation.

Transpiration

The release of water from living organisms following respiration driven by solar energy.

Evapotranspiration

The return of water to the atmosphere via evaporation and transpiration driven by solar energy.

Runoff

The funneling of water to a larger pool from surface precipitation.

Carbon Cycle

The recycling of carbon in short and long-term processes in an ecosystem.

Macronutrient

A particle that is necessary for an organism to develop.

Limiting Nutrient

A macronutrient that is relatively restricted in an area.

Nitrogen Cycle

The recycling of the limiting nutrient nitrogen via organisms and abiotic factors in an ecosystem.

Nitrogen Fixation

The chemical process of turning nitrogen gas from the atmosphere, N₂, into NO₃ and NH₄ by abiotic factors such as lightning and fires and biotic factors such as bacteria and legumes.

Nitrification

The conversion of NH₄ into a more usable form of Nitrogen as NO₃ by specialized bacteria.

Assimilation

The incorporation of NO₃ and NH₄ into organic tissues by producers.

Ammonification

The decomposition of dead organic matter into NH₄ by decomposers and fungi.

Denitrification

The conversion of NO₃ into N₂ by anaerobic bacteria.

Leaching

The process of water washing away minerals and nutrients into runoff and pools.

Phosphorus Cycle

The recycling of phosphorus as a limiting nutrient via erosion, weathering, and assimilation.

Algal Bloom

A drastic increase in algae reproduction, usually driven by eutrophic waters.

Hypoxic

An environment having low levels of dissolved oxygen, harming organisms within it.

Dead Zone

A eutrophicated area of water characterized by high amounts of algal blooming and being hypoxic.

Sulfur Cycle

The recycling of sulfur as a limiting nutrient through soil, erosion, and waterways as sulfates.

Disturbance

A chemical, biological, or physical process that disrupts the material and energy flow of an ecosystem.

Resistance

The ability of an ecosystem to withstand disturbances; a proactive measure.

Resilience

The ability of an ecosystem to return to its normal energy and material flow following disturbances; a reactive measure.

Restoration Ecology

The study of repairing damaged ecosystems to return to their original material and energy flows.

Watershed

The total area of all precipitation in an ecosystem leading into a common pool.

Intermediate Disturbance Hypothesis

A healthy ecosystem is one that experiences a medium amount of disturbances to maintain energy flow and material flow and spur change in species and growth.