BioGeochemical cycles

Ecology

The study of interactions between organisms and their environment.

Biogeochemical cycles

The cycling of important elements and nutrients through living organisms and the physical environment.

Biome

A large portion of Earth with similar temperature and rainfall conditions that determine what plants and animals can live there.

Ecosystem

A community and all of the physical things that affect it.

Biosphere

The living component of Earth.

Geosphere

The solid Earth component.

Hydrosphere

The water component of Earth.

Energy flow vs nutrient cycling

Energy has a one-way flow and is ultimately lost as heat, while nutrients are recycled through cycles.

CHONSP

The major elements that make up living organisms: carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus.

Carbon

An element found in carbohydrates and many biological molecules.

Hydrogen

An element found in many biological molecules.

Oxygen

An element found in carbohydrates and many biological molecules.

Nitrogen

An element found in proteins and nucleic acids.

Sulfur

An element found in some proteins and amino acids.

Phosphorus

An element found in DNA and RNA in the sugar-phosphate backbone.

Water cycle

The movement of water between liquid, gas, and solid forms throughout Earth.

Evaporation

The process where water molecules leave the surface of oceans and other bodies of water and enter the atmosphere.

Condensation

The process where water vapor cools and becomes liquid water.

Precipitation

Water falling from the atmosphere as rain, snow, or other forms.

Transpiration

The loss of water from plants through evaporation from their leaves.

Evapotranspiration

The combination of evaporation and transpiration.

Usable freshwater

Only about 1% of Earth's water is actually usable by humans; most water is saltwater or locked in ice.

Carbon cycle

The movement of carbon, especially carbon dioxide, through the environment and organisms.

Anthropocene

A proposed geological period where humans have greatly altered Earth's stability.

Fossil fuels

Oil, coal, and other fuels that release carbon dioxide when burned.

Carbon dioxide (CO2)

A gas important for life because plants use it during photosynthesis, but excess CO2 contributes to climate change.

Photosynthesis

The process where plants use carbon dioxide and water to make glucose.

Cellular respiration

The process where organisms break down glucose to generate ATP and release carbon dioxide.

Carbon cycle balance

CO2 removed by photosynthesis is normally balanced by CO2 released during cellular respiration.

Nitrogen cycle

The movement of nitrogen through the atmosphere, organisms, soil, and water.

Atmospheric nitrogen (N2)

The form of nitrogen found in the atmosphere that most organisms cannot directly use.

Nitrogen fixation

The process of converting atmospheric nitrogen (N2) into ammonia (NH3).

Nitrogen-fixing bacteria

Bacteria that can break apart N2 and convert it into ammonia.

Ammonia (NH3)

The product of nitrogen fixation.

Nitrate (NO3-)

The form of nitrogen most commonly used by plants.

Nitrogen conversion

The process where bacteria convert ammonia into forms such as nitrate that plants can absorb.

Denitrification

The process where bacteria convert nitrates back into atmospheric nitrogen (N2).

Denitrifiers

Bacteria that perform denitrification.

Root nodules

Structures on some plant roots that house nitrogen-fixing bacteria.

Symbiotic nitrogen fixation

A relationship where plants provide a home for bacteria and bacteria provide usable nitrogen.

Industrial nitrogen fixation

The human process of creating usable nitrogen compounds.

Nitrogen oxides (NOx)

Pollutant gases produced during burning that contain nitrogen and oxygen.

Acid rain

Rain with a lower pH caused by atmospheric pollutants such as nitrogen oxides or sulfur compounds.

Greenhouse gas

A gas that traps heat in the atmosphere and contributes to warming.

Phosphorus cycle

The movement of phosphorus through rocks, soil, organisms, and water.

Phosphorus cycle difference

Unlike carbon and nitrogen cycles, phosphorus does not have a major atmospheric component.

Phosphorus source

Phosphorus comes mainly from rocks and must often be mined from the ground.

Phosphorus importance

Phosphorus is needed for nucleic acids such as DNA and RNA.

Fertilizer

Human-added nutrients used to increase plant growth but can disrupt nutrient cycles.

Dead zones

Areas in bodies of water with very low oxygen levels caused by nutrient runoff.

Agricultural runoff

Fertilizers from farms entering bodies of water.

Algal bloom

A rapid increase in algae or phytoplankton caused by excess nutrients.

Decomposers

Organisms that break down dead material and use oxygen during decomposition.

Hypoxic condition

A condition where oxygen levels in water are extremely low.

Sulfur cycle

The movement of sulfur through rocks, organisms, soil, and the atmosphere.

Sulfur importance

Sulfur is found in some proteins and amino acids.

Sulfur dioxide

A gas released when high-sulfur coal is burned that can contribute to acid rain.

Sulfuric acid

An acid formed in the atmosphere when sulfur compounds react with water.

Biome limiting factors

Factors such as temperature, rainfall, sunlight, nutrients, wind, oxygen, and salinity that affect what organisms can live in an area.

Terrestrial biome factors

Temperature and rainfall are major factors that determine terrestrial biomes.

Aquatic biome factors

Temperature, sunlight, dissolved nutrients, oxygen levels, and salinity affect aquatic organisms.

Latitude and biomes

Biomes often occur in bands based on latitude because temperature and precipitation change from the equator toward the poles.

Desert biome

A biome defined mainly by very low rainfall, limiting plant and animal life.

Subtropical desert

A desert found in dry interior regions often caused by distance from water sources and wind patterns.

Rain shadow desert

A desert formed on the dry side of a mountain range where mountains block precipitation.

Windward side

The side of a mountain facing the source of moisture where precipitation occurs.

Leeward side

The dry side of a mountain range where less precipitation occurs.

Temperate desert

A desert formed due to latitude conditions, often containing plants adapted to store water.

Succulent

A plant adapted to store water.

Polar desert

A desert with very low precipitation where temperatures are usually below freezing.

Grassland biome

A biome with more water than deserts and large areas dominated by grasses.

Savannah

A tropical grassland near the equator with wet and dry seasons based on rainfall.

Temperate grassland

A grassland biome with temperature-based seasons, such as prairies.

Prairie

A temperate grassland biome that covers much of central North America.

Prairie plant adaptation

Deep root systems allow plants to recover after fires or droughts.

Chaparral

A shrubland biome with warm, dry summers and mild rainy winters.

Mediterranean climate

A climate type with dry summers and wetter winters.

Chaparral adaptations

Shrubby plants adapted to dry conditions and periodic fires.

Tundra

A biome that is frozen most of the year with a brief growing season.

Permafrost

Soil that remains frozen year-round.

Lichen

An organism made of a fungus and algae commonly found in tundra.

Forest biome

A biome with enough rainfall to support large trees.

Canopy

The upper layer of a forest formed by tree leaves where most forest life occurs.

Understory

The layer below the canopy containing tree trunks and smaller plants.

Forest floor

The ground level of a forest with shrubs and decomposers.

Tropical rainforest

A forest biome with the highest rainfall and warm temperatures.

Tropical rainforest nutrients

Tropical rainforests have rapid nutrient cycling but are often low in nutrients because rain washes nutrients away.

Temperate rainforest

A colder rainforest found at higher latitudes with heavy rainfall, such as the Pacific Northwest.

Temperate deciduous forest

A forest where trees lose large leaves during winter.

Deciduous

Losing leaves during a certain season, usually winter.

Leaf color change in deciduous forests

Leaves change color when trees absorb nutrients and chlorophyll before dropping leaves.

Boreal forest

A northern forest biome also called taiga.

Taiga

Another name for boreal forests.

Conifers

Trees with needle-shaped leaves common in boreal forests.

Evergreen trees

Trees that keep their leaves throughout the year.

Boreal forest adaptations

Needle-shaped leaves, wax coatings, and cone shapes help trees survive cold snowy conditions.