unit 2

Hydrologic Cycle

The movement of water through the biosphere, transitioning from the atmosphere to Earth's surface and back.

Biogeochemical Cycle

The movements of matter within and between ecosystems.

Transpiration

The release of water from leaves during photosynthesis.

Evapotranspiration

The combined amount of evaporation and transpiration.

Runoff

Water that moves across the land surface and into streams and rivers.

Carbon Cycle

The movement of carbon around the biosphere.

Producers

Organisms that take up carbon from the atmosphere via photosynthesis and pass it on to consumers and decomposers.

Consumers

Organisms that obtain energy by consuming producers or other consumers.

Decomposers

Organisms that break down dead organic matter and return nutrients to the ecosystem.

Respiration

The process by which organisms return carbon to the atmosphere and water.

Combustion

The process of burning fossil fuels and other organic matter, returning carbon to the atmosphere.

Macronutrient

One of the six key elements that organisms need in relatively large amounts, including nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

Limiting Nutrient

A nutrient required for the growth of an organism but available in a lower quantity than other nutrients.

Nitrogen Cycle

The movement of nitrogen around the biosphere.

Nitrogen Fixation

The process by which some organisms convert nitrogen gas molecules directly into ammonia (NH3).

Nitrification

The conversion of ammonium (NH4+) into nitrite (NO2-) and then into nitrate (NO3-).

Assimilation

The process by which producers incorporate elements into their tissues.

Mineralization

The process by which fungal and bacterial decomposers break down organic matter and convert it into inorganic compounds.

Ammonification

The process by which decomposers convert organic nitrogen into inorganic ammonium (NH4+).

Denitrification

The conversion of nitrate (NO3-) into nitrous oxide (N2O) and eventually nitrogen gas (N2), which is emitted into the atmosphere.

Leaching

The transportation of dissolved molecules through the soil via groundwater.

Phosphorus Cycle

The movement of phosphorus around the biosphere.

Algal Bloom

A rapid increase in the algal population of a waterway, often due to excess phosphorus.

Hypoxic

A condition low in oxygen.

Weathering

The process of breaking down rocks, releasing nutrients like phosphorus into the soil and water.

Phosphate Fertilizer

A substance that releases phosphorus into the soil and water for use by producers.

Sulfur Cycle

The movement of sulfur around the biosphere.

Sulfate Ions

Ions (SO4^2−) released from weathered rocks that can be taken up by producers.

Volcanoes

Natural events that release sulfur dioxide (SO2) into the atmosphere.

Ecosystem

A particular location on Earth with interacting biotic and abiotic components.

Biosphere

The region of our planet where life resides, encompassing all ecosystems on Earth.

Trophic Levels

The successive levels of organisms consuming one another in an ecosystem.

Producer

An organism that uses energy from the Sun to produce usable forms of energy; also known as an autotroph.

Consumer

An organism that is incapable of photosynthesis and must obtain its energy by consuming other organisms; also known as a heterotroph.

Photosynthesis

The process by which producers use solar energy to convert carbon dioxide and water into glucose and oxygen.

Cellular Respiration

The process by which cells unlock the energy of chemical compounds.

Gross Primary Productivity (GPP)

The total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given time.

Net Primary Productivity (NPP)

The energy captured by producers in a system minus the energy producers respire.

Food Chain

The sequence of consumption from producers through tertiary consumers.

Food Web

A complex model of how energy and matter move between trophic levels.

Scavenger

An organism that consumes dead animals.

Detritivore

An organism that specializes in breaking down dead tissues and waste products into smaller particles.

Decomposers

Fungi and bacteria that convert organic matter into small elements and molecules that can be recycled back into the ecosystem.

Ecological Efficiency

The proportion of consumed energy that can be passed from one trophic level to another.

Trophic Pyramid

A representation of the distribution of biomass, numbers, or energy among trophic levels.

Nitrogen Cycle

The movement of nitrogen around the biosphere.

Nitrogen Fixation

The process by which some organisms convert nitrogen gas molecules directly into ammonia (NH3).

Nitrification

The conversion of ammonium (NH4+) into nitrite (NO2-) and then into nitrate (NO3-).

Phosphorus Cycle

The movement of phosphorus around the biosphere.

Algal Bloom

A rapid increase in the algal population of a waterway, often due to excess phosphorus.

Hydrologic Cycle

The movement of water through the biosphere.

Transpiration

The release of water from leaves during photosynthesis.

Biomass

The total mass of all living matter in a specific area.

Ecological Efficiency

The proportion of ...consumed energy that can be passed from one trophic level to another.

Trophic Pyramid

•   A representation of ….of the distribution of biomass, numbers or energy among trophic levels.