Environmental Science AP Chapter 3

Producer

An organism that uses the energy of the Sun to produce usable forms of energy. Ex. plants, algae and some bacteria

Autotroph

An organism that uses the energy of the Sun to produce usable forms of energy; same def. as producer

Photosynthesis

The process by which producers use solar energy to convert carbon dioxide and water into glucose. Waste product= O₂

Cellular Respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Consumer

An organism that must obtain its energy by consuming other organisms.

Heterotrophs

An organism that must obtain its energy by consuming other organisms; same def. as consumer.

Primary Consumer

An individual incapable of photosynthesis; must obtain energy by consuming other organisms.

Secondary Consumer

A carnivore that eats primary consumers.

Tertiary Consumer

A carnivore that eats secondary consumers.

Trophic Levels

Levels in the feeding structure of organisms. Higher trophic levels consume organisms from lower levels.

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

A carnivore that consumes dead animals.

Detritivore

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

Decomposers

Fungi or bacteria that recycle nutrients from dead tissues and wastes back into an ecosystem.

Gross Primary Productivity (GPP)

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

Net Primary Productivity (NPP)

The energy captured by producers in an ecosystem minus the energy producers respire.

Biomass

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

Standing Crop

The amount of biomass present in an ecosystem at a particular time.

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.

Biosphere

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

Biogeochemical Cycles

The movements of matter within and between ecosystems.

Hydrologic Cycle

The movement of water through the biosphere.

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.

Macronutrients

The six key elements that organisms need in relatively large amounts: 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 Fixation

A process by which some organisms can convert nitrogen gas molecules directly into ammonia.

Leaching

The transportation of dissolved molecules through the soil via groundwater.

Disturbance

An event, caused by physical, chemical, or biological agents, resulting in changes in population size or community composition.

Watershed

All land in a given landscape that drains into a particular stream, river, lake, or wetland.

Resistance

A measure of how much a disturbance can affect flows of energy and matter in an ecosystem.

Resilience

The rate at which an ecosystem returns to its original state after a disturbance.

Restoration Ecology

The study and implementation of restoring damaged ecosystems.

Intermediate Disturbance Hypothesis

The hypothesis that ecosystems experiencing intermediate levels of disturbance are more diverse than those with high or low disturbance levels.

Aerobic Respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Anaerobic Respiration

The process by which cells convert glucose into energy in the absence of oxygen.

Herbivore

A consumer that eats producers.

Carnivore

A consumer that eats other consumers.

Carbon Cycle

The movement of carbon around the biosphere.

Nitrogen Cycle

The movement of nitrogen around the biosphere.

Nitrification

The conversion of ammonia (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 the organic matter found in dead bodies and waste prodcuts and convert it into inorganic compounds.

Ammonification

The process by which fungal and bacterial decomposers break down the inorganic nitrogen found in dead bodies and waste products and convert it into inorganic ammonium (NH4+).

Denitrification

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

Phosphoric Cycle

The movement of phosphorus around the biosphere.

Algal Bloom

A rapid decrease in the algal population of a waterway.

Hypoxic

Low in oxygen.

Sulphur Cycle