Unit 1 -- The Living World: Ecosystems

biosphere

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

producer

an organism that uses the energy of the sun to produce usable forms of energy (also known as an autotroph)

photosynthesis

the process by which producers use solar energy to convert carbon dioxide and water into glucose

consumer

an organism that is incapable of photosynthesis and must obtain its energy by consuming other organisms (also known as heterotroph)

herbivore

a consumer that eats producers (also known as a primary consumer)

carnivore

a consumer that eats other consumers

secondary consumer

a carnivore that eats primary consumers

tertiary consumer

a carnivore that eats secondary consumers

trophic levels

the successive levels of organisms consuming one another

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

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

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

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 ("evapo"-"transp")

runoff

water that moves across the land surface and into streams and rivers

carbon cycle

the movement of carbon around the biosphere

macronutrient

one of 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 cycle

the movement of nitrogen around the biosphere

nitrogen fixation

the process that converts nitrogen gas in the atmosphere into forms of nitrogen that producers can use

nitrification

the conversion of ammonia into nitrite and then into nitrate

assimilation

the process by which producers incorporate elements into their tissues

ammonification

the process by which fungal and bacterial decomposers break down the organic nitrogen found in dead bodies and waste products and convert it into inorganic ammonium

denitrification

the conversion of nitrate in a series of steps into the gases nitrous oxide and, eventually, nitrogen gas 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

hypoxic

low in oxygen

dead zone

when oxygen concentrations become so low that it kills fish and other aquatic animals

sulfur cycle

the movement of sulfur around the biosphere

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

terrestrial biome

a geographic region categorized by a particular combination of average annual temperature, annual precipitation, and distinctive plant growth forms on land

aquatic biome

an aquatic region characterized by a particular combination of salinity, depth, and water flow

habitat

an area where a particular species lives in nature

tundra

a cold and treeless biome with low-growing vegetation

permafrost

an impermeable, permanently frozen layer of soil

boreal forest

a forest biome made up primarily of coniferous evergreen trees that can tolerate cold winters and short growing seasons

temperate rainforest

a coastal biome typified by moderate temperatures and high precipitation

temperate seasonal forest

a biome with warm summers and cold winters with over 1 m (39 inches) of precipitation annually.

woodland/shrubland

a biome characterized by hot, dry summers and mild, rainy winters

temperate grassland/ cold desert

a biome characterized by cold, harsh winters, and hot, dry summers.

tropical rainforest

a warm and wet biome found between 20 degrees N and 20 degrees S of the equator, with little seasonal temperature variation and high precipitation

tropical seasonal forest/ savanna

a biome marked by warm temperatures and distinct wet and dry seasons

subtropical desert

a biome prevailing at approximately 30 degrees N and 30 degrees S, with hot temperatures, extremely dry conditions, and sparse vegetation

oligotrophic

describes a lake with a low level of productivity

eutrophic

describes a lake with a high level of productivity

freshwater wetland

an aquatic biome that is submerged or saturated by water for at least part of each year, but shallow enough to support emergent vegetation

salt marsh

a marsh containing nonwoody emergent vegetation, found along the coast in temperate climates

estuary

an area along the coast where the fresh water of rivers mixes with salt water from the ocean

mangrove swamp

a swamp that occurs along tropical and subtropical coasts, and contains salt-tolerant trees with roots submerged in water.

intertidal zone

the narrow band of coastline between the levels of high tide and low tide

coral reef

the most diverse marine biome on Earth, found in warm, shallow waters beyond the shoreline.

coral bleaching

a phenomenon in which algae inside corals die, causing the corals to turn white.

open ocean

deep ocean water, located away from the shoreline where sunlight can no longer reach the ocean bottom