Chapter 5 - Environmental Systems and Ecosystem Ecology

Question 1

hypoxia

Answer 1

the condition of extremely low dissolved oxygen concentration in a body of water

Question 2

feedback loop

Answer 2

a circular process in which a systems output serves as input to that same system

Question 3

negative feedback loop

Answer 3

a feedback loop in which out put of one type acts as input that moves the system in the opposite direction. the input and output essentially neutralize each others effects, stabilizing the system

Question 4

positive feedback loop

Answer 4

a feedback loop in which output of one type acts as input that moves the system in the same direction. the input and output drive the system further towards on extreme or another

Question 5

emergent tree

Answer 5

an especially tall tree that protrudes above the canopy of tropical rain-forest

Question 6

dynamic equilibrium

Answer 6

the state reached when processes within a system are moving in opposing directions at equivalent rates so that their effects balance out

Question 7

homeostasis

Answer 7

the tendency of a system to maintain constant or stable internal conditions

Question 8

runoff

Answer 8

the water from precipitation that flows into streams, rivers, lakes, and ponds, and (in many cases) eventually to the ocean

Question 9

hydrosphere

Answer 9

all water- salt or fresh, liquid, ice, and vapor- in surface bodies, underground, and in the atmosphere

Question 10

eutrophication

Answer 10

the process of nutrient enrichment. increased production of organic matter, and subsequent ecosystem degradation in a water body

Question 11

airshed

Answer 11

the geographic area that produces air pollutants likely to end up in a waterway

Question 12

estuary

Answer 12

an area where a river flows into the ocean, mixing fresh and salt water

Question 13

lithosphere

Answer 13

the outer layer of earth, consisting of crust and uppermost mantle and located just above the asthenosphere, more generally the solid part of earth, including rocks, sediments, and sail at the surface and extending many miles underground

Question 14

primary production

Answer 14

the conversion of solar energy to the energy of chemical bonds in sugars during photosynthesis, performed by autotrophs

Question 15

gross primary production

Answer 15

the energy that results when autotrophs convert solar energy to the energy of chemical bonds in sugars during photosynthesis. autotrophs use a portion of this production to power their own metabolism, which entails oxidizing organic compounds by cellular respiration

Question 16

net primary production

Answer 16

the energy or biomass that remains in an ecosystem after autotrophs have metabolized enough for their own survival through cellular respiration. net primary production is the energy or biomass that is available for consumption by heterotrophs

Question 17

net primary productivity

Answer 17

the rate at which net primary production is produced

Question 18

secondary production

Answer 18

the total biomass that heterotrophs generate by consuming autotrophs

Question 19

productivity

Answer 19

the at which plants convert solar energy to biomass. ecosystems whose plants convert solar energy to biomass rapidly are said to have high productivity

Question 20

nutrient

Answer 20

an element or compound that organisms consume and require for survival

Question 21

macronutrients

Answer 21

elements and compounds required in relatively large amounts by organisms. examples include nitrogen, carbon, and phosphate

Question 22

micronutrients

Answer 22

elements and compounds required in relatively small amounts by organisms. examples include zinc, copper, and iron

Question 23

ecotone

Answer 23

a transitional zone where ecosystems meet

Question 24

landscape ecology

Answer 24

the study of how landscape structures affects the abundance, distribution, and interaction of organisms. this approach to the study of organisms and their environment. landscape studies follow broad geographical areas that include multiple ecosystems

Question 25

patch

Answer 25

in landscape ecology, spatial area within a landscape, depending on a researchers perspective patches may consist of habitat for a particular organism, or community, or ecosystem. an array of patches forms a mosaic

Question 26

mosaic

Answer 26

in landscape ecology, a spatial configuration of patches arrayed across a landscape

Question 27

nutrient cycle (biogeochemical cycle)

Answer 27

the comprehensive set of cycle pathways by which a given nutrient moves through the environment

Question 28

reservoir (pool)

Answer 28

an artificial water body behind a dam that stores water for human use

Question 29

residence time

Answer 29

(1) in a biogeochemical cycle, the amount of time a nutrient remains in a given pool or reservoir before moving to another. (2) in the atmosphere, the amount of time a gas molecule or pollutant stays aloft

Question 30

flux

Answer 30

the movement of nutrients among pools or reservoirs in a nutrient cycle

Question 31

source

Answer 31

in a nutrient cycle, a pool that releases more nutrients than it accepts

Question 32

sink

Answer 32

in a nutrient cycle, a pool that accepts more nutrients than it releases

Question 33

water cycle (hydrologic cycle)

Answer 33

the flow of water - in liquid, solid, or gaseous form - through our biotic and abiotic environment

Question 34

evaporation

Answer 34

the conversion of a substance from a liquid to a gaseous form

Question 35

transpiration

Answer 35

the release of water vapor by plants through their leaves

Question 36

precipitation

Answer 36

water that condenses out of the atmosphere and falls into earth in droplets or crystals

Question 37

ground water

Answer 37

water held in aquifers underground

Question 38

aquifer

Answer 38

an underground water reservoir

Question 39

water table

Answer 39

the upper limit of groundwater held in an aquifer

Question 40

carbon cycle

Answer 40

a major nutrient cycle consisting of the routes that carbon atoms take through the nested networks of environmental systems

Question 41

nitrogen cycle

Answer 41

a major nutrient cycle consisting of the routes that nitrogen atoms take through the nested networks of environmental systems

Question 42

nitrogen fixation

Answer 42

the process by which inert nitrogen gas combines with hydrogen to form ammonium ions (NH4+), which are chemically and biologically active and can be taken up by plants

Question 43

nitrogen-fixing bacteria

Answer 43

bacteria that live independently in the soil or water, or those that form mutualistic relationships with many types of plants and provide nutrients to the plants by converting gaseous nitrogen to a usable form

Question 44

nitrification

Answer 44

the conversion by bacteria of ammonium ions (NH4+) first into nitrite ions (NO2-) and then into nitrate ions (NO3-)

Question 45

denitrifying bacteria

Answer 45

bacteria that convert the nitrates in soil or water to gaseous nitrogen and release it back into the atmosphere

Question 46

Haber-Bosch process

Answer 46

a process to synthesize ammonia on an industrial scale. developed by german chemistFritz Haber and Carl Bosch, the process has enabled humans to double the natural rate of nitrogen fixation on earth and thereby increase agricultural productivity, but it has also dramatically altered the nitrogen cycle

Question 47

phosphorus cycle

Answer 47

a major nutrient cycle consisting of the routes that phosphorus atoms take through the nested networks of environmental systems