Ch. 3 - Earth Systems and Ecosystems

Question 1

hypoxia

Answer 1

A state of oxygen deficiency

Question 2

nutrient

Answer 2

An element or compound that organisms consume and require for survival

Question 3

eutrophication

Answer 3

The process of nutrient enrichment, increased production of organic matter, and subsequent ecosystem degradation.

Question 4

cycle

Answer 4

Flows of elements, compounds, and energy from reservoir to reservoir through the Earth system.

Question 5

system

Answer 5

A network of relationships among a group of parts, elements, or components that interact with and influence one another through the exchange of energy, matter, and/or information.

Question 6

open system

Answer 6

A system that allows both energy and matter to cross its boundaries.

Question 7

closed system

Answer 7

A system that is self-contained with regard to exchanges of matter (but not energy) with its surroundings. Scientists may treat a system as closed to simplify some questions they are investigating, but no natural system is truly closed.

Question 8

feedback loop (or feedback cycle):

Answer 8

A circular process in which a system’s output serves as input to that same system.

Question 9

negative feedback loop (or cycle):

Answer 9

A feedback loop in which output of one type acts as input that moves the system in the opposite direction. The input and output essentially neutralize each other’s effects, stabilizing the system.

Question 10

positive feedback loop (or cycle):

Answer 10

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 toward one extreme or another.

Question 11

dynamic equilibrium

Answer 11

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

Question 12

homeostasis

Answer 12

The characteristic whereby a system tends to maintain constant or stable internal conditions.

Question 13

resistance

Answer 13

The ability of an ecological community to remain stable in the presence of a disturbance.

Question 14

resilience

Answer 14

The ability of an individual or a community (human or ecological) to change in response to disturbance, and then return to its original state or to a new state of equilibrium that is similar to the original state.

Question 15

steady state

Answer 15

A state of dynamic equilibrium or balance in which there is no net change in the system.

Question 16

emergent property

Answer 16

A characteristic that is not evident in a system’s components individually.

Question 17

geosphere

Answer 17

The solid Earth; sometimes the word lithosphere is used with this connotation, but technically it has a distinct meaning.

Question 18

atmosphere

Answer 18

The thin layer of gases surrounding planet Earth.

Question 19

air

Answer 19

The specific mixture of gaseous constituents that makes up Earth’s atmosphere.

Question 20

hydrosphere

Answer 20

Earth’s water—salt or fresh, liquid, ice, or vapour—that resides in surface bodies, underground, and in the atmosphere.

Question 21

cryosphere

Answer 21

The temporarily and perenially frozen parts of the hydrosphere, including snow, sea ice, lake and river ice, glaciers, and ice caps and sheets.

Question 22

biosphere

Answer 22

The sum total of all the planet’s living organisms and the abiotic portions of the environment with which they interact.

Question 23

anthroposphere

Answer 23

The human sphere, and the built environment; the environment as modified by human actions.

Question 24

biotic

Answer 24

Refers to any living component of the environment.

Question 25

abiotic

Answer 25

Refers to any nonliving component of the environment.

Question 26

ecosystem

Answer 26

All of the organisms and nonliving entities that occur and interact with each other and with the abiotic environment in a particular area at the same time.

Question 27

ecology

Answer 27

The science that deals with the distribution and abundance of organisms, the interactions among them, and the interactions between organisms and their abiotic environments.

Question 28

ecosystem ecology

Answer 28

The study of how the living and nonliving components of ecosystems interact and transfer energy among themselves.

Question 29

biomass

Answer 29

Biological material; consists of living and recently deceased organic matter.

Question 30

gross primary production (GPP)

Answer 30

The energy that results when autotrophs convert energy (most commonly from sunlight) to energy of chemical bonds in sugars. Autotrophs use a portion of this production to power their own metabolism, which entails oxidizing organic compounds by cellular respiration.

Question 31

net primary production (NPP)

Answer 31

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

Question 32

secondary production

Answer 32

The total biomass that heterotrophs generate by consuming autotrophs.

Question 33

productivity

Answer 33

The rate at which plants convert solar energy (sunlight) to biomass. Ecosystems whose plants convert solar energy to biomass rapidly are said to have high productivity.

Question 34

limiting factor

Answer 34

A physical, chemical, or biological characteristic of the environment that restrains population growth.

Question 35

cumulative effects

Answer 35

Repeated, local, short-timescale events, processes, or materials that add up to something bigger, more impactful, or more concentrated.

Question 36

model

Answer 36

A simplified representation of a natural process. Models can be physical, graphical, or quantitative and computer-based. They allow scientists to study natural systems and processes that are highly complex or unwieldy in their spatial or temporal scale. They also can be used to predict future behaviour in complex systems.

Question 37

ecotone

Answer 37

A transitional zone where ecosystems meet.

Question 38

landscape ecology

Answer 38

An approach to the study of organisms and their environments at the landscape scale, focusing on geographical areas that include multiple ecosystems.

Question 39

remote sensing

Answer 39

The collection of information about a target, from a distance. Most commonly refers to the collection of information about the near-surface Earth environment by instruments carried on satellites.

Question 40

geographic information system (GIS)

Answer 40

Computer software that takes multiple types of data (for instance, on geology, hydrology, vegetation, animal species, and human development) and overlays them on a common set of spatial coordinates; a common tool of geographers, landscape ecologists, resource managers, and conservation biologists.

Question 41

nutrient cycle (or biogeochemical cycle)

Answer 41

The comprehensive set of cyclical pathways by which a given nutrient moves through the environment.

Question 42

reservoir (or pool)

Answer 42

A location where materials in a cycle remain for a period of time, before moving to another reservoir.

Question 43

residence time

Answer 43

The amount of time a material in a cycle remains in a given pool or reservoir before moving to another reservoir.

Question 44

flux

Answer 44

The movement of materials or energy among pools or reservoirs in a cycle.

Question 45

source

Answer 45

In a cycle, a reservoir that releases more material than it takes in.

Question 46

sink

Answer 46

In a cycle, a reservoir that takes in more material than it releases.

Question 47

turnover time

Answer 47

The time it would take for a material to work its way through and out of a reservoir, if all of the sources or fluxes of that material into the reservoir were stopped.

Question 48

hydrologic cycle (or water cycle)

Answer 48

The flow of water—in liquid, gaseous, and solid forms—through our biotic and abiotic environment.

Question 49

evaporation

Answer 49

The conversion of a substance from a liquid to a gaseous form.

Question 50

transpiration

Answer 50

The release of water vapour by plants through their leaves.

Question 51

precipitation

Answer 51

Water that condenses out of the atmosphere and falls to Earth in droplets or crystals.

Question 52

runoff

Answer 52

The water from precipitation that flows over land into streams, rivers, lakes, and ponds, and eventually to the ocean.

Question 53

ground water

Answer 53

Water held in aquifers underground.

Question 54

Carbon (C)

Answer 54

The chemical element with atomic number six. A key element in organic compounds.

Question 55

carbon cycle

Answer 55

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

Question 56

Nitrogen (N)

Answer 56

The chemical element with the atomic number seven. The most abundant element in the atmosphere, a key element in macromolecules, and a crucial plant nutrient.

Question 57

nitrogen cycle

Answer 57

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

Question 58

nitrogen fixation

Answer 58

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 59

nitrification

Answer 59

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

Question 60

denitrification

Answer 60

A multistep chemical process in which nitrates in soil are reduced by denitrifying bacteria, and ultimately released to the atmosphere.

Question 61

Haber-Bosch process

Answer 61

A chemical process for synthesizing ammonium, thereby fixing nitrogen, on an industrial scale.

Question 62

phosphorus (P)

Answer 62

The chemical element with atomic number 15. An abundant element in the lithosphere, a key element in macromolecules, and a crucial plant nutrient.

Question 63

phosphorus cycle

Answer 63

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