C4.2 SL / HL

Question 1

Mesocosms

Answer 1

any outdoor experimental system that examines the natural environment under controlled conditions

Question 2

Closed system

Answer 2

one that cannot transfer energy to its surroundings. Biological organisms areopen systems

Question 3

biosphere

Answer 3

the region of the earth that encompasses all living organisms: plants, animals and bacteria

Question 4

Open system

Answer 4

one in which energy can be transferred between the system and its surroundings

Question 5

Laws of the conservation of matter / energy

Answer 5

the magnitude of properties within a chemical system, such as mass, energy, or charge, remain unchanged during a chemical reaction. These properties may be exchanged between components of the system; however, the total amount in the system does not increase or decrease

Question 6

Laws of thermodynamics

Answer 6

the First Law of Thermodynamics states that total energy in a closed system is neither lost nor gained — it is only transformed. TheSecond Law of Thermodynamicsstates that entropy constantly increases in a closed system

Question 7

Photons

Answer 7

a quantum of radiant energy with a visible wavelength. It is anelementary particlethat is its own antiparticle. It is a discrete concentration of energy

Question 8

Producers

Answer 8

organisms that make their own food; they are also known as autotrophs

Question 9

aphotic zone

Answer 9

the portion of a lake or ocean where there is little or no sunlight

Question 10

chemoautotrophs

Answer 10

microorganisms that use inorganic chemicals as their energy source and convert them into organic compounds. These microorganisms are able to make what they need to supply themselves with nourishment and energy

Question 11

geothermal pools

Answer 11

occurs when groundwater is geothermally heated by the earth’s crust

Question 12

hydrothermal vents

Answer 12

the result of seawater percolating down through fissures in the ocean crust in the vicinity of spreading centers or subduction zones

Question 13

Food chain

Answer 13

a linear sequence of organisms through which nutrients and energy pass as one organism eats another

Question 14

Food web

Answer 14

a complex network of interconnecting and overlapping food chains showing feeding relationships within a community

Question 15

excretion

Answer 15

the process of removing wastes and excess water from the body

Question 16

decomposers

Answer 16

organisms that break down dead or decaying organisms

Question 17

Detritivores

Answer 17

organisms that break-down and feed on dead and decaying organic materia

Question 18

saprotrophs

Answer 18

a type ofdecomposerthat feeds exclusively on dead and decaying plant matter

Question 19

Humus

Answer 19

a substance made from dead leaves and plants, that put into the ground to help plants grow. Humus is partially decayed organic matter

Question 20

topsoil

Answer 20

the upper layer of soil. It has the highest concentration of organic matter and microorganisms and is where most of the Earth’s biological soil activity occurs

Question 21

Photoautotrophs

Answer 21

organisms that can utilize light energy from sunlight and elements (such as carbon) from inorganic compounds to produce organic materials needed to sustain their own metabolism

Question 22

Carbon fixation

Answer 22

the conversion of atmospheric carbon dioxide into organic molecules by autotrophic organisms

Question 23

Chemoautotrophs

Answer 23

microorganisms that use inorganic chemicals as their energy source and convert them into organic compounds

Question 24

hydrogen sulfide

Answer 24

a chemical compound with the formula H2S. It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs

Question 25

hydrolysis

Answer 25

any chemical reaction in which a molecule of water breaks one or more chemical bonds

Question 26

ATP

Answer 26

the principal molecule for storing and transferring energy in cells

Question 27

spontaneous reaction

Answer 27

a reaction that proceeds on its own in a given set of conditions, without the external addition of energy.

Question 28

iron-fixing bacteria

Answer 28

long thread-like bacteria that “feed” on iron and secrete slime. Unlike most bacteria, which feed on organic matter, iron bacteria fulfill their energy requirements by oxidizing ferrous iron into ferric iron

Question 29

Heterotrophs

Answer 29

organisms that consume other organisms for energy

Question 30

assimilated

Answer 30

the process of absorption of vitamins, minerals, and other chemicals from food as part of the nutrition of an organism

Question 31

cellular respiration

Answer 31

the process by which biological fuels are oxidized in the presence of an inorganic electron acceptor, such as oxygen

Question 32

oxidation reactions

Answer 32

a process that occurs when atoms or groups of atoms lose electrons

Question 33

Trophic level

Answer 33

any step in a nutritive series, or food chain, of an ecosystem

Question 34

primary consumer

Answer 34

animals that eat plants as part of their diet or as their entire diet

Question 35

Secondary consumer

Answer 35

The organisms that eat the primary consumers are called secondary consumers

Question 36

Tertiary consumer

Answer 36

animals that eat other animals

Question 37

Quaternary consumer

Answer 37

an animal that consumes at the very top of the food chain, after the primary consumer

Question 38

top carnivore

Answer 38

carnivores occupying the top level of a food chain or a number pyramid

Question 39

ecological pyramids

Answer 39

a graphical representation in the form of a pyramid showing the feeding relationship of groups of organisms

Question 40

Pyramid of numbers

Answer 40

shows the total number of individual organisms at each level in the food chain of an ecosystem

Question 41

Pyramid of biomass

Answer 41

the representation of total living biomass or organic matter present at different trophic levels in an ecosystem

Question 42

Pyramid of energy

Answer 42

a model that shows the flow of energy from one trophic, or feeding, level to the next in an ecosystem

Question 43

10% Rule

Answer 43

when energy is passed in an ecosystem from one trophic level to the next, only ten percent of the energy will be passed on

Question 44

Biomass

Answer 44

biological material derived from living, or recently living organisms

Question 45

primary production

Answer 45

the production of chemical energy in organic compounds by living organisms. The main source of this energy is sunlight but a minute fraction of primary production is driven by lithotrophic organisms using the chemical energy of inorganic molecules

Question 46

Secondary production

Answer 46

the formation of living mass of a heterotrophic population or group of populations over some period of time

Question 47

Atmosphere

Answer 47

a mixture of gases that surrounds the Earth

Question 48

Lithosphere

Answer 48

the solid, outer part of Earth

Question 49

Hydrosphere

Answer 49

the total amount of water on a planet

Question 50

Source

Answer 50

any natural or artificial production site of carbon and/or any chemical compounds composed of carbon, such as carbon dioxide and methane

Question 51

Sink

Answer 51

anything that absorbs more carbon from the atmosphere than it releases

Question 52

Flux

Answer 52

the rate of exchange of carbon between the various carbon sinks / reservoirs

Question 53

methanogenic archaea

Answer 53

a unique group of strictly anaerobic microorganisms characterized by their ability, and dependence, to convert simple C1 and C2 compounds to methane for growth

Question 54

Peat

Answer 54

surface organic layer of a soil that consists of partially decomposed organic matter, derived mostly from plant material, which has accumulated under conditions of waterlogging, oxygen deficiency, high acidity and nutrient deficiency

Question 55

partial decomposition

Answer 55

incomplete decomposition of organic waste / dead matter

Question 56

waterlogged soil

Answer 56

excess water in the root zone accompanied by anaerobic conditions

Question 57

Fossilization

Answer 57

the process of an animal or plant becoming preserved in a hard, petrified form

Question 58

combustion

Answer 58

a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat and light in the form of flame

Question 59

permafrost soil

Answer 59

permanently frozen layer on or under Earth's surface. It consists of soil, gravel, and sand, usually bound together by ice.

Question 60

Fossil fuel

Answer 60

compound mixtures made of fossilized plant and animal remnants from millions of years ago. The creation of fossil fuels—either oil, natural gas, or coal—from these fossils is determined by the type of fossil, the amount of heat, and the amount of pressure

Question 61

Keeling Curve

Answer 61

a graph that represents the concentration of carbon dioxide (CO2) in Earth's atmosphere since 1958