Unit A

Question 1

What does dynamic equilibrium describe?

Answer 1

A system with constant change, in which the components can adjust to the changes without disturbing the entire system

Question 2

The Biosphere

Answer 2

The narrow zone around Earth that harbours life

Question 3

Biotic Components

Answer 3

The biological or living components of the biosphere

Question 4

Abiotic Components

Answer 4

The non-living components of the biosphere, including chemical and physical factors.

Question 5

Community

Answer 5

The populations of all species that occupy a habitat

Question 6

Ecosystem

Answer 6

A community and its physical and chemical environment

Question 7

Food chain

Answer 7

A sequence linking organisms that feed on each other, starting with a food source and continuing in order with each consumer.

Question 8

Autotroph

Answer 8

A producer, an organism that makes its own food using the Sun’s energy.

Question 9

Heterotroph

Answer 9

A consumer, an organism that consumes other organisms to gain energy.

Question 10

Indicator Species

Answer 10

A species sensitive to small changes in environmental conditions. Can provide early warning that the balance in an ecosystem is being negatively affected.

Question 11

Detritus

Answer 11

Waste from animals and plants, including their remains.

Question 12

Decomposer

Answer 12

An organism that feeds on detritus

Question 13

Habitat

Answer 13

A place or type of environment with conditions suitable for the survival of an organism or population of organisms

Question 14

What do you call a representation of ll the feeding relationships among organisms in an ecosystem

Answer 14

A food web

Question 15

Photosynthesis

Answer 15

The process by which green plants and some other organisms use solar energy, carbon dioxide, and water to produce carbohydrates

Question 16

Cellular respiration

Answer 16

The process by which cells break down glucose into carbon dioxide and water, releasing energy

Question 17

Chemosynthesis

Answer 17

The process by which non-photosynthetic organisms convert inorganic chemicals to organic compounds without solar energy

Question 18

What do you call an organism that can synthesize organic compounds from inorganic chemicals without using solar energy?

Answer 18

Chemoautotroph

Question 19

Ecological pyramid

Answer 19

A representation of energy flow in food chains and webs

Question 20

Monoculture

Answer 20

Cultivation of a single species

Question 21

Transpiration

Answer 21

The loss of water through plant leaves

Question 22

The loss of water through plant leaves

Answer 22

Transpiration

Question 23

Percolation

Answer 23

The movement of a liquid through a porous material, such water draining downward through soil particles

Question 24

Water table

Answer 24

The top level of the region below the ground that is saturated with water

Question 25

Leaching

Answer 25

The removal of soluble minerals from soil by percolation

Question 26

Which chemicals are most responsible for acid rain?

Answer 26

Sulphur dioxide, nitrous oxides

Question 27

Where does human produced Sulphur dioxide come from?

Answer 27

Burning fossil fuels, refining metal ores

Question 28

What is peat?

Answer 28

Slowly decomposing plant matter produced in low-oxygen environments such as bogs

Question 29

How does ocean limestone form?

Answer 29

1. Dissolved carbon dioxide becomes carbonate (CO₃²⁻) and bicarbonate (HCO₃⁻)
2. These react with calcium to form calcium carbonate (CaCO₃), which is used by creatures to make shells.
3. The shells of dead creatures become sediment and form limestone.
4. Volcanic activity can break apart the calcium carbonate, releasing carbon dioxide back into the air.

Question 30

How do greenhouse gases trap heat?

Answer 30

They prevent long (infrared) wavelengths from leaving the atmosphere. Because of entropy, wavelengths reflected from the earth are longer than those entering.

Question 31

What is albedo?

Answer 31

A surface’s ability to reflect radiation, expressed as the fraction of radiation reflected. (Ex. 0.08 - 8% reflection)

Question 32

Nitrogen Fixation

Answer 32

Two processes (lightning and bacteria) that convert atmospheric and dissolved nitrogen into nitrate (NO₃⁻) ions.

Question 33

Denitrification

Answer 33

A process carried out by anaerobic bacteria, breaking down nitrates into nitrites (NO₂⁻), and then into nitrogen gas.

Question 34

Why are algal blooms harmful?

Answer 34

When large amounts of algae die, decomposers use oxygen to break them down, causing oxygen levels in the water to drop and killing off animal life.

Question 35

Why are nitrites harmful to animals?

Answer 35

Nitrites can bind to hemoglobin in the blood, reducing its ability to carry oxygen.

Question 36

Describe the long-term phosphorus cycle.

Answer 36

1. Phosphate ions (PO₄³⁻) in rock are dissolved in water and absorbed by photosynthesizers.
2. Consumers that eat the photosynthesizers use phosphate to create calcium phosphate in their bones.
3. After these consumers die, their bones and shells become phosphate-containing sediment and form rock.

Question 37

Nitrate

Answer 37

NO₃⁻

Question 38

Nitrite

Answer 38

NO₂⁻

Question 39

Ammonia

Answer 39

NH₃

Question 40

Phosphate

Answer 40

PO₄³⁻