Unit B

Question 1

Ecology

Answer 1

The study of interactions between organisms and their living and non-living environment.

Question 2

Biotic factors

Answer 2

Living factors that influence an organism

Question 3

Abiotic factors

Answer 3

Non-living factors that influence an organism

Question 4

Population

Answer 4

All members of a species that live in the same ecosystem or habitat

Question 5

Community

Answer 5

The collection of all populations in a given habitat or ecosystem

Question 6

Ecotones

Answer 6

A transitional area between ecosystems, typically containing greater biodiversity than either individual ecosystem

Question 7

What is a transitional area between ecosystems called?

Answer 7

An ecotone

Question 8

Ecological niche

Answer 8

An organism’s role in the ecosystem, including its place in the food web and the places and times where it is active.

Question 9

What are the two main causes of species depletion and extinction?

Answer 9

1. Habitat loss
2. The introduction of exotic (invasive) species

Question 10

Biome

Answer 10

A large geographical region with a particular climate, and the plants and animals adapted to that climate

Question 11

Taiga

Answer 11

Also known as boreal forest; a biome dominated by coniferous trees, with warm, moist summers and cold, dry winters.

Question 12

Canopy

Answer 12

The upper layer of vegetation in a forest

Question 13

Climate

Answer 13

The average temperature and precipitation conditions of a region

Question 14

Permafrost

Answer 14

Permanently frozen soil

Question 15

Muskeg

Answer 15

Soil above the permafrost that is swampy or boggy in summer, due to poor drainage

Question 16

What do decomposing conifer needles produce?

Answer 16

Acidic soil

Question 17

Why are muskeg ecosystems fragile?

Answer 17

Low temperatures cause slow decomposition and soil formation, making damage to the ecosystem take years to repair.

Question 18

Understorey

Answer 18

The part of the forest below the canopy, usually shrubs and smaller trees

Question 19

Littoral Zone

Answer 19

The area from the shore of a lake or pond to the point where no more plants grow at the bottom

Question 20

Limnetic Zone

Answer 20

The area of a lake or a pond in which there is open water and sufficient light for photosynthesis to occur

Question 21

Profundal Zone

Answer 21

The region of a lake below the limnetic zone, where there is insufficient light for photosynthesis to occur

Question 22

Plankton

Answer 22

Autotrophic and heterotrophic microorganisms found in the limnetic zone of a lake or pond

Question 23

Litter

Answer 23

the upper layer of soil, composed mainly of partially decomposed leaves or grasses

Question 24

Topsoil

Answer 24

the soil layer beneath the litter, composed of small particles of rock mixed with humus

Question 25

Humus

Answer 25

decaying plant and animal matter

Question 26

Subsoil

Answer 26

the soil layer beneath the topsoil, usually containing more rock particles and less organic matter than the topsoil

Question 27

Bedrock

Answer 27

the layer beneath the soil, composed of rock

Question 28

Groundwater

Answer 28

water in the soil or rock below Earth’s surface

Question 29

What are the four abiotic factors that affect terrestrial ecosystems?

Answer 29

1. Soil 2. Water 3. Temperature 4. Sunlight

Question 30

What are the four abiotic factors that affect aquatic ecosystems?

Answer 30

1. Chemical environment 2. Temperature 3. Sunlight 4. Water pressure

Question 31

Epilimnion

Answer 31

the upper level of a lake, which warms up in summer

Question 32

Hypolimnion

Answer 32

the lower level of a lake, which remains at a low temperature year round

Question 33

Thermocline

Answer 33

the zone between the epilimnion and hypolimnion, in which temperature changes rapidly

Question 34

Biotic Potential

Answer 34

The maximum number of offspring that a species could produce with unlimited resources

Question 35

What four factors affect biotic potential?

Answer 35

1. Birth potential 2. Capacity for survival 3. Breeding frequency 4. Length of reproductive life

Question 36

Carrying Capacity

Answer 36

The maximum number of individuals of a species that can be supported by an ecosystem

Question 37

Law of the Minimum

Answer 37

States that the nutrient in the least supply is the one that limits growth

Question 38

Law of Tolerance

Answer 38

States that an organism can survive within a particular range of an abiotic factor

Question 39

Density-independent factor

Answer 39

A factor in an ecosystem that affects members of a population regardless of population density

Question 40

Density-dependent facto

Answer 40

A factor in an ecosystem that affects members of a population because of the population density

Question 41

List some examples of density-independent factors.

Answer 41

1. Fire 2. Flood 3. Spraying with pesticides 4. Change in climate or temperature 5. Destruction of habitat 6. Drought

Question 42

List some examples of density-dependent factors.

Answer 42

1. Food shortage 2. Competition for mates & breeding areas (habitat) 3. Infectious disease 4. Introduction of an exotic species 5. Increased predation 6. Competition for resources

Question 43

Slash-and-burn

Answer 43

The complete clearing of a forest by felling and burning the trees

Question 44

Clear-cutting

Answer 44

The removal of all trees in an area, typically for lumber and pulp

Question 45

Selective cutting

Answer 45

The harvesting of only certain trees from an area

Question 46

Prescribed burn

Answer 46

A controlled fire set intentionally in a designated area

Question 47

Oligotrophic

Answer 47

(Usually of a lake) Having low nutrient levels

Question 48

Eutrophic

Answer 48

(Usually of a lake) Having high nutrient levels

Question 49

Eutrophication

Answer 49

The evolution of a deep, oligotrophic lake, to a shallow, eutrophic lake, to dry land, often over hundreds or thousands of years

Question 50

Coliform bacteria

Answer 50

A type of bacteria that occurs naturally in the intestines of humans and other animals, and indicates the presence of fecal contamination in water

Question 51

Biological oxygen demand (BOD)

Answer 51

The amount of dissolved oxygen needed by decomposers to completely break down the organic matter in a water sample at 20 °C over five days. Measured in mg of O₂ per litre

Question 52

Watershed

Answer 52

The land that drains toward a lake or other body of water