4A,B,C,D Ecology & the Environment

Question 1

Define the term population

Answer 1

A group of organisms of the same species in an area

Question 2

Define the term community

Answer 2

A group of organisms of different species in an area

Question 3

Define the term ecosystem

Answer 3

The organisms + the environment

Question 4

Define the term habitat

Answer 4

A place where an organism lives

Question 5

TRIPLE ONLY
Define the term biodiversity

Answer 5

The variety of genes, species and habitats

Question 6

Describe the difference between biotic and abiotic factors

Answer 6

Biotic = living factors

Abiotic = non-living factors

Question 7

Give 3 examples of biotic factors

Answer 7

Predation

Competition

Disease

Question 8

Give 3 examples of abiotic factors

Answer 8

Light intensity

Temperature

Humidity

Question 9

What does the term abundance mean

Answer 9

The number of organisms

Question 10

Describe how to estimate the population size of an organism in an area using a quadrat

Answer 10

Randomly lay quadrat
ID organisms using a key
Count number of individuals
Record abiotic factors e.g. …?
Repeat several times
Calculate mean and then times by total area

Question 11

Explain how to avoid bias when sampling in biology

Answer 11

Randomly place quadrat

(i.e. use random number generator to get coordinates for placement)

Question 12

Explain how to increase reliability when sampling

Answer 12

Increase sample size - place more quadrats down

Question 13

TRIPLE ONLY
What does the term distribution mean in biology

Answer 13

Where organisms are located

Question 14

TRIPLE ONLY
State what piece of equipment you would use to measure how the distribution of organisms change from one area to another

Answer 14

Line transact

Question 15

TRIPLE ONLY
Describe how you would measure how the distribution of an organism changes

Answer 15

Lay line transect from one area to another (must be specific where)
Place quadrat at even intervals along transect (e.g. every 5m)
ID organisms using a key
Count number of individuals
Record abiotic factors e.g…?
Repeat line transect several times

Question 16

Define the term trophic level

Answer 16

Stage in a food chain

Question 17

Define these food chain terms:
Producer
Consumer
Decomposer

Answer 17

Producer = makes own food using photosynthesis

Consumer = needs to eat other organisms to get nutrition

Decomposer = breaks down decaying matter to get nutrition

Question 18

What do all food chains start with, and give common examples

Answer 18

All start with producers e.g. plants, algae

Question 19

How much energy is transferred from one stage in a food chain (trophic level) to another

Answer 19

Just 10%

Question 20

Explain why energy is lost as you move along food chains

Answer 20

Energy released for heat, movement, release of faeces

Not all parts of organisms are eaten either e.g. bark of trees

Question 21

Describe how carbon is released into the atmosphere during the carbon cycle

Answer 21

Combustion of fuels

Respiration of plants, animals, decomposers

Volcanic activity

Question 22

Describe how carbon is absorbed from the atmosphere in the carbon cycle

Answer 22

Photosynthesis

Dissolving in oceans

Question 23

TRIPLE ONLY
State the role of nitrogen-fixing bacteria in the nitrogen cycle

Answer 23

Turns atmospheric nitrogen (N2) into nitrogen compounds in soil and plants

Question 24

TRIPLE ONLY
State the role of decomposers in the nitrogen cycle

Answer 24

Break down large nitrogen compounds into ammonium compounds

Question 25

*TRIPLE ONLY* State the role of nitrifying bacteria in the nitrogen cycle

Answer 25

Convert ammonia into nitrites and nitrates

Question 26

*TRIPLE ONLY* State the role of denitrifying bacteria in the nitrogen cycle

Answer 26

Converts nitrates back into atmospheric nitrogen (N2)

Question 27

*TRIPLE ONLY* Explain the role of lightning in the nitrogen cycle

Answer 27

Atmospheric nitrogen (N2) reacts with oxygen in the air to form nitrates in the soil

Question 28

*TRIPLE ONLY* Explain why it is important for atmospheric N2 to be fixed into nitrogen compounds for organisms to use

Answer 28

Used to make amino acids and DNA

Question 29

State two main pollutant gases

Answer 29

Sulphur dioxide (SO2) Carbon monoxide (CO)

Question 30

State the biological consequences of sulfur dioxide

Answer 30

Forms acid rain - dissolves leaves and makes lakes acidic, killing fish

Question 31

State the biological consequences of carbon monoxide

Answer 31

Binds to haemoglobin Less oxygen transported to cells, so less respiration Leads to fatigue, dizziness and can lead to death

Question 32

State 5 greenhouse gases

Answer 32

Methane Carbon dioxide Water vapour Nitrous oxides CFCs

Question 33

Explain what is meant by a greenhouse gas

Answer 33

Traps heat in the earth’s atmosphere

Question 34

List the activities that have increased the number of greenhouse gases in the atmosphere

Answer 34

Burning fossil fuels Cutting down trees Increased cars, factories etc Cattle farming and rice fields (releases methane)

Question 35

Explain the main effects that too many greenhouse gases can have on the planet

Answer 35

Climate change and extreme weather Desertification Ice caps melting, causes sea level rise and flooding Affecting animal migrations

Question 36

Explain why sewage in waterways can kill aquatic life i.e. fish

Answer 36

Sewage provides nutrients for bacteria to grow Bacteria grow, respire and use up oxygen in water No more oxygen in water kills fish (water becomes anoxic)

Question 37

Describe the process of eutrophication

Answer 37

Fertiliser/nutrients flow into water i.e. pond Algae on surface grow Algae block sunlight for underwater plants Plants die (cannot photosynthesise) Bacteria feed on plants and respire, using up oxygen in water No oxygen kills fish

Question 38

Explain what leaching is

Answer 38

Fertilisers dissolve in rainwater and drains into rivers, ponds and lakes

Question 39

*TRIPLE ONLY* Describe 4 effects of deforestation on the environment

Answer 39

Leaching → mineral ions aren't taken up by roots so wash away in rainwater Soil erosion → no roots to stabilise soil, leads to land slides Evapotranspiration → less trees to recycle water vapour by transpiration Carbon dioxide → less trees means less photosynthesis so less carbon dioxide absorbed from atmosphere