Topic 8 - Ecology & the Environment

Question 1

competition and interdependence

habitat

Answer 1

place where an organism lives

Question 2

competition and interdependence

population

Answer 2

a group of organisms of the same species living in the same habitat

Question 3

competition and interdependence

community

Answer 3

all of the populations of different species living together in the same habitat

Question 4

competition and interdependence

ecosystem

Answer 4

interaction of living organisms (Biotic) and non-living organisms (abiotic) in their environment

Question 5

competition and interdependence

competition

Answer 5

interaction between organisms and species when they try to use the same limited resources

Question 6

competition and interdependence

interdependence

Answer 6

the fact that all organisms depend on each other and have complex relationships

Question 7

abiotic and biotic factors

biotic factors

Answer 7

living factors / factors caused by a living organism

Question 8

abiotic and biotic factors

example of biotic factors

Answer 8

predators eating prey

lack of food

disease

Question 9

abiotic and biotic factors

abiotic factors

Answer 9

factors not influenced by living organisms

Question 10

investigating abundance & distribution

abundance

Answer 10

how many organisms there are

Question 11

investigating abundance & distribution

distribution

Answer 11

where the organisms are

Question 12

investigating abundance & distribution

process of sampling

Answer 12

measuring a subset to make predictions on the entire population

Question 13

investigating abundance & distribution

quadrat

Answer 13

square frame divided into lots of smaller squares

Question 14

investigating abundance & distribution

quadrat method

Answer 14

1. place multiple tape measures along length + width of field to form grid
2. use random number generator to generate 10 random coordinates
3. place quadrats at coordinates + count how many organisms in each quadrat
4. calculate mean number of organism per m^2
5. estimate total population size of organism using total area of field

Question 15

investigating abundance & distribution

finding number of organisms

Answer 15

1. find mean dandelions per quadrat
2. each quadrat is 1m^2 -> multiply mean by this
3. calculate area of field
4. estimate number of dandelions in the whole field

Question 16

food chains and food webs

food chain

Answer 16

a model that shows how energy passes from organism to organism

Question 17

food chains and food webs

producers

Answer 17

organisms at the start of the food chain

produce food through photosynthesis

*producers are plants

Question 18

food chains and food webs

primary consumers

Answer 18

cannot produce their own food

they feed on the producers

Question 19

food chains and food webs

secondary consumers

Answer 19

cannot produce their own food

feed on primary consumers

Question 20

food chains and food webs

tertiary consumers

Answer 20

cannot produce their own food

feed on secondary consumers

Question 21

food chains and food webs

predator

Answer 21

top of the food chain

hunts and kills other animals for food

feeds on any consumers

Question 22

food chains and food webs

prey

Answer 22

an animal that is hunted and killed for food by another animal

Question 23

what happens to energy as it is passed down the food chain?

Answer 23

energy is lost

Question 24

trophic levels

trophic levels

Answer 24

stages in a food chain

Question 25

# trophic levels decomposer

Answer 25

an organism that breaks down other organisms

Question 26

pyramids of biomass

Answer 26

show the biomass of all organisms in that trophic level

Question 27

# pyramids of biomass biomass

Answer 27

mass of an organism

Question 28

# water cycle process of the water cycle

Answer 28

1. water from oceans, lakes, rivers, soil **evaporates** into **water vapour** in the **atmosphere** 2. water also **evaporates** from **plants** *(**transpiration**)* 3. water vapour **condenses**, forming **clouds** 4. water **falls from clouds** as rain *(**precipitation**)* 5. water seeps into soil, flows into rivers/lakes, taken up by plants 6. **cycle repeats!**

Question 29

# nitrogen cycle 1.nitrogen fixation

Answer 29

atmospheric nitrogen is converted into **nitrates** + **ammonia** in the soil via **lightning** (*nitrates*) OR via **nitrogen fixing bacteria** (*ammonia*) ## Footnote lightning converts atmospheric nitrogen -> nitrates nitrogen fixing bacteria convert atmospheric nitrogen -> ammonoa

Question 30

# nitrogen cycle 2.nitrification

Answer 30

process carried out by **nitrifying bacteria** in the soil 1. **ammonia** is converted into **nitrites** 2. these nitrites are converted into **nitrates** ## Footnote nitrifying bacteria convert ammonia -> nitrites -> nitrates

Question 31

# nitrogen cycle 3.assimilation

Answer 31

process by which plants absorb nitrates + ammonium ions, using them as biological molecules ## Footnote how nitrogen enters the food chain!

Question 32

# nitrogen cycle 4.decomposition

Answer 32

when decomposers feed on the waste excretions / rotting corpses of animals ## Footnote they convert urea + proteins into ammonia

Question 33

# nitrogen cycle 5.denitrification

Answer 33

process by which **denitrifying bacteria **convert **nitrates** back into **atmospheric nitrogen** ## Footnote denitrifying bacteria convert nitrates -> atmospheric nitrogen

Question 34

# global warming greenhouse gases

Answer 34

water vapour, methane + carbon dioxide

Question 35

# global warming process of greenhouse effect

Answer 35

1. solar radiation from sun passes through atmosphere, hitting the earth 2. some energy reflects back to space, some is absorbed by earth and remitted towards space 3. most remitted energy is absorbed by greenhouse gases in the atmosphere 4. this trapped heat energy keeps the atmsophere warmer + more stable

Question 36

# eutrophication fertiliser

Answer 36

substance applied to soil to supply it with nutrients

Question 37

# eutrophication how can fertilisers negatively impact waterways?

Answer 37

leaching + eutrophication

Question 38

# eutrophication leaching

Answer 38

process by which fertilisers are washed out of the soil by water ## Footnote this can be caused by rain or irrigation when leached nutrients wash into waterways, **eutrophication** occurs

Question 39

# eutrophication process of eutrophication

Answer 39

1. mineral ions leach into lakes and rivers, stimulating rapid algar growth 2. growth of algae on the surface blocks light from reaching the plants below 3. lack of light -> underwater plants cant photosynthesise and die 4. decomposers feed on the dead plant matter: decomposers use oxygen to respire, so more decomposers = less oxygen 5. lack of oxygen causes fish and other organisms to die

Question 40

# deforestation & land use deforestation

Answer 40

the large scale clearance of trees from an area

Question 41

# deforestation & land use causes of deforestation

Answer 41

- building towns/urbanisation - farming *(clearing land for agriculture)* - logging wood - mining

Question 42

# deforestation & land use problems with deforestation

Answer 42

- fewer trees = less photosynthesis + absorption of carbon dioxide = more carbon dioxide - often involved burning trees -> carbon dioxide is released - destroys animal habitats, reducing biodiversity

Question 43

# deforestation & land use peat bogs

Answer 43

acidic and waterlogged low oxygen levels carbon sinks

Question 44

# deforestation & land use how do peat bogs contribute to global warming?

Answer 44

- allows microorganisms to decay organic matter - release CO2 -> greenhouse gas -> global warming