Topic K - Ecology and the Enviroment

Question 1

definition of population

Answer 1

number of members of a single species

Question 2

definition of community

Answer 2

different species of organisms living n the same area

Question 3

definition of habitat

Answer 3

where living organisms live

Question 4

definition of ecosystem

Answer 4

population of different species of organism and the habitat they live in

Question 5

definition of producers

Answer 5

organisms that produce their own organic nutrients such as plants through photosynthesis

Question 6

definition of primary consumers

Answer 6

herbivores= feed on plants ( producers )

Question 7

definition of secondary consumers

Answer 7

predators that feed on primary consumers

Question 8

definition of tertiary consumers

Answer 8

predators that feed on secondary consumers

Question 9

definition of decomposers

Answer 9

bacteria and fungi that breaks down dead animals body, urea + undigested waste for energy ( using enzymes to break down compounds )

Question 10

definition of food chains

Answer 10

shows the feeding relationship between living things ( what eats what in a habitat)

Question 11

definition of food web

Answer 11

shows all the food chains in an ecosystem, showing the floe of energy in a habitat

Question 12

what do food webs show

Answer 12

interdependence = change in population of one organism will affect the population of another organism

Question 13

definition of pyramid of numbers

Answer 13

shows the population of each organism at each trophic level in a food chain

Question 14

what do the bars represent on a pyramid of numbers

Answer 14

the population- so the wider the bar, the larger the population

Question 15

what happens to energy between the trophic levels in pyramid of numbers

Answer 15

energy is lost to the surroundings from one trophic level to the next so there are usually fewer organisms at each trophic level ( less chances of survival)

Question 16

why does a pyramid of numbers not always look like a pyramid

Answer 16

because one large producer can feed many small consumers ( eg. 1 oak tree can feed many insects )

Question 17

definition of pyramids of biomass

Answer 17

shows the transfer of energy at each trophic level by calculating the dry mass of each population of species

Question 18

what is biomass ( in terms of a pyramid of biomass)

Answer 18

the mass of living material in each organism multiplied by their population at each trophic level

Question 19

why will pyramids of biomass always look like a pyramid

Answer 19

because biomass is a measure of the amount of food available - this decreases from one trophic level to the next as energy is lost ( to respiration, not digested or not eaten )

Question 20

definition of pyramids of energy transfer

Answer 20

shows the transfer of energy at each trophic level from one trophic level to the next

Question 21

why does each trophic level reduce the amount of energy available for the next

Answer 21

because only 10% of energy is passed on

Question 22

why is only 10% of energy transferred from one trophic level to the next

Answer 22

energy is lost to:

1. respiration
2. not eaten
3. not digested
4. excreted as watse

Question 23

definition of trophic level

Answer 23

feeding levels in a food chain

Question 24

definition of carbon cycle

Answer 24

describes the movement of carbon molecules in the enviroment

Question 25

what are the 4 stages in the carbon cycle

Answer 25

1. Respiration 2. Photosynthesis 3. Decomposition 4. Combustion

Question 26

explain the 1st stage of the carbon cycle - Respiration

Answer 26

all living organism will respire aerobically and release CO2 into the atmosphere

Question 27

explain the 2nd stage of the carbon cycle - Photosynthesis

Answer 27

fixes carbon atoms from atmospheric CO2 into organic molecules and becomes part of complex carbon compounds in plants

Question 28

explain the 3rd stage of the carbon cycle - Decomposition

Answer 28

Dead organisms are broken down by decomposers and carbon in their bodies are returned to the atmosphere as carbon dioxide

Question 29

explain the 4th stage of the carbon cycle- - Combustion

Answer 29

if decomposition is blocked plants and animals are available as fossil fuels after a long period of time combustion of fossil fuels release carbon dioxide back into the atmosphere

Question 30

PAPER 2 what are the 5 stages of the nitrogen cycle

Answer 30

1. Nitrogen Fixation 2. Absorption by plants 3. Moving along food chains 4. Death of organisms 5. Dentrification

Question 31

PAPER 2 explain the 1st stage of the nitrogen cycle- - Nitrogen Fixation

Answer 31

nitrogen in atmosphere to unreactive to be used directly has to be changed into soluble ions nitrogen fixing bacteria in roots nodules of legumes will convert nitrogen into nitrate lightening converts nitrogen into nitrates Haber process will convert nitrogen into ammonia & nitrifying bacteria will turn ammonia into nitrates

Question 32

PAPER 2 explain the 2nd stage of the nitrogen cycle- Absorption by plants

Answer 32

plants will absorb nitrates through roots by active transport nitrate ions help produce amino acids = protein= part of plants biomass

Question 33

PAPER 2 explain the 3rd stage of the nitrogen cycle- - Moving along food chains

Answer 33

animals will eat plants and nitrogen from plants protein will become protein in animal nitrogen is also passed from one animal to another by feeding

Question 34

PAPER 2 explain the 4th stage of the nitrogen cycle- - Death of organism

Answer 34

decomposers ( bacteria and fungi ) will break down urea, egested material and dead bodies & nitrogen compounds will be returned to the soil as ammonium ions nitrifying bacteria will convert ammonia ions into nitrates for plants to absorb

Question 35

PAPER 2 explain the 5th stage of the nitrogen cycle- - Dentrification

Answer 35

denitrifying bacteria in the soil will break down nitrates and return nitrogen gas into the air occurs in waterlogged soil so can be prevented by reducing drainage

Question 36

definition of eutrophication

Answer 36

when fertilisers are washed off from land into rivers and lakes by rain

Question 37

what are the biological consequences of eutrophication

Answer 37

1. excessive nutrients from fertilisers washed into rivers and lakes by rain 2. excessive nutrients = rapid plant growth eg. Algae Bloom ( on surface ) 3. algae bloom blocks sunlight = plants die = less photosynthesis = oxygen levels decrease 4. Decomposers ( bacteria ) will further deplete oxygen as will respire aerobically to break down dead plants 5. death of ecosystem will occur as oxygen levels reach a point where no life is possible = aquatic organisms die eg. fish

Question 38

what are the 2 biological consequences of pollution of water by sewage

Answer 38

1. Reproduction of microorganisms | 2. Depletion of oxygen

Question 39

explain reproduction of microorganisms

Answer 39

sewage = rich in minerals + nutrients = provides large amounts of energy to allow organism such as decomposers to reproduce = increase population sewage = rich in nutrients ( phosphates) = growth of algae= algae bloom form on surface.

Question 40

explain depletion of oxygen

Answer 40

decomposers will respire aerobically to break down sewage and dead plants (from lack of sunshine) so will cause depletion of oxygen = death of aquatic organisms sewage will increase population of organisms in the water so will cause more aerobic respiration to take place

Question 41

explain the pollution of air by sulphur dioxide | 2 steps

Answer 41

fossil fuels burn to produce sulphur dioxide sulphur dioxide will dissolve in water droplet in clouds = dilute sulphuric acid

Question 42

what are the consequences of pollution of air by sulphur dioxide ( 4 things )

Answer 42

leaches minerals + nutrients out of soil= plants trees die damages waxy layer of leaves= difficult for plants to absorb mineral ions ( need for growth ) makes river + lakes too acidic = aquatic organisms die corrodes metals ( steel ) + limestone in buildings

Question 43

explain the pollution of air by carbon monoxide ( 2 steps )

Answer 43

poisonous gas that produced when fossil fuels burn in limited amount of ( incomplete combustion ) binds to haemoglobin + reduces the capacity of oxygen carried in red blood cells

Question 44

what are the consequences of pollution of air by carbon monoxide ( 3 things )

Answer 44

reduces capacity of oxygen carried in blood = tiredness unconsciousness + even death less oxygen fro aerobic respiration= emphysema if pregnant - insufficient oxygen = less aerobic respiration to release energy fro growth of foetus.

Question 45

Give 5 examples of green house gases

Answer 45

1. Water vapour = rivers, lakes + oceans 2. CO2= deforestation + burning fuels 3. Nitrous oxides = Fertilisers + vehicle engines 4. Methane = rice paddy fields + cattle 5. CFCs Refrigerators

Question 46

definition of greenhouse gases

Answer 46

gases that absorb infrared radiation from the sun and remains trapped in the earths atmosphere = earths temp. to rise as a result

Question 47

explain green house effect ( 4 steps )

Answer 47

1. sun emits rays that enter earths atmosphere 2. heat is emitted back from the earths surface 3. some heat is reflected back out into space 4. BUT some heat is absorbed by greenhouse gasses + trapped within the earths atmosphere = earths av. temp. to rise

Question 48

what are the consequences of the green house effect ( 5 things )

Answer 48

earths increase in temp. = climate change high temp. = glaciers melt= sea levels rise loss of habitat - due to climate inhabitable environment = extinction of species migration of species= move to more habitable areas

Question 49

PAPER 2 what are the effects of deforestation ( 4 things )

Answer 49

1. Leaching 2. Soil erosion 3. Disturbance of water cycle 4. unbalance in atmospheric oxygen + CO2

Question 50

PAPER 2 explain leaching ( effect of deforestation )

Answer 50

without trees nutrients + minerals will remain unused in the soil = washed away into rivers + lakes by rain

Question 51

PAPER 2 explain soil erosion ( effect of deforestation )

Answer 51

without trees soil will be loose + unstable = easily washed away by rain

Question 52

PAPER 2 explain disturbance of water cycle ( effect of deforestation )

Answer 52

without trees less transpiration will occur = less water vapour released into atmosphere = less clouds form = lack of precipitation= droughts

Question 53

PAPER 2 explain unbalance in atmospheric oxygen + CO2 ( effect of deforestation )

Answer 53

removal of trees = less photosynthesis = decrease oxygen + increase CO2 deforestation = burning of trees = CO2=increase CO2 levels in atmosphere

Question 54

definition abiotic

Answer 54

non living factor that changes environment which plants and animals live in

Question 55

definition of biotic

Answer 55

living factor that changes environment which plants and animals live in

Question 56

examples of abiotic factors

Answer 56

environmental condition = temp. , light intensity , moisture level toxic chemical = bioaccumulation =each stage of food chain concentration of pesticide increases

Question 57

examples of biotic factors

Answer 57

availability of food number of predators competition = organism compete with other species for same resources