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Biology > Topic K - Ecology and the Enviroment > Flashcards

Topic K - Ecology and the Enviroment Flashcards

1
Q

definition of population

A

number of members of a single species

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2
Q

definition of community

A

different species of organisms living n the same area

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3
Q

definition of habitat

A

where living organisms live

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4
Q

definition of ecosystem

A

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

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5
Q

definition of producers

A

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

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6
Q

definition of primary consumers

A

herbivores= feed on plants ( producers )

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7
Q

definition of secondary consumers

A

predators that feed on primary consumers

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8
Q

definition of tertiary consumers

A

predators that feed on secondary consumers

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9
Q

definition of decomposers

A

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

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10
Q

definition of food chains

A

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

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11
Q

definition of food web

A

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

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12
Q

what do food webs show

A

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

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13
Q

definition of pyramid of numbers

A

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

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14
Q

what do the bars represent on a pyramid of numbers

A

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

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15
Q

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

A

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)

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16
Q

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

A

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

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17
Q

definition of pyramids of biomass

A

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

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18
Q

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

A

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

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19
Q

why will pyramids of biomass always look like a pyramid

A

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 )

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20
Q

definition of pyramids of energy transfer

A

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

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21
Q

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

A

because only 10% of energy is passed on

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22
Q

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

A

energy is lost to:

  1. respiration
  2. not eaten
  3. not digested
  4. excreted as watse
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23
Q

definition of trophic level

A

feeding levels in a food chain

24
Q

definition of carbon cycle

A

describes the movement of carbon molecules in the enviroment

25
Q

what are the 4 stages in the carbon cycle

A
  1. Respiration
  2. Photosynthesis
  3. Decomposition
  4. Combustion
26
Q

explain the 1st stage of the carbon cycle - Respiration

A

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

27
Q

explain the 2nd stage of the carbon cycle - Photosynthesis

A

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

28
Q

explain the 3rd stage of the carbon cycle - Decomposition

A

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

29
Q

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

A

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

30
Q

PAPER 2

what are the 5 stages of the nitrogen cycle

A
  1. Nitrogen Fixation
  2. Absorption by plants
  3. Moving along food chains
  4. Death of organisms
  5. Dentrification
31
Q

PAPER 2

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

A

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

32
Q

PAPER 2

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

A

plants will absorb nitrates through roots by active transport

nitrate ions help produce amino acids = protein= part of plants biomass

33
Q

PAPER 2

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

A

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

34
Q

PAPER 2

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

A

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

35
Q

PAPER 2

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

A

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

36
Q

definition of eutrophication

A

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

37
Q

what are the biological consequences of eutrophication

A
  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
38
Q

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

A
  1. Reproduction of microorganisms

2. Depletion of oxygen

39
Q

explain reproduction of microorganisms

A

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.

40
Q

explain depletion of oxygen

A

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

41
Q

explain the pollution of air by sulphur dioxide

2 steps

A

fossil fuels burn to produce sulphur dioxide

sulphur dioxide will dissolve in water droplet in clouds = dilute sulphuric acid

42
Q

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

A

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

43
Q

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

A

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

44
Q

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

A

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.

45
Q

Give 5 examples of green house gases

A
  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
46
Q

definition of greenhouse gases

A

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

47
Q

explain green house effect ( 4 steps )

A
  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
48
Q

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

A

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

49
Q

PAPER 2

what are the effects of deforestation ( 4 things )

A
  1. Leaching
  2. Soil erosion
  3. Disturbance of water cycle
  4. unbalance in atmospheric oxygen + CO2
50
Q

PAPER 2

explain leaching ( effect of deforestation )

A

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

51
Q

PAPER 2

explain soil erosion ( effect of deforestation )

A

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

52
Q

PAPER 2

explain disturbance of water cycle ( effect of deforestation )

A

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

53
Q

PAPER 2

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

A

removal of trees = less photosynthesis = decrease oxygen + increase CO2

deforestation = burning of trees = CO2=increase CO2 levels in atmosphere

54
Q

definition abiotic

A

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

55
Q

definition of biotic

A

living factor that changes environment which plants and animals live in

56
Q

examples of abiotic factors

A

environmental condition = temp. , light intensity , moisture level

toxic chemical = bioaccumulation =each stage of food chain concentration of pesticide increases

57
Q

examples of biotic factors

A

availability of food

number of predators

competition = organism compete with
other species for same resources

Biology (14 decks)

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