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AQA A Level Biology > Energy and Ecosystems > Flashcards

Energy and Ecosystems Flashcards

(57 cards)

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1
Q

Ecosystems

A

The abundance and distribution of organisms are controlled by biotic and abiotic factors

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2
Q

What are biotic factors?

A

Living

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3
Q

What are abiotic factors?

A

Non-living

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4
Q

Population

A

All the organisms of a single species in a habitat

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5
Q

Community

A

All the organisms of all the species in a habitat

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6
Q

Habitat

A

The place where an organism lives

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7
Q

Niche

A

The role of a species in an ecosystem

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8
Q

Trophic level

A

Each stage of the food chain

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9
Q

Trophic level examples

A
  • Producer
  • Primary consumer
  • Secondary consumer
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10
Q

Interspecific competition

A

Between different species

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11
Q

Intraspecific competition

A

Within a species

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12
Q

Biotic factors examples

A

Other animals or plants

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13
Q

Abiotic factors examples

A

Water, soil, air, sunlight, temperature

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14
Q

Gross primary production

A
  • The total amount of energy made by producers

- Per unit area per unit time

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15
Q

Respiratory losses

A

The energy used by organisms for respiration

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16
Q

Net Primary Production formula

A

NPP = GPP - R

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17
Q

Net primary production

A

NPP = Gross primary production - Respiratory loss

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18
Q

What is the net primary production?

A

The amount of chemical energy a producer stores as biomass per unit area per unit time

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19
Q

Net production of consumers

A

I - F + R

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20
Q

Net production of consumers what is F

A

The chemical energy lost to the environment in faeces and urine

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21
Q

Net production of consumers what is I

A

The chemical energy store in ingested food

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22
Q

Net production of consumers what is R

A

The respiratory losses to the environment

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23
Q

Sun energy transfer to producer

Study These Flashcards
A
  • very low
  • wrong wavelength
  • light strikes non photosynthetic region
  • light reflected
  • lost as heat
24
Q

Producer energy transfer to primary consumer

Study These Flashcards
A
  • low
  • respiratory loss
  • plant uses energy for metabolism
  • lost as heat
  • not all plant eaten
  • some food not digested
25
Primary consumer energy transfer to secondary consumer
- low - respiratory loss - primary consumer uses energy for metabolism - lost as heat - not whole animal is eaten - some food not digested
26
When is energy transfer especially low?
- Old animals (stop growing) - Herbivores (more poo) - Endotherms (warm blooded)
27
How to increase energy transfer efficiency in plants
1 - Shorten food web - reduce competition so the plant has more energy to create biomass - Herbicides to kill weeds - Fungicide to reduce fungal infections - Insecticide kill pests 2 - Fertilisers - prevent growth being limited by lack of nutrients
28
How to increase energy transfer efficiency in animals/livestock
3 - Reduce respiratory loss - restrict movement (less energy used to make biomass) - keep warm in winter 4 - Slaughter animal whilst still growing 5 - Keep predators away 6 - Controlled diet to increase % of food digested
29
How to increase energy transfer efficiency in animals/livestock and plants
7 - Artificially select organisms with a high yield
30
Ways of measuring biomass
Dry biomass and mass of carbon
31
How to measure dry biomass
- sample of biomass is warmed on a scale until constant mass (all water evaporated) - temperature must be low to avoid combustion - amount of water in samples varies a lot so dry biomass gives a more representative sample - kg.m^-2
32
How to measure mass of carbon
- organisms made up of organic compounds - mass of carbon is a good indicator for biomass - difficult to measure - carbon is usually about 50% of the dry biomass - kg.m^-2.yr^-1
33
How to calculate energy stored in biomass
- calorimetry is used to estimate the amount of energy stored in dry biomass - burn sample completely - heat a known volume of water - measure temperature change of water - calculate energy release
34
How are ammonium ions converted into nitrites
Nitrification
35
How are nitrites converted into nitrates
Nitrification
36
How are nitrates converted into nitrogen
Denitrification | - anaerobic conditions
37
How is nitrogen gas made usable
Nitrogen fixation - legumes - by bacteria in root nodules
38
Which form of nitrogen is usable by plants and animals
Nitrates
39
How do plants and animals use nitrates
Proteins/DNA
40
What happens to nitrogen when plants and animals die
Saprobiontic microbes (decomposers) digest dead/organic matter using extracellular enzymes
41
How are ammonium ions reformed?
Ammonification
42
What are sources of phosphate ions?
Rocks
43
How are phosphate ions removed from rocks?
By erosion and weathering into rocks and soil
44
How do plants and animals get phosphate ions?
Plants from soil, animals from eating plants
45
How are phosphate ions recycled back to the soil?
Saprobiontic nutrition
46
How do plants, animals and decomposers use phosphorus?
ATP/DNA
47
How are nutrients recycled
Microorganisms break down large organic compounds into small soluble inorganic compounds which can be absorbed by producers
48
Saprobionts
Type of decomposers that digest food by saprobiontic nutrition
49
Saprobiontic nutrition
Digestion of dead organic matter by extracellular enzymes (products are absorbed by producers)))
50
Mycorrhizae
Fungi that grow in a mutualistic relationship with plant roots
51
Benefits of mycorrhizae on the plant
- Increase in surface area of the plant | - increases absorption of minerals and water
52
Natural fertiliser
- Contain nitrogen and phosphorus in organic compounds | - Still need breaking down by saprobionts
53
Artificial fertiliser
Inorganic chemical compounds that contain nitrogen and phosphorus (water soluble)
54
Leaching
- Water soluble compounds are washed off land by rain | - More common in artificial fertilisers
55
Eutrification
- Nitrite/phosphate ions leach into fresh water - Algal bloom - Blocks out light - Plants can't photosynthesise and die - Saprobionts breakdown dead plants - Use up all oxygen - Fish die
56
Harvesting crops/livestock
- Removes N and P from cycles - Soil N and P get depleted - Add fertiliser to replace N and P - Too much fertiliser can change water potential
57
Benefits of natural fertilisers
- Aerate soil - Less leaching - Combine a wider range of elements - Consume less energy

AQA A Level Biology (13 decks)

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