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Paper 1 Important topics > 20.2 Environmental management and the Nitrogen cycle > Flashcards

20.2 Environmental management and the Nitrogen cycle Flashcards

1
Q

what is the use of a food chain?

A

to illustrate the transfer of energy between organisms within an ecosystem

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2
Q

what is an ecosystem?

A

the biotic and abiotic components of a specific area, and their interactions

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3
Q

what is a community?

A

the organisms within an ecosystem

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4
Q

what is a producer?

A

an autotrophic organism that converts light energy to chemical energy

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5
Q

what are primary consumers?

A

organisms that gain their organic molecules and chemical energy from the consumption of producers

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6
Q

what are secondary consumers?

A

carnivores/omnivores that eat primary consumers

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7
Q

what are tertiary consumers?

A

carnivores/omnivores that eat secondary consumers

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8
Q

what is a trophic level?

A

the level at which consumer eats in a food chain

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9
Q

what is the unit of energy used in energy flows?

A

MJ m-2 yr-1

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10
Q

give some examples of energy loss

A

movement

reproduction

reflected

excretion

growth

respiration

digestion

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11
Q

what is an ectotherm?

A

an animal that relies on external sources of heat for thermoregulation

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12
Q

how is energy transfer calculated?

A

(E available after transfer / E available before transfer) x 100

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13
Q

what is the Malthusian crisis?

A

the population in an area grows to exceed its food supply

resulting in mass starvation

and population decrease

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14
Q

what is overfishing?

A

over-exploitation where fish stocks are reduced to below acceptable levels

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15
Q

what is sustainable fishing?

A

removing a controlled number from the natural population, allowing the remainder to reproduce and replenish ∴ no significant reduction in adult population

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16
Q

what are four factors affecting fish populations?

A

food availability

diseases and parasites

level of predation

intensity of fishing

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17
Q

give an example of some strategies used to reduce overfishing

A

catch quotas

minimum catchable size

fishing effort limits

no-take zones

closed seasons

protected individuals

population seeding

18
Q

what four factors should be considered in aquaculture?

A

feed

stock

location

breed

19
Q

how does light affect marine productivity?

A

cannot penetrate deep water ∴ autotrophs only found in shallow water

turbid water can reduced penetrable depth

20
Q

how do nutrients affect marine productivity?

A

autotrophs absorb nutrients directly from water

productivity maintained only when nutrients are constantly arriving (e.g. mouth of river)

rarely reach open ocean

21
Q

give an example of a ruminant organism

A

cattle

sheep

goats

22
Q

what are the features of the ruminant’s digestive system?

A

contains micro-organisms that produce cellulase

cellulase hydrolyses cellulose and other complex carbs into mono- and di-saccharides

other bacteria converts these into fatty acids

23
Q

outline the role of the rumen in digestion

A

(anaerobic)

bacteria hydrolyse cellulose to B. glucose

sugars fermented to organic acids and absorbed

produces CO(2), H(2)O and CH(4)

bacteria produce proteins from ammonium salts and saliva of ruminant

24
Q

outline the role of the reticulum in digestion

A

fermented grass passes into reticulum

formed into cud - regurgitated, ground and swallowed

25
Q

outline the role of the omasum in digestion

A

very muscular walls - squeezes water out for reabsorption

26
Q

outline the role of the abomasum in digestion

A

‘normal’ digestion

secretion of proteases and HCl

27
Q

why is eructation required?

A

release of pressure from stomach

28
Q

what is a farm?

A

an ecosystem manipulated by humans to increase productivity based on biotic and abiotic factors

29
Q

what is the definition of productivity?

A

the amount of E available at one trophic level for a defined area over a defined period of time

30
Q

what units is productivity measured in?

A

KJ m-2 yr-1

31
Q

what is gross primary productivity (GPP)?

A

the rate that producers convert light E into CPE

32
Q

what is net primary productivity (NPP)? how is it calculated?

A

the E available for transfer after a plant uses some for respiration

NPP = GPP - respiration

33
Q

outline the abiotic factors that affect productivity and how they can be manipulated to increase it

A

light - ensuring constant optimal light intensity and duration

temperature - ensuring constant warmth

water - irrigation or GM to reduce drought resistance

nutrients - rotating crops with nitrogen-fixing plants

34
Q

outline the biotic factors that affect productivity and how they can be manipulated to increase it

A

pests - pesticides

competition - herbicides

disease - fungicides

35
Q

what is secondary productivity?

A

the rate at which animals convert chemical energy in the plants they consume into their own biomass

36
Q

what are the techniques used to increase the efficiency of energy transfer?

A

antibiotics

limiting movement

maintaining constant temperature

selective breeding

harvesting animals before adulthood

treatment with steroids

37
Q

what is the main benefit and criticism of techniques that increase efficiency of energy transfer?

A

+ more efficient food production

  • at general expense of animal welfare
38
Q

what is eutrophication?

A

the enrichment of a water body with nutrients, usually with an excess amount of nutrients, inducing growth of plants and algae and resulting in oxygen depletion of the water body

39
Q

what is spray drift?

A

when herbicides and pesticides kill a non-target species

40
Q

outline the benefits of conservation

A

medical use

food/agriculture

ecotourism

prevention of natural disasters

home to indigenous populations

removes CO(2) from atmosphere ∴ reduces climate change

Paper 1 Important topics (8 decks)

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