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BIOLOGY > Ecosystems and Material Cycles - Topic 9 > Flashcards

Ecosystems and Material Cycles - Topic 9 Flashcards

1
Q

what is a habitat

A

the place where an organism lives

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2
Q

what is a population

A

all the organisms of one species living in a habitat

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3
Q

what is a community

A

all the organisms of different species living in a habitat

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4
Q

what are abiotic factors

A

non living factors of the environment

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5
Q

what are biotic factors

A

living factors of the environment

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6
Q

what is an ecosystem

A

a community of organisms along with all the non living parts of their environment

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6
Q

what are the levels of organisation

A

individual —> population —–> community ——> ecosystem

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6
Q

what is the importance of interdependence in a community

A

organisms depend on each other for things like food and shelter un order to survive and reproduce and without it, a change in the population of one species can have a huge effect for other species in the community

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6
Q

what is mutualism

A

a relationship between two organisms from which both organisms benefit

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6
Q

how do bees and flowering plants have a mutualistic relationship

A

bees visit flowers to get nectar which is food for the bees and the bees spread the pollen which helps the flowers reproduce

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6
Q

how do cleaner fish and larger fish have a mutualistic relationship

A

cleaner fish feed on dead skin and parasites on the surface of larger fish which is their food and the larger fish are helped to stay healthy

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6
Q

what is parasitism

A

when the parasite takes what it needs to survive, but the host doesn’t benefit

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6
Q

how do dogs and fleas have a parasitic relationship

A

fleas feed on the dogs blood but doesn’t off the dog anything in return

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7
Q

how do trees and mistletoe have a parasitic relationship

A

mistletoe grows on trees and depends on them for water and mineral ions but the trees do not benefit and can die if too much mistletoe grows on them

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8
Q

what abiotic factors affect a community

A

temperature
light intensity
amount of water
levels of pollutants

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9
Q

how does temperature affect a community

A

if it is too hot for a species they will have to migrate

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10
Q

how does light intensity affect a community

A

as trees grow and develop more branches, the grass under them doesn’t get enough light and so gets replaced by fungi

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11
Q

how does amount of water available affect a community

A

organisms need water to survive so if there isn’t enough water, species will die out or will migrate to a place with more water available.

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12
Q

what biotic factors affect a community

A

competition and predation

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13
Q

how does competition affect a community

A

plants need light and space and water and mineral ions while animals need space, food water and mates and so they may compete with other species for the same resources.

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14
Q

how does predation affect a community

A

if the population of prey increases, so does the population of predators and as the population of predators increases the population of prey decreases

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15
Q

what are the different ways to study the distribution of an organism

A

by measuring how common an organism is in two or more sample areas e.g. by using quadrats

OR

by studying how distribution changes across an area by placing quadrats along a belt transect

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16
Q

how do you investigate distribution (CORE PRACTICAL)

A
  1. Place a 1m^2 quadrat on the ground at a random point within the first sample area
  2. Count all the organisms that you are interested in within that quadrat
  3. Repeat steps one and two as many times as you can
  4. Work out the mean number of organisms per quadrat within the first sample area.
  5. Repeat steps one and two in the second sample area
  6. Compare the two means
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17
Q

How do you collect data along a belt transect

A
  1. mark out a line in the area you want to study with a tape measure
  2. Collect data along the line with quadrats placed next to each other or at regular intervals
  3. you can also record other data such as abiotic factors in each quadrat
  4. repeat steps 1-3 several times and then find the mean number of organism per quadrat.
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17
Q

How do you collect data along a belt transect

A
  1. mark out a line in the area you want to study with a tape measure
  2. Collect data along the line with quadrats placed next to each other or at regular intervals
  3. you can also record other data such as abiotic factors in each quadrat
  4. repeat steps 1-3 several times and then find the mean number of organism per quadrat.
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18
Q

how is energy lost from food chains

A

at each trophic level, organisms need to respire to transfer energy for life processes and a lot of this energy ends up transferred to the surroundings by heat and this energy is not stored as biomass so it isn’t transferred to the organisms in the next trophic level.

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19
Q

why does energy that is stored as biomass not all get transferred to the next trophic level

A

not all of an organism gets eaten and because not all of the bits that do get eaten can be digested and hte undigested material is lost from the food in faeces.

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20
Q

why do you get fewer organisms in each trophic levels and only 5 trophic levels

A

so much energy is lost at each stage that there is not enough left to support more organisms after four or five stages

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21
Q

how does energy loss give shape to biomass pyramids

A

most of the energy is lost and so doesn’t get stored as biomass in the next level up and so it gives rise to the pyramid shape

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22
Q

efficiency of energy transfers =

A

energy transferred to the next level / energy available at the previous level X 100

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23
Q

how do humans reduce biodiversity

A

by causing eutrophication
through fish farming
by introducing non-indigenous species

24
Q

how does eutrophication reduce biodiversity

A
  1. fertilisers enter the water, adding excess nitrates
  2. The excess nitrates cause algae to grow fast and block out the light
  3. Plant cannot photosynthesise due to the lack of light and start to die and decompose
  4. With more food available, decomposers increase in number and use up oxygen in water
  5. Organisms that need oxygen for aerobic respiration such as fish will die
25
Q

how does fish farming reduce biodiversity

A
  1. food is added to the nets to feed fish and the fish produce huge amounts of waste which can leak into the water causing eutrophication and the death of wild species
  2. Fish farms can also act as a breeding ground for large numbers of parasites which can get out of the farm and infect and kill wild animals
26
Q

how does the introduction of non-indigenous species reduce biodiversity

A

they compete with indigenous species for resources like food and shelter and sometimes they are better at getting these resources than indigenous species and so they will reduce in numbers and eventually die out.

They can also bring new diseases to a habitat which often infect and kill lots of indigenous species

27
Q

how do humans maintain biodiversity

A

reforestation
conservation schemes

28
Q

how do humans maintain biodiversity

A

reforestation
conservation schemes

29
Q

how does reforestation maintain biodiversity

A

trees are replanted where a forest previously stood to form a new forest and forests have a wide variety of trees and plants which provide food and shelter and so allow lots of different animal species to live there

30
Q

how do conservation schemes maintain biodiversity

A

they prevent species from dying out and these methods can include protecting a species’ habitat and introducing captive breeding programmes

31
Q

what are the benefits of maintaining biodiversity

A

protects the human food supply
ensures minimal damage to food chains
provides future medicines
ecotourism
provides new jobs

32
Q

what are the biological factors affecting food security

A

increasing human population
increasing meat consumption and animal farming
environmental changes caused by human activity
lack of sustainability
new pests and pathogens

33
Q

how does the increasing human population affect food security

A

as the worlds population continues to grow, we need to produce more food so that each person still has the same amount of food to eat and has food security

34
Q

how does the increasing meat consumption and increasing animal farming affect food security

A

for a given area of land, you can produce a lot more food by growing crops rather than grazing animals PLUS animals which are being reared to be eaten are often fed crops that would be eaten by humans.

There is also a risk of over fishing wild fish so there wont be enough left to catch in the future

Humans are also eating more fish and meat as they get wealthier

35
Q

how does environmental change caused by human activity affect food security

A

Burning fossil fuels releases a lot of CO2 which is a greenhouse gas and causes global warming and climate change. Climate change may affect the growth of crops which could reduce yields

36
Q

how does a lack of sustainability affect food security

A

there is an increase in the growth of crops to make biofuels which means there is less land available to grow crops for food

the high input costs of farming also make it too expensive for farmers in some places to continue farming and food production

37
Q

how do new pests and pathogens affect food security

A

they can cause damage to crops and livestock and can kill them therefore reducing the yield and amount that can be sold as food

38
Q

how do different material cycle through the biotic and abiotic components of an ecosystem

A

living things are made of elements they take from the environment and they turn these elements into the complex compounds that make up the living organisms. Elements are passed along the food chain when animals eat each other and plants. When waste products and dead organisms are broken down by decomposers the elements are returned to the soil or air.

39
Q

how is carbon taken out of the air

A

carbon dioxide is removed from the atmosphere by green plants and algae

40
Q

how does carbon move through the food chains

A

some of the carbon becomes part of the fats and proteins in animals when the plants and algae are eaten.

41
Q

how is carbon returned to the air

A

when plants, algae, decomposers and animals respire

when wood and fossil fuels are burnt (combustion)

42
Q

what happens in the water cycle

A

energy from the sun makes the water from land and sea evaporate into water vapour and water also evaporates from plants (transpiration).

The warm water is carried upwards and higher up, it cools and condenses to form clouds

Water falls from clouds as precipitation onto land, where it provides fresh water for plants and animals

Water not taken up by plants or animals drain into the sea before the process starts again

43
Q

what is potable water

A

water which is safe for drinking

44
Q

what is desalination

A

a method used to produce potable water, by removing salt from salt water

45
Q

what happens in thermal desalination

A

salt water is boiled so the water evaporates and then the steam rises to the top of the vessel but the salt stays at the bottom. Then, the steam travels down a pipe and condenses into pure water

46
Q

what happens in reverse osmosis

A

salt water is treated to remove solids
Then the water is fed into a vessel with a partially permeable membrane
The pressure causes water molecules to move in opposite direction to osmosis
As water is forced through the membrane, salt is left behind

47
Q

what are the indicator species for clean water

A

stonefly larvae and freshwater shrimp

48
Q

what are the indicator species for dirt and polluted water

A

bloodworms and sludgeworms

49
Q

what are the indicator species for clean air

A

bushy lichen, blackspot fungus on roses

50
Q

what are the indicator species for polluted air

A

crusty lichen

51
Q

pros of using indicator species to assess the level of pollution

A

it is simple, cost effective

52
Q

cons of using indicator species to assess the level of pollution

A

cannot give accurate figures for how much pollution is present , there may be other factors other than pollution playing a role in the presence or absence of a species

53
Q

what factors affect the rate of decomposition

A

temperature, water availability, oxygen availability

54
Q

how does temperature affect the rate of decomposition

A

warmer temperatures increase the rate of decomposition because they increase the rate the microbial enzymes work but if it is too hot decomposition stops or slows down as the enzymes are denatured

55
Q

how does water availability affect the rate of decomposition

A

decay takes place faster in moist places as organisms involved in decay ned water to survive

56
Q

how does oxygen availability affect the rate of decomposition

A

rate of decomposition is faster when there is a lot of oxygen available as many microorganisms need oxygen to respire

57
Q

what is the optimum conditions for producing compost

A

warm, moist conditions when there is plenty of oxygen available

58
Q

what are some food preservation methods

A

storing foods in a fridge of freezer as it lowers the temperature of the food and therefore the rate of decomposition

storing foods in airtight can to stop microorganisms getting in

vacuum packing to remove the air from the packaging to prevent microorganisms from being able to aerobically respire

drying food as it removes water, by adding salt or sugar

59
Q

what is nitrogen fixation

A

the process of turning nitrogen from the air into nitrogen containing ions that plants can use

60
Q

how is nitrogen taken out of the air

A

lightning hits the ground and as there is so much energy in lightning, it is enough to make nitrogen react with oxygen in the air to produce nitrates

nitrogen fixing bacteria turn atmospheric nitrogen into ammonia and ammonia forms ammonium ions in solution that plants can use

61
Q

how does nitrogen move through food chains

A

plants absorb nitrogen containing ions from the soil and use the nitrogen in them to make proteins and the nitrogen in then passed along food chains as protein as animals eat plants and each other

decomposers break down proteins in rotting plants and animals and urea and turn them into ammonia which nitrifying bacteria turns into nitrites and nitrates and this returns nitrogen to the soil

61
Q

how does nitrogen move through food chains

A

plants absorb nitrogen containing ions from the soil and use the nitrogen in them to make proteins and the nitrogen in then passed along food chains as protein as animals eat plants and each other

decomposers break down proteins in rotting plants and animals and urea and turn them into ammonia which nitrifying bacteria turns into nitrites and nitrates and this returns nitrogen to the soil

62
Q

how is nitrogen returned to the air

A

denitrifying bacteria turns nitrates back into nitrgoen gas

63
Q

how do farmers increase the amount of nitrates in the soil to help crops grow better

A

crop rotation and using fertilisers

64
Q

what is crop rotation

A

this is where instead of growing the same crop in a field year after year, different crops are grown each year in a cycle

65
Q

how does crop rotation increase the soil nitrate content

A

the cycle usually included a nitrogen fixing crop which helps put nitrates back into the soil for another crop to use the following year

66
Q

how does using fertilisers increase the soil nitrate content

A

spreading animal manure or compost on fields recycles the nutrients left in plant and animal waste and returns them to the soil through decomposition. Artificial fertilisers containing nitrates can also be used but can be expensive.

BIOLOGY (9 decks)

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