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A level Biology > Ecosystem, Populations and sustainability > Flashcards

Ecosystem, Populations and sustainability Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what are abiotic factors ?

A

non living features of an ecosystem

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2
Q

define population size

A

total number of organisms of one species in a habitat

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3
Q

what causes population size to vary ?

A

abiotic factors

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4
Q

what is inter specific competition ?

A

competition between different species for the same resources (food / territory)

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5
Q

what are biotic factors ?

A

living features of an ecosystem

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6
Q

intraspecific competition …

A

competition between same species for the same resources (food / territory)

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7
Q

what is carrying capacity ?

A

the maximum stable population size of a species that an ecosystem can support

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8
Q

give some examples of limiting factors of population size

A

abiotic - shelter

biotic - interspecific competition (limits resources)

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9
Q

what determines the carrying capacity of an ecosystem ?

A

the limiting factors

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10
Q

define conservation of ecosystems

A

protection and management of ecosystems so that the natural resources can be used without them running out

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11
Q

what is reclamation ?

A

restoring ecosystems that have been damaged / destroyed

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12
Q

how is conservation important for economic ?

A
  • ecosystems provide many resources used to trade on local + global scale
  • less trade without ecosystems
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13
Q

how is conservation important for social ?

A

ecosystems bring joy (attractive + activities)

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14
Q

how is conservation important for ethical ?

A
  • moral responsibility to conserve ecosystems for future generations
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15
Q

define producer

A

organism that produces organic molecules using light energy

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16
Q

what does it mean that ecosystems are a dynamic system ?

A

constantly changing

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17
Q

what is biomass ?

A

mass of living material

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18
Q

what do food chains show ?

A

simple lines of energy transfer

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19
Q

what do food webs show ?

A

multiple food chains and how they overlap

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20
Q

state the reasons why not all the energy is taken in by organisms

A
  • plants can’t absorb all wavelengths of light
  • some parts of food are not eaten (roots/bones)
  • some parts are indigestible like cellulose (passed onto decomposers)
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21
Q

what is gross productivity ?

A

% of energy taken in

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22
Q

what happens to energy that is taken in ?

A
  • most is lost to environment when respiring (respiratory loss)
  • some goes to biomass
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23
Q

what is net productivity ?

A

the amount of energy available to next trophic level (biomass)

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24
Q

net productivity =

A

gross productivity - respiratory loss

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25
Q

% efficiency of energy transfer =

A

gross productivity / net productivity

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26
Q

how do you measure energy transfer ? (trophic levels)

A
  • measure dry mass (biomass) of one organism
  • multiply by size of population to get total energy in that population
  • energy transfer is difference in energy between trophic levels
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27
Q

what is the problem with the method for measuring energy transfer ?

A

consumers take in energy from multiple diff. producers/prey

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28
Q

how does human activity increase energy transfer ?

A
  • herbicides (kills weeds that compete)
  • fungicides (kills fungal infections so less energy on fighting infections)
  • insecticides (kills pests that eat - less biomass lost)
  • natural predators (eat pests)
  • fertilisers
  • rearing livestock
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29
Q

give two examples of rearing livestock to increase energy transfer

A
  • kept in warm pens where movement is restricted

- given feed high in energy

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30
Q

how is limestone/chalk involved in the Carbon cycle ?

A
  • drawn deep into Earth’s crust (movement of tectonic plates)
  • undergo chemical changes and release CO2
  • released out of volcanoes
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31
Q

how is rock involved in Carbon cycle ?

A
  • weathered chemically (rain)
  • mineral ions and bicarbonate ions are released and enter ground water to rivers/oceans
  • combine to form carbon compounds (CaCO3)
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32
Q

how much nitrogen in the air ?

A

78%

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33
Q

nitrogen fixation is when …

A

atm nitrogen is turned to ammonia

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34
Q

what causes nitrogen fixation ?

A

bacteria like Rhizobium and Azotobacter

lightning

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35
Q

where do the nitrogen fixing bacteria live ?

A

Azotobacter - soil

Rhizobium - root nodules of leguminous plants

36
Q

what is the mutualistic relationship between Rhibozium and plants ?

A

plant is provided with nitrogen compounds

bacteria provided with carbohydrates

37
Q

what is ammonification ?

A

nitrogen compounds from dead organisms are turned into ammonia by decomposers (which goes to form ammonium ions)

38
Q

what is nitrification ?

A

ammonium ions changed into nitrogen compounds

39
Q

what is the 1st nitrifying bacteria and what does it do ?

A

Nitrosomonas - ammonium ions to nitrites

40
Q

what is the 2nd nitrifying bacteria and what does it do ?

A

Nitrobacter - nitrites to nitrates

41
Q

what is denitrification ?

A

nitrates converted into atm nitrogen by denitrifying bacteria

42
Q

what causes denitrification ?

A

bacteria using nitrates for anaerobic respiration and producing atm nitrogen

43
Q

give an example of where denitrification may occur ?

A

waterlogged soil - anaerobic condition

44
Q

give formula for nitrite

A

NO2-

45
Q

what is succession ?

A

progressive change in the composition of a community, from the initial colonisation by a pioneer species to a stable climax community

46
Q

what is primary succession ?

A

succession that occurs on newly formed land (with no organic material/soil)

47
Q

give 2 examples of newly formed land

A

rock from volcanoes

sand dunes

48
Q

what is secondary succession ?

A

succession on land that has been cleared of land, but soil remains

49
Q

give 2 examples of pioneer species

A

marram grass

lichen

50
Q

how does the pioneer species start succession ?

A
  • breaks down rocks and releases minerals
  • die and decompose to form thin soil which builds up more organic material
  • soil means moisture can be retained, so other species grow
51
Q

what is the difference between pioneer species of primary / secondary succession ?

A

secondary ones are larger (e.g. shrubs)

52
Q

what is climatic climax ?

A

climax community for a particular climate

53
Q

what do peat bogs store ?

A

water and carbon dioxide

54
Q

how does moss help a peat bog form ?

A

retains water

55
Q

why do conservationists have a problem with farmers overgrazing on peat bogs ?

A
  • loss of moss species
  • soil compaction
  • peat bog erosion
56
Q

what government funded program is paying farmers to use peat bogs in a sustainable way ?

A

Environmental Stewardship Scheme

57
Q

how can farmers use peat bogs in a sustainable way ?

A
  • carry out measures to reduce water run off
  • lower no. of livestock on peat bogs
  • remove livestock in winter
58
Q

what is coppicing ?

A

cutting trees in a way that lets them grow back so new ones don’t have to be planted

59
Q

what is pollarding ?

A

similar to coppicing but cut at main stem or trunk to control height

60
Q

name some sustainable ways of managing timber

A
  • coppicing / pollarding
  • attaching post and tubes to support and protect
  • trees not too close so less competition
61
Q

state the reaction of nitrosomonas

A

2 NH3 + 3 O2 — 2 NO2- + 2 H+ + 2 H2O

62
Q

state the reaction of nitrobacter

A

2 NO2- + O2 — 2 NO3-

63
Q

state the reaction of denitrifying bacteria

A

NO3- — N2 atm

64
Q

how do you use a point quadrat ?

A
  • bar w/ legs and holes to put pins in
  • point quadrat randomly placed in area
  • pins dropped through holes
  • every plant that the pin touches is recorded
  • repeat …
65
Q

what are transects used to measure ?

A

distribution of populations

66
Q

for plant populations, how do you use line transect ?

A
  • tape measure placed along transect

- any plant that touches is recorded

67
Q

for plant populations, how do you use belt transect ?

A
  • data collected along transect using frame quadrats
68
Q

for plant populations, how do you use interrupted transect ?

A

measurements are taken at intervals

69
Q

what are the two main ways of controlling over fishing

A
  • fishing quotas

- controlling mesh size of nets

70
Q

how do fishing quotas control over fishing ?

A
  • limit amount of certain fish species fishermen are allowed to catch
  • reduces no. fish caught and killed
71
Q

what are the problems with fishing quotas ?

A
  • wrong species still caught and usually die
72
Q

how does controlling mesh size of nets control over fishing ?

A
  • reduces no. of unwanted fish accidentally caught

- allows younger fish to escape net and reach breeding age

73
Q

what is the Terai Arc ?

A
  • area of forest and grassland in Nepal

- home to variety of plants and animals, including endangered species (Bengal Tiger)

74
Q

what problem is there in the Terai Arc ?

A
  • destruction of habitat to make housing spacing for ppl living there
  • closer contact increases conflict (tigers killed for killing livestock)
75
Q

how is the problem in the Terai Arc being overcome ?

A

WWF works w/ local ppl to help balance their needs w/ conservation (e.g. supplying with solar cookers so don’t need so much wood)

76
Q

what is the Maasai Mara ?

A
  • national grassland reserve in Kenya

- home to huge populations of wildebeest/zebra/lions/cheetahs

77
Q

what problem is there in the Maasai Mara ?

A
  • ppl there make money by raising livestock

- overgrazing by livestock can destroy grassland for wildlife

78
Q

how is the problem in the Maasai Mara being overcome ?

A

conservation trusts help Maasai ppl make money through conservation and ecotourism projects and how to farm in sustainable way

79
Q

state the effects of human activities on Galapagos islands

A
  1. non native animals introduced, reducing native populations
  2. non-native plants introduced, decreases native populations
80
Q

state the methods of control at Galapagos islands

A
  1. eradication programmes remove non native animals and plants
  2. visitors must follow rules, including bringing no non native species
81
Q

state the effects of human activities on Antarctica

A
  1. visitors have caused pollution (sewage, rubbish, oil spills)
  2. hunting and fishing have reduced wildlife populations
82
Q

state the methods of control at Antarctica

A
  1. waste taken away by ship
  2. ships must use lighter fuels
  3. tourist restrictions
  4. hunting and whaling have been banned
83
Q

state the effects of human activities on Lake district / snowdonia

A
  1. erosion of footpaths and loss of soil from hillsides

2. walkers often trample on surrounding vegetation

84
Q

state the methods of control at Lake district / snowdonia

A
  1. regular repair on paths

2. walkers educated on importance of sticking to footpaths

85
Q

what is a density dependent factor and give an example

A

factor whose effect on population size varies w/ population density (e.g. food availability)

86
Q

define preservation

A

protection of an ecosystem so its kept exactly the same

A level Biology (26 decks)

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