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Biology A Level Unit 3 > Population Size and Ecosystems > Flashcards

Population Size and Ecosystems Flashcards

1
Q

population

A

group of organism of same species living in a particular area

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2
Q

intraspecific + interspecific species

A

between same species + between different species

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3
Q

population growth

A

births + immigration - deaths + emigration

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4
Q

lag phase

A

period of slow population growth

bacteria adapting/preparing for growth (e.g. enzyme synthesis)

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5
Q

log (exponential) phase

A

period of rapid cell division, cell production exceeds cell death
abundance of nutrients, low toxic waste, bacteria divide at constant rate, population doubles per unit per time

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6
Q

stationary phase

A

period where number of cells produced is equal to number of cells that die, population reaches carrying capacity
limiting factors take effect

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7
Q

death (decline) phase

A

period where cell death exceeds cell production

shortage of nutrients, build-up of toxic waste

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8
Q

carrying capacity

A

maximum population size a particular environment can support

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9
Q

population density

A

number of organisms in a given space

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10
Q

factors that limit population growth called

A

‘environmental resistance’

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11
Q

density dependent factors

A
  • pop density increases, factors (biotic) have stronger effect
  • food supply
  • predation
  • disease + parasitism
  • accumulation of toxic waste
  • components for limited resources (nesting sites)
  • oxygen concentration
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12
Q

density independent factors

A
  • affects pop no matter its density (abiotic factors)
  • weather
  • natural disasters
  • temperature (lab flask/fermenter)
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13
Q

biotic

A

caused by living organisms

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14
Q

abiotic

A

caused by non-living components of environment

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15
Q

limiting factors

A

determine carrying capacity of an environment for a species

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16
Q

population fluctuates

A

around a ‘set point’, regulated by negative feedback

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17
Q

sampling techniques

A

measuring abundance = capture - mark - recapture

measuring distribution = belt transect

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18
Q

habitat

A

place where organism lives

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19
Q

community

A

interacting population of sexual species living in same habitat at same time

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20
Q

ecosystem

A

characteristica community of interdependent species interacting with biotic + abiotic components and their habitats

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21
Q

sun as energy source for ecosystems

A

photosynthesis, light energy to chemical

22
Q

trophic level

A

feeding level

23
Q

biomass

A

mass of biological material in living/recently living organisms

24
Q

biomass transfer

A

food chain
plants, herbivores, carnivores
decomposition

25
decomposition
producers/consumers die, detritivores + decomposers feed as saprobients
26
photosynthetic efficiency
quantity of light energy incorporated into product ÷ quantity of energy falling on plant × 100
27
primary productivity
rate at which energy is converted by producers into biomass (kg/m2/yr) or rate of producing glucose in plants (kJ/m2/yr)
28
secondary productivity
rate at which consumers convert chemical energy of food into biomass
29
gross primary productivity
rate at which energy (kJm-2yr-1) is fixed inside new organic products in plants
30
net primary productivity
energy (kJm-2yr-1) in plants biomass available to primary consumers GPP - respiration = NPP
31
efficiency of energy transfer
energy available after transfer ÷ energy available before transfer × 100
32
succession
change in structure + composition of species which make up a community over time due to changes in environment produced by species at each stage
33
seral stage
stage in succession
34
pioneer species
first organisms to colonise a habitat | found in first seral stage
35
climax community
stable community, reached equilibrium | final seral stage
36
primary succession
happena in new habitat never colonised before
37
primary succession
happena in new habitat never colonised before
38
secondary succession
series of changes in a community which take place in damaged previously colonised habitat
39
human interference affecting succession
sheep grazing crops burning heather moors
40
3 factors that have a role in succession
immigration facilitation interspecific competition
41
carbon cycle
atmospheric CO2 | respiration (feeding + assimilation and decomposition involved), photosynthesis, combustion (fossilisation involved)
42
deforestation
reduced photosynthesis, reduced rate CO2 removed from atmosphere, tress burn/decay add to CO2
43
burning fossil fuels
adds to CO2
44
consequences of global warming
melting of polar ice, drought, forest fires affect distribution of species extinction rising sea levels
45
carbon footprint
total amount of CO2 generated by actions of an individual/product/service over 1 year
46
nitrogen cycle
nitrogen fixation, nitrification, putrefaction (ammonification), denitrification
47
bacteria in nitrogen cycle
azobacter - nitrogen fixation (nitrogen to ammonia) rhizobium - nitrogen fixation (nitrogen to ammonia) nitrosomonas - nitrification (ammonia to nitrite) nitrobacer - nitrification (nitrite to nitrate) pseudomonas - denitrification (nitrate to nitrogen)
48
ploughing
aerate + drain soil prevents waterlogging removes anaerobic conditions for denitrifying bacteria promotes aerobic conditions for nitrifying bacteria plant roots can take up nitrogen to make organic nitrogen compounds (improves growth)
49
fertilisers
manure + slurry contain nitrogen compounds that can be broken down by putrifying bacteria into nitrate ions/nitrogen for plants
50
artificial fertilisers
ammonium ions taken up by plants for protein synthesis
51
negative impacts of fertilizers on ecosystems
increased growth of grass + nettles shade smaller plants (biodiversity reduced) drainage ditches reduce biodivirsity eutrophication
52
eutrophication
- leaching of nitrogen into rivers by rain - eutrophication water (high in nitrates) - plant growth sped up - algae grows quickly - algal bloom blocks sunlight reaching plants at bottom - plants can't photosynthesis, die - short lived algae dies - dead plants decomposed by aerobic bacteria + fungi (biochemical oxygen demand) - fish + other oxygen requiring species die

Biology A Level Unit 3 (8 decks)

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