BIOLOGY REVISION > Ecosystems 6.5 > Flashcards

Ecosystems 6.5 Flashcards

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1
Q

Define ecosystem

A

Ecosystem is any group of living and non living things and the interactions between them

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2
Q

What are three components f an ecosystem?

A

Components of an ecosystem:

  • habitat
  • populations
  • community
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3
Q

Define habitat

A

Habitat is the place an organism lives

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4
Q

Define niche

A

Niche is the role an organism fulfills within an roganism

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5
Q

explain the difference between habitat and niche

A

A habitat is the place an organism lives whereas a niche is the role of the organism within that place/ecosystem

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6
Q

Define population

A

Populations are all organisms of one species who live in the same place at the same time and can breed together

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7
Q

Define community

A

Communities are all population of different species living in the same place at the same time that interact

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8
Q

What is the difference between biotic and abiotic factors?

A

Abiotic factors are non living

Biotic factor are living

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9
Q

Give some examples of biotic factors

A

Biotic factors;

  • predation
  • disease
  • how organisms effect each other
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10
Q

Discuss consumers producers etc

A 
producers (plants +photosynthetic bacteria)
primary consumers (herbivore)
secondary consumer (carnivore)
tertiary consumer
decomposers (bacteria and fungi)
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11
Q

Give some examples of abiotic factors

A

Abiotic factors:

  • pH
  • temperature
  • relative humidity
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12
Q

What are the levels of species performance?

A

Species performance;
(highest) reproduction
growth
(lowest) surviving

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13
Q

Why are ecosystems dynamic?

A

Ecosystems are dynamic because they are constantly changing

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14
Q

What are three types of changes that can happen to an ecosystem?

A

Types of change:

  • cyclic (repeat in a rhythm e.g. the seasons)
  • Directional (one direction change e.g. erosion)
  • erratic/unpredictable (e.g. hurricane)
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15
Q

What is the UKs climax community?

A

In the UK the final climax community is deciduous oak woodland

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16
Q

What is deflected succession and what causes it?

A

Deflected succession is where succession is put on pause resulting in a plagioclimax. This is caused by:

  • grazing
  • herbicides/pesiticides
  • manicuring gardens/ golf courses
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17
Q

define succession

A

Succession is the progressive change in a community of organisms over time

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18
Q

What is the difference between primary and secondary succession?

A

Primary succession is succession from bare, uncolonised ground
Secondary succession is from previously colonised but disturbed/damaged ground

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19
Q

How does succession alter hostility of environments? What is the result of this?

A

Succession makes environments less hostile resulting in:

  • more biodiversity
  • more habitats/niches
  • more complex food webs +increased biomass
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20
Q

Briefly outline stages of succession from a volcanic eruption

A

succession:

  1. volcanic eruption
  2. pioneer species- algae and lichen
  3. erosion of rock + build up od eead material makes soil
  4. soil has nutrients to supoort larger species (ferns) which succeed pioneer
  5. repeated until climax community reached
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21
Q

What is a pioneer community and climax community?

A

Pioneer community begins the process of succession, colonising an areas as the first living things there
Climax community is the final stable community after succession

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22
Q

What are the traits of pioneer species?

A

Pioneer species are:

  • able to withstand extremes
  • capable to asexual reproduction
  • photosynthesize
  • have spores/seeds which can disperse widely
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23
Q

Briefly describe stages of sand dune succession

A

Sand dune succession:

  1. pioneer species (sea rocket)
  2. wind blows sand to build up around pioneer making mini dunes
  3. death provides nutrients
  4. sea couch grass with underground stems stabilize ground
  5. marram grass shoots trap sand as they grow building the dune
  6. leguminous plants (nitrogen—nitrate)
  7. more species + soil created
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24
Q

What does the build up of dead material do?

A

Build up of dead material provides nutrients for other organisms to grow

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25
Define trophic level
Trophic level is the level at which an organism feeds in the food chain
26
How do you calculate the efficiency of biomass transfer? (ecological efficiency)
Efficiency of biomass transfer= | (biomass at higher level/biomass at lower level) X100
27
What are 4 ways biomass and energy are lost in a food chain?
Energy + biomass are lost: - respiration - urine - faeces - dead material used by decomposers
28
What is the consequence of loss of biomass and energy?
Losing biomass and energy means less energy and biomass is available to higher trophic levels , so a food chain tends to not be bigger than 4 levels
29
How do you calculate net production of consumers?
net production of consumers = | energy/biomass ingested (found between arrows) - (loss from faeces, urine and death + loss from respiration)
30
What does each bar on a pyramid of number represent?
Each bar on a pyramid of number is proportional to the number of individuals at each trophic level
31
What does each bar of a pyramid of biomass represent?
Each bar of a pyramid of biomass is proportional to the dry mass of all organisms at each trophic level (measured in grams per metre squared gm-2)
32
What is a limitation of pyramid of number?
Pyramid of numbers may not be representative of the relative contributions of the organisms (e.g. large tree has a small bar)
33
What is a limitation of a pyramid of biomass? How can this be combatted?
Pyramid of biomass requires organisms to be dried in an oven and this is very destructive of ecosystems. So scientists tend to use wet mass and calculate dry mass from previously published data
34
How can you work out pyramids of energy?
Pyramids of energy use bomb calorimetry, combusting the organisms and seeing how much energy they give off. This energy is measured in kJm-2 year -1
35
What is the source of energy fro all organisms?
The sun provides light energy which producers use to photosynthesise which then gets passed on to consumers
36
How do you calculate efficiency of energy transfer?
Do efficiency of bio mass transfer but replace biomass with energy efficiency of energy transfer= energy at higher trophic level/ energy at lower trophic level X100
37
What are 5 factors we can manipulate to limit energy loss and increase net primary productivity?
Limit energy loss/ increase NPP: - light levels - water availability - temperature - nutrients - biotic factors
38
how can we manipulate light levels and water availability?
Light levels- grow plants in light banks and plant them earlier for a longer growing season Water availability- good irrigation systems and grow drought resistant crops
39
How can we manipulate temperature and nutrients?
Green houses give a warmer temperature for increased photosynthesis and biomass production Nutrients- crop rotation to not leach soil, fertiliser and nitrogen fixing plants
40
How can we manipulate biotic factors to increase net primary productivity?
Biotic factors: - pesticides to stop destruction of biomass - herbicides to eliminate competition - fungicides for disease
41
What is secondary productivity?
Secondary productivity is the transfer of biomass between producers and consumers and consumers to consumers
42
How can we improve secondary productivity?
Improving secondary productivity: - harvest animals before adulthood - selective breed for high yield/fast growth - protect against disease and pests with antibiotics - reduce distance travelled to find food by cages
43
What is an issue with improving secondary productivity
Improving secondary productivity does not consider the welfare pf the animals so can become very UNETHICAL
44
What is productivity?
Productivity is the rate at which energy passes through each trophic level (gross or net)
45
What is gross primary productivity?
Gross primary productivity = rate at which plants convert light energy into chemical energy
46
What is net primary productivity?
Net primary productivity= the gross primary productivity -respiratory losses
47
Typically how much of the suns energy enters the food chain?
Only 1-8 % of the suns energy enters the food chain
48
What are the 4 main componets of the carbin cycle?
The carbon cycle comonents: - CO2 in air ans water - animals - plants - detritus, waste and hummus - fossil fuels
49
What are the processes that directly affect CO2 in air and water?
Processes directly affecting CO2; - combustion of fossil fuels - photosynthesis removes CO2 from air - respiration by plants and animals add CO2 - decomposition of detritus, waste and hummus adds CO2 - CO2 in water absorbed by plants
50
What are other processes in the crbo cycle that indirectly affect CO2 in air and water?
Other carbon cycle processes; - animals feeding and digesting plants - death of animals and plants adds to destritus, waste and hummus - death and fossilaisation of animals and plants creates fossil fuels
51
What is the chemical formula of UREA?
UREA = CO ( NH2 ) 2
52
What is the chemical formula of AMMONIUM IONS?
AMMONIUM IONS = NH4+
53
What is the chemical formula of NITRITES
NITRITES = N02-
54
What is the chemical formula of NITRATES?
NITRATES = NO3-
55
What is the chemical formula of NITROGEN OXIDE and NITROGEN GAS?
NITROGEN OXIDE = NO | NITROGEN GAS = N2
56
What are the components of fertiliser in the nitrogen cycle?
Fertilser adds to ammonium ions (NH4+) and nitrates (NO3-)
57
What is the action of NITROSOMONAS and NITROBACTER?
``` NITROSOMONAS = nitrification of NH4+ to NO2- NITROBACTER = nitrification of NO2- to NO3- ```
58
What is the action of RHIZOBIUM?
RHIZOBIUM= nitrogen gas fixation to organic nitrogen in leguminous plants
59
What is the action of AZOTOBACTER?
AZOTOBACTER = nitrogen gas fixation to organic nitrogen in the soil
60
What is leaching?
Leaching is where nitrates (NO3-) leak into rivrs and streams
61
What does excretion of animals release
Exrection releases urea CO ( NH2) 2
62
Other than rhizobium action how can plants aquire nitrates?
Plants aquire nitrates NO3- by absorbing them into their roots
63
What does death of plants and animals do?
Death of plants and animals adds organic nitrogen to the soil
64
What are nitrosomonas and nitrbacter?
NITROSOMONAS and NITROBACTER are chemoautotrophic bacteria, meaning they get their energy from their processes in the nitrogen cycle (as plants get their energy from photosynthesis)
65
What are saprotrophs and what is their process?
Saprotrophs are decomposers: 1. secrete enzymes on to dead and waste material 2. the ezymes digest it into small molecules 3. saprotrophs absorb the small molecules into its body
66
What are the 4 NITROGEN FIXING processes in the nitrogen cycle?
NITROGEN FIAXTION: - haber process into fertiliser - lightening to nitrogen oxide - azotobacter to organic nitrogen in soil - rhizobium bacteria into organic nitrogen in plants
67
What are the 2 NITRIFICATION processes in the nitrogen cycle?
NITRIFICATION: - ammonium ions to nitrites by nitrosomonas bacteria - nitrites to nitrates by nitrobacter
68
What are the 2 AMMONIFICATION processes in the nitrogen cycle?
AMMONIFIACTION: - urea to ammonium - organic nitrogen in soil to ammonium
69
What is the denitrification that happens in the nitrogen cycle?
DENITRIFICATION: | - Nitrates to nitrogen gas
70
How many examples of each of the 4 processes are there in the nitrogen cycle?
Nitrogen cycle: - 4 nitrogen fixations - 2 nitrifications - 2 ammonifications - 1 denitrification
71
What is NITROGEN FIXATION?
NITROGEN FIXATION is conversion of atmospheric (gas) nitrogen into nitrate or ammonium
72
What is NITRIFICATION?
NITRIFICATION is oxidation of ammonium to nitrite and nitrite to nitrate
73
What is DENITRIFICATION?
DENITRIFICATION is conversion of nitrates to nitrogen gas. This is anaerobic and the bacteria use nitrates as a source of oxygen for their respiration producing N2 and nitrous oxide N2O
74
What is abundance?
Abundance is the total number of invidials in a species in an area
75
Why do we have to use sampling?
We sample as actually working out abundance is impossible
76
What is sampling?
A sample is a small representative area of a habitat
77
What are two methods of random sampling
Random sampling can use a point frame/quadrat, where you count all the species touching the pin, or a frame quadrat where you can count species or work out percentage cover. You generate random coordinates.
78
How do you know how many samples to take?
Construct a cumulative frequency table and when it seems no new species are occurring this is how many samples should be used
79
What is something that needs to be considered when doing random sampling?
Random sampling needs to consider: - size pf the quadrat - number of samples
80
How do you calculate total population size from a sample?
Total population size = | mean number of individuals of a species in each quadrat / fraction of total habitat covered by each single quadrat
81
What is systematic ampling good for?
Systematic smpling is good for when thee is something running through a habaita and you want to see how things change around it
82
Hwo can you do systematic sampling?
Lay down tape meausure and do interrupted or continuous belt transect
83
What are 4 ways to measure abundance?
Measuring abidance: - count individuals - work out frequency/ absence of a species to work out probability of them being in the quadrat - percentage cover - mark release capture technique for animals
84
How do you work out estimated population size from mark capture and release technique?
Estimated population technique= (total number of individuals in the first sample X individuals in second sample) / number of marked individuals recaptured
85
What does the mark release capture technique assume?
Assumption of mark capture release technique: - the species spread evenly once released after marking - there are no births, deaths, immigrations or emigrations - the mark cant be rubbed off or is toxic and the mark doesn't alter the species chances of survival
BIOLOGY REVISION
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