Ecosystems Flashcards
0
Q
Denitrification
A
- denitrifying bacteria get energy from turning nitrate back to N2
- found in compost heaps and sewage plants
1
Q
Nitrogen fixation by the haber process
A
- N2 + 3H2 NH3
- lots of energy
- in fertilisers
2
Q
Nitrogen fixation
A
- the conversion of nitrogen from unreactive N2 to a more reactive form
- ie ammonia or nitrate ions
3
Q
Nitrogen fixation by living organisms
A
- prokaryotes & archeans
- ie rhizobium in soil - mutualistic with roots of leguimous plants
- rhizobium colonises in root nodules
- N2 -> NH4+
- H+ from NADred
- ATP resp& photosynthesis
- anaerobic conditions from leghaemoglobin
4
Q
Fixed nitrogen in plants
A
- rhizobium
- used to make amino acids
- moved and synthesised to make proteins
- others - N2 from soil active transport through root hairs
- Nitrate ions-> nitrite ions-> ammonia -> amino acids
5
Q
Nitrogen in animals
A
- from diet (proteins + some nucleic acid)
- broken down in digestion to amino acids
- absorbed by and transported by blood
- waste deaminated in liver -> urea
6
Q
Ammonification
A
- the production of ammonia
7
Q
From living organisms to nitrogen in the soil
A
- bacteria and fungi break down dead organisms with protease
- some used some broken down to ammonia
- NH3-> nitrosomonas -> NO2 -> nitrobacteur -> NO3
- nitrifying bacteria
- require O2
8
Q
Nitrogen fixation in the atmosphere
A
- energy from lightning = nitrogen oxides
- dissolved is soil from rain
- stormy countries contribute more
9
Q
Studying succession
A
- sand dunes
- transects
- line transect (next to tape)
- belt transect (quadrats at intervals)
- Continuous transect- record whole length of tape
- interrupted transect - record at intervals
10
Q
Succession stages
A
- pioneer species - abiotic factors
- they add nitrogen to the soil & produce humus, stabilise the soil and increase biodiversity
- other plants can then colonise- biotic factors
11
Q
Pioneer plants
A
- the first living organism to colonise an area
- later outcompeted
- grow sparse, in low nitrate soils and have good disperal techniques
- alter the soil
- produce nutrients for decomposers
12
Q
Seral stages
A
- the different communities present in succession
13
Q
Climax community
A
- the final community of succession
- normally stable
- dont change much over time
14
Q
Secondary succession
A
- if the area was disturbed
- if soil was already present
15
Q
Primary succession
A
- if the original area had no soil
- and no living organisms present
16
Q
Succession
A
- a directional change in a community over time
17
Q
Maximising energy transfer in animals
A
- primary consumers - less trophic levels
- fertiliser - more energy in plant
- medicines to kill parasites - all energy in animal no lost to parasites
- indoors - controlled heat& movement
18
Q
Maximising energy transfer in crops
A
- crops close together - more sunlight on leaves less on floor
- more H20 - isnt a limiting factor
- extra minerals ie fertiliser - not a limiting factor
- herbicides - specific to weeds
19
Q
Monocultures
A
- grow a single variety of crop in an area
- all light energy for the plant
- herbicides - kill weeds
- pesticides - kill insects
20
Q
Measuring energy transfer
A
- measure pop size
- calculate mean dry mass of an organism (killing and drying)
- calculate energy transfer per gram ( burning and calorimeter)
- calculate energy content
21
Q
Net primary productivity
A
- the energy that is left as chemical energy after the plant has supplied its own needs by respiration
22
Q
Gross primary productivity
A
- The total quantity of energy transferred by plants from sunlight into plant tissue
23
Q
Productivity
A
- the rate at which plants turn light energy into chemical energy
24
Q
Loss of chemical energy
A
- breaking down molecules in respiration- energy lost as heat
- ATP made used for activities
- not all energy from plants eaten
- not all the plant digested ie faeces
- energy lost as heat in digestion
- overall efficiency = about 10%
25
Q
Loss of light energy
A
- sunlight missing leaves
- some wavelengths reflected
- some pass through and dont hit pigments
- only some wavelengths absorbed
- energy lost during photosynthesis
26
Q
Decomposers
A
- feed on detrius
27
Q
Detritus
A
- organic matter in dead organisms and wate material
- ie dead leaves/faeces/ urine
28
Q
Food web
A
- the interrelationships between food chains
29
Q
Trophic level
A
- the stages of a food chain at which an organism eats
30
Q
Food chain
A
- the way in which energy flow from
producer to consumer - may contain multiple consumers ie primary/secondary/tertiary
31
Q
Consumer
A
- an organism that obtains its energy from organic compunds
- ie carbs, fats & proteins
- all animals and fungi - consume mainly plants
32
Q
Producers
A
- an organism that transfers light/ inorganic energy into organic molecules ie carbs
- and supply the rest of the ecosystem
33
Q
Abiotic factors
A
- non-living components of the enviroment
- ie temperature/light intensity/PH/wind speed/O2 conc/CO2 conc/ water availability/soil
34
Q
Competition
A
- in which 2 organisms both require something which is in short supply
35
Q
Parasitism
A
- one organism (the parasite) lives in close association with an organism of another species
- and does it harm
36
Q
Mutualism
A
- a close relationship between 2 organisms where both benefit
37
Q
Biotic factor
A
- factors that involve other living organisms
- ie feeding (on plants)/predation/competition/parasitism
38
Q
Ecosystem
A
- relatively self contained system including all the living organisms and the enviroment interacting with each other
