Ecosystems 2 Flashcards

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1
Q

Ecosystem

A

All the living organisms that interact with one another in a defined area

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2
Q

Factors affecting ecosystems

A

Biotic and abiotic factors

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3
Q

Biotic factors

A

Interactions between organisms
Competition for food territory and breeding partners

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4
Q

Abiotic factors

A

Light
Temperature - effect enzymes in metabolic reactions can trigger migration
Water availability- lack of water leads to death
Oxygen availability- in aquatic ecosystems require fast flowing cold water containing O2
Soil factors

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5
Q

Trophies levels

A

Each stage in the food chain
First tropic level= producer - light energy into chemical energy
Trophies levels after are all consumers
Rare to have more that quaternary consumer

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6
Q

Biomass

A

Mass of living material present in particular place or particular organisms can be equated to energy content
To calculate biomass multiply dry mass by total number of organisms at that level g per square metre

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7
Q

Efficiency of biomass and energy transfer

A

Biomass is nearly always less than tropic level below
When animals eat tropic level below only transfer small proportion into making new tissues - only this part of the biomass the next level can eat
Energy available measures in kJ per m^2 per yr

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8
Q

Ecological efficiency

A

Efficiency with which biomass is transferred from one tropic level to the next
Net production = gross production- respiratory losses
Ecological eff. = energy after transfer/ energy before transfer x 100

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9
Q

Consumer efficiency

A

Convert 10% of biomass to tissue because
- not all biomass is eaten leaving bones and roots
- some energy transferred to environment
-some parts are not edible sheared into faeces
- some energy is lost via urine

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10
Q

Human manipulation of biomass

A

Plants and animals provided with abiotic factors required to thrive
Competition is removed and predators
Farming animals 3 tropic levels more biomass to consume
Crops only 2 tropic levels
Minimum energy is lost max biomass eaten

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11
Q

Ammonification

A

Sabriobonts to undergo extra cellular digestion of nitrogen containing matter
Decomposing

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12
Q

Nitrification

A

NH4- released into soil
Bacteria in the soil converts ammonia to nitrates
nitrifying bacteria (nitrosomas) oxidise ammonia to nitrites
Nitrobacter oxidise nitrites to nitrates for plants

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13
Q

Denitrification

A

Bacteria in soil break down nitrates and release nitrogen into the atmosphere
Only anaerobic conditions

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14
Q

Nitrogen fixing

A

Atmospheric nitrogen converted to ammonia using nitrogen fixing bacteria
Rhizobium
Using nitrogenase

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15
Q

Nitrogen cycle

A

Ammonification
Denitrification
Nitrification
Nitrogen fixation

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16
Q

Carbon cycle

A

Decomposers - break down dead organisms respiring CO2 into atmosphere
Dead organic matter become trapped making fossil fuels
Consumers carbon macromolecules passed from producer respire releasing CO2
Producers take CO2 from atmosphere for photosynthesis release during respiration

17
Q

Atmospheric CO2

A

Atmospheric CO2 levels are higher at night and during winter as photosynthesis levels are low
Combustion of fossil fuels once levels of CO2
Deforestation- less CO2 is removed from atmosphere
Temp increasing sea cannot dissolve CO2 as it’s too warm etc

18
Q

Primary succession

A

Occurs on areas of land taht has been newly formed eg bare rock no organic matter or soil to begin with
V slow process

19
Q

Seral stages

A

Succession steps
Pioneer community - colonisers (lichen)
Intermediate community - secondary colonisers tertiary , scrubland -> climax community dominant species

20
Q

Climax community

A

Less hostile conditions
High species diversity
Stable
Eg woodland

21
Q

Secondary succession

A

Occurs where soil is present but contains no plant or animal species
Eg bare earth after forest fire
Recolonised -> rapid process

22
Q

Pioneer species adaptions

A

Ability to produce large quantities of spores which are blown by wind
Seeds germinate rapidly
Ability to photosynthesise or produce own energy
Tolerance to extreme conditions
Ability to fix nitrogen from atmosphere

23
Q

Animal succession

A

Primary consumers first to colonise area- much slower than plant succession
Secondary consumers arrive once suitable food source established
Larger animals then colonise the area

24
Q

Deflected succession

A

Activities which prevent ecosystems reaching climax community - stopped artificially (plagioclimax)
Grazing of animals or mowing grass clearing field for crops forest clearance to promote biodiversity

25
Q

Measuring abundance of plants

A

Estimated number in population= number of individuals in sample /area of sample

26
Q

Measuring abundance of animals

A

Mark release recapture
Lincoln index = No in first x No in 2nd/ number of recaptured