Topic 5 Flashcards

Question

Net primary productivity equation

Answer 1

NPP=GPP-R - NPP = Net primary productivity - GPP = Gross primary production - R = respiratory loss

Answer 2

Energy available after transfer/ energy available before transfer x 100 - kJm-2 yr-1

Answer 3

N=I-(R+F) - N = net production - I = total energy ingested - R = Respiratory loss - F = Faeces and Urine

Answer 4

- very low - long wavelength - light hits non photosynthetic region - light reflected - lost as heat

Answer 5

- low - respiratory loss (plant uses energy for metabolism - lost as heat - not all the plant may be eaten - some food is not digested

Answer 6

- low - respiratory loss (primary consumer uses energy for metabolism) - lost as heat - not all of the animal is eaten - some of the food is digested

Answer 7

Sun - (2%) - producer - (10%) - primary producer - (10-15%) - secondary producer

Answer 8

- especially low for: old animals, herbivores, homeotherms, endotherms

Answer 9

- shorten food web, reduce competition so the plant has energy to create biomass. (Herbicides, kill weeds. Fungicide, reduce fungal infections. Insecticide, chemical control of pests) - fertilisers prevent growth being limited by lack if nutrients

Answer 10

- reduce respiratory loss (restrict movement = less respiration. Keep warm in winter = less respiration) - slaughter animal while still growing - keep predators away - controlled diet = higher % of their food will be digested

Answer 11

- artificially select organisms with a high yield

Answer 12

- a sample of biomass is warmed on a scale until the mass remains constant (all water has evaporated) - temperature must be low to avoid combustion - amount of water in samples varies a lot (dry biomass gives a more representative sample) - units: Kgm-2

Answer 13

- organisms are made from organic compounds - mass of carbon is a good indicator for biomass - difficult to measure - carbon is usually about 50% of the dry biomass - units: Kgm-2 yr-1

Answer 14

- burn a sample of biomass completely - heat a known volume of water - measure the temperature change of water - calculate energy released

Answer 15

- ammonification - nitrification - nitrogen fixation - denitrification

Answer 16

- nutrients are taken up by producers as simple organic molecules - producers incorporate the nutrients into the complex organic molecules - producer is eaten and nutrients pass to the consumer - nutrients pass along the food chain when animals are eaten by consumer - producer and consumer die the complex molecules are broken down by saprobiontic microorganisms

Answer 17

- increases surface area of the roots | - increase the absorption of rare minerals and water

Answer 18

Plants exchange these for organic compounds

Answer 19

- still need breaking down by saprobiotics - slows release of Nitrogen and phosphate - Benefits: aerate soil, less leaching, contain a wider range of elements, consume less energy

Answer 20

- when soluble compounds are washed off land by rain - more common in artificial fertilisers - rainwater dissolves soluble nutrients - carried deep into the soil, beyond the roots - enter the watercourse

Answer 21

Process by which nutrient concentrations increases in water 1) nitrate/ phosphate ions leach into fresh water 2) algal bloom 3) blocks out the light 4) plant can’t photosynthesise - die 5) sabrobionts break down dead plants 6) respire aerobically - use up oxygen/ increase demand 7) oxygen concentration decreases as nitrates increase 8) oxygen become limiting factor so fish etc die 9) without aerobic organisms less competition for anaerobic organisms 10) anaerobic organisms further decompose dead material releasing more nitrate and toxic waste

Answer 22

- removes N and P from their cycles - soil N and P becomes depleted - add fertiliser to replace N+P - too much fertiliser can be harmful eg change water potential

Answer 23

- phosphorous ions in the form of sedimentary rock deposits - weathering and erosion of rocks helps phosphate ions to become dissolved and available for absorption by plants - excess phosphate ions are excreted and accumulate in waste material - when plants and animals die, decomposers break them down releasing phosphate ions into water or soil - some phosphate ions will remain in bones and shells, which take longer to break down - dissolved phosphate ions are transported by streams and rivers to lakes and oceans and form sedimentary rocks

Answer 24

- production of ammonia from organic nitrogen containing compounds - compounds: Urea, protein, nucleic acid, vitamins - saprobiontic microorganisms feed on faeces/dead organisms releasing ammonia, leading to the formation of ammonium ions in the soill

Answer 25

- bacteria obtain their energy from chemical reactions involving inorganic ions - one reaction is the conversion of ammonium ions to nitrate ions > oxidative reaction, which releases energy - bacteria area called nitrifying bacteria - the conversion occurs in two stages: oxidation of ammonium ions to nitrite ions, oxidation of nitrite ions and nitrate ions - oxygen is required for these reactions, they require soil with many air spaces

Answer 26

- nitrogen gas converted into nitrogen-containing compounds - this can occur industrially or naturally when lightning pass through the atmosphere - two microorganisms: free-living and mutualistic - free living: reduces gaseous nitrogen to ammonia, used to manufacture amino acids - mutualistic: live in nodules on the roots of plants, obtain carbohydrate from plants, plant acquires amino acids from bacteria

Answer 27

- when soil is waterlogged and has a low oxygen concentration, the type of microorganism present changes - fewer aerobic nitrifying and nitrogen fixing bacteria and an increase in anaerobic denitrifying bacteria - these bacteria convert soil nitrates into gaseous nitrogen, reduces the availability of nitrogen for plants

Answer 28

- mutual symbiotic associations between certain fungi and the roots of the vast majority of plants - the fungi acts like extensions of the roots increasing surface area for absorption - they hold water and minerals around the roots - helps to survive droughts - mutualistic as plant receives water and inorganic ions from fungi and fungi receives organic compounds from the plant

Answer 29

- contain dead and decaying remains of plants and animals | - can also contain manure, slurry and bone meal

Answer 30

- mined from rocks and deposits - converted into different forms and blended together to give different quantities of minerals for specific crops - compounds containing nitrogen, phosphorus and potassium are always present - mixture of the two gives the greatest impact and greatest increase in productivity - an increase in minerals will not impact productivity

Answer 31

- nitrogen required for amino acids, ATP and nucleotides in DNA, needed fo plant growth - nitrate ions are in good supply, plants develop earlier, grow taller and leaves have a greater surface area. Increase photosynthesis and improve crop productivity

Answer 32

- reduced species diversity - leaching - eutrophication

Answer 33

- nitrogen rich soil: favour growth of grasses, nettles ad other rapidly growing species - species then outcome other species, causing them to die - for an area to be species rich: nitrogen levels need to be sufficiently high, but low enough so that other species can compete

Answer 34

- lower concentrations available to plants - enter watercourse that are drinking sources, prevent efficient oxygen transport in babies, cause stomach cancer in humans

Topic 5 Flashcards

(58 cards)