5B - Energy transfer and nutrient cycles

Question 1

biomass

Answer 1

• mass of living organism
• chem eng stored in plant

measuring biomass
- dry mass
- calorimetry

Question 2

dry mass

Answer 2

• mass of organism with water removed
  water living tissue varies so dry mass used to measure
• to measure = org dried , often in oven to loe temp
• the sample weighed at regular interval until mass = constant
• mass of carbon present geneally taken 50% of the dry mass
  unit = kg m-2

Question 3

calorimetry

Answer 3

• estimate the amount of chemical eng stored in biomass by burning the biomass in calorimeter
  -amout of heat given off = how much eng is in it

a sample of dry biomass burnt and eng rele used to heat known volume of water
- change in temp = used to calcu chem eng of dry biomass

Question 4

primary production

Answer 4

gross primary production ( GPP ) = total amount of chem eng converted from light energy
50% of chem eng = lost during respiration

NPP = net primary production
NPP = GPP - R ( repiration )

NPP = used for plant’s growth and reproduction
- also eng available to org at next stage in food chain

Question 5

Net production in consumers

Answer 5

Consumers get energy by ingesting plant marerial, or animals that have eaten plant materials

only about 10% of biomass transfered into next org in the food chain, eng lost
- lost to envi through repiration of org
- some indigestable, urine or lost with faeces

NP = I - (F + R)
n = net production
i = food injected
f = eng lost in faeces and urine
r = eng lost in respi

newt production can also be called = secondary

Question 6

efficiency of energy transfer

Answer 6

NP of trophic level / NP of next trophic level x 100

• eng transfer become more effieicnt as move up the food chain
• as plant have more indigestable materials than animals

Question 7

Food and food web

Answer 7

shows us the eng trans in ecosystem
- decomposers also in food chain = breaks down dead material / undigfested material
- recycles thew nutrients

Question 8

increasing efficiency for human consumption

Answer 8

by increasing the NPP of crops and increasing NP of animals
2 ways
- eng lost to oither org - reduced through simplyfing food web
- reducing amount of respi in livestock

Question 9

simplifying food webs

Answer 9

pests = org that reduce a,ount of eng available for crop growth and therefore NPP of crops

• reduces the eng available for humans
• by simplifying food web = getting rid of food chain that’s not human - eng lost reduced and NPP for crop inc

Question 10

How reduce number of pests and why

Answer 10

farmer can reduce pest numbers using chemical pesticides
- insecticids = kill pests
- herbicides = kill unwanted weeds

bio agents = reduce number of pests
farmner = caqn use integrated sys combine both chem and biological methods

ehy = so crops lose less ang and biomass increasing effieicnet of eng trans to humans

Question 11

reducing chem eng lost in respi

Answer 11

chem eng lost in respi to reduce control
- envi livestock live in
- reduce activities that increases rate of respiration

more chem eng stored, inc NP = inc effiency of eng trans
- benifitg = more food can be produced in shoeter space

raises ethical issues

Question 12

imp of microorgsnisms

Answer 12

microorg = bac, fungi = imp part of food chain - known ad saprobionts

does 2 things
- feed on dead organism and break down waster product -saprobionts = type of decomposer - allow imp chem from wastes = recycled
- secreates enzyme and digests their food externally, absorbing the nuritents they need (extracellular digestion) - organic mole turnede into inorganic ions

obtaining nuritents from dead organic matter and ani waste using extracellular digestion = saprobiotic nutrition

Question 13

Mycorrhizae

Answer 13

some fungi and root of plant = symbiortic relation called mycorrhizae

• fungi = made of long thin strand = hyphae = connect to plant root
• inc the SA of root = more ion and water can be ab from soil
• in return fungi obtain organic mole ( glu ) from the plant

Question 14

nitrogen cycle

Answer 14

plants and ani= need nitro to make protein and nucleic acids
- athmosphere made up about 78% nitrogen gas - but plant and nani can’t use that
- use bac to fuirst convert into nitrogen - containing comp

Question 15

ammonification

Answer 15

uses saprobionts to trans waster product / dead org into ammonia go on to form ammonium ions

Question 16

nitrogen fixation

Answer 16

• converts nitrogen from air into ammonia
• nitrogen fixing bac = rhizobium - forms mutualistic relationship with plants - found inside root nodules
• converts nitrogen from air = plant use to grow in return plant provide carbohydrates ( glu )

Question 17

nitrification

Answer 17

• ammonium ions in soil = into nitrates ( by nitosomonas bac)
• nitragtes into nitriles ( by nitrobacter bac )

Question 18

what plants take in

Answer 18

• ammonuim ions and nitrates

Question 19

denitrification

Answer 19

when nitrates in soil converted into nitrogen gas
- by denitrifying bac = use nitrates in soil to respire ands produces nitrogen gas
- only in anaerobic condition ( water logged soil )