Energy Transfer and Nutrient Cycles

Question 1

define population?

Answer 1

all organisms of single species in habitat

Question 2

define community?

Answer 2

all organisms of ALL species in habitat

Question 3

define habitat?

Answer 3

place where organism lives

Question 4

define niche?

Answer 4

role of species in ecosystem

Question 5

define trophic level?

Answer 5

each stage of food chain

Question 6

measuring dry biomass?

Answer 6

• sample of biomass warmed on scale until mass remains constant
• at low temp in oven

Question 7

why must temp be low?

Answer 7

avoid combustion (loss of biomass)

Question 8

why is dry mass a more representative sample?

Answer 8

water content in sample varies

Question 9

units for dry biomass?

Answer 9

kJ/m2

Question 10

what is a good indicator of biomass?

Answer 10

carbon

Question 11

carbon is how much of biomass?

Answer 11

50%

Question 12

units for mass of carbon?

Answer 12

Kg/m2/year

Question 13

what is calorimetry used for?

Answer 13

estimate amount of energy stored in dry biomass

Question 14

calculating energy stored in biomass?

Answer 14

• burn sample of biomass
• heat known vol of water
• measure temp change of water
• calc energy rel

Question 15

define GPP (gross primary productivity)?

Answer 15

total amount of energy made by producers

• per unit area per unit time

Question 16

define respiratory loss?

Answer 16

energy used by organisms for respiration

Question 17

define net primary production?

Answer 17

amount of chemical energy a producer stores as biomass

• per unit area per unit time

Question 18

formula to calc NPP?

Answer 18

NPP = GPP - R

Question 19

formula to calc net productivity?

Answer 19

N = I - (F + R)

Question 20

natural fertilisers?

Answer 20

• organic comp
• contain nitrogen and phosphorous
• still need breaking down by saprobionts
• slow rel of N and P
  e. g. manure, compost

Question 21

benefits of natural fertilisers?

Answer 21

• aerobic soil
• less leaching
• contain wider range of elements
• consume less energy

Question 22

artificial fertiliser?

Answer 22

• inorganic chemical comp
• contain N and P - water soluble
• e.g. ammonium nitrate, urea

Question 23

leaching

Answer 23

when soluble comp washed off into waterways by rain

MORE COMMON IN ARTIFICIAL FERTILISERS

Question 24

eutrophication?

Answer 24

• nitrate/phosphate ions leach into fresh water
• algal bloom
• blocks out light
• plants cant photosynthesis - die
• sapriobionts break down dead plants
• respire aerobically - use up oxygen
• fish etc die

Question 25

harvesting crops/livestock?

Answer 25

• remove N and P from cycles
• soil N and P = depleted
• add fertiliser to replace N and P
• too much fert = harmful
• changes water potential

Question 26

phosphorous cycle?

Answer 26

• inorganic phosphate absorbed by plants (contain ATP etc)
• animals eat plants to get phosphate (contain ATP, phospholipids = cell memb etc)
• animals egest / plants and animals die
• saprobionts - saprobiotic nutrition - return to soil
• inorganic phosphate in rocks weathered / eroded - return to soil

OR

• ends up in lakes/ oceans

Question 27

nitrogen cycle 4 main steps

Answer 27

nitrogen fixation

ammonification

nitrification

denitrification

Question 28

nitrogen cycle?

Answer 28

• nitrogen gas from atmosphere fixated into plants e.g. legumes/ pea plants
• by bacteria at root nodules
• plants and animals die & decompose
• saprobionts feed on remains of dead plants and animals and waste prod (SAPROBIOTIC NUTRITION)
• nitrogen containing comp converted into ammonium ions
• ammonium ions converted into nitrites then nitrates
• nitrates used by plants
• nitrates also converted back to nitrogen gas by denitrifying bacteria

Question 29

define saprobiotic nutrition?

Answer 29

digestion / decay of dead organic matter by extracellular digestion

Question 30

what are sapriobionts?

Answer 30

type of decomposers that digest their food by sapriobiotic nutrition

Question 31

what are mycorrhizae?

Answer 31

fungi that grow in a mutualistic relationship with plant roots

Question 32

how do plants play a major role in recycling nutrients?

Answer 32

break down large organic comp into small inorganic comp

• absorbed by producers

Question 33

how energy lost from sun to producer?

Answer 33

• wrong wavelength
• light strikes non photosynthetic region (bark)
• light reflected
• lost as heat

Question 34

how energy lost from producer to primary consumer?

Answer 34

• plant uses energy for metabolism (AT)
• lost as heat
• not all plant eaten (roots)
• some food not digested (faeces)

Question 35

how energy lost from primary consumers to secondary consumers?

Answer 35

• energy used for metabolism (muscle contraction)
• lost as heat
• not all animal eaten (bones/teeth)
• some food not digested

Question 36

what is energy transfer especially low for?

Answer 36

• old animals (stopped growing)
• herbivores (more poo)
• homotherms/endotherms (warm blooded)