Energy Transfer - Energy and Ecosystems

Question 2

what is a producer?

Answer 2

a photosynthetic organism that manufactures organic substances using the sun’s energy

Question 3

what is a consumer?

Answer 3

An organism that feeds on another organism

Question 4

what is a trophic level?

Answer 4

a stage in a food chain

Question 5

what are saprobionts?

Answer 5

organisms that break down the complex material in dead organisms into simple ones

Question 6

what is biomass?

Answer 6

the total mass of living material in a specific area at a given time

Question 7

what is a food web?

Answer 7

a series of linked food chains

Question 8

what is a food chain?

Answer 8

a linear representation of the feeding relationship in an ecosystem

Question 9

what is the ultimate source of energy in all ecosystems?

Answer 9

sunlight

Question 10

how is sunlight conserved in plants?

Answer 10

as chemical energy

Question 11

what do most plants use sunlight for?

Answer 11

making organic substances, usually sugars

Question 12

what are the two forms of biomass?

Answer 12

fresh mass

dry mass

Question 13

what is fresh mass?

Answer 13

all of the biomass of an organism

Question 14

what is dry mass?

Answer 14

the biomass of an organism when all the water has been removed

Question 15

what is an advantage of using fresh mass?

Answer 15

it is easy to access

Question 16

what is a disadvantage of using fresh mass?

Answer 16

different organisms have varying amounts of water so not representative of the amount of other biological molecules present

Question 17

what is an advantage of using dry mass?

Answer 17

it is more reliable

Question 18

what are the disadvantages of using dry mass?

Answer 18

time consuming

organisms have to be killed

Question 19

what are the units for biomass?

Answer 19

dry mass per given area

eg kg m^-2

Question 20

how can the energy at each trophic level be calculated?

Answer 20

collect a sample of the organism

weigh sample

burn in pure oxygen in a sealed chamber called a bomb

measure temp increase in a fixed volume of water

calculate energy released

Question 21

why is energy lost between the sun and a producer?

Answer 21

over 90% of sun’s energy reflected into space

not all wavelengths can be absorbed

light may not hit the chlorophyll

Question 22

why is energy lost between the producer and primary consumer?

Answer 22

some plant material cannot be accessed (eg roots)

some cannot be digested

excretory losses

respiratory losses

death and decay

Question 23

why is energy lost between consumers?

Answer 23

excretory and respiratory losses

indigestible material

movement

death + decay

Question 24

what is gross primary production?

Answer 24

the total amount of chemical energy converted from light energy in plants, in a given area

Question 25

what is the equation for net primary production in plants?

Answer 25

NPP = GPP - respiration losses

Question 26

what is the equation for npp in animals?

Answer 26

NPP = I - (F + R) or net primary production = food ingested - (faeces + respiration losses)

Question 27

what is the equation for energy efficiency?

Answer 27

energy available after transfer divided by energy available before transfer then x100

Question 28

what is ammonification?

Answer 28

the production of ammonium ions from ammonium containing compounds

Question 29

what carries out ammonification?

Answer 29

saprobionts

Question 30

what is nitrification?

Answer 30

the production of nitrate ions from ammonium ions

Question 31

what carries out nitrification?

Answer 31

nitrifying bacteria

Question 32

what are the stages of nitrification?

Answer 32

ammonium ions nitrite ions nitrate ions

Question 33

what is nitrogen fixation?

Answer 33

converting nitrogen gas into ammonium ions

Question 34

what causes nitrogen fixation?

Answer 34

lightning mutualistic bacteria living in plant root nodules free living bacteria

Question 35

what is denitrification?

Answer 35

converting nitrates into nitrogen gas

Question 36

what causes denitrifiction?

Answer 36

anaerobic conditions denitrifying bacteria

Question 37

what is assimilation?

Answer 37

when plants take up nitrate ions from the soil

Question 38

draw a diagram of the phosphorus cycle

Answer 38

Question 40

what is guano?

Answer 40

accumulation of seabird faeces

Question 41

what assists plants in the absorption of phosphate ions?

Answer 41

mycorrhizae

Question 42

what is mycorrhizae?

Answer 42

the mutualistic relationship between fungi and the roots of plants where the fungi help absorb minerals for the plant and the plant provides organic compounds for the fungi

Question 43

how do the fungi help increase the uptake of minerals in mycorrhizae?

Answer 43

they increase the surface area of the roots of the plant

Question 44

what is eutrophicaton?

Answer 44

the prescence of excessive nutrients in a waterway, causing the death of fish and plants

Question 45

why are fertilisers used?

Answer 45

in natural ecosystems the minerals removed are returned by dead plants/animals in farming they are not returned as crops are harvested so need fertilisers to replace lost minerals

Question 46

what is leaching?

Answer 46

the washing away of water soluble compounds in the soil

Question 47

what are the types of fertilisers?

Answer 47

natural/organic artificial

Question 48

what do natural/organic fertilisers contain?

Answer 48

dead + decaying remains of plants+animals as well as waste such as slurry and manure

Question 49

what do artificial fertilisers contain?

Answer 49

pure chemicals as powders or pellets