Energy And Ecosystems

Question 1

Gross primary production

Answer 1

The total amount of energy made by producers per unit area per unit time
Total quantity of chemical energy stored in plant biomass, in a given area or volume, in a given time

Question 2

Respiratory loss

Answer 2

The energy used by organisms for respiration
(Active transport, movement/ muscle contraction, heat)

Question 3

Net primary production

Answer 3

The amount of chemical energy a producer stored as biomass per unit area per unit time (after respiratory losses to the environment have been taken into account)
The energy available to the next trophic level

Question 4

I

Answer 4

R+F+N
Total energy ingested by consumer (chemical energy store in ingested food)

Question 5

Energy transfer efficiency

Answer 5

N/I x100

Question 6

Population

Answer 6

All the organisms of a single species that occupy the same habitat at the same time

Question 7

Community

Answer 7

All the organisms of all the species in a habitat/ an ecosystem at a given time

Question 8

Habitat

Answer 8

Place where an organism lives

Question 9

Niche

Answer 9

Role of a species in an ecosystem

Question 10

Trophic level

Answer 10

Each stage of the food chain

Question 11

Ecosystem

Answer 11

Abiotic and biotic factors interchanging with each other in a dynamic equilibrium
The abundance and distribution of organisms are controlled by biotic and abiotic factors
A biological community of interacting organisms and their physical environment

Question 12

Productivity

Answer 12

How much energy is transferred from one trophic level to the next
Rate of primary or secondary production (biomass in a given area in a given time)

Question 13

Why is energy transfer efficiency low from sun to producer

Answer 13

Wrong wavelength (not all wavelengths can be absorbed and used for photosynthesis)
Light strikes non photosynthetic region
Light reflected back into space by clouds and dust, or is absorbed by the atmosphere
Lost as heat
A factor such as low carbon dioxide levels may limit rate of photosynthesis

Question 14

Why is energy transfer efficiency low from producer to primary consumer

Answer 14

Respiratory loss (plant uses energy for metabolic processes)
Lost as heat
Not all the plant is eaten
Some food isn’t digested

Question 15

Why is energy transfer efficiency low from primary to secondary consumer

Answer 15

Respiratory loss (primary consumer uses energy for metabolic processes)
Lost as heat due to respiration (maintaining body temperature)
Not all the animal is eaten
Some of the food isn’t digested
Lost as excretory material (urine)

Question 16

Causes of energy transfer efficiency being especially low

Answer 16

Old animal (stopped growing so less energy goes to biomass)
Herbivores (more faeces)
Homiotherms and endotherms (warm blooded) as increased metabolism to keep warm

Question 17

Increasing energy transfer efficiency, plants

Answer 17

Shorten food web
Use fertilisers

Question 18

Shortening the food web

Answer 18

Reduces competition so the plant has more energy to make biomass
Herbicides (kill weeds), fungicides (reduce fungal infections), insecticide (chemical control of pests), biological controls (natural predators of pests)

Question 19

Fertilisers

Answer 19

Prevent growth being limited by lack of nutrients
Nitrates

Question 20

Increasing energy transfer efficiency, animals/ livestock

Answer 20

Reduce respiratory loss
Slaughter animal while still growing (more energy being made into biomass)
Keep predators away
Control diet (higher percentage of food digested, less faeces)

Question 21

Reducing respiratory loss

Answer 21

Restrict movement so less respiration so more energy goes to making biomass
Keep warm in winter so less respiration

Question 22

Way of increasing energy transfer efficiency both plants and animals

Answer 22

Artificially select organisms with a high yield

Question 23

NPP equation

Answer 23

Chemical energy stored in ingested food (I)- (energy lost in faeces and urine (F) + energy lost in respiration (R)

Question 24

Producer

Answer 24

An organism that synthesises organic molecules from simple organic ones (CO2 and H2O)
Most are photosynthetic

Question 25

Saprobiont

Answer 25

An organism that obtains its food from the dead or decaying remains of other organisms

Question 26

Consumer

Answer 26

An organism that obtains energy by eating another

Question 27

Biomass

Answer 27

Total mass of living material in a specific material at a given time

Question 28

Why is measuring biomass unreliable

Answer 28

Volume of water in living organisms varies
Measure mass of carbon or dry mass instead

Question 29

Problems with measuring dry mass

Answer 29

Organisms have to be dead so only small samples can be measured so not representative

Question 30

Calculating biomass from dry mass

Answer 30

Sample of biomass warmed on a scale until the mass remains constant meaning all water has evaporated
Temperature must be low to avoid combustion
Kgm-2

Question 31

Calorimetry to calculate biomass

Answer 31

Burn a sample of biomass completely
Heat a known mass of water
Measure temperature change of water
Calculate energy released

Question 32

Percentage efficiency

Answer 32

Energy available after transfer/ energy available before transfer x100

Question 33

Measuring biomass

Answer 33

Mass of carbon
Dry mass of tissue per given area (chemical energy store can be estimated using colorimetry)

Question 34

Biomass definition

Answer 34

Total mass of living material in a specific area at a given time

Question 35

Calculating NPP

Answer 35

GPP-R