Energy & Ecosytems

Question 1

Trophic level

Answer 1

Feeding level

Question 2

Photoautotroph

Answer 2

Plant

Question 3

Heterotroph

Answer 3

Animal

Question 4

Saprotroph

Answer 4

Fungi

Question 5

Producer

Answer 5

An organism that synthesises organic molecules from simple inorganic molecules such as CO2 and H2O, most are photosynthetic from the first tropic level.

Question 6

Primary consumer

Answer 6

Any organism that obtains energy by eating another.

Question 7

Secondary consumer

Answer 7

Organisms feeding on primary consumer.

Question 8

Tertiary consumer

Answer 8

Organisms feeding on secondary consumers.

Question 9

Decomposers

Answer 9

Eg. Bacteria/fungi. Break down complex materials into simple components.

Question 10

Detritivores

Answer 10

Organisms that feed off decaying material.

Question 11

Ecosystem

Answer 11

All of the organisms living in a particular area and all the non-living (abiotic) conditions.

Question 12

What’s an agricultural ecosystem?

Answer 12

Made up largely of domesticated animals and plants used to produce food for mankind.

Question 13

What is productivity?

Answer 13

The rate at which something is produced

Question 14

Natural ecosystem

Answer 14

Ecosystem that hasn’t been changed by human activity

Question 15

Energy input

Answer 15

Amount of sunlight captured by the producers in an ecosystem

Question 16

Intensive farming/agricultural ecosystem

Answer 16

Changing an ecosystem by controlling the biotic and abiotic conditions, to make it more favourable for crops or livestock

Question 17

How do intensive farming methods increase productivity?

Answer 17

They increase the efficiency of energy conversion, so more energy can be used for growth.

They remove the growth limiting factors, so more energy is available for growth.

They increase energy input, as more energy added to the ecosystem means more energy for growth.

Question 18

Biological agents

Answer 18

They reduce the numbers of pests, so crops lose less energy and biomass, increasing productivity.

Question 19

Pests

Answer 19

Organisms that reduce the productivity of a crop by reducing the amount of energy available for growth.

Question 20

Fertilisers

Answer 20

Chemicals that provide crops with the minerals needed for growth e.g. Nitrates. Adding fertilisers replaces the lost minerals so more energy from the ecosystem can be used to grow, increasing the efficiency p energy conversion.

Question 21

Organic farmers don’t use artificial chemicals on their land. Describe and explain how an organic farmer might increase productivity by reducing pest numbers on their farm. 5marks

Answer 21

Organic farmers might use biological agents.
Biological agents reduce the number of pests, so crops lose less energy and biomass, therefore increasing productivity.
They include natural predators that eat the pest species to reduce their numbers.
They could also use parasites that live in or lay eggs on pest insects, killing the pests or reducing their ability to function.
They could also introduce pathogenic bacteria or viruses that kill pests.

Question 22

The gross productivity of an arctic hare is 5410kjm-2yr-1 and the net productivity of grass is 13883kjm-2yr-1.
Explain why the gross productivity of the arctic hare is less than the net productivity of the grass. 3marks.

Answer 22

Not all of the energy is taken in by the arctic hares.
Some parts of the grass aren’t eaten so energy isn’t taken in.
Some parts of the grass are indigestible so they’ll pass through the hairs and come out as waste.