A2 1 Ecological energetics

Question 1

What is a producer

Answer 1

The autotrophic plants that produce food through photosynthesis and support all other levels

Question 2

What is a consumer and what are he types

Answer 2

Primary consumer (herbivores) 
Feed on producers 

Secondary consumers (carnivores)
Feed on primary consumers (herbivores)

Tertiary consumers/top consumers
Feed on secondary consumers

Question 3

What are decomposers

Answer 3

Most bacteria and fungi

Also Detrivores (earthworms and woodlice) feed on accumulated debris of dead organic matter

Question 4

What is a pyramid of numbers and what’s it’s disadvantages

Answer 4

Represents total numbers of the organisms at each tropic level in an ecosystem

Disadvantage -
Some organisms difficult to determine what represents a single individual (eg buttercups with extensions)

Does not take into account size of organism eg oak tree has more producer material than single buttercup

Can be inverted

Question 5

Pyramid of biomass and disadvantages

Answer 5

Represents the total biomass of the organisms at each tropic level.
More representative of all material at each tropic level.

Disadvantages - represents the standing crop and what is present at that moment and time. May not be accurate. Esp with aquatic ecosystems eg phytoplankton generates exceedingly to support zooplankton

Question 6

Praymid of productivity and disadvantages

Answer 6

Known as pyramid of energy’s
Represents energy value of new material produced at each tropic level over time.

Disadv-
Takes time so obtain data

Adv - provides meaningful relationship

Productivity refers to the amount of energy entering a trophic level that remains as energy in biomass.

• for a given area of ecosystem
• over a period of time

Question 7

Primary productivity

Answer 7

The production of new organic matter by plants

Question 8

Secondary productivity

Answer 8

Production of new organic matter by consumers

Question 9

Reason for reduction in energy at progressive trophic levels

Answer 9

Efficiency only 5-20%

Some material not consumed eg inaccessible, inedible

Some material not digested
Not absorbs and appears in faeces eg cellulose is not easily digested and skin and bones

Some material ends up as waste product of metabolism and excreted in urine

Many materials used in respiration to generate ATP for active processes in organism

Question 10

NP = C - (R + U + F)

Answer 10

Read

Question 11

Points to remember about efficient energy transfer

Answer 11

More energy is used in respiration than available for met production for next trophic level. Respiration generates energy for all active processes

More energy from net production passes to the decomposers than to next trophic level -
Some trade will be trampled on or spoiled by animal faeces so only available to decomposers