5- Energy And Ecosystem

Question 0

How is energy released from indigestible parts?

Answer 0

By decomposers

Question 1

The main route for energy into a ecosystem and the pathway it takes when in a ecosystem?

Answer 1

Photosynthesis

Trophies levels:

Producer
⬇️
Primary consumer 
⬇️
Secondary consumer 
⬇️
Tertiary consumer

Question 2

Plants don’t absorb all sunlight - why?

Answer 2

• Not all absorbed - wrong wavelength
• light reflected
• Doesn’t hit chloroplast
• Lost to environment and other limiting factors

Question 3

All energy not transferred- why?

Answer 3

• some parts not eaten

* some lost as indigestible parts - faeces

Question 4

Net productivity

Answer 4

NP- energy available to next trophic level

NP=Gross productivity-Respiratory loss

Question 5

Energy value

Answer 5

kJ m-2 year-1.

Question 6

What’s more productive intensive farming systems or natural ecosystems ?

Answer 6

Intensive farming system

Question 7

How does intensive farming increase efficiency ?

Answer 7

Changes biotic and abiotic factors - favouring … Leading to increase biomass and productivity :
• decrease growth limiting factors
• increase energy in ecosystem
• increase energy efficiency - more for growth

Question 8

Chemical control +ve

Answer 8

• Acts quickly + easily applied
• herbicides kill weeds-decrease competition - more energy-grow faster
• fungicides kill fungal infections - less energy used to fight infection
• insecticides- less insects - increase biomass, grows larger , increase productivity

Question 9

Chemical control -ve

Answer 9

• Needs to be repeatedly used- expensive
• resistance develops
• Can affect other non targeted species
• persist in environment-bioaccumulation

Question 10

Biological controls +ve

Answer 10

• specific to pests
• doesn’t have to be reintroduced
• unlikely pest resistance develops

Question 11

Biological control -ve

Answer 11

• natural predators/ control can become pests
• takes time to take effect
• can affect other non-targeted species

Question 12

Integrated systems

Answer 12

• combined effect- affects pests more - increasing productivity
• decrease costs by using expensive method less
• decrease environmental impact (E.G.pesticides) use them less

Question 13

Use of fertilisers

Answer 13

Provide minerals - needed for growth (nitrates) -replaces lost minerals

Question 14

What is Natural fertilisers ?

Answer 14

Organic matter:

• manure • sewage sludge

Question 15

What is Artificial fertiliser ?

Answer 15

Inorganic:

•pure chemicals E.G ammonium nitrate

Question 16

Fertiliser -ve

Answer 16

• Fertilisers washed in river or pond kill fish

* changes balance of nutrients in soil- too much causes crops+plants to die

Question 17

What is Rearing livestock intensively?

Answer 17

Controlled conditions- more energy for growth- increase energy conversion , biomass + productivity

Question 18

How is rearing livestock intensively done ?

Answer 18

• animals kept warm indoors

* fed food high in energy