Energy and Ecosystems

Question 1

Why isn’t all energy transferred to the neck trophic level?

Answer 1

• not all is consumed
• some can’t be digested: is faeces
• used in respiration

Question 2

What is gross primary production?

Answer 2

Total quantity of energy that plants in a community convert to organic matter

Question 3

Net primary production =

Answer 3

Gross primary production - respiration losses

Question 4

Energy transferred =

Answer 4

Energy available after divided by energy before x100

Question 5

What does pyramid of numbers express?

Answer 5

Number of each organisms

Question 6

What does pyramid of biomass express?

Answer 6

Total dry mass of organisms

Question 7

What does pyramid of energy express?

Answer 7

Amount of energy available in each organism

Question 8

What is intensive farming?

Answer 8

Using technology to maximise yield

Question 9

What is extensive farming?

Answer 9

Minimal input from farmer

Question 10

What is organic farming?

Answer 10

Using few agrochemicals

Question 11

What is subsistence farming?

Answer 11

For family’s own needs

Question 12

What is factory farming?

Answer 12

Indoors in large number

Question 13

Characteristics of a natural ecosystem? 8

Answer 13

• High biodiversity
• long food chain
• high genetic diversity
• decomposition replenishes nutrients
• sun is the only input
• varied productivity
• sustainable
• efficient

Question 14

Characteristics of an agricultural ecosystem? 8

Answer 14

• low biodiversity
• short food chain
• low genetic diversity
• fertilisers replenish nutrients
• fertilisers are the input
• high productivity
• unsustainable
• low efficiency

Question 15

What makes pesticides effective? 4

Answer 15

• specific to direct pest
• biodegrade once applied
• cost-effective
• don’t accumulate

Question 16

What is biological control?

Answer 16

Using other organisms to control pests population

Question 17

Disadvantages of biological control?

Answer 17

Doesn’t eradicate pest
Not quick
Could become pest itself

Question 18

What does integrated pest control involve? 6

Answer 18

• choosing species that are pest- resistant
• manage environment next to crop to give suitable habitat for predators
• monitor crops regularly
• remove pests mechanically if exceeding acceptable level
• biological agents
• pesticides as last resort

Question 19

How does intensive domestic livestock rearing increase energy conversion ? 4

Answer 19

• restricts movement-reduces muscular contraction
• warmth- lowers heat loss
• feeding controlled-decrease wastage
• predators excluded

Question 20

Alternative ways to improve energy conversion?

Answer 20

Selective breeding

Hormones

Question 21

Features of intensive rearing? 11

Answer 21

• efficient energy conversion
• low cost
• low quality food
• less space
• increased safety
• increased disease if occurs
• increased pollution
• antibiotic resistance
• low animal welfare
• low genetic diversity
• fossil fuels used

Question 22

Environmental issues with intensive farming? 7

Answer 22

• removal of hedgerows and woodlands
• monocultures created
• fill in ponds
• overgrazing of land, low regeneration of woods
• pesticides and fertilisers move into water
• farm waste into water
• poor soil structure

Question 23

The 3 types of fertiliser?

Answer 23

• nitrogen-fixing crops
• inorganic fertiliser
• organic fertiliser

Question 24

How do nitrogen fixing crops work?

Answer 24

• using legumous plants on rotation
• nitrogen-fixing bacteria in roots make ammonia and organic nitrogen compounds from atmospheric nitrogen
• whole crop is ploughed into soil : releasing nitrogen compounds and ammonia

Question 25

How do inorganic fertilisers work?

Answer 25

• soluble and artificial
• ratio of nitrate, phosphate and potassium
• tailored to each crop
• sprayed on the crop

Question 26

How do organic fertilisers work?

Answer 26

-contain ratio of NPK which is digested by soil decomposers: release inorganic ions for plants to take up
-animal manure etc.
Released slowly - no leaching

Question 27

Drawback to crop rotation?

Answer 27

Lose out on crop production in that field

Question 28

Drawback to inorganic fertilisers? 3

Answer 28

• eutrophication
• expensive
• uses fossil fuels to make

Question 29

Drawbacks to organic fertilisers?3

Answer 29

• bulky and less concentrated
• heavy machinery
• may contain unwanted substances

Question 30

Process of eutrophication?

Answer 30

-fertilisers run into rivers
-algae bloom
-either :block light from plants - die
: consumers can’t consume fast enough- dead algae
-detritus
-more decomposers
-use up oxygen in water for respiration
-anaerobic bacteria release chemicals
-fish etc. die

Question 31

Why could energy NOT be taken in by producers?

Answer 31

• reflected
• the incorrect wavelength
• not fall on a chlorophyll molecule
• limiting factors