Energy and Ecosystems Flashcards
Why isn’t all energy transferred to the neck trophic level?
- not all is consumed
- some can’t be digested: is faeces
- used in respiration
What is gross primary production?
Total quantity of energy that plants in a community convert to organic matter
Net primary production =
Gross primary production - respiration losses
Energy transferred =
Energy available after divided by energy before x100
What does pyramid of numbers express?
Number of each organisms
What does pyramid of biomass express?
Total dry mass of organisms
What does pyramid of energy express?
Amount of energy available in each organism
What is intensive farming?
Using technology to maximise yield
What is extensive farming?
Minimal input from farmer
What is organic farming?
Using few agrochemicals
What is subsistence farming?
For family’s own needs
What is factory farming?
Indoors in large number
Characteristics of a natural ecosystem? 8
- High biodiversity
- long food chain
- high genetic diversity
- decomposition replenishes nutrients
- sun is the only input
- varied productivity
- sustainable
- efficient
Characteristics of an agricultural ecosystem? 8
- low biodiversity
- short food chain
- low genetic diversity
- fertilisers replenish nutrients
- fertilisers are the input
- high productivity
- unsustainable
- low efficiency
What makes pesticides effective? 4
- specific to direct pest
- biodegrade once applied
- cost-effective
- don’t accumulate
What is biological control?
Using other organisms to control pests population
Disadvantages of biological control?
Doesn’t eradicate pest
Not quick
Could become pest itself
What does integrated pest control involve? 6
- 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
How does intensive domestic livestock rearing increase energy conversion ? 4
- restricts movement-reduces muscular contraction
- warmth- lowers heat loss
- feeding controlled-decrease wastage
- predators excluded
Alternative ways to improve energy conversion?
Selective breeding
Hormones
Features of intensive rearing? 11
- 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
Environmental issues with intensive farming? 7
- 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
The 3 types of fertiliser?
- nitrogen-fixing crops
- inorganic fertiliser
- organic fertiliser
How do nitrogen fixing crops work?
- 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
How do inorganic fertilisers work?
- soluble and artificial
- ratio of nitrate, phosphate and potassium
- tailored to each crop
- sprayed on the crop
How do organic fertilisers work?
-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
Drawback to crop rotation?
Lose out on crop production in that field
Drawback to inorganic fertilisers? 3
- eutrophication
- expensive
- uses fossil fuels to make
Drawbacks to organic fertilisers?3
- bulky and less concentrated
- heavy machinery
- may contain unwanted substances
Process of eutrophication?
-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
Why could energy NOT be taken in by producers?
- reflected
- the incorrect wavelength
- not fall on a chlorophyll molecule
- limiting factors
