C4.2 Transfers of Energy and Matter Flashcards
Closed system
only energy can pass in and out, not matter
only exists experimentally, although the global geochemical cycles approximate to close system
Open system
both energy and matter can enter and exit
sustainable ecosystems
Why is sunlight needed as energy in ecosystems
for organisms to carry out activities, they need energy - ATP
Producers
autotrophic organism that can synthesis glucose
first trophic level in food chain
exceptions of producers
hydrothermal vents, caves
areas where there is no sunlight
how does energy enter through food chains
enters usually as sunlight, leaves as heat
where does an arrow point in a food chain
direction of energy flow
food chain
sequence of organisms within a community in which each is food of the next, starting with producer
consumer
organisms that are unable to synthesise glucose and so eat other organisms or organic matter to obtain it and other nutrients
food web
interconnected food chains in an ecological community
trophic levels
feeding level within a food chain
usually 3-4
decomposers
organisms that feed on dead plants and animal material, causing matter to be recycled by other living things
bacteria, fungi
how does cycling of nutrients occur
- break up of animal body
- succession of micro-organisms
- releasing of simple inorganic molecules like oxygen, water, and all absorbed by plant roots for reuse
why is cycling of nutrients needed
- essential for survival of living things
- limited resources and nutrients
what completes the last step of cycling of nutrients
detrivores begin breakdown and saphrotrophs finish it
photoautotrophs features
- transfer solar energy into chemical energy
- nearly all plants
chemoautotrophs features
- use chemical energy from oxidation reactions to create glucose
- nitrifying bacteria
- iron oxidising bacteria
what do redox reactions do
- release energy and are useful in living organisms
- photosynthesis and respiration
what is common in autotrophs and heterotrophs in terms of release of energy
- ability to release stored chemical energy to produce ATP - life processes
- release of energy - oxidation of carbon compounds in cell respiration
what form is all energy released in
heat
producers
bottom of the food chain
1st level
primary consumer
2nd trophic level
organisms that feed on producers
secondary consumer
3rd trophic level
carnivore that feeds on herbivore
tertiary consumer
4th trophic level
animal that feeds on secondary consumer
why is energy reduced as it moves up trophic levels
it is used for cell respiration to provide energy for MSGREN
why is 90% of energy lost
- biomass not being eaten
- food not being digested
- excretion
- loss of heat from respiration
- loss as inedible parts - bones, teeth, fur
steps of reductions in energy in a plant
- light energy from sun to plant
- energy used for life processes
- stored in organic molecules in plant
- heat energy lost as respiration and metabolism
- chemical energy to tissues of a green plant
- final energy lost when plant dies
what animals will pass on less energy
- greater respiration rate
- cold blooded animals which loose more heat
Heat loss in ecosystem
- due to conversion of chemical energy to heat
- transfer of energy is inefficient
why is there restriction on number of trophic levels
- only 10% of energy is transferred in each tropic level
consequences of 10% of energy being passed in each trophic level
- at each stage in food chains there are fewer organisms (less biomass)
- number of trophic levels are restricted
food chains and world hunger
huge population and excessive demands on food supply and resources
ethics and world hunger
- well nourished people living with malnourished and starving people
what does being vegetarian do
- trophic level is extended by one which leaves more food for others
Primary production
accumulation of carbon compounds in biomass by autotrophs
occurs when autotrophs grow and reproduce
Gross primary productivity (GPP)
total gain in biomass per unit area per unit time fixed by producers
Net primary productivity (NPP)
gain by producers in biomass per unit area per unit time remaining after allowing for respiratory losses (R)
available to consumers in an ecosystem
NPP
GPP - R
why do rainforests have highest NPP
so much energy at producer level that can support a number of trophic levels
Secondary production
accumulation of carbon compounds in biomass by heterotrophs
when heterotrophs grow and reproduce
Gross secondary productivity (GSP)
the total gain by consumers in energy or biomass per unit area per unit time through absorption
Net secondary productivity (NSP)
the gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R)
biochemical cycles
nutrients are recycled in a circular path
carbon cycle
- burning of fossil fuels
- combustion
- volcano erruptions
- decay by detrivores and saphrotrophs
why is secondary production lower that primary production
loss of biomass when carbon compounds are converted to Co2 and H2O in respiration
Sink
absorbs more carbon from atmosphere that it releases
- plants, ocean, soils, forest
- deforestation causes carbon emissions
- forest regrowth - carbon sequestration
Source
releases more carbon in atmosphere than it absorbs
burning of fossil fuels
Peat
- formed over millions of years by plant matter
- erroded by wind due to no water logging
- more likely for it to catch fire
climate drying
Burning of fossil fuels
- coal as a source of energy
- carbon that has been locked away for 350 million years is being reduced to atmosphere
- large coal, oil and gas reserves led to more burning
- leads to global warming and natural disasters
- movement away from fossil fuels resources
fires in the amazon
- drought tolerance had its limits
- land use activites increase susceptibility to fires
- forests burning for crops or pasture and to improve pasture forage
- frequently burn beyond boundaries to nearing forests
kneeling curve
a daily record of global atmospheric carbon dioxide concentration kept since the 1950s
