Topic K - Ecology and the Enviroment Flashcards
definition of population
number of members of a single species
definition of community
different species of organisms living n the same area
definition of habitat
where living organisms live
definition of ecosystem
population of different species of organism and the habitat they live in
definition of producers
organisms that produce their own organic nutrients such as plants through photosynthesis
definition of primary consumers
herbivores= feed on plants ( producers )
definition of secondary consumers
predators that feed on primary consumers
definition of tertiary consumers
predators that feed on secondary consumers
definition of decomposers
bacteria and fungi that breaks down dead animals body, urea + undigested waste for energy ( using enzymes to break down compounds )
definition of food chains
shows the feeding relationship between living things ( what eats what in a habitat)
definition of food web
shows all the food chains in an ecosystem, showing the floe of energy in a habitat
what do food webs show
interdependence = change in population of one organism will affect the population of another organism
definition of pyramid of numbers
shows the population of each organism at each trophic level in a food chain
what do the bars represent on a pyramid of numbers
the population- so the wider the bar, the larger the population
what happens to energy between the trophic levels in pyramid of numbers
energy is lost to the surroundings from one trophic level to the next so there are usually fewer organisms at each trophic level ( less chances of survival)
why does a pyramid of numbers not always look like a pyramid
because one large producer can feed many small consumers ( eg. 1 oak tree can feed many insects )
definition of pyramids of biomass
shows the transfer of energy at each trophic level by calculating the dry mass of each population of species
what is biomass ( in terms of a pyramid of biomass)
the mass of living material in each organism multiplied by their population at each trophic level
why will pyramids of biomass always look like a pyramid
because biomass is a measure of the amount of food available - this decreases from one trophic level to the next as energy is lost ( to respiration, not digested or not eaten )
definition of pyramids of energy transfer
shows the transfer of energy at each trophic level from one trophic level to the next
why does each trophic level reduce the amount of energy available for the next
because only 10% of energy is passed on
why is only 10% of energy transferred from one trophic level to the next
energy is lost to:
- respiration
- not eaten
- not digested
- excreted as watse
definition of trophic level
feeding levels in a food chain
definition of carbon cycle
describes the movement of carbon molecules in the enviroment
what are the 4 stages in the carbon cycle
- Respiration
- Photosynthesis
- Decomposition
- Combustion
explain the 1st stage of the carbon cycle - Respiration
all living organism will respire aerobically and release CO2 into the atmosphere
explain the 2nd stage of the carbon cycle - Photosynthesis
fixes carbon atoms from atmospheric CO2 into organic molecules and becomes part of complex carbon compounds in plants
explain the 3rd stage of the carbon cycle - Decomposition
Dead organisms are broken down by decomposers and carbon in their bodies are returned to the atmosphere as carbon dioxide
explain the 4th stage of the carbon cycle- - Combustion
if decomposition is blocked plants and animals are available as fossil fuels after a long period of time
combustion of fossil fuels release carbon dioxide back into the atmosphere
PAPER 2
what are the 5 stages of the nitrogen cycle
- Nitrogen Fixation
- Absorption by plants
- Moving along food chains
- Death of organisms
- Dentrification
PAPER 2
explain the 1st stage of the nitrogen cycle- - Nitrogen Fixation
nitrogen in atmosphere to unreactive to be used directly has to be changed into soluble ions
nitrogen fixing bacteria in roots nodules of legumes will convert nitrogen into nitrate
lightening converts nitrogen into nitrates
Haber process will convert nitrogen into ammonia & nitrifying bacteria will turn ammonia into nitrates
PAPER 2
explain the 2nd stage of the nitrogen cycle- Absorption by plants
plants will absorb nitrates through roots by active transport
nitrate ions help produce amino acids = protein= part of plants biomass
PAPER 2
explain the 3rd stage of the nitrogen cycle- - Moving along food chains
animals will eat plants and nitrogen from plants protein will become protein in animal
nitrogen is also passed from one animal to another by feeding
PAPER 2
explain the 4th stage of the nitrogen cycle- - Death of organism
decomposers ( bacteria and fungi ) will break down urea, egested material and dead bodies & nitrogen compounds will be returned to the soil as ammonium ions
nitrifying bacteria will convert ammonia ions into nitrates for plants to absorb
PAPER 2
explain the 5th stage of the nitrogen cycle- - Dentrification
denitrifying bacteria in the soil will break down nitrates and return nitrogen gas into the air
occurs in waterlogged soil so can be prevented by reducing drainage
definition of eutrophication
when fertilisers are washed off from land into rivers and lakes by rain
what are the biological consequences of eutrophication
- excessive nutrients from fertilisers washed into rivers and lakes by rain
- excessive nutrients = rapid plant growth eg. Algae Bloom ( on surface )
- algae bloom blocks sunlight = plants die = less photosynthesis = oxygen levels decrease
- Decomposers ( bacteria ) will further deplete oxygen as will respire aerobically to break down dead plants
- death of ecosystem will occur as oxygen levels reach a point where no life is possible = aquatic organisms die eg. fish
what are the 2 biological consequences of pollution of water by sewage
- Reproduction of microorganisms
2. Depletion of oxygen
explain reproduction of microorganisms
sewage = rich in minerals + nutrients = provides large amounts of energy to allow organism such as decomposers to reproduce = increase population
sewage = rich in nutrients ( phosphates) = growth of algae= algae bloom form on surface.
explain depletion of oxygen
decomposers will respire aerobically to break down sewage and dead plants (from lack of sunshine) so will cause depletion of oxygen = death of aquatic organisms
sewage will increase population of organisms in the water so will cause more aerobic respiration to take place
explain the pollution of air by sulphur dioxide
2 steps
fossil fuels burn to produce sulphur dioxide
sulphur dioxide will dissolve in water droplet in clouds = dilute sulphuric acid
what are the consequences of pollution of air by sulphur dioxide ( 4 things )
leaches minerals + nutrients out of soil= plants trees die
damages waxy layer of leaves= difficult for plants to absorb mineral ions ( need for growth )
makes river + lakes too acidic = aquatic organisms die
corrodes metals ( steel ) + limestone in buildings
explain the pollution of air by carbon monoxide ( 2 steps )
poisonous gas that produced when fossil fuels burn in limited amount of ( incomplete combustion )
binds to haemoglobin + reduces the capacity of oxygen carried in red blood cells
what are the consequences of pollution of air by carbon monoxide ( 3 things )
reduces capacity of oxygen carried in blood = tiredness unconsciousness + even death
less oxygen fro aerobic respiration= emphysema
if pregnant - insufficient oxygen = less aerobic respiration to release energy fro growth of foetus.
Give 5 examples of green house gases
- Water vapour = rivers, lakes + oceans
- CO2= deforestation + burning fuels
- Nitrous oxides = Fertilisers + vehicle engines
- Methane = rice paddy fields + cattle
- CFCs Refrigerators
definition of greenhouse gases
gases that absorb infrared radiation from the sun and remains trapped in the earths atmosphere = earths temp. to rise as a result
explain green house effect ( 4 steps )
- sun emits rays that enter earths atmosphere
- heat is emitted back from the earths surface
- some heat is reflected back out into space
- BUT some heat is absorbed by greenhouse gasses + trapped within the earths atmosphere = earths av. temp. to rise
what are the consequences of the green house effect ( 5 things )
earths increase in temp. = climate change
high temp. = glaciers melt= sea levels rise
loss of habitat - due to climate
inhabitable environment = extinction of species
migration of species= move to more habitable areas
PAPER 2
what are the effects of deforestation ( 4 things )
- Leaching
- Soil erosion
- Disturbance of water cycle
- unbalance in atmospheric oxygen + CO2
PAPER 2
explain leaching ( effect of deforestation )
without trees nutrients + minerals will remain unused in the soil = washed away into rivers + lakes by rain
PAPER 2
explain soil erosion ( effect of deforestation )
without trees soil will be loose + unstable = easily washed away by rain
PAPER 2
explain disturbance of water cycle ( effect of deforestation )
without trees less transpiration will occur = less water vapour released into atmosphere = less clouds form = lack of precipitation= droughts
PAPER 2
explain unbalance in atmospheric oxygen + CO2 ( effect of deforestation )
removal of trees = less photosynthesis = decrease oxygen + increase CO2
deforestation = burning of trees = CO2=increase CO2 levels in atmosphere
definition abiotic
non living factor that changes environment which plants and animals live in
definition of biotic
living factor that changes environment which plants and animals live in
examples of abiotic factors
environmental condition = temp. , light intensity , moisture level
toxic chemical = bioaccumulation =each stage of food chain concentration of pesticide increases
examples of biotic factors
availability of food
number of predators
competition = organism compete with
other species for same resources
