Year 11 Term 1 Flashcards
What happens to living organisms in the environment
They remove materials for growth and other processes these materials are passed along a food chain as one organism feeds on another all materials removed from environment are eventually returned and recycled providing building blocks for future organisms
Carbon cycle info
Plants and algae remove CO2 from air for photosynthesis carbon is incorporated into compounds (carbohydrates, fats, proteins) that make up plants and algae some CO2 returned to air when plants respire when plants eaten, these carbon compounds are then in their body and so on when animals respire CO2 released
Decomposition
Microorganisms and detritus feeders break down dead organisms in ecosystems, recycling materials which is vital in an ecosystem
Water cycle
Changes to water when it evaporates into the air. condenses into clouds and then precipitates down to earth
Evaporation
When water changes from a liquid to a gas when heated
Transpiration
Passage of water vapour from plant to atmosphere
Condensation
Cooling of water changing from gas to liquid
Precipitation
Water droplets fall from atmosphere in form of rain, snow, sleet or hail
Percolation
Water trickles through gaps in soils and rocks
Run off
Rainfall that isn’t absorbed by soil and travels to the ocean
Why is the water cycle so important
responsible for distributing water across the earth vital for sustaining life on earth by providing water to plants, animals and humans
Why is water important
Solvent, transpiration stream, osmosis, expands on freezing, metabolic functions, lubricant, support, thermoregulation
How does decomposition work
Detrius feeders/detritivores start process of deacy by breaking plant tissue into smaller pieces, increasing SA for action of decomposers which are bacteria and fungi that make things rot by releasing enzymes onto the dead animal or plant, breaking them down into soluble ones that can be absorbed by decomposers
What factors affect the rate of decay
Temperature
Availability of water
Availibility of oxygen
Recycling kitchen or garden waste
Compost heap and put grass cuttings, weeds and vegetable peelings etc.
bacteria and fungi break down the material giving off CO2
once broken down, material used as fertiliser can take about a year to make
How do farmers/gardeners try to provide optimum conditions for rapid deacy
Warmth
Moisture
Oxygen
How does putting a plastic sheet over the compost waste, with tyres holding it down increase the rate of decay
Holes in plastic, allowing organisms to respire
Not too hot so enzymes don’t denature
cover holds in moisture but may need to water occasionally if dry
Warmth generated by respiring organisms
Aerated by pitch fork
Examples of where decay of microorganisms is useful
Compost heap
gardeners putting horse manure on roses etc.
farmers decomposing animal waste
in sewage works
What are biogas generators
Flammable mixture of gases formed when bacteria break down waste material
mainly methane but varies depending on type of bacteria and waste used
bacteria work best at 30*C exothermic reaction
variety of bacteria used
What goes into the biogas generator
Animal/human dung
farm waste
garden rubbish e.g faeces/urine of cows and sheep
What comes ot of a biogas generator
Methane for cooking, heating and refridgeration
Slurry, which can be used as fertiliser
Used in developing countries as electricity as well
Scaling up of biogas generators
Many countries experimenting using on larger scale
waste from sugar factories, sewage farms + rubbish tips can be used to make biogas
Pro’s of floating drum biogas generator
Easy construction
Easy to operate
Steady gas pressure produced
Reliable, well tried technology
Con’s of floating drum biogas generator
Metal holder expensive
Metal holder may rust
Pro’s of fixed dome biogas generator
Intitial cost low
Long useful life-no moving or rusting parts involved
well insulated
Con’s of fixed dome biogas generator
Sealing of the gas holder is not always tight
Gas pressure fluctuates
What is water pollution caused by
Fertilisers
Toxic chemicals- kill animals and plants if they drink the water , reducing biodiversity
Sewage- causes increase in bacteria in water which remove O2 from water when respiring so kill fish
What is air pollution caused by and what problems does it cause
When fossil fuels burned, acidic gases + smoke released
can cause breathing problems and lead to acid rain, damaging the environment
leads to death of animals and plants
How is smog formed
Smoke and chemicals e.g Sulfur dioxide and nitrogen add together forming smog
Forms haze of small particles and acidic gases that can be seen in air over major cities
Exponential drowth of human population is due to:
Lack of predators
Advances in medicine
Increased efficiency of food production
Modern farming methods which increase productivity
How do human reduce the amount of land for animals and plants
Building
Farming
Quarrying
Dumping waste
How is the land polluted
Landfill or toxic chemicals from houshold/indutry waste
Pesticides and herbicides used in farming may be washed from land by rain into streams etc.
these all have an effect on biodiversity
What’s the problem with pollution of the land
May kill insects e.g predators of the pest leading to pest resurgence
May kill food plants reducing wild flower biodiversity
May cause long term damage, accumulating along the food chain
pests could develop resistance through genetic mutation
What is bioaccumulation
Occurs when toxic chemicals are taken up by producers and get passed along the food chain to the primary consumers to secondary and so on.
at each stage, toxin accumulates in larger amounts as organisms consume large numbers of the organism below them in the food chain.
Normally most harmful to top carnivores and can cause their death
Why do countries with strict controls over sulfur dioxide levels still suffer from acid rain
Because of prevailling winds from other countries blow the sulfur over causing the acid rain
What are the effects of acid rain
Makes water acidic and increases the amount of water which enters lakes from the soil
Damages forests and leaves directly
leaches essential mineral ions out of the soil and releases toxic aluminium ions into soil
What is biodiversity
The variety of all different organisms on earth, or within an ecosytem
What does high biodiversity help us to ensure
Ensures stability of ecosytems as reduces dependency of of one species on another for food, shelter and the maintenance of the physical environment
How are humans affecting biodiversity
Increased human population means more waste causing polltuion of water, land etc. this can kill plants and animals, reducing biodiversity
Global warming and rising sea levels
Leads to flooding resulting in loss of habitat in low-lying places. higher temps makes ice melt so water currently ‘trapped’ on land e.g. glaciers and poles, runs into the sea rising level even more.
As sea gets warmer, it expands causing sea level rise
Global warming and changes in the distribution of organisms
Species become more widely distributed e.g species needing warmer climates spread further as warmer temps are now spread over a wider area.
species needing colder temps become less widely distributed as conditions they thrive in exist over a smaller area
Global warming and changes to migration patterns
Lots of birds migrates. studies shown birds living in Africa in winter have started to migrate back to Europe in summer earlier than before due to temp change as their food source appears earlier
Global warming and less biodiversity
Some species may be unnable to adapt to a change in climate. may not survive and species will beome extinct
Why is deforestation happening
To clear land for farming (e.g cattle or rice crops) to provide more food/ paper industry
To grow crops from which biofuels could be produced
Quarrying and dumping waste
Problems caused by deforestation
Less biodiversity as fewer habitats
More CO2 released into atmosphere from burning
less CO2 locked up in trees and amount of CO2 removed from atmosphere is reduced as trees lock up some of the carbon they absorb during photosynthesis in their wood.
What are peat bogs
Areas of acidic and water-logged land where there’s a lack of decay and not enough oxygen.
partly rotten plants build up to form brown soil like material- peat
They act as carbon sinks and are often drained and used as farmland, fuel or sold to gardeners as compost
Peat is being used quicker than its formed
What are the problems of peat bogs
Draining peat means more air so more decomposition, the microbes release CO2
CO2 also released when peat is burned
Destroying the bogs reduces natural habitats so biodiversity
Examples of maintaining biodiversity
Breeding programmes and protecting rare habitats
Field margins and hedge-rows where farmers can only grow one type of crop
Reduction of deforestation and CO2 emissions by government
recycling resources rather than dumping waste in landfill
Conflicting pressures on how biodiversoty is maintained
Costs money- e.g. hedgerows costs to put in place and need to be checked
Cost to livelihoods- e.g. reducing deforestation means people left out of work effecting economy
Conflict when protecting food security- e.g. farmers need to kill pests to protect crops
Development- e.g. houses need to be built and hugh demand for land usage
