IGCSE Human Influences
intraspecific competition
Size control Fish separated by size to prevent INTRASPECIFIC PREDATION where larger fish eat smaller fish. Removes predator prey relationships.
DEF of EUTHROPHICATION
Sudden increase in the nutrient content of a waterway 1. By sewage (treated or untreated) 2. Artificial fertilises (phosphate and nitrate)= nitrates are v soluble and leach out to waterways
Lead
Toxic and non-biodegradable The industrial Pb exposures are mainly due to the particulates generated by coal burning and roasting of minerals i.e., iron pyrite, Leaded petrol in cars Brain damage to young
Natural greenhouse gases are
Water vapour (H2O), methane CH4 nitrous dioxide N2O, some are human produced like CFCs
Case Study on effects of deforestation - Tropical Rainforest: how to tackle
Ways to tackle deforestation 1. Wild life parks 2. Seed banks e.g., Kew gardens 3. Legal protection 4. Education 5. Sustainable timber production = replanting what is lost so there is no ecological damage to environment
HUMAN ACTIVITIES THAT CONTRIBUTE TO GREENHOUSE GASES
1. Deforestation of tropical rainforests 2. Human population growth 3. Farming practices e.g., use of inorganic fertilisers, slash and burn method
steps of EUTHROPHICATION
1. Increase of mineral ions e.g., farmer add nitrate fertiliser to increase crop yield and it rains so that nitrates leaches into e.g., lake 2. ALGAL BLOOM = occurs with rapid growth and blocks photosynthesis by other plants 3. Death of algal bloom = short life cycle leaves dead material behind 4. Decomposing by aerobic bacteria using up more O2 in respiration 5. Falls in oxygen levels (ANOXIC = little oxygen) 6. Aerobic organisms can no longer survive due to 5 = dead lake (death of fish and aerobic plants etc)
Two main pollutants of freshwater
1. Sewage 2. Fertilisers - Eutrophication
Treated sewage
1. removal of organic matter and pathogenic microorganism so cleaner waste is discharged into waterways. 2. Monitored e.g., indicator species presence e.g., bloodworms
ACID RAIN Sulphuric acid Nitric acid
Acid rain can be carried hundreds of KM before falling as acid rain. Leads to acidification of soil by leaching into soil and lakes= death of wildlife NOTES: prevention of acid rain by reducing SO2 and NO2 1. Catalytic converters in cars to reduce pollutants in vehicles 2. Furnaces with wet scrubbers to remove SO2 3. Clean coal and oil before using so less sulphur is present ACID rain is made when fossil fuels are burned making SO2 and NO2 + combine with water droplets in air. Natural rain water is pH5.5 due to slight CO2 dissolved in water but in acid rain sulphur dioxide and nitrogen oxides dissolve in water droplets to make acids (sulfuric acid and nitric acid) Two types of · Natural acid rain · Human made acid rain Natural Volcanic eruptions, water vapour from clouds and rain Human made Burning fossil fuels EFFECTS: · Building damage erosion of stonework and metals · Leaching of minerals from soil (also poisons make wash into water systems like mercury) · Damages plants die to acidity
Growth of human population due to no natural predators in wild advantages and disadvantages
Advantages: Refinement of agricultural methods to produce better varieties of seeds and methods Development of medicine Technology Increase in living standards Negatives: Disease= rise of monoculture which means more likely to be disease resistant e.g., bananas Depletion of limited resources Pollution from growing population
Biochemical oxygen demand (BOD)
BOD is a measure of the amount of oxygen required to remove waste organic matter from water in the process of decomposition by aerobic bacteria (those bacteria that live only in an environment containing oxygen).
Case Study on effects of deforestation - Tropical Rainforest BIODIVERSITY
Biodiversity and what it provides · Habitat for many plants/animals (50-70% of worlds species) =possible extinction for some species · Canopy layer - to prevent leaching · Homeland for communities · Trees anchor the fertile soil ( not washed away) · Dead material for decomposer= fertile soil · Provides Oxygen to air via photosynthesis · CO2 absorbed by photosynthesis to reduce greenhouse effect · Natural medicines
CFCs CHLOROFLUOROCARBONS
CHLOROFLUOROCARBONS make holes in ozone layer. Layer protects us from harmful UV rains from Sun. Man made impact on ozone layer; some areas are thinning. Ozone layer protects living organisms from harmful UV from sun. once commonly used as solvent in aerosols and fridges as a coolant. More UV light passing through ozone holes= increases risk of developing skin cancers
DEF of deforestation
Deforestation DEF: large scale/permanent removal of forests for timber, farming and housing "Slash and burn" Clearing method for trees. Increases CO2 massive release into atmosphere.
negatives of aquaculture
Disease Overcrowding = quicker spread of disease 1. Antibiotic resistance via food pellets 2. Increase of fish lice in wild salmon 3. Use DICHLORVOS to treat fish lice which kills off lobsters = disruption in food chain Ways to combat fish lice naturally: Fish lice on salmon is a problem so use natural predators like wassle to eat lice off salmon · Pollution from Eutrophication =from fish pellet feed (contains hormones and antibiotics) and faeces · Uneaten pellets and faeces fall to bottom = decomposers use up more O2 leading to drops in O2 and death of some organisms 1. Eutrophication =from fish pellet feed (contains hormones and antibiotics) and faeces 2. Chemical pollution e.g., use of dichlorvos to treat fish lice affects food chain when fish farm water is discharged into the sea . Build up of toxicity along the food chain.
Case Study on effects of deforestation - Tropical Rainforest EFFECTS
Effects of Deforestation Destruction of habitat and biodiversity 1. Extinction of species 2. Medicine lost Soil erosion Fertile top soil washed away as no longer anchored by roots Leaching of minerals in soil Loss of canopy leads to increased leaching of valuable nutrients in fertile soil = rising water levels and lowland floods Infertile soil Due to leaching, no more material to change into nitrates Slash and burn Increased in CO2 into atmosphere = increases greenhouse effect= climate change Less transpiration Less rainfall = drought = changes in wate cycle Less trees Less photosynthesis but more CO2 = increase greenhouse effect (80% of greenhouse cases is CO2)
Carbon Monoxide
From burning of carbon e.g., fossil fuels Dangerous as colourless, odourless, and tasteless and can be fatal Formed When carbon is burned in limited O2 supply It can be fatal to living organisms as it inhibits take up of oxygen. Haemoglobin binds to CO more than O2. Can be fatal due to lack of O2 starves major organs like brain. e.g., petrol fuelled cars
Fish farming other benefits
Genetically bred to be passive and larger 1. Some farms raise fish kept in tanks by size, densely populated for fish to fatten up so they use up less energy swimming 2. Fish yields are higher to meet increased demand of lean protein at a lower cost than wild fish
Normal Greenhouse Effect
Greenhouse gases' are crucial to keeping our planet at a suitable temperature for life. Without the natural greenhouse effect, the heat emitted by the Earth would simply pass outwards from the Earth's surface into space and the Earth would have an average temperature of about -20°C
Case Study on effects of deforestation - Tropical Rainforest WHERE
Hot and wet areas around parts of the equator. EG South America/Indonesia
DISTURBANCE OF TRANSEVAPORATION
How does evapotranspiration affect climate? As the world warms, evapotranspiration will accelerate, speeding up the drying of land and vegetation. Weather patterns can also be affected: Increased evaporation from land can create droughts in some regions
Problems with increasing greenhouse effect:
Human activities are polluting the atmosphere with extra greenhouse gases e.g., CO2. Contributes to rise in earths temperature = GLOBAL WARMING. A rise in temp of a few degrees may/will 1. Melt polar ice caps = rise in sea levels and flooding = loss of habitat 2. Change ocean currents= warm water flowing into previously cooler areas 3. Changes in global rain patterns + increase in temp = more evaporation = rainfall may increase or decrease in some areas. Long term climate change. 4. Change ecosystems = e.g., species may not be able to adapt fast enough to changes in habitat = extinct/endangered Farming practices - deal with increased number of pests due to higher temperatures. Higher temps may lead to insects completing life cycles faster.
Untreated sewage effects
If untreated and discharged into waterways there are 2 problems 1. Aerobic bacteria use up O2 in water as it breaks down organic matter. Leaves less oxygen for freshwater fish and insects 2. Pathogenic bacteria = affects humans
effects of CO2
Increase in CO2= raises greenhouse effect
Aquaculture modifying conditions
Modify conditions 1. Amount of water and cleanliness 2. pH levels 3. Food - food pellets 4. Light - mimic summer to speed up growth 5. Efficient waste removal from the fish No INTERSPECIFIC predation: interaction in which an individual of one animal species kills an individual of another species for dietary use as kept in pens or cages. Food pellets made from wild stocks of fish (25% f caught fish) used to make pellets
effects of Methane CH4
Natural gas made when microorganisms ferment larger organic molecules to release energy. Although there is less methane in atmosphere the methane molecules are larger than CO2 and impacts on greenhouse effect. EG Decomp of buried waste at landfill EG Fermentation by microorganisms in cattle stomachs (rumen) EG Fermentation by bacteria in rice fields
greenhouse effect
Natural situation in which heat is retained in Earth's atmosphere by carbon dioxide, methane, water vapor, and other gases
Use of fertilisers
Nitrates= needed by plants to make proteins. There is a circulation of nitrogen e.g., in a farm · Outputs of nitrogen = sale of crop · Circulation = fodder ( animal feed) , farm manure, legumes (e.g., clover grown to create nitrogen nodules). · extra inputs like growing legumes (clover fields) and fertilisers.
FISH FARMING (AQUACULTURE) (indoor and outdoor) good and bad!
PROS Meeting demand and low cost · Sustainable Good protein to meet demand for fish. Grow faster · Less pressure on wild fish stocks so they can recover · Can farm indoors or outdoors ·BUT Pollution issues e.g., outdoor farmed salmon in cages in inlets · Fishing quotas to combat over fishing - affect income of fishermen Ethics of farmed fish vs wild Monitor conditions E.g., air pumped in/food intake/light
BIOLOGICAL CONSEQUENCES OF POLLUTION BY SULPHUR DIOXIDE AND CO2 summary examples
Summary of effects: examples are · Thinning of ozone layer · Increase in green house gases = global warming with trapped heat. · Acid Rain = burning of fossil fuels + H2O · Deforestation = Increase of C2O, soil erosion · Eutrophication= untreated sewage/fertilisers leaching into water system · Increase in the concentration of toxicity and pollution down the food chain eg mercury/tuna
Smog
fog or haze combined with smoke and other atmospheric pollutants. Traps pollutants = dangerous to health and lungs "pea-soupers"
soil leaching
loss of soil nutrients due to rain and irrigation (coarse-textures soils more vulnerable)
Def of sewage
sewage is wet waste from houses and commercial activities e.g., farming
Indicator species are
· Indicator species= monitoring of air pollution by study of indicator species e.g., lichen to look at Sulphur dioxide pollution. ·eg Abundant Lichen = low SO2 levels therefore cleaner air
