Flashcards
Human Impact on the Environment
Cards in this deck (62)
- 1What are the main human impacts on the environment?1. Deforestation
2. Desertification
3. Global warming
4. Non-native species
5. Overharvesting - 2Reasons for species becoming endangered• Natural selection
• Habitat destruction such as deforestation and loss of hedgerows
• Pollution such as PCBs and oil
• Hunting and collecting
• Competition from domestic animals - 3What is extinction?The process in which groups of organisms die out
- 4What is mass extinction?periodic rises in the extinction rate above the background level. Events which are not caused by changes in habitat or competition but catastrophes e.g., the asteroid, ice age etc
- 5What three factors follow mass extinction?1. Geologically rapid
2. Had a large number of species going extinct in the same time period
3. Spread across the worlds ecosystems - 6Factors that increase the chances of a species becoming extinctloss of habitat, fragmentation, lack of food, small population size, overhunting, introducing species, environmental pollution, global warming leading to rapid changes in biomes
- 7Reasons for trying to prevent extinction:Ethical – species have as much right to exist as we do
Aesthetic – we get pleasure from nature
Genetic resource – for food, medicine
Commercial – value of species if sustainably managed provide long term resources
Ecosystem stability – the more complex the ecosystem the more stable it tends to be - 8What is pollution?Poisons all forms of life and contributes to climate change. These chemicals can directly affect biodiversity or lead to chemical imbalances in the environment that kill individuals, species and habitats
- 9What are PCBsmanmade chemicals that are resistant to extreme temperature and pressure. Widely in electrical equipment like capacitors and transformers
- 10How do PCBs spread?PCBs have been released into the environment through spills, leaks and from electrical equipment. Once in the environment, they can be transported long distances and bind strongly to soil and sediment.
- 11Why are animals hunted?food, medicinal purposes, for sport, trophies, decoration, clothing, symbol of wealth, accessories
- 12What are non-indigenous species?Invasive species are harmful to our natural resources (fish, wildlife, plants and overall ecosystem health) because they disrupt natural communities and ecological processes. The invasive species can outcompete the native species for food and habitats and sometimes even cause their extinction
- 13What is climate change?Brought about by emissions of greenhouse gases when fossil fuels are burnt
Can lead to change in the abundance and distribution of individual species around the globe and will affect the crops we grow, rise in sea levels and problems to many coastal ecosystems - 14What is ocean acidification?carbon dioxide accumulates in the atmosphere and reacts with sea water to form carbonic acid. Results in slower growth rates in marine life and extinction, and harms key species in marine food webs, affecting fish, birds and mammals.
- 15Reasons for deforestationRemoval of hardwood for high-quality furnishings, Removal of softwood for chipboards, paper and other wood products, Clearance for cattle ranching and for cash crop agriculture, Clearance for urban development (roads and towns being built), Reduction in soil fertility, Flooding and landslips
- 16Harmful effects of overfishing• Creates a food shortage for humans
• Destroys the food source that many animals need for survival
• Results in unwanted marine life (bycatch) to be caught in fishing nets
• Not enough fish catch for fisheries so many people lose their jobs - 17Solutions for overfishinglimit on number of fish caught and processed
Use techniques that prevent harm to bycatch
Increase mesh size to allow smaller fish to escape, grow larger and breed
Protect fish habitats for spawning, breeding, nursing or feeding - 18What is desertification caused by?Natural or physical factors
Over cultivation, greater demand on the land for production of staple crops
Poor irrigation- loss of productive land due to water logging and salinisation
Deforestation, removal of woodland for fuel
Overgrazing results from increased herd size and decreased pasture area - 19What is conservation?the sensible management of the biosphere and enhancement of biodiversity locally
- 20Concepts of conservationpreservation and protection of features of the environment thought to be of amenity value, maintenance of environmental quality against pollution, planned use of resources to ensure their continuing supply, maintenance of ecological and species diversity
- 21What are hedgerows?rows of closely planted bushes, forming a long hedge
- 22What are hedgerows used for?• Used as shelter for insects, small mammals, and birds
• Provide corridors for farmland birds to disperse around farms
• Provide food for invertebrates, mammals, and birds
• Provide habitat for range of animals - 23meaning of conservationmaintenance of the biosphere and enhancement of biodiversity locally
- 24main methods of conservationhabitat protection by nature reserves and SSSI
international cooperation restricting trade
breeding programmes by zoos and botanic gardens, sperm banks and seed stores
Reintroduction programmes (e.g., red kite)
Pollution control - 25importance of conserving gene poolsSpecies conservation of existing gene pools, which may be potentially useful for future generations.. Breeding increases genetic uniformity with loss of rarer alleles. Breeders neglect some qualities e.g., resistance to cold and disease. These need to be added back into highly cultivated varieties using species as gene banks.
- 26Seed banksSeed banks are a type of gene bank that store seeds of different species of plant. Dried seeds stored in very cold conditions to ensure that they can be used in the future
- 27agricultural exploitationHumans are dependent on Earths resources for survival
Increase in population – more food needed
Conflict between demand for production and need for conservation
Use of pesticides and fertilisers increase crop yields but create environmental problems - 28Why does deforestation happen?Use of land for agriculture by subsistence farmers (small farms; grow enough to eat and some to sell) and for cash crops (bananas, palm oil, tobacco, coffee)
Clearing land for roads
Large scale timber extraction for building, fuel, paper, and packaging - 29loss of habitatsReduction in biodiversity and loss of valuable sources of plant chemicals that might have potential benefits for humans
- 30soil erosionRemoval vegetation on higher slopes- heavy rain sweeps exposed soil to flood plains below. Increased sediment deposits
- 31climate changeCO2 levels rising. Removal of vegetation reduces rainfall and accelerates desertification
- 32lowland floodingPlants and leaf litter would normally absorb water and release it into the soil, instead evaporation occurs which is slower, so soil conditions become wetter
- 33forest managementManagement can be based on conservation, economics or a mix of the two
Techniques include timber extraction, planting and replanting of various species, cutting roads and pathways through forests, and preventing fire - 34Management techniques for sustainability:coppicing, selective cutting, long rotation time, planting trees, controlling pests and diseases, protected areas, ecotourism
- 35harmful effects of overfishing• Creates a food shortage for humans
• Destroys the food source that many animals need for survival
• Results in unwanted marine life (bycatch) to be caught in fishing nets
• Not enough fish catch for fisheries so many people lose their jobs - 36solutions to overfishingquotas, increase mesh size, close at-rish fishing areas, enforce fishing laws and apply penalties
- 37nitrogen fertilisersHarvesting of crops removes mineral elements
Nutrients lost can be replaced by adding natural organic waste materials- compost or artificial inorganic fertilisers
Contributed to increased productivity and enabled poorer areas of land to be used for agriculture - 38environmental monitoringEnvironmental monitoring is needed for conservation. Science and technology should enable the effects pf human activities to be predicted and taken into account and made part of the overall planning
- 39examples of environmental monitoringforest mapping, species identification, biomass estimation, fire detection, planting, storm damage assessment, beach replenishment planning, deforestation/erosion/farming monitoring
- 40management techniquesMuch work done by conservation volunteers
Standard trees felled for wood, regenerated from seedling
Pruning of shrubs and mowing of rides to prevent succession
Coppicing on rotation to provide different habitat for organisms - 41meaning of planetary boundariesprovides a framework for organisations to ensure there is a safe operating space for humanity
- 42biodiversity boundarytogether species interactions produce ecosystem services that the biosphere depends on. Human impact has caused environmental changes that are too fast for natural selection help organisms from extinction. As habitats change, so do the ecosystems that developed there, which can cause species extinctions
- 43easing the biodiversity boundaryTo help prevent the loss of species through extinction, scientists store the genes of many different organisms in gene banks
Zoos can be used to breed rare organisms and are often involved in reintroducing organisms into the wild
There are many biodiversity-related conventions - CBD - 44climate change boundaryMeasured by atmospheric CO2 concentrations and radiative ability of the atmosphere
Main sources – fossil fuel use, deforestation, methane (electricity, transportation, industry) - 45causes of the greenhouse effectincreased human population, combustion of fossil fuels, deforestation, intensive farming, aerosols, organic waste decay, car exhaust emission, cows for food, rice fields
- 46effects of the greenhouse effectsea levels rise, change in weather patterns, species migration, less water in tropical areas, reduction in grain crops, polar ice caps melt, effect on world food production
- 47biofuelsany type of fuel that is biological in origin (wood, straw, biogas from animal waste, ethanol, diesel)
- 48bioethanolfuel made through fermentation of sugars by yeast
- 49biodieselan oil substitute manufactured from oil seed rape
- 50biogasmainly methane, used on small scale to power generators
- 51disadvantages of biofuel• Habitat destruction
• Rainforest destruction
• Conflict over land use - 52nitrogen/phosphorus boundaryThe cycling of mineral through biotic and abiotic components of an ecosystem
Use of fertilisers has increased considerably- eutrophication - 53eutrophicationAlgal bloom, high O2 uptake at night
Outgrow nutrient supply death
Decomposed by aerobic bacteria, takes up oxygen, sudden death of fish (fish kill)
Decreases biodiversity
Algal bloom also stops light penetration so less photosynthesis of water plants which die - 54what has caused the fresh water boundary to go overchanging landscape, agriculture, increased demand for drinking water, water pollution, climate change
- 55potable waterNot all fresh water is drinkable
It may be contaminated with industrial pollution, dusts, salts, acids
Fresh water is not equally distributed around the world
Global supply has diminished - 56increase in potable waterWater conservation
Water efficiency- washing machines
Waste water reclamation- for irrigation or industrial use
Urban runoff and storm water capture
Drip irrigation systems for crops
Desalination - 57chemical pollution boundaryOrganic pollutants, radioactive materials, nanomaterials and microplastics
Some are so toxic they have been banned (DDT)
Some are difficult to quantify so their boundaries have not been identified - 58what are the effects of chemical pollutionAir pollution (sulphur dioxide and nitrous oxides)
Aerosol pollution results in weather effects (early monsoons)
Ozone destruction from CFCs
Other chemical pollutants (electrical, radioactivity, organic pollutants) - 59aerosol boundaryMicroscopic particles (soot and inorganic salts, nitrates and sulphates) concentrations have doubled since industrial revolution
- 60effects of the aerosol boundaryAerosols exacerbate respiratory problems- increased death from lung disease
Deposits on leaves reduce light absorption for photosynthesis- crop yield reduced
Sulphates reflect sunlight- cooling effect
Soot absorbs sunlight and reradiates- warming effect - 61biological effects of the ocean acidification boundary• Reduces availability of carbonates for marine organisms’ shells and skeletons causing slower growth rates and weaker shells, overall fewer crustaceans and shellfish which affects entire ecosystem
• Damages coral reefs
• Damages gill structure of fish - 62the ozone boundaryOzone depleting pollutants include CFCs (refrigerators) and oxides of nitrogen (lightning)
Less ozone means more harmful UV rays reach earth causing sunburn and genetic mutations in plants and animals
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- A level Biology (ENERGY FOR LIFE) Flashcards on Human Impact on the Environment, created by Aafreen Butt on 21/04/2021.
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