B6.1 - Global Challenges Flashcards
What is deforestation?
The practice of cutting down trees
Causes of deforestation?
- Industrial use
- Agriculture
- Lifestyle (eg making space for homes)
Environmental impacts of deforesation?
- Less trees absorbing CO2 from environment
- Trees release carbon stores as C02 when cut down
- Many habitats destroyed
What are Peats?
Peats are partially decomposed plants and moss
Where are peats formed?
They are formed in waterlogged bogs and acidic fens over thousands of years.
How are Peats formed?
It is formed as the moss and plants don’t completely decompose in the waters with lack of oxygen (anaerobic waters) fully.
How are peats useful?
1) As fuel: Peats can be decomposed as fuel due to stored CO2.
2) For Agriculture: Mixing peat with soil increases water retention, mineral retention and soil structure
Issues with using peats?
1) Releases CO2 (Global warming)
2) Habitats destroyed - bogs are drained in order obtain peat.
What is waste?
Something unwanted that we need to rid of.
What is bioaccumulation?
The build up of toxic chemicals at the top of the food chain. The higher up the food chain, the higher concentration of toxic chemicals.
How is acid rain formed?
When gases from combustion of fossil fuels react with water producing acid.
3 gases that cause acid rain:
- Sulphur dioxide
- Nitrogen oxide
- Carbon dioxide
3 equations for acid rain:
Sulphur dioxide + water -> Sulphuric acid
Nitrogen oxide + water -> Nitric acid
Carbon dioxide +water -> Carbonic acid
How are the 3 gases in acid rain formed?
Sulphur dioxide = Burning oil and coal
Nitrogen oxide = Burning petrol in cars
Carbon dioxide = Burning fossil fuels and deforestation
Effects of acid rain?
- Causes mineral deficiency in soil
- washed aluminium ions into water affecting fish gills
- damages roots and leaves of plants
- acidifies water so aquatic organisms can’t survive
What is Eutrophication?
A process which occurs when fertilisers are washed into waters.
Steps to Eutrophication:
1) Farmers add an addition of nitrates (fertilisers) into soil in order to increase the growth of crops.
2) The fertilisers are washed into bodies of waters and cause an increased growth of aquatic plants (like pondweeds).
3) These aquatic plants grow at the surface of waters preventing sunlight to pass through to plants submerged in water. These plants die due to lack of Photosynthesis.
4) Microorganisms decompose the dead plant material and respire while doing so.
5) The microorganisms respiring cause oxygen deficiency in waters.
6) Aquatic animals die as they suffocate due to lack of oxygen.
How does a fuel burning power station work?
COAL -> FURNACE -> THERMAL ENERGY -> HEATS WATER TO BOILING WHERE IS TURNS TO A GAS (KINETIC ENERGY) -> TURNS GENERATOR -> ELECTRICAL ENERGY.
What is Carbon dioxide in the combustion of fossil fuel?
It is a by product
FUEL + OXYGEN -> WATER + CARBON DIOXIDE
What is the enhanced greenhouse effect?
1) The sun emits rays to Earth and some reflect
2) Sun rays try to travel back out to space once deflected off Earth
3) The greenhouse gases absorb suns rays and emit them back to Earth
4) This trapment of rays increases Earths temperature
What is an indicator species?
A species which can be used to measure environmental change.
What are Lichens?
They are an indicator species measuring air quality:
They are sensitive to sulphur dioxide
High pollution : low lichen population
Low pollution: High pollution population
Indicator species for water quality:
- Alderfly larva : Can’t survive in polluted waters (indicated low polluted waters)
- Mayfly larva: Survive in semi polluted waters (indicated semi polluted waters)
- Sludgeworm: Can survive in polluted waters (indicated very polluted waters)
What is conservation?
Includes the protection of species from extinction, maintaining and restoring habitats, preventing deforestation, enhancing ecosystems and protecting biodiversity
Why do we conserve?
- To protect a species
- Moral responsibility
- More plant species for medicines
- To protect future food supply
- To protect food chains and food webs
What is food security?
When all people have access to sustainable, safe and nutritious food to meets their needs for an active,affordable and healthy life.
What are the 4 components of food security?
Availability - The quantity of food and its distribution
Access - covers economic and physical access to food (can people recieve the food)
Utilisation - About how to food is used by body, do people have the knowledge and healthy enough to utilise food nutritiously.
Stability - Is food stable and predictable (For example if there was a natural disaster will it cause a fatal food crisis).
What has been the changes in farming in modern era?
- Pollution levels have increased
- Increased use in chemicals (like pesticides and fertilizers)
- Machinery (technological advancements)
- More farming land use (human population growth)
- Distributions change: food can be traded due to transport
What damaging processes can pesticides and fertilizers cause?
Pesticides - bioaccumulation
Fertilizers - Eutrophication
What factors affect food security?
- Cost -> LIC countries
- Natural disasters
- Rates of production and distributions (is it an equal distribution)
- global warming (changing weather patterns)
- Human conflicts
- Increasing populations
- increasing diets in developing countries
What is the negative effect of increased demand for meat?
1) Space is needed for cows to be reared so deforestation takes place for cow space
2) Methane is produced by cows which is a greenhouse gas
3) When meat is exported, pollution is produced through transportation.
What is the negative effect of pest and pathogens in farming?
1) The more pest and pathogens, the more pesticides used, lead to bioaccumulation
2) Pest and pathogens consume crops, less availability for humans
What is the negative effect of rising global temperature?
-Affects global weather patterns, also accelerates desertification, less rainfall for crops
What are the two types of farming?
Organic and Intensive
What is Organic farming?
- Relies on natural recycling of organic matter
- animals manure and compost are used for fertilisers
- Farmers can rotate crops in a yearly cycle
What is Intensive farming?
- relies on artificial fertilizers
- Artificial fertilizers have higher nutrients concentration than manure
- Has single intention to make as many crops as fast as possible
What is organic farming and pest control like?
- uses natural biological process
- Introduces natural predators
- Use of resistant plants
- Natural pesticides are used responsibly
What is Intensive farming and pest control like?
- Relies on made chemicals sprayed on crops which is very effective and kills all pest and diseases
- Helps for bigger yields but chemical residue is left behind
Intensive Farming case study 1: Hydroponics
1) Instead of growing in soils, plant roots are grown in ‘rock wool’ and nutrient rich waters
2) Plants are in closed and controlled system so no minerals are wasted, less risk of pollution and disease
Intensive Farming case study 2: Battery Farming
+ Disadvantage
1) Animals are fed protein rich foods and held in close confinements in temperature controlled environments
2) Less energy is used for maintaining body temperature and movements through respiration and instead stored as biomass
DISADVANTAGE
1) Increased effectivity but many ethical concerns.
Intensive Farming case study 3: Fish Farms
+DISADVANTAGES
1) Fish grown in controlled area separate form open waters
2) Fish fed high protein foods so they grow quickly
DISADVANTAGES
1) The closeness of fish make them prone to diseases
What is phenotype and genotype?
Phenotype: Gene that is presented (the physical characteristic presented)
Genotype: the entire genetic information of the organism
Steps of selective breeding in animals?
1) The desired characteristics identified
2) The individual with the characteristics are bred together
3) The offspring will contain and express the desired characteristic
4) This is repeated over generations until desired trait is fully developed
What are the problems with selective breeding?
- many animals suffer from deformities
- Increased risk of genetic diseases caused by recessive genes
- Supermarkets will only sell produce which looks attractive _> food wastage
What is genetic engineering?
Taking a gene from one organism and inserting it into the genome of another organism
Benefits of genetic engineering?
1) Faster than selective breeding
2) Allows breeding between 2 different organisms of different species
Steps of genetic engineering (General)?
1) Select desired characteristic
2) Isolation of gene
3) Insert gene into another organism’s genome
4) Reproduce organism
Steps of genetic engineering using bacteria?
1) DNA containing desired gene is removed from cell
2) Restriction enzymes cut out desired gene from DNA
3) Plasmid is taken from the bacteria (vector) and cut using same restriction enzyme
4) DNA ligase Enzyme inserts desired gene into the plasmid (It seals sugar phosphate backbone of DNA back together)
5) Plasmid is inserted back into bacteria
6) The bacteria reproduces creating a large number of bacteria with new characteristic
What are sticky ends?
-They are short sections of single stranded DNA
1) The are created when same restriction enzyme cut complementary sticky ends.
2) The restriction enzymes cut diagonal to create sticky ends
3) They help insert gene into plasmid as bases match up
How can we use genetic modification for food security?
1) Introduce herbicide resistance genes into crops . When whole field sprayed with weed killer the crops aren’t harmed, allows more space for growth and less competition
2) Introduce genes that act as insecticides
What is sampling?
estimating the amount of organism in an ecosystem by looking at a smaller area
Why is it hard to sample?
- Some things are very small - such as bacteria
- Many organism avoid humans - hard to detect
- Many organisms look very similar and difficult to determine what species they are
Sampling methods for stationary or slow moving organisms - like plants?
Quadrats : A 1m by 1m square used to estimate organisms present in an ecosystem with the same abiotic factors throughout
Line transects : a line (rope or tape) laid through an ecosystem to sample organisms and observe change in organisms due to change in abiotic factors
Belt transects: a line (rope or tape) laid through an ecosystem with quadrats place along it to sample organisms and observe change in organisms due to change in abiotic factors
Sampling methods for mobile organisms - like animals?
Capture methods:
1) Pit fall trap: There is a pit concealed to be undetected by insects. The insect fall into it when stepped on
2) Pooter: Person sucks on straw which
will suck up any insects to be collected
3) Net: used for aquatic and flying organism to collect
Why is the pooter method not a random sampling method?
Pooter: will disproportionately capture more visible and slower insects and will not give reliable data
What is the capture-recapture method?
- It estimates population size of animals
1) Capture the animals - using capture method (pitfall trap, pooter or nets) and mark the animals in a harmless way to their survival before releasing them again
2) After a few days capture the animals again
3) Use formula:
(Number of animals in 1st capture X Number of animals in 2nd capture) / Number of Marked animals in 2nd capture
Why might marking the organisms in capture-recapture method limit the experiment?
- May make animals more visible and less camouflage to predators
- May come undone or washed off and results unreliable
- Toxic chemicals may be dangerous
