Effects of Human Activities and Sustainablilty - finished Flashcards
How have humans contributed to superpests such as warfarin resistant rats?
Overuse of Warfarin (anti-coagulant (stops blood clotting)) as a rat poison.
First appeared in Wales in the 1950’s
due to a beneficial mutation (selective advantage - Only when warfarin is being used)
Survival - Reproduce - Pass on beneficial allele - more common in future generation.
Rats that are resistant to warfarin need raised levels of vitamin K in their diet - DISADVANTAGE IF THERE IS NO WARFARIN PRESENT
What can cause antibiotic resistance in bacteria?
Farmers who inject cattle with antibiotics when they are NOT required/ to promote growth
Irresponsible doctors
Irresponsible patients
Why is it bad to administer antibiotics if they are not needed?
Not needed antibiotics kill of normal bacteria who could have outcompeted the mutant
What is artificial selection?
When humans select for particular traits within a species
What to thing can cattle be artifically selected for?
High milk yeild
Quality of milk
Advantage and disadvantage of inbreeding
Advantage - Intensifies features
Disadvantage - Increased chance of deleterious (bad for individuals) genes
What is biodiversity?
The number of species and individuals of each species present in the environment
The variety of organisms on earth
Why is biodiversity falling?
Pollution Hunting Deforestation Agrochemicals (Bioaccumulation) Hedgerow clearences - habitats (birds nesting) Competition from livestock
What are the four ways to prevent loss of biodiversity?
C.I.T.E.S - Convention on International Trade in Endangered Species
S.S.S.I - Site of Special Scientific Interest
Whaling ban
Reintroduction of species (e.g. Red Kite)
Why do we want to maintain species diversity?
Medicine - Potential chemicals to cure acncer and other medical conditions might be lost forver if they go extinct
maintain large gene pool - Modern varieties are inbred / issues with homozygosity - ressesive alleles - lead to problems / Old varieities dont produce high yeilds / source of genes for GM
What is monoculture?
Growing one crop plant in a feild
Why is monoculture a problem for the environment?
The use of big feild means there are no hedgerows - lack of habitats for birds.
Can lead to mineral depletion and pests and diseases. To overcome these issues agrochemicals are used such as fertilizers and herbicides which can result in problems like eutrophication and bioaccumulation.
Why do people clear forests through deforestation?
Agricultural clearence - make room for growing crops
Wood
Housing/Road building
What problems does deforestation lead to?
The canopy slows rainfall and the roots stablize the soil. When the tree’s are cut down the soil gets washed away and soil erosion occurs.
What are pine woodlands used for?
Paper
Wood building
Wood furniture
How are pine woodlands managed?
Cleared all at once
Arranged in a row
What are Willows and Birch used for?
Biomass
What is Coppicing
Willow/Birch management
Tree is cut down to a stump then multiple trees grow out of the stump.
What is Ecotourism?
Tourists visiting encourages native populations to maintain their natural environment.
What is the Maximum Sustainable Yeild?
Hunt/fish out a set quantity that can be replaced by those that remain.
Why is it difficult to calculate a sustainable yeild?
Need to know: Fish population Carrying capacity Reproductive rate Surviorship of juveniles Age structure of population
How can you tell the age of a fish?
Scales
Ear bones
How do you prevent overfishing?
- Increase mesh size so that smaller fish can swim out.
- Limit how much fish you can catch - fined if over the limit
- Limit the number of days you can fish (fishing effort)
- Temporal bans (Open/closed season)
- Geographic exclusion zone in breeding territories
Disadvantages of fish farming?
- Very high density of stock which can lead to stress, wounds, and to the easy spread of disease
- Eutrophication from food, faeces and nitrogenous waste
- Holes in the nets mean fish can escape and effect the food chain/ reproduce with the natural population who are not genetically suited
Why are drainage ditches used?
WAterlogged soil means there is no air spaces which creates anaerobic conditions ideal for denitrification. This reduces soil fertiltiy.
Drainage ditches lowers the water table so the soil becomes aerobic so there is no denitrification and the soil stays fertile.
Disadvantage of drainage ditches?
Less marshland - less wildlife
What are the different types of biofuels you can uses for renewable energy?
Wood - coppiced trees are renewable
Biogas - Waste is put into an anaerobic digester which creates methane which can be burnt to generate electricity.
Biodiesel - Rape seed - disadvantage is you’re growing fuel instead of food.
Biothenanol - Ethanol from cereal crops/sugar cane is mixed with petrol.
