B6

• Sampling technique: pooter

  • Jar with rubber bung sealing the top and two trusses stuck through the bung
  • Suck shorter tube. insect is sucked through larger tube
• Sampling technique: Pit fall trap

  • steep sided containers that are sunk in a hole in the ground
  • top is partly open
  • leave trap overnight-> insects fall in and can't get out
  • count them
  • Set up another and compare
• Sampling technique: Net 


  Sweep net

  > lined with strong cloth to collect from long grasss

  > Stand still and sweep left/right

  > Repeat and compare

  Pond net

  > Collect from ponds and rivers

  > Sweep along bottom of river

  > Turn net onto white tray and count

  > repeat and compare
• Sampling technique: quadrat


  > Square frame enclosing known area

  > Compare how common an organism is in two sample areas

  1. place quadrant on random spot
  2. Count organisms you're interested in
  3. Repeat - larger sample the better
  4. Work out mean per quadratic
  5. Repeat 1-4
  6. Compare means
• Sampling technique: Capture recapture calculation 


  no. first sample x no. second sample / no. in second sample previously marked
• Sampling technique: key

  • series of questions to figure unknown organism
  • Correctly identify
• Abiotic factors (Non-living)

  • Temperature
  • pH soil level
  • Moisture level
  • right intensity
• Biotic factors (living)

  • competition
  • Food
• measure temperature 


  thermometer
• measure light intensity 


  electronic light sensor
• measure moisture in soil

  soil moisture metre
• measure pH in soil

  indicator liquid

  or electric pH monitor
• Sampling technique: transects 


  Distribution gradually changes across an area

  Belt transect

  1. mark out line in the area using a measure tape
  2. place quadrant at start and count number of organisms
  3. move quadrant along line
  4. Calculate percentage covered
  5. plot results on kite diagram
• Human interactions impact on ecosystem

  • increasing population
  • pressure on environment- higher standards of living
  • raw materialised are used quicker than they're being replaced and run out
  • Create waste and causes harmful pollution
  • Negative impact on local biodiversity and global biodiversity
• Habit destruction

  • Woodland clearance- reduced trees species (biodiversity)
  • Destroys habitat- species die or migrate
  • More Co2 in atmosphere as trees don't photosynthesise, contributes to global warming
  • Monoculture grows single crop - reduces biodiversity
• Impact of waste on land

  Pollution- kills plants and animals

  • toxic chemicals pollute rivers
  • Smoke and gases pollute air
• Hunting

  • causes extinction
  • reduces biodiversity
  • impacts food chain
• Positive interactions with ecosystem

  • Protecting habitats- controlling water levels to conserve wet lands and coppicing to conserve woodlands
  • Controlling or preventing introduction of harmful species- protect local biodiversity
  • Creating protected areas- national parks, nature reserves
  • zoos, botanical gardens, seed banks, captive breeding
• Maintaining benefit wildlife and Humans

  • Protecting human food supply
  • ensuring minimal damage on food chains- conserving species help others to survive
  • Providing future medicines- medicine comes form plants
  • providing industrial materials and fuels- plants and animals involved in production, if extinct resources hard to produce
• Ecotourism

  • focuses on appreciation of nature and its conservation without having final negative impact
  • high biodiversity provides opportunity for ecotourism
  • Eden project- educates visitor about conservation
  • Brings money to areas where conservation is taking place
  • Fund conservation works
  • Supports local economy
• Challenged of maintaining biodiversity

  Agreement about conservation schemes

  > require different countries to work together

  > require the local residences to agree

  Difficult to monitor

  > e.g fishing quotas
• Environmental changes affect distribution - availability of water

  • in the tropics changes between dry and wet season
• Environmental changes affect distribution - atmospheric gas

  • changes in area of air pollution
• Environmental changes affect distribution - Temperature

  • seasonal factors
  • Geographic factors
  • Human interactions
• Global warming

  • Climate change
  • Temperature is balanced by energy from the sun and energy radiated back into space
  • Insulating layer- Gases in atmosphere
  • Gases absorb the energy re-radiate it back to earth
  • Greenhouse gases
• Impact of global warming

  • Sea water to expand, ice melt- sea levels rise -> flooding and loss of habitat
  • Distribution change due to increased temperature
  • change in migration patterns
  • Biodiversity reduced if species are unable to survive and become extinct
• Facts that effect levels of food security

  • Changing diets - wealthier include wider variety, less biomass moving up food chain so produce crops with higher biomass
  • Pests and pathogens- Insects and bacteria, fungi and viruses result in loss of crops or livestock-> widespread famine
  • Environmental change- affect ability to produce food, yield - pollution, rising sea levels
  • Agricultural inputs- expensive to grow food
  • Sustainability- meeting needs without harming the environment for future generations
• Ways of increasing agricultural yield- Fertilisers

  elements: nitrogen, potassium, phosphorus

  • fertilisers to replace missing elements
  • Run off fields and pollute bodies of water which can result in death of organisms
• Ways of increasing agricultural yield- pesticides

  • Chemical pest control
  • Sprayed onto crops to kill the pests and damage them
  • poisonous to humans, keep peptide levels low
  • Insecticides, herbicides, fungicides
  • harm wildlife and cause a shortage of food for animals higher up food chain
  • Passed along food chain and can kill organisms
• Ways of increasing agricultural yield- Biological control

  • using other organisms to reduce number so pests
  • Longer lasting effect =, less harmful
  • Safer alternatives to pesticides, no chemicals used, less pollution
• Ways of increasing agricultural yield: Hydroponics

  • Plants grown in nutrient solutions rather than soil
  • Pests and disease controlled, nutrient levels controlled to ensure maximum growth, higher yield
  • Costs are high, disease can spread easier and quickly
• Ways of increasing agricultural yield- GM plants

  • Gene modified for desired characteristics
  • insect resistant- increases crop yield
  • virus resistant
  • Herbicides resistant
• Selective breeding - drawbacks

  • reduces gene pool- inbreeding
  • Inbreeding- health problems and harmful genetic disorders
  • Not much variation that all are likely to die of disease appears
• Vectors - Transfer DNA

  Plasmids are used as vectors- small and circular that can be transferred between bacteria

  1. DNA cut out by restriction enzyme (recognises specific sequence of DNA)
  2. Plasmids cut out by same restriction enzyme
  3. Creates sticky ends on DNA (Short tail of unpaired bases that are complementary to each other
  4. Plasmids and DNA (you're inserting) are mixed with ligase enzymes
  5. Ligase joins sticky Des
  6. Plasmid vector inserted into new cell
  7. Select part of host cel that was successfully received with desired gene
• Antibiotic markers

  • Select cells with new DNA
  • Find host cell that contains new DNA
  • Markers inserted into the vector at the same time
  • Host cell grown on special plate containing antibiotic
  • Only the bacteria that contains the marker will have the gene to survive and reproduce
• Agrobacterium Tumefaciens

  • Genetically modify plants
  • Invades plant cells and inset its genes into the DNA
  • Allowed to infect cells of the target plant
  • Insert gene into the plants DNA
• benefits of GM 


  Improve crop yield

  1. resistant to insect pests
  2. bacterium that produces toxin that kills insect larvae
  3. Genes are inserted into crops which produces toxin In their stems and leaves
  4. toxin is specific to insect pests and harmless to humans, animals and other insects
  5. Bt crops require less pesticides, less of a negative intact
  6. Bt risks insects becoming resistant
• risks of GM

  • Transplanted genes get into environment
  • affect food chain
  • People against GM- create unforeseen problems which could pass to future generations
  • effect numbers of weeds and slopes that usually live around the plants and reduce biodiversity
• Ethical issues GM

  • wrong to do it to just benefit humans, if animals are suffering as a result
  • worry we won't stop at plants and animals
  • Irresponsible and creates uncertainty of consequences
• Causes of disease

  • Infected by pathogens
  • Mutation in genes
  • environmental conditions