biodiversity

• define biodiversity

  a measure of the variety of all the different species of organisms on Earth or within an ecosystem
• why is high biodiversity important?

  reduces the dependence of one specie son another for food etc
• what are threats to biodiversity?

  • habitat loss
  • diseases
  • climate change
  • over-consumption
  • introduced species
  • pollution
  • population growth
• why is population increasing?

  improving health care - improving birth rate and reducing death rate
• what are the problems caused by human population growth?

  • land needed for homes + farming - > habitats destroyed
  • harvesting of resources -> deforestation
  • different types of pollution
• what are the different types of pollution?

  • unrecyclable rubbish - landfill
  • air pollution
  • global warming
  • sewage and fertilisers in rivers and lakes
  • chemical spills
• what causes algal blooms?

  runoff from land use of fertilisers
• explain bioaccumulation

  toxins from pesticides transfer and increase up the food chain ( which then become unbalances)
• define eutrophication

  artificial enrichement of waterways that leads to changes that encourage growth of organisms in the water that eventually starve and die
• how does acid rain kill trees?

  lowering the pH effects the activity of enzymes

  so less respiration. photosynthesis etc.
• what are the two main causes of acid rain?

  • sulphur dioxide from burning fossil fuels
  • nitrogen oxides from car exhausts
• formation of acid rain?

  • burning of fossil fuels
  • this releases sulphur dioxide into atmosphere
  • sulphur dioxide dissolves into moisture in clouds
  • blows into another country, and acid rain pours from clouds
• how does increasing sulphur dioxide emissions affect global biodiversity?

  • increase acid rain, which damages plants and contaminates soils and waterways
  • -> kills organisms, damages ecosystems and potential extinction of species
• define bio-indicator

  a species whose population can reveal the quality of the environment
• what type of pollution can be measured by a pH probe?

  acid rain
• what types of pollution can be analysed form water samples?

  fertilisers, oil, sewage
• example of a bio-indicator>

  lichen
• why are peat bogs being destroyed?

  • burned as fuel
  • compost for gardeners
• why s peat bog destruction bad?

  • releases carbon dioxide (carbon sinks)
  • being destroyed way faster than it is forming
  • destroys habitats
• local effects of deforestation?

  • loss of habitats and biodiversity
  • effects on food webs and population numbers of organisms
  • erosion of soil
  • flooding
  • leaching of minerals
• global effects of biodiversity?

  • less CO2 is removed from atmosphere
  • more co2 added to atmosphere when tees are burnt or decay
• define slash and burn

  method of deforestation when trees are felled and burned to clear land. to make nutrients higher before planting crops.

  causes wildfires
• causes of deforestation?

  economic development + to support human population

  - pal, oil plantations

  • rice paddies (produces methane"
  • building dams, and towns
  • trees used as fuel, timber, pulp
  • grazing cattle and planting crops
• how do pesticides and hervicides cause pollution?

  bioaccumulation
• how do fertilisers effect pollution?

  eutrophication
• what causes acid rain / smog?

  nitrogen oxides and sulphur dioxide
• two sources of methane?

  cattle

  growing rice
• 6 sources of carbon dioxide?

  • burning fossil fuels
  • burning peat
  • using peat as compost
  • deforestation/burning trees
  • decay/respiration
  • volcanic eruptions
• how do greenhouse gases contribute to greenhouse effect?

  absorb the infrared radiation from the sun in the form of heat and re-radiate it back to earth. acting as an insulating blanket
• why are oceans becoming less efficient carbon sinks?

  as temperature increases, gases become less soluble in water