Biodiversity

• What is biodiversity?

  The variety of different species of organisms on Earth, or within an ecosystem
• Why is high biodiversity important?

  • Ensures that ecosystems are stable as different species depend on each other for things like food and shelter
  • different species depend on each other for things like food and shelter
  • different species help to maintain the right physical environment for each other (eg acidity of soil)
• Why is there an exponential rise in human population?

  introduction of modern medicine and farming methods, which have reduced the number of people dying from disease and hunger
• How does the growing population increases the demand on the environment?

  • puts pressure on the environment, as we take resources we need to survive
  • people demand a higher standard of living, so we use more raw materials and use more energy for the manufacturing processes. So we're taking in more resources from the environment more quickly
• Process of eutrophication

  1. excessive nutrients from fertilisers are flushed from land into rivers and lakes or by rainwater
  2. plants flourish as these pollutants cause aquatic plant growth of algae, duckweed and other plants
  3. algae bloom and prevent sunlight from reaching other plants. Plants die and cannot produce oxygen in photosynthesis, so it is depleted
  4. decomposition further depletes oxygen as dead plants are broken down by bacteria decomposers, using up more oxygen in the water
  5. oxygen levels reach a point where no life is possible. Fish and other organisms die
• Air pollution

  • Combustion of fossil fuels and other fuels releases carbon dioxide. This contributes to the greenhouse effect and leads to global warming.
  • it also releases sulphur dioxide and nitrogen oxides which can cause acid rain. Air pollution can also be caused by tiny particulates from smoke which can cause smog. 
• Land pollution

  • we use toxic chemicals for farming (eg pesticides and herbicides)
  • we bury nulear waste underground and dump household waste in landfill sites
• What is the greenhouse effect?

  • gases in the atmosphere naturally act like an insulating layer
  • they absorb most of the energy that would normally be radiated out into space and re-radiate it in all directions (including back to earth)
  • this increases the temperature of the planet
• Why is global warming happening?

  • our increased levels of greenhouse gas release into the atmosphere trap more heat
  • so less is radiated back into space and the earth is warming faster than it should
• How does global warming contribute to rising sea levels and the consequences?

  • higher temperatures cause seawater to expand and ice to melt, causing sea levels to rise
  • If it keeps rising, it can lead to flooding in low-lying places, resulting in a loss of habitats
• Impact of global warming on animals and plants

  • the distribution of many wild animal and plant species may change as temperatures increase and amount of rainfall changes in different areas.
  • Some species may become more widely distributed
  • species that need warmer temperatures may spread further as the conditions they thrive in exists over a large area
  • there could be changes in migration patters (eg birds might migrate further north, as more northern areas are getting warmer)
  • biodiversity may be reduced if some species are unable to survive a change in the climate, so may become extinct
• How does human's land use harm the environment?

  • we use land for things like buildings, quarrying, farming and dumping waste
  • so there's less land for other organisms
  • to gain this land, it typically requires deforestation or the destruction of habitats like peat bogs - which harms the environment
• Why is deforestation done?

  • to clear land for farming (cattle or crops)
  • to grow crops from which biofuel based on ethanol can be produced
• Problems of deforestation

  • cutting down trees means that the amount of carbon dioxide removed from the atmosphere from photosynthesis is reduced
  • trees store some of the carbon they absorb during photosynthesis. Removing trees means less is stored
  • carbon dioxide is released when trees are burnt to clear land (either from being stored in the trees or the process of combustion)
  • microorganisms feeding on bits of dead wood release carbon dioxide as a waste product of respiration
  • when forests are destroyed, there is the danger of many species becoming extinct, reducing biodiversity
• What are peat bogs?

  Bogs are areas of land that are acidic and waterlogged. Plants that live in bogs don't fully decay when they die, as there's not enough oxygen. The partly-rotted plants gradually build up to form peat
• Why are peat bogs being destroyed?

  • they are drained so that the area can be used as farmland
  • cut up and used as fuel
  • sold to gardeners as compost
• How does the destruction of peat bogs affect the environment?

  • when peat is drained, it comes into contact with air and some microorganisms start to decompose it. When these microorganisms respire, they use oxygen and release carbon dioxide, contributing to global warming
  • carbon dioxide is released when peat is burned as a fuel
  • destroying the bogs also destroys the habitats of some of the plants, animals and microorganisms that live there, reducing biodiversity
  • peat is being used faster than it forms
• How do breeding programmes prevent prevent endangered species from becoming extinct?Animals are bred in captivity to make sure species survives if it dies out in the wild. Individuals can also be released into the wild to boost or re-establish a population
• How do breeding programmes prevent prevent endangered species from becoming extinct?

  Animals are bred in captivity to make sure species survives if it dies out in the wild. Individuals can also be released into the wild to boost or re-establish a population
• How can programmes protect biodiversity and ecosystems?

  • There are programmes to regenerate rare habitats (mangroves, heathland and coral reefs) to protect the species that live there - preserving the ecosystem and biodiversity in the area
  • There are programmes to reintroduce hedgerows and field margins around fields on farms where a single type of crop is grown. Here wild flowers and grasses are left to grow which provide a habitat for a wider variety of organisms than could survive in a single crop habitat
• How have government regulations helped the environment?

  Some governments have introduced regulations and programmes to reduce the level of deforestation taking place and the amount of carbon dioxide being released into the atmosphere by businesses. This could reduce the increase of global warming
• Economic issues of maintaining biodiversity

  • protecting biodiversity costs money
  • governments sometimes pay farmers a subsidy to reintroduce hedgerows and field margins
  • it can cost money to keep a watch on whether the programmes and regulations designed to maintain biodiversity are being followed
  • can cause conflict between protecting biodiversity and saving money
• How can there be conflict between protecting biodiversity and protecting our food security?

  • certain organisms are seen as pests by farmers (locusts and foxes)
  • they are killed to protect crops and livestock so that more food can be produced
  • the food chain and biodiversity may be affected
• How does development affect the environment

  • land can be in such high demand that previously untouched land with high biodiversity has to be used for development
  • such as housing developments on the edge of towns or new agricultural land in developing countries