Bio18

• • We have discovered how to grow more food than we could ever gather from the wild
  • We can cure or prevent many killer diseases
  • We have no natural predators
• People use the resources of the Earth - we use fossil fuels to generate energy, for transport and to make materials such as plastics, minerals and soil to grow food
• There has also been an increase in manufacturing and industry to produce the goods needed by the growing population
• If waste is not handled properly, it can cause serious problems - water can be polluted by sewage, by fertilisers from farms, and by chemicals from industry. The air we breathe may be polluted with poisonous gases, such as sulfur dioxide. The land itself can be contaminated with toxic chemicals from farming, such as pesticides, and can also be contaminated with industrial waste
• These chemicals can be washed from the land into water bodies
• Trees and other plants use carbon dioxide in photosynthesis, taking it from the air and locking it up for years (sometimes for hundreds of years) in plant material such as wood
• Loss of biodiversity means we lose the potential for discovering new medicines or food for the future
• Global warming

  Increase in the average temperature of the Earth's atmosphere
• The land produced by deforestation is often used to grow rice (which releases methane as it grows) or cattle (which produce methane and release it regularly as they digest grass)
• Greenhouse effect

  The way gases such as carbon dioxide and methane in the atmosphere absorb some of the energy transferred as the Earth cools down, keeping the Earth and its surrounding atmosphere warm and ideal for life
• Energy from the Sun reaching the Earth

  1. Warming the Earth

  2. Much of it radiated back out into space

  3. Gases in the atmosphere absorb some of the energy transferred as the Earth cools down

  4. Keeping the Earth and its surrounding atmosphere warm and ideal for life
• As a result, many glaciers, including the primary glacier, Ascension Island, may disappear, and whole countries may depend on desalinated seawater for drinking
• Changes in distribution patterns as climate change makes some areas more favourable for some animals and they expand their range, while others may find that the range they can survive in is reduced or disappears completely from an area or a country
• Some species of birds and amphibians now only exist in captive breeding programmes, and will only be released when the natural habitat is protected and restored
• To protect coral reefs, carbon dioxide emissions and global warming must be tackled as raised temperatures and decreased pH levels are the major threats to these most biodiverse marine habitats
• Reintroducing field margins and hedgerows helps increase biodiversity by providing habitats for a wide variety of plants and animals
• The rest of the biomass is used for the consumer's own life processes, transferred to the surroundings, or lost in waste
• The biomass of the decomposers is probably more than the biomass of the other organisms in an ecosystem
• Detritivores and decomposers break down the dead bodies of other living organisms, recycling the nutrients
• Tackling the problem of overfishing

  Tackling the problem of overfish

  1. Allowing fish to grow large enough to breed

  2. Having a breeding season and very strict quotas

  3. Strictly enforcing a limit on the amount allowed to be caught

  4. Throwing excess dead fish back into the ocean to maintain populations

  5. Reducing the number of fishing boats and fishermen needed to make a living
• Overfishing


  • Leads to loss of livelihood for fishermen
  • Leads to cheap food and environmental damage