biodiversity and environmental changes

• what affects the distribution of organisms?

  environmental changes
• examples of environmental changes

  temperature, availability of water and the composition of atmospheric gases
• what causes environmental changes?

  seasonal factors, geographic factors or human interaction
• biodiversity


  the variety of life in the world or in a particular habitat or ecosystem.
• why is high biodiversity important?

  it makes sure that ecosystems are stable because different species depend on each other for things like shelter, food and maintaining the right physical environment for each other
• what human actions are reducing biodiversity?

  deforestation, waste production, pollution, global warming
• why are human actions having a more widespread effect on the environment?

  increasing population puts pressure on the environment as we take the resources we need to survive and a higher stand of living is also being demanded of means that more raw materials are being extracted and energy is being used to provide for this standard
• water pollution


  sewage and toxic chemicals from industry can pollute lakes, rivers and oceans, affecting the plants and animals that rely on them for survival and the chemicals used on land (e.g. fertilisers, pesticides and herbicides) can be washed into water
• land pollution


  toxic chemicals are used for farming (e.g. pesticides and herbicides), nuclear waste is buried underground and a lot of household waste in disposed of in landfill sites
• air pollution


  smoke and acidic gases released into the atmosphere can pollute the air (e.g. sulfur dioxide can cause acid rain)
• global warming


  an increase in the average temperature of the earth's atmosphere (especially a sustained increase that causes climatic changes)
• what does global warming cause?

  - sea levels rising

  - changes in species distribution

  - changes in migration patterns

  - reduction in biodiversity
• sea levels rising


  higher temperatures cause seawater to expand and ice to melt, causing the sea level to rise. this rise is beginning is beginning to increase the frequency of flooding in some areas and if sea level keeps rising, it could result in the loss of habitats for animals living in low-lying areas
• changes in species distribution

  the distribution of many wild animal and plant species is changing as temperatures increase and the amount of rainfall changes in different areas. some species are becoming more widely distributed (e.g. species that need warmer temperatures are spreading further as the conditions they thrive in exist over a wider area) whereas other species are becoming less widely distributed (e.g. species that need cooler temperatures are being found in smaller ranges as the conditions they thrive in exist over a smaller area)
• changes in migration patterns

  there have been changes in migration patterns, with some birds may be migrating further north, as more northern areas are getting warmer
• reduction in biodiversity


  as different habitats have been destroyed, many plants and animals have become extinct as they are unable to survive the change in the climate
• why do humans use land?

  for building, quarrying, farming and dumping waste
• why is humans needing to use land bad for nature?

  because the environment will be negatively impacted with deforestation and the destruction of habitats due to human activity, meaning that there will be less land available for other organisms
• peat bogs


  - areas of land that are acidic and waterlogged

  - plants that live there don't fully decay due to lack of oxygen

  - partly rotted plants build up to form peat

  - carbon in plants is stored in peat instead of being released into atmosphere
• what does the destruction of peat bogs result in?

  the addition of more carbon dioxide to the atmosphere
• why are peat bogs often drained?

  so that the area can be used as farmland or to cut up and dry the peat to use as fuel. peat is also sold to gardeners as compost
• how does destroying peat bogs affect the environment?

  - when peat is drained, it comes into more contact with air and some microorganisms start to decompose it: these microorganisms use oxygen and release carbon dioxide when they respire, contributing to global warming

  - carbon dioxide is realised when peat is burned as a fuel

  - destroying the bogs destroys (or reduces the area of)

  the habitats of some of the animals, plants and microorganisms that live there, so reduces biodiversity
• deforestation


  the cutting down of forests
• why is deforestation done?

  - to clear land for farming (e.g. cattle or rice crops) to provide MORE food.

  - to grow crops from, which biofuels based on ethanol can be produced
• what problems does deforestation cause?

  less carbon dioxide taken in, more carbon dioxide in the atmosphere and less biodiversity
• less carbon dioxide taken in due to deforestation

  - cutting down loads of trees means that the amount of carbon dioxide removed from the atmosphere during photosynthesis is reduced

  - trees 'lock up' some of the carbon that they absorb during photosynthesis in their wood, which can remove it from the atmosphere for hundreds of years: removing trees means that less is locked up.
• more carbon dioxide in the atmosphere due to deforestation

  - carbon dioxide is released when trees are burnt to clear land (carbon in wood doesn't contribute to atmospheric pollution until it's released by burning)

  - microorganisms feeding on bits of dead wood release carbon dioxide as a waste product of respiration
• less biodiversity due to deforestation

  - biodiversity is the variety of different species: the more species, the greater the biodiversity

  - habitats like forests can contain a huge number of different species of plants and animals, so when they are destroyed there is a danger of many species becoming extinct, hence biodiversity is reduced
• what can be done to protect ecosystems and biodiversity?

  breeding programmes, habitat protection, preventing global warming and reducing waste
• breeding programmes


  - breeding programmes have been set up to help prevent endangered species from becoming extinct

  - these are where animals are bred in captivity to make sure the species survives if it dies out in the wild

  - individuals can sometimes be released into the wild to boost or re-establish a population
• habitat protection


  - programmes to protect and regenerate rare habitats like mangroves, heathland and coral reefs have been started. protecting these habitats helps 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 only a single type of crop is grown. field margins are areas of land around the edges of fields where wild flowers and grasses are left to grow. hedgerows and field margins provide a habitat for a wider variety of organisms than could survive in a single crop habitat
• preventing global warming


  - 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
• reducing waste


  - people are encouraged to recycle to reduce the amount of waste that gets dumped in landfill sites

  - this could reduce the amount of land taken over for landfill, leaving ecosystems in place
• what conflicting pressures affect how biodiversity is maintained?

  the cost of programmes, the effect on the local economy, protecting food security and the development of society
• the cost of biodiversity protection programmes

  - protecting biodiversity costs money

  - for example, governments sometimes pay farmers a subsidy to reintroduce hedgerows and field margins to their land

  - it can also cost money to keep a watch on whether the programmes and regulations designed to maintain biodiversity are being followed

  - there can be conflict between protecting biodiversity and saving money, which may be prioritised for other things
• biodiversity protection's effect on the local economy

  - protecting biodiversity may come at a cost to local people's livelihoods

  - for example, reducing the amount of deforestation is great for biodiversity, but the people who were previously employed in the tree-felling industry could be left unemployed

  - this could affect the local economy if people move away with their family to find work
• protection of biodiversity's effect on protecting food security

  - there can be conflict between protecting biodiversity and protecting our food security

  - sometimes certain organisms are seen as pests by farmers (e.g. locusts and foxes) and are killed to protect crops and livestock so that more food can be produced

  - as a result, however, the food chain and biodiversity can be affected
• protection of biodiversity's effect on the development of society

  - development is important, but it can affect the environment

  - many people want to protect biodiversity in the face of development, but sometimes land is in such high demand that previously untouched land with high biodiversity has to be used for development

  - for example, for housing developments on the edges of towns, or for new agricultural land in developing countries
• what affects the distribution of organisms?

  environmental changes
• examples of environmental changes

  temperature, availability of water and the composition of atmospheric gases