Ecology

• What is an ecosystem?

  The interaction of a community of living organisms (biotic) with the non living (abiotic) parts of the environment
• What do organisms require to survive and reproduce?

  a supply of materials from their surroundings and from the other living organisms
• Name the 8 abiotic factors that can impact a community

  • Light intensity
  • temperature
  • moisture levels
  • soil pH
  • mineral content
  • wind Intensity and direction
  • carbon dioxide levels for plants
  • oxygen levels for aquatic animals
• Name the 4 biotic factors that affect a community

  • Availability of food
  • new predators
  • new pathogens
  • a new successful competitor species
• What are two types of decomposers?

  Microorganisms (bacteria) and détritivores
• What is the name for material containing carbon?

  Organic compounds
• What does decomposition of dead material produce?

  nutrients and Organic compounds
• In what conditions does the rate of decomposition increase?

  Warm temperatures, moist and oxygen rich conditions- as decomposers are more active
• What is extinction?


  When there are no remaining members of a species still alive
• How does deforestation affect climate change?

  Fewer trees result in a decrease in photosynthesis. This means that less carbon dioxide will be taken in from the atmosphere which results in an increase in greenhouse gases and leads to global warming. Also burning trees releases the stored carbon dioxide.
• Name three factors that affect biodiversity

  water availability, human activity (like waste production, agriculture and deforestation) and climate
• Why is biodiversity important?

  it is needed for ecosystems to remain stable as species are less likely to rely on a single different species for survival.
• What are the effects of reduction in biodiversity?

  Loss of ecosystem stability, climate change, food availability and air quality
• How has growth in human population damaged the environment?

  More resources are needed and more food, land, water, and fuel is needed
• How does waste pollute water?

  • sewage- encourages the breeding of harmful bacteria which causes cholera
  • excess fertiliser- cause eutrophication
  • toxic chemicals- can kill or be corrosive (Dissolve)
• How does waste pollute the air?

  emissions of gases and smoke causes damage
• How does waste pollute the land?

  Herbicides and pesticides are toxic chemicals that can kill plants and animals. Waste in landfill also pollutes habitats
• What is pollution?

  an unwanted substance or waste product in an unwanted place
• Why is combustion of fossil fuels harmful?

  Coal oil and gas produce harmful substances when burnt which pollutes the environment
• Why are carbon dioxide emissions dangerous?

  Leads to global warming because of increased greenhouse gases in the atmosphere
• Why are sulfur dioxide emissions dangerous?

  causes acid rain and respiratory problems. Sulfur dioxide dissolves in the clouds and forms sulfuric acid Which erodes limestone and affects acidity of soils
• Why is smoke dangerous?

  it can be toxic and contains carcinogen that cause cancer. It also affects photosynthesis as some chemicals destroy chlorophyll and make the stomata close up- impacts carbon dioxide levels.
• Why are carbon monoxide emissions dangerous?

  It is a silent killer- an odourless, colourless gas which prevents red blood cells from transporting sufficient oxygen by attaching to haemoglobin and taking the place of oxygen in red blood cells
• Why are suspended particulates dangerous?

  they cause respiratory problems and can penetrate lung and blood tissue which irritates and blocks airways and can cause asthma
• Why are lichens an indicator species?

  they help to identify pollution levels. Sulfur dioxide and nitrogen dioxide impacts its growth. So, low levels of lichen means high levels of pollution.
• What is eutrophication?

  it is when surface run off means that fertilisers and herbicides are washed into the nearby water sources, causing excessive growth of algae, resulting in the death of other organisms in the ecosystem- algae block light for other aquatic plants below which reduces photosynthesis (and oxygen levels) and so these plants die and decay. Decomposers respire and further reduce oxygen levels so there isn’t enough oxygen to sustain life anymore. The whole ecosystem dies.
• How do humans reduce the amount of land available for other species?

  by building, quarrying, farming and dumping waste in landfill sites
• What is deforestation?

  intentional destruction or removal of trees and other vegetation
• Why is Deforestation happening?

  To provide land for cattle, rice fields, to provide more food by growing crops, and building. (And biofuel)
• How does deforestation increase levels of greenhouse gases ?

  carbon dioxide is released by burning trees and increased microbial activity during decomposition. there Is also less photosynthesis and so biodiversity decreases
• What are peat bogs?

  Areas of land that are acidic and waterlogged with low oxygen levels. Organisms die here and don’t fully decompose and decay due to the conditions. this matter builds up forming peat (brown soil like material which is rich in nutrients and contains a lot of carbon which was stored instead of being released)
• Why are peat bogs being destroyed?

  to produce garden compost and this increases carbon dioxide levels and reduces habitats
• What are the programs that have been put in place to reduce negative impacts of human activity on biodiversity?

  • breading programs in captivity (for endangered species)
  • protection and regeneration of rare habitats e.g. mangroves
  • reintroduction of field margins and hedgerows in agricultural areas
  • reduction in deforestation
  • reduce reuse recycle schemes
• What are the negatives of trying to maintain biodiversity?

  its expensive, can reduce people’s livelihoods, may risk human food security and may reduce land available for development for housing or agricultural land in developing countries
• What are the advantages of breeding programs?

  it protects species, makes sure they don’t go extinct and maintains biodiversity
• What environmental changes can affect the distribution of a species in an ecosystem?

  temperature, availability of water and composition of atmospheric gases