Human impact

• Greenhouse effect


  The trapping of the sun's warmth in a planet's lower atmosphere, due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface.
• Carbon footprint


  a measure of the amount of carbon dioxide released into the atmosphere as a result of the activities of a particular individual, organization, or community.
• 3 ways deforestation affect the carbon cycle?

  1) the rate at which CO2 is removed from the atmosphere by plants is reduced due to deforestation

  2) when trees are cut down they may either be burnt or left to decay both of these release CO2 into the atmosphere

  3)this leads to an enhanced greenhouse effect as carbon dioxide along with other gases like methane create a layer which causes heat from the sun to pass through but not escape which heats up the earth
• How does combustion and other similar human activities affect the carbon cycle? (2 marks)

  1) CO2 is being returned to the atmospherefasterthan it can be absorbed by plants and aquatic producers2) Warmer temperatures mean thatless CO2 can be dissolved in the oceans, so is released into the air
• why does increased atmospheric carbon dioxide leads to an enhanced greenhouse effect?

  this leads to an enhanced greenhouse effect as carbon dioxide along with other gases like methane create a layer which causes heat from the sun to pass through but not escape which heats up the earth
• How does global warming affect the distribution of species and be a possible cause of extinction?

  global warming causes habitats to change like warmer ocean temprature or more extreme weather conditions. This could lead to species having to migrate to other climates and or habitats.
• What is the nitrogen cycle

  is the flow of organic and inorganic nitrogen within the abiotic an d biotic components of an ecosystem where there is an interchange between certain nitrogenous compounds and atmospheric nitrogen
• What are the 4 key processes within the nitrogen cycle?

  1) Nitrogen fixation

  2) Ammonification

  3) nitrification

  4) Denitrification
• Where is nitrogen found?

  all amino acids, chlorophyll and the nitrogenous bases
• How is nitrogen taken up by the roots of plants

  active transport and facilitated diffusion
• What are the main processes of the nitrogen cycle

  assimilation of inorganic nitrogen compounds into plants, decay, involving ammoni fication, nitrification, nitrogen fixation and denitrification;
• What are the names of the 4 most common bacteria within the nitrogen cycle

  Nitrosomonas, Nitrobacter, Azotobacter and Rhizobium
• Why do farmers want to maximise the nitrates and ammonia conc in the soil

  nitrates in the soil help to produce a bigger crop yield which leads to more money
• How can farmers maximise the nitrate and ammonia conc

  they can maximise nitrates in the soil by exploiting the symbiotic relationship between legumes and nitrogen fixing bacteria such as Rhizobium

  this is done

  drainage + ploughing