ecosystems

• What is intensive farming?

  • Different methods used in agriculture to maximise the amount of food produced in the quickest and most cost effective way
  • it is done by using chemicals and carefully controlling growing conditions for plants & animals
  • These increase livestock and plant yields
• What are fertilisers?

  Chemicals which contain essential nutrients to support plant growth and makes soil more fertile
• What are the advantages of using fertilisers?

  • make up for missing nutrients used up by previous crops
  • prevents plant growth and health being affected by lack of nutrients
  • increased crop yield
• What are the disadvantages of using fertilisers?

  • Excess fertilisers may run into water
  • negative effect on wildlife
• What are pesticides?


  Chemicals that kill pests for example, insects, rats and mice
• What are the advantages of using pesticides?

  • kills pests that would eat or damage crops
  • increase crop yield
• What are the disadvantages of using pesticides?

  • excess pesticides can be washed into water and pollue the freshwater environment
  • negative effect on wildlife
  • can build up in food chains
• What is disease control?

  Giving animals antibiotics to kill bacteria to prevent disease
• What are the advantages of disease control?

  • fewer animals lost to disease
  • increased livestock yield
• What are the disadvantages of disease control?

  • risks of antibiotic resistance bacteria development which can spread to humans via consumption or contact
• What is battery farming?

  Limiting the movement of animals and keeping them in a carefully controlled enviroment
• What are the advantages of battery farming?

  • animals will use less energy and body temperature is controlled meaning that the animal will have more energy for growth
  • increased livestock yield
• What are the disadvantages of battery farming?

  • animals in close contact can increase risk of disease spreading
  • inhumane treatment
• Sunlight


  Source of all energy in biological systems
• Photosynthetic organisms (producers)

  Absorb sunlight and convert it to chemical energy (biomass) during photosynthesis
• Biomass

  Chemical energy transferred between organisms during feeding
• Decomposers

  Break down dead material and waste, returning nutrients to the soil
• Food chain

  1. Producer

  2. Primary consumer

  3. Secondary consumer

  4. Tertiary consumer
• Producers are always the first trophic level because they provide all energy for the food chain via photosynthesis, and the rest of the food chain involves the transfer of this energy
• Primary consumers

  Normally herbivores
• Food web

  Shows how different food chains are interlinked and how members of an ecosystem are interdependent
• Energy transfer is inefficient - 90% of the sun's energy is reflected, energy is lost through respiration, some parts of organisms are indigestible, and through egestion and excretion
• There are rarely more than four or five trophic levels in a food chain; above this, there is insufficient energy to support another breeding population
• Pyramid of numbers


  Represents the number of organisms per unit area at each trophic level
• Pyramid of biomass


  Shows the dry mass of living material per unit area at each trophic level
• Pyramids of biomass generally take a 'true pyramid' form, while pyramids of numbers are often not pyramid shaped as they don't take size and mass of organisms into account

  
• Decomposition


  The breakdown of dead materials into simpler organic matter
• Decomposers


  Bacteria and fungi that release enzymes to catalyse the breakdown of dead material into smaller molecules, recycling vital nutrients to the soil
• Nutrient cycles


  The processes by which materials cycle through the living and non-living components of an ecosystem
• There is a fixed amount of nutrients on Earth which must be constantly recycled
• Carbon cycle

  1. Photosynthesising plants remove CO2 from the atmosphere

  2. Eating passes carbon compounds along a food chain

  3. Respiration in plants and animals returns CO2 to the atmosphere

  4. Organisms die and decompose, with decomposers releasing CO2 via respiration

  5. Combustion of materials releases CO2
• Nitrogen cycle

  1. Organisms die and decompose, with decomposers breaking down proteins and urea into ammonia

  2. Bacteria in the soil convert ammonia into nitrates which are taken up by plants

  3. Nitrogen-fixing bacteria convert nitrogen gas into nitrates taken up by plants

  4. Feeding passes nitrogen through the food chain

  5. Denitrifying bacteria convert nitrates in the soil back to nitrogen gas
• The needs of the human population sometimes conflict with the conservation of the environment, e.g. a rising human population means we need more food, however, farmland disrupts natural habitats and reduces biodiversity
• It is important to balance the need for resources with the need to preserve the biodiversity of ecosystems, to protect ecosystems and endangered species whilst maintaining quality of life for humans