B4

• How are materials recycled

  • living things take in elements from the environment
  • turn it into complex compounds which are then taken in by animals when they eat plants
  • Return to the environment through waste products, decay
  • Waste products decay as they're broken down by decomposers
• Carbon cycle

  1. Photosynthesis- plants use carbon to make carbohydrates, glucose and proteins
  2. Animals consume the plants which passes CO2 along food chain
  3. Animals respire, releasing CO2
  4. Animals/Plant die and decompose, or killed and turned into useful products
  5. Broken down by decomposers: Fungi, Bacteria which release CO2 back into the environment via respiration
  6. CO2 released via combustion of fossil fuels
• Nitrogen cycle


  > Atmosphere 78% Nitrogen Gas, unreactive can't be used directly

  1. Plant gets Nitrogen from soil , Nitrogen in the air is turned into nitrate
  2. Nitrogen compound Passed along food chain as animal eats plant
  3. Decomposers break dab proteins in rotting plants and animals, and urea in animal waste, into ammonia which forms ammonium ions
  4. Returns nitrogen into the soil
• Nitrogen fixation


  Turning N2 into nitrogen compounds in the soil

  Lightening- lots of energy, reacts with O2 to give nitrated

  Nitrogen fixing bacterias:

  > Decomposers- decompose proteins and urea to turn into ammonia which forms ammonium ions

  > Nitrifying bacteria- turn ammonium ions to nitrates

  > Nitrogen-fixing bacteria- Turns atmospheric Nitrogen into nitrogen compounds

  > Denitrifying bacteria- Nitrates back into Nitrogen gas, found in waterlogged soil
• Where are nitrogen fixing bacteria found?

  • Soil
  • Nodules on roots of legumes plants
  • Plants and nitrogen fixing bacteria have mutualistic relationship: Bacteria gains food (sugar), plant gets nitrogen compounds to make into proteins by combining nitrogen and oxygen from the air
• Water cycle

  1. Sun makes water evaporate from land and sea into water vapour
  2. Water evaporates from plants transpiration
  3. Water vapour is carried upwards (warm air rises)
  4. The higher up, it cools and condenses to form clouds
  5. Water falls from clouds and precipitation (rain, snow,hail) returned to land and sea
  6. Flow of fresh water through water cycle allows nutrients to be transported
• Decomposers

  • microorganisms
  • Bacteria, Fungi
• Factors that effect rate if decomposition

  Oxygen

  > needed for aerobic respiration, the higher the increase.

  > Some decomposers respire anaerobically but transfers less energy

  Temperature

  > highest at 50 °C

  > Decomposers contain enzymes to digest

  > Enzymes become denatured causes it to stop

  Water

  > Water for survival

  > Increases in moist conditions

  > Waterlogged soils has less oxygen so decrease if too much water
• Ecosystem levels

  Individuals- a single organism

  Population- All the organisms of one species in a habitat

  Community- All organisms living in a habitat

  Ecosystem- A community of organisms along with the non-living (Abiotic) conditions
• Competition 


  > in order to survive and reproduce

  Plants need:

  > Light, space, watering minerals (nutrients) from soil, CO2

  Animals need:

  > Territory, food, water, mate, shelter
• Abiotic factors


  Temperature

  Moisture levels

  Light intensity

  pH of the soil
• Biotic factors (living)


  > Food

  > number of Predators
• Interdependence 


  Predation- cycle shows interdependence

  Parasitism- Parasite live off host, harms host

  Mutualism- both organisms benefit
• Food chain

  1. Producer- make their own food
  2. Primary consumer- eat producers, eaten by secondary consumer
  3. Secondary consumer eaten by tertiary consumer
  4. All organism die and get eaten by decomposers
  5. Each stage is called a trophic level
  6. Apex predator- top of the food chain
• Pyramid of biomass


  > Amount of biomass decreases as you move up trophic level
• How is energy transferred between organisms

  1. energy from the sun is transferred by light to the chlorophyll in the cells of a producer
  2. CO2 and H2O react to produce glucose which is stored within its chemical bonds
  3. Glucose converted into carbohydrates fat, proteins which are used as energy stores for growth and repair
  4. Consumers eat producers when the organism respires, the energy stores is transferred in the production of ATP
  5. Organism grows, its biomass increases
• Biomass transfer


  > lost at each trophic level

  1. Green plants use energy from the sun to make glucose during photosynthesis
  2. Glucose is used for plant to respire
  3. Rest of glucose is used to make biological molecules such as cellulose
  4. Animals use biomass for respiration, movement and to keep warm
  5. Eegstion- undigested food
  6. Excretion- getting rid of waste products from chemical reactions in the body: Breathing, urinating, sweating