Not finished Ecology (does not include cycles)

• Ecology

  Study of the interaction between groups of organisms and their environment
• Population

  Group of organisms of same species living in part of an ecosystem
• Community

  Group of organisms of different species
• Ecosystem

  Community of organisms interacting with their environment
• Biosphere

  Part of the earth and its atmosphere where organisms can live
• Habitat

  Place where an organism lives
• Biotic factors are

  Living factors
• Abiotic factors are

  Non living factors
• Climatic factors

  Effect of weather over long periods of time
• Weather: short term conditions


  Climate: long term conditions
• Edaphic

  Soil factors
• Competition

  Plants and animals fight for food, water, space etc
• Predators

  Organism which kills and eats another organism called prey
• Parasites

  Organism that lives in or on another living organism called a host for nourishment causing it harm
• Pollinationand seed dispersal

  Plants and animals carry pollen and seeds
• Abiotic factors examples

  • Soil temperature
  • Temperature
  • Soil pH (measured with pH metre)
• Climatic factors examples

  • Light intensity (affects rate of photosynthesis
  • Salinity - salt content
• Edaphic factors examples

  • Sand (few earthworms and humus)
  • Water content
• Sun is primary source of energy
• Producers(autotrophs)

  Green plants which make their own food by photosynthesis
• Consumers (heterotrophs)

  Organisms that eat other organisms
• Types of consumers

  1. Primary consumers - eat producers (herbivores)
  2. Secondary consumers - eat primary consumers (carnivores)
  3. Tertiary consumers - eat secondary consumers (omnivore)
• Food chain

  Feeding relationship between organisms in which energy is transferred from the sun to plants and then to animals
• Types of food chains

  • Grazing - starts with living green plant (rose leaves → greenfly → ladybird → spider)
  • Detritus - starts with dead organisms (dead oak leaves → Woodlouse → blackbird)
• Why are food chains generally short?

  Large energy loss at each trophic level
• Decomposers (sapprophytic nutrition)

  Break down the dead remains of plants and animals to recycle nutrients and back to the soil
• Food web

  A series of interconnected food chains
• Trophic level

  Feeding stage in a food chain
• Pyramid of numbers

  A diagram which shows the number of each organism at each trophic level
• Food niche

  Functional role of an organism
• Niche example

  Blackbird eats fruit and worms
• Nutrient recycling

  The conversion of mineral elements such as carbon and nitrogen back and forth between abiotic and biotic forms for use in the ecosystem
• Importance of nutrient recycling

  Return elements to the environment so they can be reused
• Examples of decomposers

  Woodlice and beetles
• Three outcomes of fertilisers in agriculture

  1. More plant growth
  2. More atmospheric nitrogen
  3. More nitrification
• Biological similarities between nitrogen and carbon cycle

  • Micro-organisms involved
  • Death and decay
  • Excretion
• Pollution

  Any addition of harmful substances to the environment
• Pollutant

  Substance which contaminates the environment
• Inference of pyramid shape

  1. Number of organisms decline as you go up the pyramid. Due to large energy loss at each trophic level. Less energy available for the organisms the higher up the pyramid you go
  2. Organisms increase in size
• Limitations of pyramid of numbers

  • Does not take into account the size of the organisms. Single rose bush (producer) can support thousands of greenfly (consumer)
  • Parasites cannot be represented to scale. This can lead to distorted pyramid