19.6 - Succession

• 2 alterations to the environment that a new species can cause ?

  • Less suitable for the previous species
  • More suitable for other species with different adaptations
• When does primary succession occur ?

  On newly formed or exposed land with no soil or organic material
• What is succession ?

  Process by which ecosystems change over time due to changes in the environment, causing the plant and animal species present to change
• When does secondary succession occur ?

  Occurs in areas where an exists community has been removed leaving soil intact but no plant or animal species
• Explain how primary succession occurs ?

  • Pioneer species initially colonise the area
  • Pioneer species alters the abiotic environment, contribute organic matter to for soil and make it more hospitable for other species
  • Intermediate species (secondary colonisers) can now survive and continue to change the abiotic conditions, making the area less hostile
  • Overtime the variety of species increases leading to the arrival of larger complex organisms
  • Reach a climax community, remains stable and there’s much biodiversity
• What can the abiotic changes that organisms cause lead to ?

  Less hostile environment and changes in biodiversity
• 6 typical adaptations of pioneer species ?

  • Asexually reproduce
  • Seeds that can be dispersed by wind
  • Rapid germination
  • Ability to photosynthesise
  • Nitrogen fixation to enrich soil
  • Extreme condition tolerance
• What is the climax community determined by ?

  The limiting abiotic factor