biology

• what is an ecosystem

  self sustaining unit made up of a community of organisms in an area, the physical environment and the interactions between them.
• What is biodiversity?


  Biodiversity refers to the variety of life forms, including plants, animals, and microorganisms, in a particular ecosystem or on Earth as a whole.
• Predator/Prey

  1. An organism that eats another species
  2. An organism that gets eaten by another species
• What is Mutualism?

  Mutualism is a type of symbiotic relationship where both organisms benefit from each other.
• Commensalism 


  One sided interaction between species, from which one benefits and the other is not harmed nor benefiting.
• Paratism 


  Relationship between two species a parasite and host, parasite derives nutrients from host- harming not always killing host
• Dynamics of Predator/Prey

  • Balanced though conditions can unbalance
  • Adverse conditions can cause prey population to decrease, causing increased intraspecific competition in predator population. Predators will turn to other prey while the original population increases again.
• Interactions of Predator/Prey

  • One organism (predator) killing another (prey) for food.
  • Usually a proffered prey species as this becomes beneficial for the predator, however unusual to just depend on one
• Keystone Species 


  Species of relatively low abundance that has a disproportionally large influence over lower trophic levels, determining the coexistence of these species in an area

  EG: Grey nurse shark
• Role of a keystone species

  • nutrient recycling
  • sea dispersal
  • predation
• Consequences of a keystone species being removed?


  Change the structure and biodiversity of a ecosystem
• Biome 


  Large scale category of an ecosystem across a large geographical area
• Food chain

  • Each organism obtains its energy from the preceding one
  • Position organism holds is trophic level
  • Top consumer, Tertiary consumer, secondary consumer, primary consumer, producer
• independent variable

  The variable that has been changed
• Dependant variable

  The variable being measured
• DV and IV on graph

  DV= Y axis

  IV= X axis
• Quadrat

  Often used for stationary organisms. Square placed on ground and each organism counted to check biodiversity and abundance.
• biomagnification


  sequence of processes in an ecosystem by which higher concentrations of a particular non-biodegradable chemical accumulates in the tissues of organisms higher up trophic levels
• Pyramid of biomass 


  Total mass (dry organic matter) of organisms at each trophic level.
• Where is carbon in an ecosystem? 


  Biosphere, geosphere, lithosphere and atmosphere (four major reservoirs)
• How does carbon get added to the atmosphere?

  Combustion, respiration, decompisition
• How is carbon removed from the atmosphere?

  Photosynthesis
• Where is nitrogen in an ecosystem?


  Atmosphere, soil, living organisms.
• Role of roots and legumes in the nitrogen cycle?


  Nitrogen fixation.

  Organisms cannot take nitrogen from air so instead bacteria bacteria invade the root hairs of legumes and roots supplying the bacteria with nitrogen while also replacing some to the atmosphere/plants
• Process of nitrification


  Nitrifying bacteria first convert ammonia released in faeces and urine into nitrites this takes place during chemical steps in which energy is released as heat. Bacteria then uses this to build up their own organic compounds while other bacteria convert the nitrites to nitrates allowing plants to finally absorb the nitrogen.
• What form of nitrogen to plants absorb?


  Nitrate
• What process allows nitrogen to go through the cycle, then return to the atmosphere? 


  Abiotic processes including volcanic activity and by bacterial conversion of nitrites to nitrogen gas.
• Why does high biodiversity offer protection from invasive species? 


  Resistance and Resilience.

  High biodiversity increases the resilience of an ecosystem
• Invasive species 


  A species that has been intentionally or unintentionally been introduced and has a competitive advantage over native species allowing them to outcompete for food, shelter etc and has evolved into new ecosystems/areas.
• Human impact of predator/prey


  Introducing species such as (cane toad) can effect the predator levels or prey levels inbalancing the normal interactions