Ecology

• what do organism compete for

  food

  water

  space

  light

  co2/ o2

  mate
• interdependence

  organisms depending on each other for survival. When this happens, a community is formed
• Abiotic Factors

  non-living factors e.g. light, temperature, moisture, soil, pH, co2 & o2 concentration
• Biotic Factor

  the impact of other organism on an ecosystem e.g. food, predators/ prey and pathogens
• Sampling

  place quadrat in random positions in area

  count number of chosen organism in each, calculate mean then multiply by total area to get estimate for population

  moving it along transect allows you to observe change in population density over a distance
• food chain

  show the direction of biomass transfer between organisms
• apex predator


  are always at the top of the food chain, and have an natural predator.
• organisms exist in trophic levels, and their population will fluctuate over time
• order of the food chain

  producer > primary consumer > secondary consumer > tertiary consumer.
• the water cycle

  rain (precipitation) > runs into rivers, sea > evaporation
• biodiversity

  the variety of species of organism that exist in an ecosystem
• What does high biodiversity mean?

  makes for a stable ecosystem as organism will be able to be dependent on a greater number of other species for survival
• Human Development

  usually results in reduced biodiversity due to destruction of habitats. Disposing of waste in safe ways in order to reduce our impact is getting harder.
• Land

  is needed by us for building, quarrying, farming & disposing of waste
• Peat Bogs

  are being destroyed in order to make compost. This reduces the biodiversity of that ecosystem, especially for microorganisms. Burning peat releases CO 2 - contributes to global warming
• Deforestation

  also reduces biodiversity - usually done to create farmland
• Pyramid of Biomass

  indicates how much biomass is transferred between trophic levels
• Biomass is lost at each level due to not all of it being consumed/absorbed and organisms losing it while they are alive via excretion
• food security

  is current big concern due to changing diets and growing environments, fuel & energy prices, cost of farming, and conflicts
• Farmers are trying to farm more efficiently : increasing biomass input while reducing wasted biomass.
• sustainable fishing

  ensures that fish are not caught faster than they can breed, so population remain constant e.g. by using nets with large holes so juvenile (young) fish can escape and breed.