Ecological Relationships and Energy Flow

• environment

  all the conditions that surround a living organism - both the other living things and nonliving things or physical surroundings.
• living things are biotic
• non living things are abiotic
• habitat


  place here animals and plants live (a pond)
• population


  all members of a single species that live in a habitat
• community


  all popluations of different organisms living together in a habitat
• ecosystem


  community of animals, plants and microorganisms, together with the habitat in which they live
• biodiversity


  measure of the variety of different species present (species richness)
• abiotic factors

  • light intensity/availability
  • temperature range
  • rainfall levels and rate of water flow
  • water content of soil
  • humus content of soil
  • soil PH and nutrient levels
  • dissolved oxygen levels
  • pollutant concentration
  • wind speed
• biotic factors

  • which producers are present
  • which consumers and predators are present
  • number and type of competitors
  • pathogens and parasites present
  • number and type of insect species present
  • number and type of decomposers
  • species diversity
• ecosystems depend on flow of energy and recycling of nutrients
• if a habitat has similar conditions and similar distribution of species, random sampling can be done.
• if a habitat has a gradual change, for example from the centre of a forest to the edges, a systematic sample in the form of a belt transect can be used
• random number generators are used to find coordinates to study to make it a fair test.
• a quadrat is usually a metal 1m x 1m square
• pooter

  A) gauze

  B) glass collecting tube

  C) glass mouthpiece

  D) clear plastic tube

  E) rubber bung

  
• orgasims only survive if the have suitable adaptations for the habitat in which they live.
• Plant compete for

  • Water
  • light
  • space
  • minerals
• Animals compete for

  • Water
  • food
  • territory
  • mates
  • predators
• if the environment changes and adaptations no longer benefit the species may become extinct
• the sun is the source of energy for all life
• arrows on food chains show the direction of energy flow
• food chains begin with producers
• the trophic level is the level the organism is on the food web/chain
• consumers are all organisms that come after the producer on the food chain
• decomposition prevents the build up of waste and recycles the useful nutrients trapped in it
• organisms that carry out decomposition are saprophytic bacteria and fungi
• factors affecting decomposition

  temperature

  water
• organisms such as woodlice and earthworms are called deteriorators' and speed up decomposition by breaking waster material down into smaller bits and increasing surface area
• fungi are heterotrophic
• plants are autotrophic
• Fungi secrete enzymes onto dead and waste material and these enzymes digest the waste by extracellular digestion. digested material is absorbed back into the fungus tissue and used as food.
• fungi do not move
• fungi cell walls are made of chitin
• Structure of a fungus

  A) mycelium

  B) hyphae

  C) reproductive part of the fungus

  
• nitrates are needed for growth and protein
• magnesium is needed to make chlorophyll for plants
• calcium is needed to make strong cell walls
• phosphates are needed to make ATP, used in cells for energy
• fungi and bacteria release nutrients back into the soil