Unit 3

• Abiotic


  Refers to physical factors, such as temperature and light intensity, that affect ecosystems.

  
• Adaptation


  Feature of an organism that helps it to survive.

  
• aerobic


  In the presence of, or involving the use of, oxygen.

  
• Algal bloom


  A seasonal abundance of algae.

  
• Ammonium


  NH4; a nitrogen-containing waste product of decomposition.

  
• Biodiversity


  Refers to the number and abundance of species.

  
• Biological control


  Natural control of pests using natural predators, parasites or disease.

  
• Biome


  Region of the planet with characteristic climate, flora and fauna.

  
• Biotic


  Factor related to the biological aspects of an ecosystem such as predation and competition.

  
• Carnivore


  Consumer which eats other animals.

  
• Community


  All the organisms living in a habitat.

  
• Competition


  Interaction between organisms seeking the same limited resources.

  
• Consumer


  Animal which eats ready-made food. (Does not make their own food like plants do)

  
• Decomposers


  Organisms such as bacteria and fungi responsible for the breakdown of dead organic material.

  
• Denitrifying bacteria


  Convert nitrates in the soil into nitrogen gas, which is released into the atmosphere.

  
• Ecosystem


  Complex community of different species of animals and plants that are dependent on each other and the environment.

  
• Fauna


  The animals in a particular region/environment.

  
• Fertiliser


  Chemical added to the soil to improve plant growth or crop yield.

  
• Flora


  The plants of a particular region.

  
• Genetically modified


  (GM) Term given to a cell or organism that has had its genetic code altered, usually by adding a gene from another organism.

  
• Grazing


  Method of feeding on plants by herbivores.

  
• Habitat


  The place where an organism lives.

  
• Habitat destruction


  Human destruction of natural habitat by activities such as deforestation and over-grazing livestock on natural grassland.

  
• Herbivore


  Consumer which eats plants.
• Indicator species


  Organisms that by their presence, abundance or absence give information such as level of pollution in the environment.

  
• Interspecific competition


  Competition between organisms of two different species for a common resource.

  
• Intraspecific competition


  Competition between organisms within the same species.

  
• Mutation


  A random and spontaneous change in the structure of a gene, chromosome or number of chromosomes; only source of new alleles.

  
• Niche


  The role an organism plays within its community in an ecosystem.

  
• Nitrifying bacteria


  Produces nitrate, which is released into the soil.

  
• Nitrogen cycle


  Sequence of events or processes involved in the recycling of nitrogen.

  
• Nitrogen-fixing bacteria


  Bacteria found free living in the soil or in the root nodules of some plants that convert nitrogen gas into nitrate.

  
• Omnivore


  Consumer which eats a mixture of plants and animals.

  
• Over-exploitation


  Human activities, such as over-fishing, over-hunting and over-grazing, that cause extinctions and destroy the food web balance.

  
• Parasitism


  An interaction between two organisms in which one benefits and the other is harmed.

  
• Pesticides


  General name for chemicals used to kill organisms that damage or feed on crop plants.

  
• Pitfall trap


  Sampling technique used to trap animals living on the soil surface or in leaf litter.

  
• Pollution


  Environmental damage caused by humans usually by release of substances to the environment.

  
• Precipitation


  Water such as rain, snow, sleet, hail and dew.

  
• Predation


  Obtaining food by hunting and killing prey organisms.