biology topic B

• Ecological niche


  The role of a species in an ecosystem, including the biotic and abiotic interactions that influence its growth, survival and reproduction, and how it obtains food
• Obligate anaerobes


  Organisms that cannot tolerate the presence of oxygen gas in their environment
• Facultative anaerobes


  Organisms that can survive with or without oxygen
• Obligate aerobes

  Organisms that require oxygen for cellular respiration
• Photosynthesis is the mode of nutrition in plants, algae and several groups of photosynthetic prokaryotes
• Holozoic nutrition


  The mode of nutrition in animals where food is ingested, digested internally, absorbed and assimilated
• Mixotrophic nutrition


  The mode of nutrition in some protists that are both autotrophic and heterotrophic
• Saprotrophic nutrition


  The mode of heterotrophic nutrition in some fungi and bacteria, where they are referred to as decomposers
• Archaea are metabolically very diverse, using light, oxidation of inorganic chemicals or oxidation of carbon compounds to provide energy for ATP production
• Deductions can be made from theories, as observation of living mammals led to theories relating dentition to herbivorous or carnivorous diets, which allowed the diet of extinct organisms to be deduced
• Factors affecting distribution


  • temperature
  • water
  • light (intensity/wavelength)
  • breeding sites
  • soil pH
  • food supply
  • soil salinity
  • territory
  • mineral nutrient availability
• Habitat


  The physical location where a species lives
• Niche


  How a species fits within its environment, encompassing both the physical and environmental conditions it requires and the interactions it has with other species
• Each species plays a unique role within a community because of the unique combination of its spatial habitat and interactions with other species
• Species pool


  The species that occur within a region
• Species sorting


  The process by which species present within the regional species pool are sorted into different communities based on their adaptations and interactions
• Fundamental niche


  The potential of a species based on its adaptations and tolerance limits
• Realized niche


  The actual extent of a species' niche when in competition with other species
• High species richness in the tropics results at least in part from the presence of a great variety of ecological resources
• Species diversity is paralleled by the functional diversity or niche diversity of the species in a community
• As species diversity increases, so does the niche diversity
• Ecological equivalents are species that occupy similar niches but live in different geographical regions
• Interspecific competition occurs where the niches of two species overlap

  One species will be better suited to the niche and the other will either be pushed out or become extinct, the niche will be divided, or the two species will further diverge
• Competitive release occurs when a species expands its niche in response to the removal of a competitor or when a species invades an island and expands into unoccupied habitats
• Archaea


  One of the three domains of life, metabolically very diverse
• Energy sources used by archaea

  • Light
  • Oxidation of inorganic chemicals
  • Oxidation of carbon compounds
• Herbivore adaptations


  • Piercing and chewing mouthparts of leaf-eating insects
  • Plants resist herbivory using thorns and other physical structures
  • Plants produce toxic secondary compounds in seeds and leaves
  • Some animals have metabolic adaptations for detoxifying these toxins
• Predator adaptations


  • Chemical, physical and behavioural adaptations
• Prey adaptations


  • Chemical, physical and behavioural adaptations
• Plant adaptations for harvesting light

  • Trees reaching the canopy
  • Lianas
  • Epiphytes growing on branches of trees
  • Strangler epiphytes
  • Shade-tolerant shrubs and herbs growing on the forest floor
• Fundamental niche


  Potential of a species based on adaptations and tolerance limits
• Realized niche


  Actual extent of a species niche when in competition with other species
• Competitive exclusion


  • Elimination of one of the competing species or the restriction of both to a part of their fundamental niche
• Nutrition


  The process of nourishing or being nourished and obtaining and utilizing food
• Nutrients


  Substances needed to keep a living thing healthy and alive
• Modes of nutrition


  • Autotrophic
  • Heterotrophic (Saprotrophic, Parasitic, Holozoic)
• Autotrophs


  Organisms that synthesize their own organic molecules from simple inorganic substances
• Heterotrophs


  Organisms that obtain organic molecules from other organisms
• Photosynthesis is the most important process for the continuation of life on Earth
• Each year photosynthesis synthesizes 160 billion tons of carbohydrate