Nutrition

• Ecological niche


  The role of a species in an ecosystem
• Ecological niche


  • The zone of tolerance for abiotic and biotic variables (which determine the habitat)
  • Mode of nutrition
  • Adaptations
  • Interactions
  • Life history- Maturing
• Fundamental niche


  A niche that an organism could potentially occupy (based on its adaptations and tolerance) in the absence of competition from other species
• Realised niche


  A niche that an organism does occupy due to competition with other species
• Types of respiration


  • Obligate anaerobes
  • Obligate aerobes
  • Facultative aerobes
• Obligate anaerobes


  Must do anaerobic respiration, live away from oxygen
• Obligate aerobes


  Cannot survive in the absence of oxygen, carry out aerobic respiration
• Facultative aerobes


  Can survive in either if necessary
• Autotroph


  An organism that can produce its own chemical energy using light, inorganic compounds or other energy sources
• Autotroph


  • Photoautotroph
  • Chemoautotroph
• Photoautotroph


  An organism that can make its own energy using light and carbon dioxide via the process of photosynthesis
• Chemoautotroph


  An organism that derives energy from the oxidation of inorganic compounds via chemosynthesis
• Heterotroph


  Organisms that cannot produce their own food, consumers; they must ingest nutrients from other organic sources
• Heterotroph


  • Saprotrophs
  • Parasites
  • Holozoic
• Saprotrophs


  Organisms that obtain energy by secreting digestive enzymes followed by absorbing and assimilating the nutrients
• Parasites


  Gains nutrition from a host
• Holozoic


  Refers to organisms that take in solid or liquid food internally
• Mixotroph


  Organisms that are able to use a combination of methods of generating their nutrients and are neither fully autotrophic or heterotrophic
• Photosynthesis


  6CO2 + 6H2O = C6H12O6 + 6O2
• Holozoic nutrition


  A form of heterotrophic nutrition where an organism ingests food, internally digests food, and absorbs and assimilates the nutrients from digested food
• Saprophytic nutrition


  Heterotrophs that obtain nutrients by external digestion of food
• Archae nutrition


  • Phototrophic archaea
  • Chemotrophic archaea
  • Heterotrophic archaea
• Phototrophic archaea


  Use energy from light to generate ATP
• Chemotrophic archaea


  Can produce their own carbon compounds using chemosynthesis
• Heterotrophic archaea


  Gain their carbon compounds from other organisms and then use these to generate ATP
• The evolution of nutrition can be demonstrated when looking at the dental structure of species throughout time
• Early human ancestors such as Paranthropus robustus and Archaic megadonts are assumed to have a diet primarily consisting of fibrous plants requiring extensive chewing
• Pre-modern Homo species had larger teeth and smaller jaws which suggests that they have omnivorous diets involving both plants and meat
• Modern-day Homo sapiens have both small teeth and jaws, expressing evolution that reflects dietary shifts in surviving across diverse environments
• Plant adaptations for harvesting light

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

  Trees in a forest make up the uppermost layer of plants, known as the canopy. Some trees may grow above the main canopy, and some form a layer beneath the main canopy, known as the understory.
• Lianas


  Woody vines that use the trunks of trees as their main supporting structure to gain height, allowing their leaves to reach the forest canopy where they can absorb light for photosynthesis.
• Epiphytes growing on branches of trees

  Use the height of trees to increase their absorption of sunlight by growing high up in tree branches, but they do not begin their lives on the forest floor and often gain their nutrients from high in the canopy.
• Strangler epiphytes


  Some epiphytes grow roots downward to the forest floor, allowing them to gain nutrients and water from the soil, while still taking advantage of height from trees to absorb sunlight.
• Shade-tolerant shrubs and herbs growing on the forest floor


  Shade tolerant plants grow on the forest floor and are adapted to absorb the limited range of light wavelengths that reach the ground through the leaves of the canopy and understory.