Tuesday, October 21, 2014

Ectotherms and endotherms



  1. Analogy: endotherms consume more energy (food) than ectotherms; similarly, houses with AC consume more energy than those using external factors (wind, angle to sun rays, ...) (biomimicry) (high cost vs low cost)
  2. Insulation (cost), also clue for eco-housing

That's Why

  1. That's why pothos variegated leaves show up when there is enough exposure to strong direct sunlight.
  2. That's why you have to stay hydrated when exposed to strong direct sunlight!
  3. That's why we can catch cold when we are exposed to cold temperature for a while.
  4. Hibernation: to escape the cost of endothermy.
  5. Humans have a built-in AC! endotherms (scientifically proven).
  6. Fat insulates heat loss, that's why fat people feel hot!
  7. That's why red cheeks in cold weather.
  8. Shade plants (that's why).


  1. Structure: Interesting, thoughts (do), summary; in paragraph form? (post Is on FB page/blog?
  2. Show diagrams (graphs) in plants course (to explain phenomena) (science).


  • ectotherms: "rely on external sources of heat."; organisms that have the same body temperature of their environment; they acquire the temperature of the medium in which they live:
    • a parasitic worm in the gut of a mammal
    • a fungal mycelium in the soil
    • a sponge in the sea
  • endotherms: "regulate their temperature by the production of heat within their own bodies"
    • "terrestrial organisms, exposed to the sun and the air, acquire heat directly by absorbing solar radiation or are cooled by the latent heat of evaporation of water"
    • "the reflective, shiny or silvery leaves of many desert plants reflect radiation that might otherwise heat the leaves"
    • "a lizard chooses to warm itself by basking on a hot sunlit rock or escapes from the heat by finding shade"
    • insects: "bumblebees raise their body temperature by shivering their flight muscles"
    • "birds and mammals use metabolic heat almost all of the time to maintain an almost perfectly constant body temperature"
  • Heat loss in endotherms is moderated by:
    • insulation in the form of
      • fur
      • feathers
      • fat
    • controlling blood flow near the skin surface
  • Endotherms pay the price of a large expenditure of energy to regulate their temperature. An even larger amount of energy is used outside the organism's thermoneutral zone.
  • "The responses of endotherms and ectotherms to changing temperatures are not so different."
    • Both are at risk of being killed by even short exposures to very low temperatures and by more prolonged exposure to moderately low temperatures
    • Both have an optimal environmental temperature and upper and lower lethal limits
    • There are also costs to both when they live at temperatures that are not optimal.
    • Temperatures only a few degrees higher than the metabolic optimum are liable to be lethal to endotherms as well as ectotherms
  • Ectotherms are not more primitive than endotherms.
  • "Most environments on earth are inhabited by mixed communities of endothermic and ectothermic animals."
  • Contrast
    • endotherms: high cost–high benefit strategy
    • ectotherms: the low cost–low benefit strategy


  1. What would it be like if humans were ectotherms?
  2. What are the advantages of ectotherms and the advantages of endotherms?
  3. Why are there ectotherms and endotherms, why not just one type?