Ecology Chapter 4

  1. Concept 4.3: The water balance of organisms is determined by
    exchanges of water and solutes with the external environment.
  2. Concept 4.2: The temperature of organisms is determined by
    exchanges of energy with the external environment.
  3. Concept 4.1: Each species has a range of environmental tolerances that determines
    its potential geographic distribution.
  4. Environmental temperatures ------------ throughout the biosphere.Some habitats experience little variation, while others have large seasonal or daily variation.
    vary greatly
  5. Some organisms can survive periods of extreme heat or cold by entering
    a state of dormancy, in which little or no metabolic activity occurs.
  6. Bacteria in hot springs have enzymes that are stable up to
  7. Energy exchange with the environment can be by:
    Conduction—Convection—Latent heat transfer—
  8. Conduction—
    transfer of energy from warmer to cooler molecules.
  9. Convection—
    heat energy is carried by moving water or air.
  10. Latent heat transfer—
    water absorbs heat as it changes state from liquid to gas.
  11. For terrestrial plants, energy inputs include---------
    Losses of energy include -----------
    • sunlight and longwave (infrared) radiation from surrounding objects.
    • emission of infrared radiation to the environment, and through evapotranspiration.
  12. Transpiration rates can be controlled by
    specialized guard cells surrounding a pore, called a stomate.Variation in the size of the opening and number of stomates control the rate of transpiration and thus control leaf temperature.
  13. pubescence—
    hairs on leaf surfaces that reflect solar energy.  But hairs also reduce conductive heat loss.
  14. If soil water is limited------------is not a good mechanism.
    , transpirational cooling
  15. If air temperature is lower than leaf temperature, heat can be lost by --------, dependent on --------------
    • convection,
    • speed of air moving across the leaf surface.
  16. Know that long equation thingie
  17. Ectotherms:
    : Primarily regulate body temperature through energy exchange with the external environment.
  18. Endotherms:
    • Rely primarily on internal heat
    • generation, mostly birds and mammals.
  19. Larger surface area allows ----------, but makes it harder to ----------------
    • greater heat exchange
    • maintain internal temperature.
  20. A smaller surface area relative to volume ------------ the animal’s ---------------
    • decreases
    • ability to gain or lose heat.
  21. As body size increases, surface area-to-volume ratio decreases, and ------------ are thus improbable.This had led to speculation that
    • large ectotherms
    • large dinosaurs may have had some degree of endothermy.
  22. Some large ectotherms can maintain body temperature above the environmental temperature, such as...
    Skipjack tuna use muscle activity in conjunction with heat exchange between blood vessels to maintain a body temperature as much as 14°C warmer than the surrounding seawater.
  23. Many terrestrial ectotherms can------- to adjust temperature.
  24. Many insects and reptiles --------- to warm up after a cold night. Because this increases risk from predators, many are -----------
    • bask in the sun
    • also camouflaged.
  25. Ectotherms in temperate and polar regions must avoid or tolerate freezing.Avoidance behavior includes
    seasonal migration to lower latitudes or microsites that are above freezing (e.g., burrows in soil).
  26. Small endotherms may regularly undergo ------------ to minimize energy needed during cold nights.Long-term torpor is possible only for animals that have enough food and can store enough energy reserves, such as -------------
    • 1daily torpor
    • 2marmots.
  27. Three problems must be overcome for an organism to withstand freezing:
    • 1Water forms needle-like ice crystals that can pierce cell membranes.
    • 2Oxygen supply to tissues is restricted due to lack of breathing and circulation.
    • 3When ice forms, it pulls water from cells.
  28. Concept 4.3: The water balance of organisms is determined by
    exchanges of water and solutes with the external environment.
  29. Water is the medium in
    which all biochemical reactions necessary for life occur.
  30. Water has unique properties that make it a
    universal solvent for biologically important solutes.
  31. -------------- have the highest resistance to water loss.The outer exoskeleton of -----is covered by ------that are impervious to water.
    • Desert invertebrates
    • chitin is covered by waxy hydrocarbons
  32. Reptiles have been very successful in dry environments. They have thick skin with layers of
    dead cells, fatty coatings, and plates or scales.
  33. Mammals and birds have ------------- and ------- or ------ minimize water loss.
    similar skin, and fur or feathers to
Card Set
Ecology Chapter 4
Ecology Chapter 4 ECU Terms