2.4 - metabolism in conformers and regulators

• what is a conformer?

  an organism whose internal environment is dependent upon their external environment. they derive heat from surroundings
• give 2 example of conformers?

  lizards and snakes
• conformers have lower metabolic costs and occupy a narrower range of ecological niches
• define a regulator?

  an organism that maintains their internal environment regardless of external environment. they derive heat from their metabolism
• regulators have higher metabolic costs and occupy a wider range of ecological niches
• advantages of conformers ?

  • lower metabolic costs
  • can tolerate variation in external environment due to behavioural responses
• advantages of regulators?

  • occupy wider range of niches
  • adaptable to environmental change
• define homeostasis ?

  the maintenance of the internal environment of an organism within tolerable limits despite changes in the external environment
• Name species x and y

  A) Conformer

  B) Regulator

  
• Homeostasis can also be called negative feedback
• define thermoregulation?

  the ability of an organism to control its internal body temperature despite changes in external temperature
• why is thermoregulation important for mammals?

  • their metabolism is dependent on enzymes, which are temperature dependent
  • they need to maintain high diffusion rates to maintain metabolism
• what is the hypothalamus?

  temperature monitoring centre within the brain
• how does the hypothalamus contribute to homeostasis?

  regulate temperature
• Stages of homeostasis?

  Receptors -> control centre -> messenger -> effector -> corrective response -> system switched off
• define receptor?

  detects changes in conditions outwith normal limits
• define control centre?

  determines optimum level of internal environment and causes response when conditions are outwith this
• define messenger?

  carries message from control centre to effector
• Define effector?

  organ which responds
• define corrective response?

  reverses original change and then switches off
• Corrective responses for an increase in body temperature ?

  • sweating
  • vasodilation
  • hair erector muscles relax
  • decreased metabolic rate
• corrective responses for a decrease in body temperature?

  • shivering
  • vasoconstriction
  • hair erector muscle contract
  • increased metabolic rate
  • decrease in sweat production
• how does sweating cool down an organism?

  body heat is used to evaporate water in the sweat, cooling the skin
• how does vasodilation cool down an organism?

  increased blood flow to the skin increases heat loss
• how does shivering increase body temperature?

  skeletal muscle contraction generates heat
• how does hair erector muscles contracting increase body temperature?

  raises hairs, trapping layer of insulating air
• what is the importance of thermoregulation?

  optimal enzyme activity and high diffusion rates to maintain metabolism