Ectotherms and Endotherms

• Endotherms 


  Animals that use metabolic processes to generate their own heat to maintain their internal temperature within tolerance range (eg. birds and mammals)

  • maintains stable internal temperature independent of external temperature fluctuations
• Ectotherms 


  Animals whose body temperature is determined by the external environment (eg. reptiles and fish)

  • rely on external sources to gain heat
  • body temperature fluctuates with the external environment
• Endotherms - Costs

  • may have a higher metabolic rate
  • need to spend more energy to maintain higher metabolic rate
  • higher food requirements and more time spent finding food
• Ectotherms- Costs

  • body temperature is dependent on the external environment
  • limited to living in less extreme temperatures
  • can't tolerate very low or very high external temperatures
• Endotherms - Benefits

  • body temperature is independent of external temperature
  • can live in more extreme environments
  • can be active at night or more often during the day and in cold weather
  • being more active may reduce chance of predation
• Ectotherms - Benefits

  • lower energy requirements
  • consume less food
  • spend less time finding/hunting food
  • can tolerate larger fluctuations in their internal body temperature