ectotherm

Examples of ectotherm in the following topics:

• Homeostasis: Thermoregulation

  • Ectotherms use external sources of temperature to regulate their body temperatures.
  • Since ectotherms rely on environmental heat sources, they can operate at economical metabolic rates.
  • Ectotherms usually live in environments in which temperatures are constant, such as the tropics or ocean.
  • Many endotherms have a larger number of mitochondria per cell than ectotherms.
  • Some ectotherms can also be homeotherms.

• Characteristics of Reptiles

  • Reptiles are ectothermic tetrapods that lay shelled eggs on land and possess scaly skin and lungs.
  • Reptiles are ectotherms: animals whose main source of body heat comes from the environment .
  • In addition to being ectothermic, reptiles are categorized as poikilotherms: animals whose body temperatures vary rather than remain stable.
  • Reptiles, such as these sunbathing Florida redbelly turtles, are ectotherms: they rely on their environment for body heat.

• Heat Conservation and Dissipation

  • For example, a desert ectothermic animal may simply seek cooler areas during the hottest part of the day in the desert to keep from becoming too warm.
  • Other ectotherms use group activity, such as the activity of bees to warm a hive to survive winter.

• Transferring of Energy between Trophic Levels

  • In general, cold-blooded animals (ectotherms), such as invertebrates, fish, amphibians, and reptiles, use less of the energy they obtain for respiration and heat than warm-blooded animals (endotherms), such as birds and mammals.
  • Therefore, many endotherms have to eat more often than ectotherms to obtain the energy they need for survival.
  • In general, NPE for ectotherms is an order of magnitude (10x) higher than for endotherms.

• Animal Bioenergetics

  • The absence of insulation in ectothermic animals increases their dependence on the environment for body heat.
  • Metabolic rate is estimated as the basal metabolic rate (BMR) in endothermic animals at rest and as the standard metabolic rate (SMR) in ectotherms.
  • An ectotherm such as an alligator has an SMR of 60 kcal/day.

• Modern Reptiles

  • As with birds, they have a four-chambered heart and a unidirectional system of air flow around the lungs; however, in contrast to birds, they are ectotherms, as are all other reptiles.
  • Similar to other reptiles, turtles are ectotherms.

• Evolution of Reptiles

  • It is not known whether dinosaurs were endotherms or ectotherms.