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- Cold-blooded animals, or poikilotherms, rely on environmental conditions to regulate their body temperature. Unlike warm-blooded species, these creatures do not generate their own heat. Instead, they must adapt to their surroundings to maintain their body temperature.
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Are cold blooded and warm-blooded ectotherms a scientific term?
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Are ectotherms cold blooded?
Mar 5, 2024 · Mechanisms. Ectothermic animals regulate their body temperature through behavioral adaptations. For instance, a lizard basks in the sun to warm up or seeks shade to cool down. They also adjust their activities based on the temperature; they are more active when it’s warm and become sluggish in colder conditions. Evolutionary Appearance.
Oct 31, 2023 · Ectotherms use external sources of temperature to regulate their body temperatures. Ectotherms are colloquially referred to as “cold-blooded” even though their body temperatures often stay within the same temperature ranges as warm-blooded animals.
- Overview
- Key points
- Introduction
- Endotherms and ectotherms
- Why regulate temperature?
- Temperature balance
- Check your understanding: graphs of metabolic rate
The difference between endotherms and ectotherms. How to read graphs related to endotherms and ectotherms.
•Most animals need to maintain their core body temperature within a relatively narrow range.
•Endotherms use internally generated heat to maintain body temperature. Their body temperature tends to stay steady regardless of environment.
•Ectotherms depend mainly on external heat sources, and their body temperature changes with the temperature of the environment.
•Animals exchange heat with their environment through radiation, conduction—sometimes aided by convection—and evaporation.
•Radiation: Radiation is the transfer of heat from a warmer object to a cooler one by infrared radiation, that is, without direct contact.
•Most animals need to maintain their core body temperature within a relatively narrow range.
•Endotherms use internally generated heat to maintain body temperature. Their body temperature tends to stay steady regardless of environment.
•Ectotherms depend mainly on external heat sources, and their body temperature changes with the temperature of the environment.
•Animals exchange heat with their environment through radiation, conduction—sometimes aided by convection—and evaporation.
What’s it like outside today? If it’s winter where you are, it might be pretty cold. If it’s summer, it might be pretty hot. Either way, odds are that your core body temperature is right around 98.6∘F /37∘C . As we saw in the article on homeostasis, mechanisms like shivering and sweating kick in when your body gets too cold or too hot, keeping your internal temperature steady.
Not all organisms keep their body temperature in as narrow a range as we humans do, but virtually every animal on the planet has to regulate body temperature to some degree—if only to keep the water in its cells from turning to ice or to avoid denaturing its metabolic enzymes with heat.
People, polar bears, penguins, and prairie dogs, like most other birds and mammals, are endotherms. Iguanas and rattlesnakes, like most other reptiles—along with most fishes, amphibians, and invertebrates—are ectotherms.
Endotherms generate most of the heat they need internally. When it's cold out, they increase metabolic heat production to keep their body temperature constant. Because of this, the internal body temperature of an endotherm is more or less independent of the temperature of the environment.
[What is metabolism?]
This pattern is shown on the graph below: the mouse maintains a steady body temperature close to 37∘C across a wide range of external temperatures.
For ectotherms, on the other hand, body temperature mainly depends on external heat sources. That is, ectotherm body temperature rises and falls along with the temperature of the surrounding environment. Although ectotherms do generate some metabolic heat—like all living things—ectotherms can't increase this heat production to maintain a specific internal temperature.
There are some basic limits on survivable body temperature for most animals. At one end of the spectrum, water freezes at 32∘F / 0∘C to form ice. If ice crystals form inside a cell, they'll generally rupture its membranes. At the other end of the spectrum, enzymes and other proteins in cells often start to lose shape and function, or denature, at temperatures above 104∘F / 40∘C .8
Why do many organisms—including you and me—keep their body temperature in a narrower range than this? The rate of chemical reactions changes with temperature, both because temperature affects the rate of collisions between molecules and because the enzymes that control the reactions may be temperature-sensitive. Reactions tend to go faster with higher temperature, up to a point, beyond which their rate drops sharply as their enzymes denature.
For both endotherms and ectotherms, body temperature depends on the balance between heat generated by the organism and heat exchanged with—lost to or gained from—the environment.
Heat always moves from warmer to cooler objects, as described in the Second Law of Thermodynamics.
There are three main ways that an organism can exchange heat with its environment: radiation, conduction—along with convection—and evaporation.
•Radiation: Radiation is the transfer of heat from a warmer object to a cooler one by infrared radiation, that is, without direct contact.
[May I see an example?]
•Conduction: Heat can be transferred between two objects in direct contact by means of conduction. Conduction of heat between your skin and nearby air or water is aided by convection, in which heat is transferred through movement of air or liquid.
The graph below shows metabolic rate as a function of external temperature for two animals: an endotherm and an ectotherm.
Which curve represents the endotherm, and which represents the ectotherm?
Choose 1 answer:
Choose 1 answer:
•(Choice A)
Curve A represents the endotherm; curve B represents the ectotherm.
ectotherm, any so-called cold-blooded animal —that is, any animal whose regulation of body temperature depends on external sources, such as sunlight or a heated rock surface. The ectotherms include the fishes, amphibians, reptiles, and invertebrates.
- The Editors of Encyclopaedia Britannica
Examples of poikilotherms include the "cold-blooded" animals (Kearney et al. 2009), such as most fish, amphibians, and reptiles. On the other hand, homeotherms have specific physiological...
In addition to behavioral adaptations, physiological adaptations help ectotherms regulate temperature. Diving reptiles conserve heat by heat exchange mechanisms, whereby cold blood from the skin picks up heat from blood moving outward from the body core, re-using and thereby conserving some of the heat that otherwise would have been wasted.
Jun 30, 2016 · Both endotherms and ectotherms have adaptations—features that arose by natural selection—that help them maintain a healthy body temperature. These adaptations can be behavioral, anatomical, or physiological. Some adaptations increase heat production in endotherms when it’s cold.
