Ectothermic and Endothermic Metabolism



Comparing Ectothermic and Endothermic Metabolism

Metabolism Rate

Definition

“The amount of energy liberated or expended in a given unit of time. Energy is stored in the body in energy-rich phosphate compounds (adenosine triphosphate, adenosine monophosphate, and adenosine diphosphate) and in proteins, fats, and complex carbohydrates”.

The chemical reactions of cells, linked together in series to form pathways, are collectively referred to as metabolism. Metabolic pathways are interdependent and exquisitely regulated for efficient extraction of energy from fuels and for synthesis of biological macromolecules. Cellular processes produce unique chemical fingerprints or metabolite profiles, and a complete quantitative set of metabolic intermediates associated with a cellular process is referred to as the metabolome. Metabolomics is the study of changes in the metabolome that may arise from metabolic regulation or alteration in gene expression, or a combination of both mechanisms. Studies of metabolism and metabolomics are subject areas of biochemistry, which also includes the structural chemistry of biological molecules and the chemistry of molecular genetics.

Endotherm

An endotherm is an organism that is able to maintain and regulate its internal body temperature across a wide range of conditions present in the surrounding external environment. Hypothalamic regulation in such organisms has enabled colonization and exploitation of more variable environments.

Ectotherms

Many marine animals are ectotherms because it is too difficult to maintain an increased body temperature in water. Heat transfers much more quickly in water than it does in air thus meaning it requires a body to produce much more heat to stay at a stable temperature.

As an example - If it was 50 degrees outside, it wouldn't be very hard for you to go out with very little clothing on and stay outside for an extended period of time. However, if you jumped into 50 degree water, you would very quickly become cold and soon develop signs of hypothermia.

Marine animals avoid this by simply changing their body temperature to suit the surrounding environment. Some can keep their body temperature higher. As an example, Great White sharks gain some of the benefits from a high metabolism. For marine mammals, the situation is a bit different. Since mammals, by nature, are warm blooded they have had to develop different ways to insulate themselves from the water. Some examples are blubber in whales and seals, and thick or waterproof fur/feathers like polar bears, otters, and penguins.

Difference In Metabolic Rates Between An Endotherms And Ectotherms

This study examines the difference in metabolic rates between an endotherm and ectotherms, and between different ectotherms. Endotherms are animals that maintain a constant body temperature even when the temperature of their environment fluctuates. In contrast, ectotherms are animals whose temperature is regulated by their environment. It was hypothesized that an endothermic rat would have a higher metabolic rate than ectothermic crickets, worms, and a snake since it has to work harder to maintain its temperature. In addition, large ectotherms have a disproportionate increase in skeletal and other tissue, compared with overall size, which is metabolically inactive (Gould and Keeton 1996). Therefore, it was also hypothesized that the ...