Short Essay: The Evolution of Endothermy

Since I haven’t uploaded anything in a while, I thought I’d share my latest essay with you. Unfortunately, it is limited to 1000 words, and so some of the more interesting details are left out. However, you can investigate the subject yourselves! It’s quite exciting.

The Evolution of Endothermy

This essay attempts to gather evidence, from several sources, for the reasons behind the appearence of endothermy, the necessary changes in the heart and circulatory system to accomodate endothermy, and during which time periods endothermy is likely to have arisen. It is proposed that endothermy has evolved multiple times: during the evolution of early mammals, and during the divergence of Triassic Theropods. The advantages and disadvantages to both endothermy and the contrasting ectothermy are suggested, and it is proposed that endothermy is not an advanced state, but simply an adaptation to a specific niche in a given ecosystem. To support this, the stem crocodilian Poposaurus gracilis is referenced as an example of an endothermic species that shares a strong evolutionary link with todays modern ectothermic crocodilians, seemingly adapting to an ectothermic lifestyle from a previously endothermic lifestyle. The formation of the heart during embryonic development is briefly considered, and a study is referenced that observed a gene, Tbx5, that has a role in forming the ventricular septation required to accomodate endothermy in an organism. Separation of blood in this manner allows for a multiple pressure system, vital to endothermy.

Endothermy is the ability of an organism to maintain it’s internal temperature through it’s metabolism. Endothermic organisms are able tolive in a greater range of habitats and temperatures as they can produce their own body heat and, unlike ectotherms, do not require a constant environmental temperature depedence. The usual source of internal heat comes from digestion of food and muscle contraction.

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