Why does temperature affect heart rate in ectothermic organisms?

Answer 1

The fact that they can't sweat is just one example of how ectotherms are reliant upon temperature. But eating fecal matter, or having a smaller colon doesn't have anything to do with this. In reality, specialized heart muscle cells in an organism must depolarize and then send an action potential to the surrounding cells for the heart to beat. The depolarization process is dependent upon ions diffusing across a semipermeable membrane, and, because the rate of diffusion varies directly with temperature, the colder these specialized heart muscles get, the slower the heart will beat.

This process of a beating heart is akin to ALL animals with a beatable heart. In the case of ectotherms, however, they are incapable of maintaining a warm body temperature, and, therefore, their heart slows down. In endotherms with severe hypothermia, the heart rate will slow as well, and, if it slows too much, the organism will die.

Answer 2

Because, in cold-blooded (ectothermic) animals they have to have heat or their heart rate will decrease. Kind of like when humans do activity, our heart beats faster. In reptiles the warmer the temperature, the faster the heart rate.

Answer 3

Cooler temperatures will cause an ectotherm to move and react sluggishly.

Too cold and they hibernate.