In contrast, many animals including some fishes and invertebrates are ectothermic, meaning their body heat is derived from the environment rather than metabolism. As a result of ectothermy, they have lower rates of metabolism compared to endotherms and are poorly insulated (Miller, 2010). Most endoderms are homeotherms whose body temperature is maintained relatively constant, and most ectoderms are poikilotherms whose internal temperature varies with its environment. There are many advantages and limitations of being endothermic or ectothermic in association with heat. For better adaptations, many ectotherms and endotherms have developed physiological and behavioral responses to adjust the rate of heat exchange with their surroundings. In many cases, endotherms can vary heat production to match changing rates of heat loss, and ectotherms can maintain body temperature relatively stable, which shows that there is no fixed relationship between the source of heat and the stability of body temperature (Campbell et al, …show more content…
Enzymes speed up the rates of most biochemical reactions by helping reactants interact with each other. Since enzymes are highly specific for a specific reaction, they only catalyze one or a few types of reaction. One of important enzymes in human body and many other animals is amylase that hydrolyzes starch, a major part of human diet for many people in the world. There is a variety of amylase produced from many sources in our body such as salivary glands in the mouth, pancreas cells, and small intestines (Scott, 2014). Amylase initiates the breakdown of starch which is a common plant polysaccharide composed of repeating glucose monomers into smaller subunits (Campbell et al, 2008). There are many environmental and ecological factors that strongly affect the enzymatic activities within a living organisms. Temperature is a factor related directly to physiological processes as well as enzymatic activities of animals. Since temperature and the survival of an organism are strongly linked to each other, it is very important to understand how and why all living organisms are considerably affected by temperature. Unlike endotherms such as humans, daphnia and goldfish are perfect examples of ectotherms which rely mainly on environmental sources of heat to warm their bodies. They are also scientifically