Fur, Feathers, Scales and Insulation
See Also: Fur, Feathers, Scales and Insulation Materials List | Download Text in MSword | Teachers Suggested Additional Activities Using Fur, Feathers, and Scales
In this unit, you will examine the different types of coverings reptiles, birds and mammals have and learn how some of these coverings protect (insulate) their owners from cold and hot temperature environments. Animals and even plants generally need to keep their temperatures within a fairly narrow range in order to survive. The chemical reactions that do work in living organisms function best within a narrow range and physical damage occurs if an individual becomes too hot or too cold. Many organisms have mechanisms to cool themselves down or to warm themselves up, but these processes require energy and energy is expensive, requiring the procurement and processing of food. Thus, mammals and birds have developed body coverings that help protect them from gaining or losing too much heat.
Most of the skins in this trunk belong to mammals. Mice, cats, bears, kangaroos, dogs and humans are some examples of mammals. Mammals, like birds, use energy to produce and maintain a constant internal body temperature. Mammals maintain body temperatures between 36 and 38oC or 97 and 101oF, while birds maintain even higher body temperatures (40-42oC or 104 - 108oF). Birds use feathers to help them keep their warm body temperatures, while mammals use hair. Most mammals have hair all over their bodies. We call this fur. Reptiles do not use internal energy to maintain a constant temperature. They have a broader temperature range than mammals and birds and lack a body covering that helps to maintain heat. Instead, their body covering protects them against water loss.
Thus while the body coverings of mammals, birds and reptiles are all made of the same material, keratin, they look different and serve two different functions. The exercises in this unit are divided into two parts. Exercise 1. Animal Covering Match, introduces students to the variety of fur, feathers and scales seen in the higher vertebrates: reptiles, birds and mammals. Exercise 2. Insulation Power, provides qualitative and quantitative exploration into the insulation properties of body coverings.