3. What is the explanation of the various forms of exoskeletons found? 4. Of what substances are exoskeletons composed? #B. PROTECTIVE COLORATION# #To show how Color may be Protective# _Materials._ Specimens such as the Kny-Scheerer mimicry collections, diagrams, etc. _Definitions._ _General protective resemblance_, the general resemblance between the color of an animal and its surroundings. _Variable protective resemblance_, the changing of the color of an animal to correspond to the change in its background. _Special protective resemblance_, the resemblance of an animal to some object found in its background in color and form. _Mimicry_, the resemblance of an unprotected animal to a well-protected one. _Warning colors_, bright colors which protect animals by causing other animals to avoid it. _Questions._ 1. Show how the transparent color of a paramecium, the green color of a cabbage worm, or the green color of a certain species of hydra may result in protecting an animal from its enemies. Mention as many other examples as you can. 2. What is gained by the ability of a squid to change its color? How is this change brought about? 3. Explain the protective coloration of the following: Dead-leaf butterfly, walking stick, geometrid larva. Hunt up other examples. 4. Explain the protective coloration in the following: Hover flies, clear-winged moths, viceroy butterflies. 5. Make a list of several invertebrates that are protected by their bright color. Explain the reason for the bright color. 6. How may the difference between the color of the upper and lower surfaces of animals be explained on the basis of use to the animal? 7. (Optional) Find out some other uses of color to an animal aside from protection. _Summary._ 1. Name four uses of color. 2. Name four ways an animal is protected by being like its background. 3. Name one way it is protected by being unlike its background. 4. What disadvantages in this method of protection? #C. ANIMAL ASSOCIATIONS# #To show Another Method of Protection from Enemies# _Materials._ Specimens, charts, etc., illustrating animal associations. _Definitions._ _Animal communities_, associations of many animals of the same species in communities in which there is a greater or less division of labor. _Gregarious_, associations where there is but little division of labor. _Parasitism_, an association where one animal lives at the expense of the other. The animal on which the parasite lives is called the host. If there are two hosts during the life cycle of the parasite, the second host is called an intermediate host. _Symbiosis_, an association where two animals live together in mutually helpful relations. _Commensalism_, an association where two animals live together in relations not mutually helpful but without injury to either. _Observations and questions._