There is another free download called "Why Use Dichotomous Keys?" Lesson which can accompany this powerpoint. If you like what you see, please take a second to give me a rating. Thanks!
This colorful powerpoint is full of creative commons animal photos which will show students why classification tools are so necessary. It briefly overviews classification (Linnaeus) and the concept of how a species is defined (Biological Species Concept). This is meant to be an introductory powerpoint for a section about using or making Dichotomous Keys in class. There are teacher notes in the note section of the powerpoint slides.